Twin-screw extruder, gear box and method for extrusion

Patent metadata

Field	Value
Publication number	US-11618199-B2
Application number	US-201916969412-A
Country	US
Kind code	B2
Filing date	Feb 13, 2019
Priority date	Feb 13, 2018
Publication date	Apr 4, 2023
Grant date	Apr 4, 2023

Abstract

A twin-screw extruder is provided in which screws have different rotational speeds depending on the process of treating the raw material and in which degradation of the raw material is less likely to occur.Twin-screw extruder 1 has two screws 3, 5 that extend in parallel to each other. Each screw 3, 5 has cylindrical upstream screw 31 and downstream screw 35, wherein upstream screw 31 has shaft hole 315 that extends in longitudinal direction X and screw flight 316 on an outer circumferential surface thereof, and downstream screw 35 includes large diameter portion 353 having screw flight 357 on an outer circumferential surface thereof and small diameter shaft portion 351 that has a smaller diameter than large diameter portion 353, wherein small diameter shaft portion 351 of downstream screw 35 is inserted into shaft hole 315 of upstream screw 31. Upstream screw 31 and downstream screw 35 can be independently rotated. Twin-screw extruder 1 further includes upstream rotating mechanism 84 that rotates upstream screws 31 of two screws 3, 5, and downstream rotating mechanism 83 that rotates downstream screws 35 of two screws 3, 5.

First claim

What is claimed is:

1. A twin-screw extruder comprising:
two screws that extend in parallel to each other, wherein each screw has a cylindrical upstream screw and a downstream screw, wherein the upstream screw has a shaft hole that extends in a longitudinal direction and a screw flight on an outer circumferential surface thereof, and the downstream screw includes a large diameter portion having a screw flight on an outer circumferential surface thereof and a small diameter shaft portion that has a smaller diameter than the large diameter portion, wherein the small diameter shaft portion of the downstream screw is inserted into the shaft hole of the upstream screw, and the upstream screw and the downstream screw can be independently rotated;
an upstream rotating mechanism that rotates the upstream screws of the two screws;
a downstream rotating mechanism that is provided independent of the upstream rotating mechanism and that rotates the downstream screws of the two screws;
an upstream input shaft;
a downstream input shaft;
a first upstream output shaft that is connected to the upstream screw of one of the screws and that has the shaft hole;
a second upstream output shaft that is connected to the upstream screw of the remaining screw and that has the shaft hole;
a first downstream output shaft that penetrates through the shaft hole of the first upstream output shaft and that is connected to the downstream screw of the one of screws;
a second downstream output shaft that penetrates through the shaft hole of the second upstream output shaft and that is connected to the downstream screw of the remaining screw;
an upstream transmission element that transmits rotation of the upstream input shaft to the first upstream output shaft and to the second upstream output shaft; and
a downstream transmission element that transmits rotation of the downstream input shaft to the first downstream output shaft and to the second downstream output shaft.

2. The twin-screw extruder according to claim 1 , wherein the screw flights of the respective upstream screws of the two screws at least partially mesh with each other, and the screw flights of the respective downstream screws of the two screws at least partially mesh with each other.

3. The twin-screw extruder according to claim 1 , wherein each upstream screw of the two screw constitutes a kneading portion, and each downstream screw of the two screw constitutes a metering portion.

4. The twin-screw extruder according to claim 1 , wherein labyrinth grooves are formed on an outer circumferential surface of the small diameter shaft portion of the downstream screw of at least one of two screws.

5. The twin-screw extruder according to claim 1 , wherein the upstream screw includes a cylindrical member having the shaft hole, as well as a screw piece that has the screw flight on an outer circumferential surface thereof and that is fitted onto the cylindrical member, and the screw piece of the upstream screw is removable from the cylindrical member.

6. The twin-screw extruder according to claim 1 , wherein the downstream screw has the small diameter shaft portion, as well as a screw piece that is fitted onto the small diameter shaft portion so as to constitute the large diameter portion, and the screw piece of the downstream screw is removable from the small diameter shaft portion.

