阅读说明：本技术 双轴挤出机、减速器以及挤出方法 (Twin-screw extruder, decelerator and extrusion method ) 是由 泉屋和寿 住田克己 木村嘉隆 谷本正史 大熊博幸 金子胜幸 上繁志都男 田中伸明 中 于 2019-02-13 设计创作，主要内容包括：提供能够根据原料的处理工序来变更螺杆的旋转速度并且加工过的原料难以劣化的双轴挤出机。双轴挤出机(1)具有相互平行地延伸的两个螺杆(3、5)。各螺杆(3、5)具有：筒状的上游侧螺杆(31),其具有沿长度方向(X)延伸的轴孔(315),并在外周面具有螺旋螺纹(316)；以及下游侧螺杆(35),其包括在外周面具有螺旋螺纹(357)的大径部分(353)和直径比大径部分(353)小的小径轴部(351),下游侧螺杆(35)的小径轴部(351)插入上游侧螺杆(31)的轴孔(315)。上游侧螺杆(31)与下游侧螺杆(35)能够相互独立地旋转。双轴挤出机(1)还具有：上游侧旋转机构(84),其使两个螺杆(3、5)的上游侧螺杆(31)旋转；以及下游侧旋转机构(83),其使两个螺杆(3、5)的下游侧螺杆(35)旋转。(Provided is a twin screw extruder in which the rotational speed of a screw can be changed according to the process of processing a raw material and the processed raw material is less likely to deteriorate. The twin-screw extruder (1) has two screws (3, 5) extending parallel to each other. Each screw (3, 5) has: a cylindrical upstream screw (31) having a shaft hole (315) extending in the longitudinal direction (X) and having a helical thread (316) on the outer circumferential surface; and a downstream screw (35) having a large-diameter portion (353) having a spiral thread (357) on the outer peripheral surface thereof and a small-diameter portion (351) having a diameter smaller than that of the large-diameter portion (353), wherein the small-diameter portion (351) of the downstream screw (35) is inserted into the shaft hole (315) of the upstream screw (31). The upstream screw (31) and the downstream screw (35) can rotate independently of each other. The twin-screw extruder (1) further comprises: an upstream-side rotating mechanism (84) that rotates an upstream-side screw (31) of the two screws (3, 5); and a downstream side rotating mechanism (83) which rotates the downstream side screw (35) of the two screws (3, 5).)

1. A twin-screw extruder in which, in the extruder,

the twin-screw extruder comprises:

two threaded rods extending parallel to each other, each of said threaded rods having: a cylindrical upstream screw having a shaft hole extending in a longitudinal direction and having a helical thread on an outer peripheral surface; and a downstream screw including a large-diameter portion having a spiral thread on an outer peripheral surface thereof and a small-diameter shaft portion having a diameter smaller than that of the large-diameter portion, the small-diameter shaft portion of the downstream screw being inserted into the shaft hole of the upstream screw, the upstream screw and the downstream screw being rotatable independently of each other;

an upstream-side rotating mechanism that rotates the upstream-side screws of the two screws; and

and a downstream side rotating mechanism which is provided independently of the upstream side rotating mechanism and rotates the downstream side screw of the two screws.

2. The twin screw extruder according to claim 1,

the helical threads of the upstream-side screws of the two screws are at least partially intermeshed with each other, and the helical threads of the downstream-side screws of the two screws are at least partially intermeshed with each other.

3. The twin-screw extruder according to claim 1 or 2,

the upstream screws of the two screws constitute kneading sections,

the downstream screws of the two screws constitute metering portions, respectively.

4. The twin screw extruder according to any one of claims 1 to 3,

a labyrinth groove is formed in an outer peripheral surface of the small diameter shaft portion of at least one of the screws on the downstream side.

5. The twin screw extruder according to any one of claims 1 to 4,

the upstream screw has: a cylindrical member having the shaft hole; and a screw having the helical thread on an outer circumferential surface thereof and fitted to an outer side of the cylindrical member, wherein the screw of the upstream screw is detachable from the cylindrical member.

6. The twin screw extruder according to any one of claims 1 to 5,

the downstream side screw has: the small-diameter shaft part; and a screw that is fitted to the outside of the small-diameter shaft portion and that constitutes the large-diameter portion, the screw of the downstream screw being detachable from the small-diameter shaft portion.

7. The twin screw extruder according to any one of claims 1 to 6,

the twin-screw extruder comprises:

an upstream-side input shaft;

a downstream side input shaft;

a first upstream output shaft connected to the upstream screw of one of the screws and having a shaft hole;

a second upstream output shaft having a shaft hole and connected to the upstream screw of the other screw;

a first downstream output shaft that penetrates the shaft hole of the first upstream output shaft and is connected to the downstream screw of one of the screws;

a second downstream output shaft that penetrates the shaft hole of the second upstream output shaft and is connected to the downstream screw of the other screw;

an upstream transmission element that transmits rotation of the upstream input shaft to the first upstream output shaft and the second upstream output shaft; and

and a downstream transmission element that transmits rotation of the downstream input shaft to the first downstream output shaft and the second downstream output shaft.

8. The twin screw extruder according to claim 7,

the second upstream-side output shaft extends in parallel with a part of the first upstream-side output shaft,

the upstream side transmission element includes: an upstream-side intermediate shaft connected to the upstream-side input shaft; a first upstream side gear that connects the upstream side intermediate shaft with a portion of the first upstream side output shaft that is not adjacent to the second upstream side output shaft; a second upstream gear that connects the upstream intermediate shaft and the second upstream output shaft and has a smaller diameter than the first upstream gear; and a plurality of upstream-side intermediate transmission elements which connect the upstream-side intermediate shaft and the second upstream-side gear, respectively, and are independent of each other.

