extruder

Abstract

The present invention reduces the size of an extruder 10 in a feeding direction. The extruder 10 includes: an upstream part screw 52 that is positioned inside a cylinder 36 and includes a progressive flight 54; and a downstream part screw 62 that is positioned inside a cylinder connected to the cylinder 36. When the valley diameter of the upstream part screw 52 is d1, the mountain diameter thereof is D1, the valley diameter of the downstream part screw 62 is d2, and the ridge diameter thereof is D2, D1 / d1 < D2 / d2 is established.

Description

Technical Field

[0001] The present disclosure relates to an extruder.

Background Art

[0002] Patent Document 1 discloses a twin-screw extruder. A pair of screws provided in a cylinder is composed of a transport section, a kneading section, and a discharge section from the upstream side.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When an extruder includes two cylinders, in the cylinder located on the upstream side in the resin material transport direction, it is necessary to increase the pressure to transport the resin material toward the downstream cylinder. As a method of increasing the pressure, it is conceivable to set the length of the upstream cylinder in the transport direction to be long, but in this case, the size of the extruder in the transport direction becomes large.

[0005] Other problems and novel features will become apparent from the description of this specification and the accompanying drawings.

Means for Solving the Problems

[0006] An extruder according to an embodiment includes an upstream screw portion including a transport section located in an upstream cylinder and the kneading section and a downstream screw portion located in a downstream cylinder connected to the upstream cylinder and includes other conveying sections and other kneading sections . When the trough diameter of the conveying section is d1 and the crest diameter is D1, and the trough diameter of the other conveying section is d2 and the crest diameter is D2, the relationship D1 / d1 < D2 / d2 holds. When the radius of the upstream cylinder is D3, the radius of the downstream cylinder 2 is D4, the trough diameter of the kneading section is d5, the crest diameter is D5, the trough diameter of the other kneading section is d6, and the crest diameter is D6, the relationships D5 / d5 < D6 / d6 and D3 / d5 < D4 / d6 hold .

Effects of the Invention

[0007] According to one embodiment of the present invention, the size of the extruder in the conveying direction can be reduced compared to a configuration where D1 / d1 ≥ D2 / d2. [Brief explanation of the drawing]

[0008]

Figure 1

Figure 2A

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Figure 10

Figure 11

Figure 12A

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Figure 13B

Figure 14A

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Figure 15A

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Figure 15C

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Mode for Carrying Out the Invention

[0009] Hereinafter, each embodiment of the present invention will be described in detail with reference to the drawings. In all the drawings for explaining each embodiment, members, devices, etc. having the same or substantially the same functions are denoted by the same reference numerals, and repeated explanations are omitted.

[0010] In the following description, the transport direction of the resin material P to be described later may be referred to as the Y direction. The Y direction is included in the horizontal direction. The arrow Y in the figure means the Y direction. The base end side of the arrow Y corresponds to the upstream side. The tip end side of the arrow Y corresponds to the downstream side.

[0011] Also, the vertical direction orthogonal to the transport direction may be referred to as the Z direction. The arrow Z in the figure means the Z direction. The base end side of the arrow Z corresponds to the lower side. The tip end side of the arrow Z corresponds to the upper side.

[0012] Furthermore, the left-right direction, which is perpendicular to both the conveying direction and the vertical direction, is sometimes referred to as the X direction. The X direction is included in the horizontal direction. The arrow X in the figure represents the X direction. The base end of arrow X corresponds to the left side of the extruder 10 when viewed from the upstream side to the downstream side in the conveying direction. The tip end of arrow X corresponds to the right side of the extruder 10. The X, Y, and Z directions are perpendicular to each other.

[0013] [Embodiment 1] As shown in Figure 1, the extruder 10 of Embodiment 1 is used for the melt-kneading process of resin pellets PR, which is an example of a resin material P. The extruder 10 is supported by a base 12 fixed to the installation floor FL. The extruder 10 is, as an example, a twin-screw extruder equipped with two screws 50 (Figures 2A and 2B). Specifically, the extruder 10 comprises a drive unit 20 for rotating the two screws 50 and a kneading unit 30 including the two screws 50.

[0014] [Drive unit] The drive unit 20 includes an electric motor 22 and a reduction gear 24. Specifically, the rotational force generated by the electric motor 22 is transmitted to the reduction gear 24, and the reduced, high-torque rotational force is transmitted from the reduction gear 24 to the two screws 50 (Figures 2A and 2B) of the kneading section 30 via a gear mechanism 26, etc. As a result, the two screws 50 rotate in the same direction. However, the two screws 50 can also be rotated in different directions depending on the purpose of the melting and kneading process, etc.