7. The twin-screw extruder according to claim 1 , wherein the second upstream output shaft extends parallel to a portion of the first upstream output shaft,
the upstream transmission element includes:
an upstream intermediate shaft that is connected to the upstream input shaft;
a first upstream gear that connects the upstream intermediate shaft to a portion of the first upstream output shaft where the first upstream output shaft is not adjacent to the second upstream output shaft;
a second upstream gear that connects the upstream intermediate shaft to the second upstream output shaft and that has a smaller diameter than the first upstream gear; and
a plurality of upstream intermediate transmission elements that are independent of each other, wherein each upstream intermediate transmission element connects the upstream intermediate shaft to the second upstream gear.

8. The twin-screw extruder according to claim 1 , wherein the second downstream output shaft extends parallel to a portion of the first downstream output shaft,
the downstream transmission element includes:
a plurality of downstream intermediate transmission elements that are independent of each other and that connect a portion of the first downstream output shaft, where the first downstream output shaft is not adjacent to the second downstream output shaft, to the second downstream output shaft;
a first downstream gear that connects the downstream input shaft to the first downstream output shaft, and
a second downstream gear that connects the plurality of downstream intermediate transmission elements to the second downstream output shaft and that has a smaller diameter than the first downstream gear.

9. A method of extrusion using the twin-screw extruder of claim 1 ,
supplying raw material to the upstream screws of the two screws;
rotating the upstream screws of the two screws by means of the upstream rotating mechanism; and
rotating the downstream screws of the two screws by means of the downstream rotating mechanism, wherein the downstream screws are rotated at a rotational speed different from a rotational speed of the upstream screws.

10. The method of claim 9 , wherein:
the first upstream output shaft and the second upstream output shaft of the two screws are rotated by transmitting rotation from the upstream input shaft to the first upstream output shaft and to the second upstream output shaft through the upstream transmission element; and
the first downstream output shaft and the second downstream output shaft of the two screws are rotated by transmitting rotation from the downstream input shaft to the first downstream output shaft and to the second downstream output shaft through the downstream transmission element.

11. A gear box that is incorporated into a twin-screw extruder, wherein the extruder includes two screws that extend in parallel to each other, wherein each screw has an upstream screw having a flight on an outer circumferential surface thereof and a downstream screw having a flight on an outer circumferential surface thereof, and the upstream screw and the downstream screw can be independently rotated, the gear box comprising:
an upstream input shaft;
a downstream input shaft;
a first upstream output shaft that is connected to the upstream screw of one of the screws and that has a shaft hole;
a second upstream output shaft that is connected to the upstream screw of the remaining screw and that has a shaft hole;
a first downstream output shaft that penetrates through the shaft hole of the first upstream output shaft and that is connected to the downstream screw of the one of screws;
a second downstream output shaft that penetrates through the shaft hole of the second upstream output shaft and that is connected to the downstream screw of the remaining screw;
an upstream transmission element that transmits rotation of the upstream input shaft to the first upstream output shaft and to the second upstream output shaft; and
a downstream transmission element that transmits rotation of the downstream input shaft to the first downstream output shaft and to the second downstream output shaft.

Assignees

• Japan Steel Works Ltd
• Tokyo Printing Ink Mfg Co Ltd

Inventors

• Izumiya Kazutoshi
• Sumida Katsumi
• Kimura Yoshitaka
• Tanimoto Masashi
• Okuma Hiroyuki
• Kaneko Katsuyuki
• UESHIGE Shizuo
• Tanaka Nobuaki
• NAKAMARU Takahiro

Classifications

• B29B7/48

  with intermeshing devices, e.g. screws · CPC title

• B29B7/58

  Component parts, details or accessories; Auxiliary operations · CPC title

• F16H1/22

  with a plurality of driving or driven shafts; with arrangements for dividing torque between two or more intermediate shafts · CPC title

• B29C48/64

  Screws with two or more threads · CPC title

• B29C48/2526 Primary

  Direct drives or gear boxes · CPC title