9. The twin-screw extruder according to claim 7 or 8,

the second downstream side output shaft extends in parallel with a part of the first downstream side output shaft,

the downstream side transmission element includes: a plurality of downstream-side intermediate transmission elements which connect a portion of the first downstream-side output shaft which is not adjacent to the second downstream-side output shaft and which are independent of each other; a first downstream side gear connecting the downstream side input shaft with the first downstream side output shaft; and a second downstream gear that connects the plurality of downstream intermediate transmission elements to the second downstream output shaft and has a smaller diameter than the first downstream gear.

10. An extrusion method using a twin screw extruder having two screws extending in parallel to each other, each of the screws having: a cylindrical upstream screw having a shaft hole extending in a longitudinal direction and having a helical thread on an outer peripheral surface; and a downstream screw including a large diameter portion having a spiral thread on an outer peripheral surface thereof and a small diameter portion having a smaller diameter than the large diameter portion, the small diameter portion of the downstream screw being inserted into the axial hole of the upstream screw, the upstream screw and the downstream screw being rotatable independently of each other,

wherein the content of the first and second substances,

the extrusion process has the following steps:

supplying a raw material to the upstream side screw of the two screws;

rotating the upstream-side screws of the two screws by an upstream-side rotating mechanism; and

the downstream screw of the two screws is rotated at a different rotational speed from the upstream screw by a downstream side rotation mechanism provided independently of the upstream side rotation mechanism.

11. The extrusion process of claim 10,

the upstream side rotation mechanism includes: an upstream-side input shaft; a first upstream output shaft connected to the upstream screw of one of the screws and having a shaft hole; a second upstream output shaft having a shaft hole and connected to the upstream screw of the other screw; and an upstream transmission element for transmitting rotation of the upstream input shaft to the first upstream output shaft and the second upstream output shaft,

the downstream side rotating mechanism includes: a downstream side input shaft; a first downstream output shaft that penetrates the shaft hole of the first upstream output shaft and is connected to the downstream screw of one of the screws; a second downstream output shaft that penetrates the shaft hole of the second upstream output shaft and is connected to the downstream screw of the other screw; and a downstream transmission element for transmitting rotation of the downstream input shaft to the first downstream output shaft and the second downstream output shaft,

the upstream-side screws of the two screws are rotated by transmitting rotation from the upstream-side input shaft to the first upstream-side output shaft and the second upstream-side output shaft via the upstream-side transmission element,

the downstream side screw of the two screws is rotated by transmitting rotation from the downstream side input shaft to the first downstream side output shaft and the second downstream side output shaft via the downstream side transmission element.

12. A decelerator assembled to a twin screw extruder having two screws extending in parallel with each other, each of the screws having: an upstream screw having a helical thread on an outer peripheral surface thereof; and a downstream screw having a spiral thread on an outer peripheral surface thereof, the upstream screw and the downstream screw being rotatable independently of each other,

wherein the content of the first and second substances,

the speed reducer has:

an upstream-side input shaft;

a downstream side input shaft;

a first upstream output shaft connected to the upstream screw of one of the screws and having a shaft hole;

a second upstream output shaft having a shaft hole and connected to the upstream screw of the other screw;

a first downstream output shaft that penetrates the shaft hole of the first upstream output shaft and is connected to the downstream screw of one of the screws;

a second downstream output shaft that penetrates the shaft hole of the second upstream output shaft and is connected to the downstream screw of the other screw;

an upstream transmission element that transmits rotation of the upstream input shaft to the first upstream output shaft and the second upstream output shaft; and

and a downstream transmission element that transmits rotation of the downstream input shaft to the first downstream output shaft and the second downstream output shaft.

Technical Field

The invention relates to a twin-screw extruder, a decelerator and an extrusion method.

The present application is based on japanese patent application 2018-22961, which is a japanese application filed on day 13/2/2018, and claims priority based on the application. The entirety of which is incorporated by reference into the present application.

Background

An extruder for processing a raw material such as a resin or an elastomer generally includes an elongated cylindrical sleeve and a screw housed inside the sleeve. The raw material supplied to the extruder is rotated and stirred by the screw in the sleeve, and extruded as a molded article having predetermined material properties and shape. The screw housed inside the sleeve is a rod-shaped member having a spiral thread (blade of the screw) on an outer peripheral portion thereof, and the shape thereof differs depending on the position inside the sleeve. That is, the extruder includes a supply portion (conveying portion), a kneading portion (compressing portion, stirring portion, or plasticizing portion), and a metering portion in this order from the upstream side in the flow direction of the raw material. The supply section compresses the solid raw material and supplies the compressed solid raw material to a downstream kneading section. The kneading section melts and plasticizes the raw material supplied from the supply section. The metering section adjusts the discharge amount so as to uniformly discharge the material plasticized by the kneading section. According to the treatment of each part of such an extruder, the screws have different shapes from each other in the longitudinal direction. However, since the conventional screw is formed of one rod-shaped member having a helical thread on the outer peripheral portion as described above, the rotational speed cannot be locally changed in the longitudinal direction. In order to change the rotation speed of the screw according to the processing contents of each part of the extruder, tandem extruders such as those disclosed in patent documents 1 and 2 are used.

