JP3534483B2 - Method and apparatus for measuring side force of extruder screw - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for measuring a side force of a screw for a plastic extruder.

[0002]

2. Description of the Related Art When a plastic raw material is extruded while giving various actions by the rotation of a screw in a cylinder of an extruder, the plastic pressure of the plastic raw material increases due to plasticization of the plastic raw material, uneven pressure in each part, and drive motor from Due to the influence of the rotational force transmitted to the screw, a load is generated on the screw in a direction perpendicular to the axis of the screw.

Conventionally, there has been no method for directly measuring the side force, which is a load applied in the direction perpendicular to the shaft center during the operation of the screw of the plastic extruder, and most of them have been estimated based on the experience and intuition of engineers. . As a method of indirectly measuring the side force in some cases, the load applied to the tip of the screw shaft is measured and combined in two directions orthogonal to the shaft center, and the force is applied to the shaft center at the right angle. It was estimated by calculating the direction and size of.

4 (a) and 4 (b) are respectively a front sectional view and a side view of a screw shaft load measuring device using a load converter capable of simultaneously measuring in two directions. In the figure, 401 is a cylinder of an extruder, 402 is a screw shaft, 403 is a screw flight, 404 is a bearing that supports the screw shaft, 405 is a casing that supports the bearing, 40
Reference numeral 6 is a housing connected to the cylinder 401, and reference numeral 407 is a load converter that interposes the casing 405 and the housing 406 and measures the load applied to the casing 405 in two directions simultaneously.

The load applied to the load converter 407 via the bearing 404 and the casing 405 in the direction perpendicular to the axis of the screw is applied by the load converter 407 in the orthogonal X and Y directions in FIG. 4B. The component force is measured and the direction and force of the load are calculated by vector composition.

[0006]

As described above, the side force acting in the direction perpendicular to the axial center of the screw has been estimated based on the long experience and intuition of the engineer, but the side force more than expected is applied. In this case, the peripheral speed of the screw flight and the contact pressure destroy the resin lubrication layer between the outer surface of the screw flight and the inner surface of the cylinder, causing metal to come into direct contact with each other, causing a “striking” phenomenon. There was a problem of making it.

For this reason, it is desired to measure the side force accurately, but in the method of measuring the load applied to the tip of the screw shaft with a load converter, when the weight of the screw shaft and the number of kneading parts are different, Since the load generated from the above is measured in a mixed state, it is impossible to measure a pure side force, and there is a problem that the side force distribution in the axial direction of the screw cannot be accurately measured.

Particularly with the recent increase in the size of extruders, it has become necessary to accurately grasp the side force as one of the indicators in designing the machine in terms of safety and economy.

The present invention has been made to solve the above-mentioned problems, and it is necessary to determine the screw shape of a safe and economical plastic extruder in a direction perpendicular to the axis of the screw. It is an object of the present invention to provide a side force measuring method and a measuring device for an extruder screw, which can accurately estimate such side force.

[0010]

In the method for measuring the side force of an extruder screw according to the present invention, a torpedo portion having no screw flight is provided on the extruder screw, and one end of a spindle penetrating the cylinder wall of the extruder is attached to the screw of the torpedo portion. The side force component at the detection point of the screw is detected at the other end of the spindle by making contact with the outer circumference of the shaft.

Further, the side force component applied to the screw is measured at two positions separated from each other on the same plane perpendicular to the axis of the screw, and vector synthesis is performed from the respective side force components to measure the screw axis on the measurement surface. The side force direction and the load may be calculated.

Further, the side force component of the screw can be measured at a plurality of positions in the axial direction of the screw to calculate the side force distribution in the axial direction of the screw.

The extruder screw side force measuring apparatus of the present invention comprises a load converter which converts a load into an electric signal and outputs the electric signal to an external arithmetic unit, and a extruder which penetrates the cylinder wall of the extruder and contacts the screw shaft of the extruder screw. Then, the spindle for transmitting the side force component of the screw shaft to the load converter, the body of the side force measuring device that is fixed to the extruder cylinder wall and slidably holds the load converter and the spindle, and the body is screwed. And a setting device for positioning and fixing the load transducer.