In the tandem type extruders described in patent documents 1 and 2, the resin discharge port of the extruder on the upstream side is connected to the raw material supply port of the extruder on the downstream side via a connection pipe. The extruder on the upstream side substantially corresponds to the supply section and the kneading section, and the extruder on the downstream side substantially corresponds to the metering section. That is, in the tandem type extruders described in patent documents 1 and 2, the supply section, the kneading section, and the metering section are configured as separate devices (an upstream side extruder and a downstream side extruder) which are independent of each other. Thus, not only the shape of the screw can be changed according to the processing content, but also the rotational speed of the screw can be changed according to the processing content, and appropriate processing can be performed.

Patent document 1: japanese laid-open patent publication No. 2007-130775

Patent document 2: japanese patent laid-open publication No. 2016-88093

Disclosure of Invention

In the tandem type extruders described in patent documents 1 and 2, an upstream side extruder and a downstream side extruder are connected by a connecting pipe. However, the high-temperature raw material plasticized in the extruder on the upstream side may be sintered on the inner wall surface of the connection pipe having no moving element therein and may be retained in the connection pipe for a long period of time. When the sintered raw material is peeled off and flows into the downstream extruder, there is a possibility that the raw material processed by the downstream extruder is deteriorated. If the extruder on the upstream side is integrated with the extruder on the downstream side, the connecting pipe is not necessary, but the rotation speed of the screw cannot be made different depending on the location.

In view of the above-described problems, an object of the present invention is to provide a twin screw extruder in which the rotational speed of a screw can be changed according to the process of processing a raw material and deterioration of the raw material is less likely to occur, an extrusion method using the twin screw extruder, and a speed reducer used in the twin screw extruder.

The twin-screw extruder of the present invention comprises: two threaded rods extending parallel to each other, each of said threaded rods having: a cylindrical upstream screw having a shaft hole extending in a longitudinal direction and having a helical thread on an outer peripheral surface; and a downstream screw including a large-diameter portion having a spiral thread on an outer peripheral surface thereof and a small-diameter shaft portion having a diameter smaller than that of the large-diameter portion, the small-diameter shaft portion of the downstream screw being inserted into the shaft hole of the upstream screw, the upstream screw and the downstream screw being rotatable independently of each other; an upstream-side rotating mechanism that rotates the upstream-side screws of the two screws; and a downstream side rotating mechanism which is provided independently of the upstream side rotating mechanism and rotates the downstream side screw of the two screws.

The extrusion method of the present invention uses a twin screw extruder having two screws extending in parallel to each other, each of the screws having: a cylindrical upstream screw having a shaft hole extending in a longitudinal direction and having a helical thread on an outer peripheral surface; and a downstream screw including a large diameter portion having a spiral thread on an outer peripheral surface thereof and a small diameter portion having a smaller diameter than the large diameter portion, the small diameter portion of the downstream screw being inserted into the axial hole of the upstream screw, the upstream screw and the downstream screw being rotatable independently of each other, the extrusion method including the steps of: supplying a raw material to the upstream side screw of the two screws; rotating the upstream-side screws of the two screws by an upstream-side rotating mechanism; and rotating the downstream screw of the two screws at a different rotational speed from the upstream screw by a downstream side rotating mechanism provided independently of the upstream side rotating mechanism.

The speed reducer of the present invention is assembled in a twin screw extruder having two screws extending in parallel to each other, each of the screws having: an upstream screw having a helical thread on an outer peripheral surface thereof; and a downstream screw having a spiral thread on an outer peripheral surface thereof, the upstream screw and the downstream screw being rotatable independently of each other, the speed reducer comprising: an upstream-side input shaft; a downstream side input shaft; a first upstream output shaft connected to the upstream screw of one of the screws and having a shaft hole; a second upstream output shaft having a shaft hole and connected to the upstream screw of the other screw; a first downstream output shaft that penetrates the shaft hole of the first upstream output shaft and is connected to the downstream screw of one of the screws; a second downstream output shaft that penetrates the shaft hole of the second upstream output shaft and is connected to the downstream screw of the other screw; an upstream transmission element that transmits rotation of the upstream input shaft to the first upstream output shaft and 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 the second downstream output shaft.

According to the present invention, it is possible to provide a twin-screw extruder in which the rotation speed of a screw can be changed according to the process of processing a raw material and deterioration of the processed raw material is less likely to occur, an extrusion method using the twin-screw extruder, and a speed reducer used in the twin-screw extruder.

The above and other objects, features and advantages of the present application will be apparent from the following detailed description with reference to the accompanying drawings illustrating the present application.

Drawings

Fig. 1 is a plan view of a twin-screw extruder according to an embodiment of the present invention and an extruder for a feeding section for supplying a raw material to the twin-screw extruder.

Fig. 2 is a plan view showing the structure of the inside of a sleeve of the twin-screw extruder shown in fig. 1.

Fig. 3A is a partially cut-away plan view showing the structure of a screw used in the twin-screw extruder shown in fig. 2.

Fig. 3B is an enlarged view of a portion B of fig. 3A.

Fig. 3C is a sectional view taken along line C-C of fig. 3A.

Fig. 3D is a sectional view taken along line D-D of fig. 3A.

Fig. 4 is a plan view showing an upstream side screw of the screw shown in fig. 3A.

Fig. 5 is a plan view showing a downstream side screw of the screw shown in fig. 3A.

Fig. 6A is a plan view showing the structure of the inside of a decelerator used in the twin-screw extruder shown in fig. 2.

Fig. 6B is an enlarged view of a portion F of fig. 6A.

Fig. 7 is a schematic diagram showing the structure of the speed reducer shown in fig. 6A.

Description of the reference numerals

1: a twin-screw extruder; 2: an extruder for a feed section; 3: a left screw; 31: a left upstream side screw; 311: a cylindrical member; 312: a screw; 313: an insertion section; 314: a fitting portion; 315: a shaft hole; 35: a left downstream side screw; 351: a transmission shaft portion; 352: a rotation shaft portion; 353: a screw; 354: a labyrinth groove; 355: a recess; 356: a fitting portion; 5: a right screw; 51: a right upstream side screw; 55: a right downstream side screw; 7: a speed reducer; 71: an upstream-side input shaft; 72: a downstream side input shaft; 73: a left upstream side output shaft; 74: a left downstream side output shaft; 75: a right upstream side output shaft; 76: a right downstream side output shaft; 77: an upstream-side intermediate shaft; 78. 79: a downstream side intermediate transfer element; 83: a downstream-side rotating mechanism; 84: an upstream-side rotating mechanism; 85: a downstream side transfer element; 86: an upstream side transmission element; 9: a sleeve; 91: a raw material supply unit; 92: a discharge unit; g 1-g 18: a gear.

Detailed Description

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

Fig. 1 is a plan view of a twin-screw extruder 1 according to an embodiment of the present invention and an extruder 2 for a feeding section for supplying a raw material to the twin-screw extruder 1. The twin screw extruder 1 and the extruder 2 for a feed part are connected to each other to constitute a tandem type extruder.

The extruder 2 for the feeding section performs preliminary mixing of raw materials supplied from a feeder (not shown). The raw materials preliminarily mixed by the extruder 2 at the feeding portion are supplied to the twin-screw extruder 1. Fig. 2 is a plan view showing the structure of the inside of the sleeve 9 of the twin-screw extruder 1. The twin-screw extruder 1 includes a first screw (left screw) 3 and a second screw (right screw) 5. The left-side screw 3 and the right-side screw 5 have substantially the same structure, and extend in the longitudinal direction X in the sleeve 9 close to each other and in parallel with each other. The left screw 3 includes: a first upstream-side screw (left upstream-side screw) 31 and a first downstream-side screw (left downstream-side screw) 35. Likewise, the right-side screw 5 includes: a second upstream-side screw (right upstream-side screw) 51 and a second downstream-side screw (right downstream-side screw) 55. The left screw 3 and the right screw 5 mesh with each other while rotating in the same direction. Thereby, the left screw 3 and the right screw 5 wipe the outer surfaces of the other screws 5, 3 and the inner wall of the sleeve 9 around themselves. Such self-cleaning performance of the left screw 3 and the right screw 5 suppresses sintering of the raw material on the outer surface of the screws and the inner wall of the sleeve 9.

< screw Structure >

Next, the structure of the left screw 3 and the right screw 5 will be described in detail. The right screw 5 has substantially the same structure as the left screw 3, and therefore, description thereof is omitted. Fig. 3A is a plan view showing the structure of the left-hand screw 3 used in the twin-screw extruder 1. Fig. 3B is an enlarged view of a portion B of fig. 3A. Fig. 3C is a sectional view taken along line C-C of fig. 3A. Fig. 3D is a sectional view taken along line D-D of fig. 3A. Fig. 4 is a plan view showing the left upstream screw 31 of the left screw 3 shown in fig. 3A. Fig. 5 is a plan view showing the left downstream side screw 35 of the screw 3 shown in fig. 3A.

The left upstream screw 31 of the left screw 3 has a double cylindrical structure including a cylindrical screw 312 and a cylindrical member 311 accommodated inside the screw 312. That is, the cylindrical member 311 is a hollow cylinder and has a shaft hole 315 extending in the longitudinal direction (axial direction) X. A cylindrical fitting portion 313 (see fig. 3B and 4) as a protruding portion is formed at the downstream end of the left upstream screw 31 into which the left downstream screw 35 is inserted. The fitting portion 313 is fitted into a recess 355 formed in the downstream-left screw 35 described later. The fitting portion 314 is formed by involute working the outer peripheral surface of the cylindrical member 311. The screw 312 is a hollow cylindrical member having a screw thread 316 on an outer circumferential surface thereof, and has a fitting groove portion (not shown) formed on an inner circumferential surface thereof so as to correspond to the fitting portion 314 of the cylindrical member 311. Therefore, the screw 312 is fitted to the outside of the tubular member 311 so that the fitting portion 314 is fitted to the fitting groove portion (see fig. 3C). A screw thread 316 of the screw 312 is disposed on the outer peripheral portion of the left upstream screw 31. The screw 312 is a member that can be removed from the cylindrical member 311 and replaced. Therefore, the screw 312 can be replaced according to the specifications of the raw material, the product produced by the twin-screw extruder 1.