Further, the setting device includes a spring,
A pusher for transmitting the force applied to the load converter to the spring, a spring case that holds the spring and the pusher slidably, and a spring case that is screwed into the spring case to compress the spring at one end and It may be constituted by a bolt having a threaded portion capable of being screwed with the body of the side force measuring device while holding the initial compression pressure.

[0015]

The component force of the side force applied to the screw shaft is directly transmitted to the detection part of the load converter via the spindle, converted into an electric signal by the load converter, output to the external arithmetic device, and output by the external arithmetic device. The side force at the detection point is calculated.

In the method of measuring the force component of the side force applied to the screw at two positions separated from each other on the same plane perpendicular to the axis of the screw, an vector is synthesized from each side force component by an external computing device. The direction of the side force of the screw shaft and the load on the measurement surface are calculated.

In the method of measuring the component force of the side force applied to the screw at a plurality of positions in the axial direction of the screw,
The side force distribution in the axial direction of the screw can be calculated by an external calculation device.

The setting device includes a spring, a pusher for transmitting the force applied to the load transducer to the spring,
A spring case that slidably holds the spring and pusher,
The spring case is screwed to compress the spring at one end thereof to hold a predetermined initial compression pressure of the spring, and the other end thereof is composed of a body of the side force measuring device and a bolt having a threadable screw portion. In this case, when the load applied to the load converter is below the initial compression pressure of the spring, the load converter is fixed at the positioned position and the side force applied to the screw shaft is directly measured. Then, the load converter compresses the spring via the pusher and retracts, so that the load converter is not subjected to a load higher than the initial compression pressure of the spring.

[0019]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a sectional view of a side force measuring device for an extruder screw according to a first embodiment of the present invention. In the figure, 101 is a cylinder of an extruder, 102 is a screw shaft of the extruder, 103 is a side force measuring device, 104 is a load converter that converts a load into an electric signal, and specifically, 105 is a load converter. An output cable for transmitting the generated electric signal to an external arithmetic device, 106 a spindle for transmitting a side force applied in a direction perpendicular to the axis of the screw to the detecting portion of the load converter, and 107 a fixed position of the cylinder 101. Wearing side force measuring device 103
The body 108, a cap 108 that is a part of the body 107, and a setting device 109 that is screwed with the cap 108 to position the load transducer.

The side force measuring device 103 is attached by a body 107 to a mounting hole provided at a predetermined position of the cylinder 101 corresponding to the torpedo portion where the screw flight of the screw shaft 102 is not arranged. The load transducer 104 contacts the opposite surface of the spindle 106 which is in contact with the unloaded screw shaft 102 and is positioned by a bolt 109 screwed into the cap 108 so as to be slightly loaded.

When a load is applied to the screw shaft 102 and a side force is generated, the side force component force in the direction perpendicular to the shaft center at the contact point of the screw shaft 102 with the spindle 106 is transferred to the load converter 104 via the spindle 106. After being transmitted to the detection unit, the load converter 104 converts the side force component force into an electric signal, and the electric signal is output to an external arithmetic device such as a personal computer by the output cable 105, and the side force measuring device 103.
The side force component in the direction of is calculated.

It is desirable that the contact portion of the spindle 106 of the screw shaft 102 be finished with high circularity with respect to the center of rotation.

FIG. 2A is a conceptual sectional view of the second embodiment of the present invention. The extruder is a two-axis co-rotating type, 20 in the figure.
1 is a cylinder, 202 is a left screw center, 203 is a right screw center, 204 is a mounting direction of the first side force measuring device, and 205 is a mounting direction of the second side force measuring device.

The first side force measuring device 204 and the second side force measuring device 205 are mounted at positions 90 degrees apart from each other in the same plane perpendicular to the axis. As shown, two side force measuring devices 20
By vector-adding the side force component forces applied to the respective Nos. 4 and 205 with an arithmetic device such as a personal computer, the side force direction and load at the measurement position of the screw shaft can be calculated.

Although the present embodiment is a twin-screw co-rotating type extruder, it may be a two-axis different-direction rotating type or a single-screw type. Further, although the angle at which the first side force measuring device 204 intersects with the vertical line is 25 degrees, it may be any number of times.
The first side force measuring device 204 and the second side force measuring device 205 are mounted at positions 90 degrees apart from each other on the same plane perpendicular to the axis, but if the vector addition can be performed with high accuracy, it is not 90 degrees. It doesn't matter.