The left and downstream screws 35 include a transmission shaft 351, a rotation shaft 352, and a screw 353. The screw 353 constitutes a large diameter portion 353 located at one end side of the left downstream side screw 35. The transmission shaft portion 351 and the rotation shaft portion 352 are continuous (integrated) concentric shaft-like members adjacent to each other in the longitudinal direction X. The transmission shaft 351 constitutes a small diameter shaft 351 located on the other end side of the left downstream screw 35 and having a smaller diameter than the large diameter portion 353. A plurality of annular grooves, i.e., labyrinth grooves 354, formed in the circumferential direction are formed on the outer peripheral surface of the transmission shaft portion 351 (see fig. 3B). The labyrinth groove 354 is not formed on the outer peripheral surface of the rotation shaft portion 352. The transmission shaft 351 is inserted into the shaft hole 315 of the left upstream screw 31 and penetrates the shaft hole 315. Therefore, the outer diameter of the transmission shaft 351 is slightly smaller than the inner diameter of the shaft hole 315 of the cylindrical member 311 of the left upstream screw 31.

The rotation shaft portion 352 has a hexagonal cross-sectional shape and functions as a fitting portion 356. The screw 353 is a hollow cylindrical member having a screw thread 357 on the outer peripheral surface thereof, and has a fitting hole 358 formed therein so as to correspond to the fitting portion 356 of the rotation shaft portion 352. The diameter of the circumscribed circle of the fitting hole 358 is slightly larger than the diameter of the circumscribed circle of the rotation shaft portion 352. Therefore, the screw 353 is fitted to the outside of the rotation shaft 352. The length of the screw 353 in the longitudinal direction X is shorter than the sum of the length of the transmission shaft portion 351 in the longitudinal direction X and the length of the rotation shaft portion 352 in the longitudinal direction X, and at least a part of the transmission shaft portion 351 is exposed without being covered with the screw 353. The outer diameter of the screw 353 is larger than the outer diameters of the transmission shaft 351 and the rotation shaft 352, and is substantially equal to the outer diameter of the screw 312. The diameter of the circumscribed circle of the rotary shaft portion 352 is slightly smaller than the inner diameter of the cylindrical member 311 of the left upstream screw 31. The screw 353 can be detached from the transmission shaft 351 and the rotation shaft 352 and replaced. A recess 355 (see fig. 3B) which is a cylindrical hole extending in the longitudinal direction X is formed in an upstream end of the screw 353 into which the rotating shaft portion 352 is inserted. The recessed portion 355 is fitted into a fitting portion 313 formed in the left upstream screw 31.

The screw 312 and the screw 353, which are configured in this way and have substantially the same outer diameter, are disposed adjacent to each other in the longitudinal direction X, and the screw threads 316 and 357 having substantially the same shape are disposed substantially continuously along the longitudinal direction X on the outer peripheral surface. However, the screw 312 having the spiral flight 316 of the left upstream screw 31 and the screw 353 having the spiral flight 357 of the left downstream screw 35 are not integrated and can rotate independently of each other.

< speed reducer >

Next, the structure of a speed reducer for transmitting a rotational driving force to each of the screws 3 and 5 of the twin screw extruder 1 will be described. Fig. 6A is an internal configuration diagram showing the configuration of the speed reducer 7 used in the twin-screw extruder 1. Fig. 6B is an enlarged view of a portion F of fig. 6A. The speed reducer 7 includes an upstream input shaft 71, a downstream input shaft 72, a left upstream output shaft (first upstream output shaft) 73, a left downstream output shaft (first downstream output shaft) 74, a right upstream output shaft (second upstream output shaft) 75, and a right downstream output shaft (second downstream output shaft) 76.

The left upstream output shaft 73 and the right upstream output shaft 75 are hollow shafts made of hollow cylindrical members. A left downstream output shaft 74 concentric with the left upstream output shaft 73 is disposed inside the left upstream output shaft 73. Similarly, a right downstream output shaft 76 concentric with the center axis of the right upstream output shaft 75 is disposed inside the right upstream output shaft 75.

The downstream input shaft 72 is coupled to the left and right downstream output shafts 74, 76, and transmits rotational force to the left and right downstream output shafts 74, 76. The left-downstream output shaft 74 is coupled to the transmission shaft 351 of the left-downstream screw 35 of the left screw 3, and transmits rotational force to the transmission shaft 351 of the left-downstream screw 35. The right downstream output shaft 76 is connected to the transmission shaft 351 of the right downstream screw 55 of the right screw 5 having substantially the same configuration as the left screw 3 described above, and transmits a rotational force to the transmission shaft 351 of the right downstream screw 55. On the other hand, the upstream input shaft 71 is coupled to the left upstream output shaft 73 and the right upstream output shaft 75, and transmits rotational force to the left upstream output shaft 73 and the right upstream output shaft 75. The left upstream output shaft 73 is coupled to the cylindrical member 311 of the left upstream screw 31 of the left screw 3, and transmits rotational force to the cylindrical member 311 of the left upstream screw 31. The right upstream output shaft 75 is coupled to the cylindrical member 311 of the right upstream screw 51 of the right screw 5 having substantially the same configuration as the left screw 3 described above, and transmits rotational force to the cylindrical member 311 of the right upstream screw 51.

The upstream input shaft 71 of the reduction gear 7 is coupled to an upstream actuator 81 (see fig. 7). On the other hand, the downstream input shaft 72 of the speed reducer 7 is coupled to a downstream driver 82 (see fig. 7).

Fig. 7 schematically shows an example of the structure of the speed reducer 7. In the drawings, g1 to g18 represent gears. Like gear g1 and gear g2, the adjacent illustrated gears are meant to intermesh.

First, a transmission mechanism of the rotation from the upstream input shaft 71 will be described. The upstream side input shaft 71 is provided with a gear g 1. Gear g1 meshes with gear g 2. A shaft (upstream intermediate shaft 77) on which the gear g2 is provided with a gear g3 and a gear g5 which are coaxial with the gear g 2. The gear g3 meshes with a gear (first upstream side gear) g4 provided on the left upstream side output shaft 73. That is, the rotation of the upstream input shaft 71 driven by the upstream actuator 81 is transmitted to the left upstream output shaft 73 via transmission elements including the gear g1, the gear g2, the gear g3, and the gear g 4.

Further, the gear g5 meshes with the gear g6 and the gear g 7. Gear g6 meshes with gear g 8. On the other hand, the gear g7 meshes with the gear g 9. The gear g8 and the gear g9 are meshed with a gear (second upstream side gear) g10, respectively. The gear g10 is provided on the right upstream side output shaft 75. That is, the rotation of the upstream input shaft 71 driven by the upstream actuator 81 is transmitted to the right upstream output shaft 75 via transmission elements including the gear g1, the gear g2, the gear g5, the gear g6, the gear g7, the gear g8, the gear g9, and the gear g 10. The gears g1 to g10 and the upstream intermediate shaft 77 constitute an upstream transmission element 86 that transmits the rotation of the upstream input shaft 71 to the left upstream output shaft 73 and the right upstream output shaft 75. The upstream transmission element 86, the upstream input shaft 71, the left upstream output shaft 73, and the right upstream output shaft 75 constitute an upstream rotation mechanism 84 for rotating the left upstream screw 31 and the right upstream screw 51.

Here, the relationship among the gear g5, the gear g6, the gear g7, the gear g8, the gear g9, and the gear g10 will be described in more detail. The rotation transmitted from the gear g5 is transmitted to the gear g10 via the gear g6 and the gear g8, and is transmitted to the gear g10 via the gear g7 and the gear g 9. The gear g6 and the gear g8 constitute one upstream-side intermediate transmission element, and the gear g7 and the gear g9 constitute the other upstream-side intermediate transmission element, which are provided independently of each other. In other words, the rotation transmitted from the gear g5 is transmitted from both the gear g8 and the gear g9 to the gear g 10. Since the same rotation (rotation from the gear g 5) is transmitted from the two gears (the gear g8 and the gear g9) to the gear g10 in this manner, stress applied to one meshing portion of the gear g10 can be reduced.

Next, a mechanism for transmitting the rotation from the downstream input shaft 72 will be described. The downstream-side input shaft 72 is provided with a gear g 11. The gear g11 meshes with a gear g12 (first downstream side gear) provided on the left downstream side output shaft 74. That is, the rotation of the downstream input shaft 72 driven by the downstream driver 82 is transmitted to the left downstream output shaft 74 via the transmission elements including the gear g11 and the gear g 12.

Further, the left downstream side output shaft 74 is provided with a gear g 13. Gear g13 meshes with gear g14 and gear g 15. A gear g16 coaxial with the gear g14 is provided on the shaft 78 provided with the gear g 14. On the other hand, a gear g17 coaxial with the gear g15 is provided on the shaft 79 on which the gear g15 is provided. The gear g16 and the gear g17 are respectively meshed with a gear (second downstream side gear) g 18. The gear g18 is provided on the right downstream side output shaft 76. That is, the rotation of the downstream input shaft 72 driven by the downstream actuator 82 is transmitted to the right downstream output shaft 76 via transmission elements including the gear g11, the gear g12, the gear g13, the gear g14, the gear g15, the gear g16, the gear g17, and the gear g 18. Gear g18 transfers rotation from two gears, gear g16 and gear g 17. That is, the shafts 78, 79 constitute a plurality of downstream intermediate transfer elements 78, 79 independent of each other. Since the same rotation (rotation from the gear g 13) is transmitted from the two gears (the gear g16 and the gear g17) to the gear g18, stress applied to one meshing portion of the gear g18 can be reduced.

In the reduction gear 7, a position where the gear g11 meshes with the gear g12, a position where the gear g3 meshes with the gear g4, a position where the gear g16, the gear g17, and the gear g18 mesh, and a position where the gear g5, the gear g6, the gear g7, the gear g8, the gear g9, and the gear g10 mesh are arranged in this order in proximity to the upstream side actuator 81 and the downstream side actuator 82. The right upstream output shaft 75 and the right downstream output shaft 76 are shorter than the left downstream output shaft 74. Therefore, the right upstream output shaft 75 and the right downstream output shaft 76 are not disposed adjacent to the left downstream output shaft 74 at the position where the gear g11 of the left downstream output shaft 74 close to the downstream side driver 82 meshes with the gear g 12. Further, the right upstream output shaft 75 and the right downstream output shaft 76 are not disposed adjacent to the left upstream output shaft 73 at the position where the gear g3 of the left upstream output shaft 73 meshes with the gear g 4.

However, the left upstream output shaft 73 and the left downstream output shaft 74 are adjacent to the right downstream output shaft 76 at the positions where the gear g16, the gear g17, and the gear g18 of the right downstream output shaft 76 mesh with each other. Further, the left upstream output shaft 73 and the left downstream output shaft 74 are adjacent to the right upstream output shaft 75 at positions where the gear g5, the gear g6, the gear g7, the gear g8, the gear g9, and the gear g10 of the right upstream output shaft 75 mesh with each other. Therefore, the gear g18 and the gear g10 are made small in diameter and do not interfere with the adjacent left upstream output shaft 73 and left downstream output shaft 74.