FIG. 2B is a conceptual front sectional view of the third embodiment of the present invention. In the figure, 241 is a cylinder, 242 is a screw shaft, 243 is a screw flight, 244 is a bearing at both ends of the screw shaft, 251 is material input,
252 is discharge, 253 is kneading part, 254 is side force component measuring position, 255 is load, 256 is load curve,
257 shows a fulcrum.

By providing a plurality of side force component measurement positions in the axial direction of the screw shaft, the load at a plurality of positions is measured, and the load curve 256 is calculated by the structural mechanical analysis of the external arithmetic unit, and the load in the axial direction is calculated. FIG. 3 is a sectional view of an extruder screw side force measuring apparatus according to a fourth embodiment of the present invention, which enables the distribution to be scientifically estimated. In the figure, 301 is the cylinder of the extruder, 302 is the screw shaft of the extruder, and 303.
Is a side force measuring device, 304 is a load converter for converting a load into an electric signal, specifically, 305 is an output cable for transmitting the electric signal converted by the load converter to an external arithmetic device, and 306 is an axis. A spindle for transmitting a side force component force applied in a direction perpendicular to the axial center to a sensor portion of the load converter, a body 307 of a side force measuring device 303 attached to a predetermined position of a cylinder 301, and a body 308.
Is a cap that is a part of the body 307, and 309 is a setting device that is screwed into the cap 308 to position the load transducer.

The setting device 309 includes a spring 310 for escaping the load converter 304 when the load converter 304 receives a load larger than the allowable load, and the load converter 304.
Pusher 31 for transmitting the force applied to the spring 310 to the spring 310
1, a spring case 312 that stores the spring 310 and the pusher 311 and a spring case 312 that is screwed into the spring case 312 and is attached to the tip of the spring 311.
Is pre-compressed to a predetermined initial compression pressure and is bolted to the cap 308 of the body 307 with a screw at the other end.

The side force measuring device 303 is attached by a body 307 to a mounting hole provided at a predetermined position of the cylinder 301 corresponding to the torpedo portion of the screw shaft 302 where the screw flight is not arranged. The spring case 312, which stores the spring 310 and the pusher 311, is configured such that the internal spring 310 is compressed to a predetermined initial compression pressure by the tip of the screwed bolt 309 and is integrated with the bolt 309 to set the setting device 3.
09 is configured. The load transducer 304 is positioned by a setting device 309 screwed to the cap 308 so that it is in contact with the opposite surface of the spindle 306 which is in contact with the unloaded screw shaft 302 and is in a slightly loaded state.

When a load is applied to the screw shaft 302 and a side force is generated, a side force component force in a direction perpendicular to the shaft center at a contact point of the screw shaft 302 with the spindle 306 causes a load converter 304 to move through the spindle 306. When transmitted to the detection unit, the load converter 304 converts the side force component force into an electric signal, and the electric signal is output to an external computing device such as a personal computer by the output cable 305, and the side force in the direction of the side force measuring device 303. The component force is calculated.

Since the side force component force applied to the screw shaft is directly transmitted to the load converter 304 via the spindle 306, when the side force component force applied to the screw shaft is excessive, the allowable load of the load converter 304 is exceeded. The load converter 304 may be destroyed. In the present embodiment, since the load converter 304 is positioned via the spring 310 that has been compressed in advance with the initial compression pressure, the spring 31
When the load is within the initial compression pressure of 0, the load converter 304
Is fixed at the positioned position and performs normal measurement. When the load exceeds the initial compression pressure of the spring 310, the spring 3
As 10 is displaced, the load transducer 304 retracts and the load on the load transducer 304 does not exceed the initial compression pressure of the spring. Therefore, it is safe if the initial compression pressure of the spring 310 is set within the allowable load of the load converter 304.

According to the method and apparatus of the present invention, the side force can be accurately calculated. Therefore, by comparing with the torque generated by the driving motor measured by the known method,
The relationship between the generated torque and the side force can be clarified, and the side force can be estimated by measuring the generated torque.

[0034]

As described above, in the extruder side force measuring method and measuring apparatus according to the present invention, the side force component force applied in the direction perpendicular to the axis of the screw can be directly measured. can get.

1) The side force component force applied to the measuring point of the screw can be directly measured with high accuracy.