With this configuration, the transmission path of the rotation from the upstream actuator 81 and the transmission path of the rotation from the downstream actuator 82 are independent of each other. Therefore, when the upstream-side actuator 81 and the downstream-side actuator 82 drive the upstream-side input shaft 71 and the downstream-side input shaft 72 at different rotational speeds, respectively, the cylindrical member 311 of the left upstream-side screw 31 connected to the left upstream-side output shaft 73 and the cylindrical member 311 of the right upstream-side screw 51 connected to the right upstream-side output shaft 75, and the transmission shaft 351 of the left downstream-side screw 35 connected to the left downstream-side output shaft 74 and the transmission shaft 351 of the right downstream-side screw 55 connected to the right downstream-side output shaft 76 can be rotated at different rotational speeds. Therefore, as shown in fig. 3, the spiral flight of the left upstream screw 31 and the spiral flight of the left downstream screw 35 of the left screw 3, which have substantially the same shape and are substantially continuously arranged, can be rotated at different rotational speeds from each other. Similarly, the helical flight of the right upstream screw 51 and the helical flight of the right downstream screw 55 of the right screw 5, which have substantially the same shape and are arranged substantially continuously, can be rotated at different rotational speeds from each other. At this time, the screw threads of the left upstream screw 31 and the right upstream screw 51, which are arranged at substantially the same position in the longitudinal direction, rotate at the same rotational speed. Similarly, the screw threads of the left downstream screw 35 and the screw threads of the right downstream screw 55, which are arranged at substantially the same position in the longitudinal direction, rotate at the same rotational speed.

< extrusion method >

Next, an extrusion method of the twin screw extruder 1 will be explained. In processing the raw material, the twin screw extruder 1 drives the upstream side driver 81 and the downstream side driver 82. The upstream-side actuator 81 transmits the rotational power to the upstream-side input shaft 71 of the reduction gear 7. The reduction gear 7 transmits the input rotation to the left upstream output shaft 73 and the right upstream output shaft 75 (see fig. 7). On the other hand, the downstream side driver 82 transmits the rotational power to the downstream side input shaft 72 of the speed reducer 7. The reduction gear 7 transmits the input rotation to the left downstream output shaft 74 and the right downstream output shaft 76.

Here, the left upstream output shaft 73 is coupled to the left upstream screw 31, and the right upstream output shaft 75 is coupled to the right upstream screw 51. On the other hand, the left downstream output shaft 74 is coupled to the left downstream screw 35, and the right downstream output shaft 76 is coupled to the right downstream screw 55. Thereby, the left upstream screw 31, the right upstream screw 51, the left downstream screw 35, and the right downstream screw 55 are rotated, respectively (see fig. 2).

Therefore, the twin-screw extruder 1 can extrude the raw material supplied from the extruder 2 for the feed section after being processed by the left upstream screw 31, the right upstream screw 51, the left downstream screw 35, and the right downstream screw 55. That is, the raw material supplied from the feeding section extruder 2 to the raw material supply section 91 is stirred and heated by the left upstream screw 31 of the left screw 3 and the right upstream screw 51 of the right screw 5 in the liner 9, and is gradually conveyed to the downstream side while being melt-kneaded. Thereafter, the melt-kneaded raw materials are metered while being rotated at a different rotational speed from the left upstream screw 31 and the right upstream screw 51 by the left downstream screw 35 of the left screw 3 and the right downstream screw 55 of the right screw 5, and are discharged from the discharge portion 92 at a predetermined discharge amount. That is, in this configuration, the left upstream screw 31 and the right upstream screw 51 substantially function as a supply section and a kneading section, and the left downstream screw 35 and the right downstream screw 55 substantially function as a metering section (however, it is not necessary that the boundary portion between the upstream screw and the downstream screw, the boundary portion between the supply section and the kneading section, and the boundary portion between the metering section coincide with each other).

The raw material supplied to the twin screw extruder 1 by the extruder 2 for the feed portion is low in temperature. Therefore, the raw material is not sintered on the wall surface of the connecting portion where the material is supplied from the extruder 2 for a feeding portion to the twin screw extruder 1. In the present embodiment, the extruder 2 for the feeding section and the twin screw extruder 1 are disposed so that their screw axes are orthogonal to each other, but may be disposed in parallel. In the case of being arranged in parallel, the extruder 2 for the feeding portion and the biaxial extruder 1 are connected by a connecting member.

< effects >

The operation and effect of the present embodiment will be described below.

In the present embodiment, the actuators are different for the left and right upstream screws 31 and 51 and the left and right downstream screws 35 and 55. Therefore, the left and right upstream screws 31 and 51 as the upstream screws and the left and right downstream screws 35 and 55 as the downstream screws can be rotationally driven. Therefore, the rotation speeds can be made different for the upstream-side screw and the downstream-side screw. This twin screw extruder 1 can thereby perform processing of raw materials according to various specifications.

For example, when a high-strength kneading of a raw material is desired for a specific application, it is necessary to increase the rotation speed of the kneading section. In an extruder in which the entire screw is composed of one rod-shaped member rotating at a constant rotational speed, since the kneading section and the metering section that perform high-intensity kneading rotate at the same rotational speed, there is a risk that a desired metering cannot be accurately performed or that the discharge of the raw material from the extruder through the metering section becomes unstable. Therefore, in order to achieve both high-intensity kneading and accurate metering and stable discharge of the raw materials, it is necessary to use a tandem type extruder in which a kneading section and a metering section are formed and connected as separate devices. When the discharge of the raw material from the extruder is unstable, there is a risk that a good molded product cannot be produced.

However, in the twin-screw extruder 1 of the present embodiment, the left upstream screw 31 and the right upstream screw 51 function as kneading sections, the left downstream screw 35 and the right downstream screw 55 function as metering sections, and the rotation speeds of the screws in the kneading sections and the metering sections can be set independently of each other. For example, even if the rotation speed of the screw in the kneading section is increased, the rotation speed of the screw in the metering section can be prevented from increasing. That is, even when high-intensity kneading is performed in the kneading section, the discharge of the raw material from the extruder through the metering section does not become unstable, and the possibility of producing a defective product is low.

In the case of a tandem type extruder in which the kneading section and the metering section are configured as separate apparatuses, it is necessary to connect the extruder on the kneading section side and the extruder on the metering section side by a connecting member. When the two extruders are connected by the connecting member, the high-temperature raw material melted by the extruder on the kneading unit side may be sintered and adhered to and accumulated on the inner wall surface of the connecting member when passing through the connecting member.

However, the twin-screw extruder 1 of the present embodiment can be configured such that the kneading section and the metering section are continuous, and no connecting member is present between the two. Therefore, in the twin screw extruder 1, there is no risk that the raw material is sintered to the inner wall surface of the connecting member. Further, the left screw 3 and the right screw 5 rotate, and the screw thread performs an operation of rubbing against the inner wall surface of the sleeve 9. Therefore, in the twin screw extruder 1, there is little risk that the raw material is sintered to the inner wall surface of the sleeve 9.

The left upstream screw 31 and the right upstream screw 51 of the present embodiment are configured to engage with each other in a helical thread manner. The left downstream side screw 35 and the right downstream side screw 55 are configured to mesh with each other with helical flights, and the screw shape is also a double helix having self-cleaning property, that is, a so-called Ball Flight (shape having a rugby-Ball-shaped cross section). Therefore, in the twin screw extruder 1, the raw material on the surface of the screw and the inner wall of the cylinder is less likely to be sintered.

In this way, the twin screw extruder 1 of the present invention has a low possibility that the raw material is sintered in each part of the apparatus, and can suppress deterioration of the raw material due to sintering.

As shown in fig. 3B, the recessed portion 355 of the left downstream screw 35 is fitted with the fitting portion 313 of the left upstream screw 31. This makes it difficult for the raw material to enter the shaft hole 315 of the left upstream screw 31. Further, the labyrinth groove 354 is formed in the transmission shaft portion 351 that penetrates the shaft hole 315 of the left upstream screw 31, thereby further preventing the raw material from entering the shaft hole 315 of the left upstream screw 31.

The screw 312 of the left upstream screw 31 and the screw 353 of the left downstream screw 35 can be replaced. This allows the screw 312 and the screw 353 to be replaced according to the application, and makes it easy to use an appropriate screw.

As described above, the left upstream output shaft 73 and the left downstream output shaft 74 are adjacent to the right downstream output shaft 76 at the position where the gear g18 of the right downstream output shaft 76 meshes with the gear g16 and the gear g17 shown in fig. 7. Further, the left upstream output shaft 73 and the left downstream output shaft 74 are adjacent to the right upstream output shaft 75 at the position where the gear g10 of the right upstream output shaft 75 meshes with the gear g8 and the gear g 9. Therefore, the gear g18 and the gear g10 are not gears having an excessively large diameter, but gears having a small diameter so as not to interfere with the adjacent left upstream output shaft 73 and left downstream output shaft 74. Large torques cannot be transmitted via small-diameter gears. However, in the reduction gear 7 of the present embodiment, the gear g18 and the gear g10 transmit rotation from two gears, respectively (see fig. 7). That is, stress applied to the teeth of the gear can be reduced as compared with the case where rotation is transmitted from one gear. Therefore, in the reducer 7, the gear g10 and the gear g18 can transmit the torque required for kneading the raw materials to the right upstream output shaft 75 and the right downstream output shaft 76, respectively.

< modification example >

In the above embodiment, in the twin screw extruder 1, the left upstream screw 31 and the right upstream screw 51 function as kneading sections, and the left downstream screw 35 and the right downstream screw 55 function as metering sections. However, the present invention is not limited to such a configuration, and the positions of the kneading section and the metering section may be freely determined.

In the above embodiment, the labyrinth groove 354 is an annular groove, but the labyrinth groove 354 may be a spiral groove or another groove known as a known labyrinth groove. The labyrinth groove 354 may be provided on at least the outer peripheral surface of the small diameter shaft portion of any of the screws 3 and 5.

The helical threads 316, 357 of the left-hand screw 3 and the helical threads 316, 357 of the right-hand screw 5 may not be partially or fully engaged. That is, the present invention can be applied to a configuration in which the left screw 3 and the right screw 5 are arranged only in parallel.

The fitting portion 314 may have any cross-sectional shape as long as it can be fitted to the screw 312. Specifically, the cross-sectional shape of the fitting portion 314 may be a polygon, in addition to the involute shape. Similarly, the fitting portion 356 may have any cross-sectional shape as long as it can be fitted to the screw 353. The fitting portion 314 and the fitting portion 356 may have the same cross-sectional shape.

It is to be understood that although several preferred embodiments of the present invention have been illustrated and described in detail, various changes and modifications can be made without departing from the spirit and scope of the appended claims.