2) By mounting two side force measuring devices at positions separated from each other on the same plane perpendicular to the axis, the direction and load of the side force applied to the cross section can be calculated, and the mechanical axis of the structure can be calculated. The load distribution in the direction can also be estimated.

3) The load distribution in the axial direction can be more accurately estimated by providing a plurality of side force measuring devices also in the axial direction.

4) By elucidating the relationship between the generated torque and the side force, the relationship between the torque and the behavior of the screw can be elucidated.

5) Since the complex behavior of the screw can be digitized and analyzed as described above, effective data for screw design can be obtained and can be utilized for various problem solving techniques.

6) By supporting the load converter via the spring, the load converter can be protected against an excessive load.

[Brief description of drawings]

FIG. 1 is a sectional view of a side force measuring device for an extruder screw according to a first embodiment of the present invention.

FIG. 2A is a conceptual sectional view of a second embodiment of the present invention. (B) is a conceptual front sectional view of a third embodiment of the present invention.

FIG. 3 is a sectional view of a side force measuring device for an extruder screw according to a fourth embodiment of the present invention.

FIG. 4 is a structural explanatory view of a screw shaft load measuring device using a load converter capable of simultaneously measuring in two directions. (A) is
It is a front sectional view. (B) is a side view.

[Explanation of symbols]

101, 201, 241, 301, 401 Extruder cylinders 102, 242, 302, 402 Extruder screw shafts 103, 303 Side force measuring device 104, 304 Load converter 105, 305 Output cable 106, 306 Spindle 107, 307 Body 108, 308 Cap (part of body 107, 307) 109, 309 Setting device 202 Left screw center 203 Right screw center 204 First side force measuring device 205 Second side force measuring device 243, 403 Screw flight 244, 404 Bearing 251 Material input 252 Discharge 253 Kneading section 254 Measuring position 255 Load 256 Load curve 257 Support point 310 Spring 311 Pusher 312 Spring case 313 Bolt 405 Casing 406 Ujingu 407 in two directions simultaneously measurable load transducer

Continuation of the front page (56) Reference JP-A-6-31795 (JP, A) JP-A-61-241124 (JP, A) JP-A-2-293116 (JP, A) (58) Fields investigated (Int .Cl. ⁷ , DB name) B29C 47/00-47/96 G01L 5/00-5/28

Claims (5)

(57) [Claims] 1. A method for measuring a side force acting in a direction perpendicular to the axis of an extruder screw, wherein a spindle (106, 306) is provided which has a torpedo section having no screw flight and which penetrates the extruder cylinder wall. Of the side force component at the detection point of the screw is detected at the other end of the spindle (106, 306). Extruder screw side force measurement method. 2. The method for measuring the side force of an extruder screw according to claim 1, wherein the side force component force applied to the screw is measured at two positions separated from each other on the same plane perpendicular to the axial center of the screw. Then, the screw shaft (10
2, 302) side force direction and load of the extruder are calculated. 3. The extruder screw side force measuring method according to claim 1, wherein the side force component force of the screw is measured at a plurality of positions in the axial direction of the screw, and the side force distribution of the screw in the axial direction is measured. A method for measuring the side force of an extruder screw, which is characterized by calculating. 4. A side force measuring device (103, 303) acting in a direction perpendicular to the axis of an extruder screw, wherein a load converter (104, 304) for converting a load into an electric signal and outputting the electric signal to an external arithmetic device. ), A spindle (106, 306) penetrating the extruder cylinder wall and contacting the screw shaft of the extruder screw to transmit a side force component of the screw shaft to the load converter, and the extruder cylinder wall The body (107, 307) of the side force measuring device that is fixedly attached to the body to hold the load transducer and the spindle slidably, and the setting device (10) that is screwed into the body to position and fix the load transducer.
9, 309), and a side force measuring device for an extruder screw. 5. The extruder screw side force measuring apparatus (303) according to claim 4, wherein the setting device (309) is a spring (31).
0), a pusher (311) for transmitting the force applied to the load converter to the spring, a spring case (312) for slidably holding the spring and the pusher, and screwing to the spring case. Then, the spring is compressed at one end thereof to maintain a predetermined initial compression pressure of the spring, and the other end thereof is provided with the body (307) of the side force measuring device (303).
The side force measuring device for an extruder screw according to claim 4, comprising: a bolt (313) having a threaded portion capable of being screwed.