[0015] [Mixing Section] The mixing section 30 includes a hopper 32, a cylinder unit 34, two screws 50 (Figures 2A and 2B), and a discharge section 46.

[0016] <Hopper> The resin pellets PR stored in the hopper 32 descend by gravity and are supplied to the supply port 37A, which will be described later. In the kneading section 30, the side to which the resin pellets PR before melting and kneading are supplied is the "upstream side". The side from which the molten resin MR after melting and kneading is discharged from the discharge section 46 is the "downstream side".

[0017] <Cylinder Unit> The cylinder unit 34 is supported by the base 12. The cylinder unit 34 is positioned parallel to the installation floor FL. The cylinder unit 34 includes, as an example, a cylinder 36 extending along the Y direction and a cylinder 42 connected to cylinder 36 and also extending along the Y direction. Within the cylinder unit 34, the area with radius D3 (Figure 2A) is defined as the upstream zone K1. Also, within the cylinder unit 34, the area with radius D4 (Figure 2B) is defined as the downstream zone K2.

[0018] The cylinder 36, as an example, consists of two blocks 37 aligned in the Y direction. Each of the two blocks 37 has a cylindrical upstream transport path 39 that penetrates in the Y direction. Two upstream transport paths 39 are aligned in the X direction (Figure 2A). The upstream block 37 has a supply port 37A. The supply port 37A penetrates from the outside to the upstream transport path 39.

[0019] The cylinder 42, as an example, consists of four blocks 43 arranged in the Y direction. A cylindrical downstream transport path 44 is formed in the four blocks 43, penetrating in the Y direction. Two downstream transport paths 44 are arranged in the X direction (Figure 2B). Downstream of the cylinder 42 in the Y direction, there is a discharge section 46 through which the molten resin MR is discharged.

[0020] As shown in Figure 2A, the radius of cylinder 36 (upstream transport path 39) is D3 (mm).

[0021] As shown in Figure 2B, the radius of the cylinder 42 (downstream transport path 44) is D4 (mm).

[0022] In Figures 2A and 2B, the size of radius D3 is smaller than the size of radius D4. In other words, in the XZ cross section perpendicular to the Y direction, the cross-sectional area S1 of the upstream transport path 39 is smaller than the cross-sectional area S2 of the downstream transport path 44. A step 45 (Figure 1) is formed between block 37 and block 43. The two upstream transport paths 39 partially overlap in their opposing portions in the X direction and communicate with each other in the overlapping portions. The two downstream transport paths 44 partially overlap in their opposing portions in the X direction and communicate with each other in the overlapping portions.

[0023] <Screw> As shown in Figure 1, the two screws 50 (Figures 2A and 2B) are located inside cylinders 36 and 42. The two screws 50 are, for example, a double-screw type. The two screws 50 have the function of conveying the resin material P (resin pellets PR, molten resin MR) present in the upstream conveying path 39 and the downstream conveying path 44 while kneading it from the upstream side to the downstream side in the Y direction.

[0024] The rotation centers of the two screws 50 coincide with the center C of the two upstream transport paths 39 and the center C of the two downstream transport paths 44. Therefore, in the following explanation, the position of the central axis of the screw 50 will also be referred to as center C. The two screws 50 do not interfere with each other and can rotate smoothly. From now on, the explanation will mainly focus on the screw 50 on the +X side (right side), and the explanation of the screw 50 on the -X side (left side) will be omitted.

[0025] The screw 50 includes an upstream screw 52 located inside the cylinder 36 and a downstream screw 62 located inside the cylinder 42. The upstream screw 52 and the downstream screw 62 have the same central axis and rotate together. In Figure 1, the range A1 indicated by the arrow represents the installation range of the upstream screw 52 in the Y direction. Similarly, the range A2 indicated by the arrow represents the installation range of the downstream screw 62 in the Y direction. In this embodiment, as an example, the downstream end of the upstream screw 52 is located inside (enters) the cylinder 42, but it is preferable that the boundary position between the upstream screw 52 and the downstream screw 62 is at the boundary position between the upstream zone K1 and the downstream zone K2.

[0026] <<Definition of peak diameter and valley diameter>> Using the screw SQ schematically shown in Figure 3, the definitions of "peak," "valley," "peak diameter," and "valley diameter" of the screw 50 (Figure 1) in this embodiment will be explained. Note that Figure 3 shows the XZ cross-section of the screw SQ. The axial direction of the screw SQ is along the Y direction. The position of the central axis of the screw SQ is represented by center C. The "peak" of the screw SQ is denoted as peak M. The "peak diameter" of the screw SQ is denoted as peak diameter D (mm). The "valley" of the screw SQ is denoted as valley V. The "valley diameter" of the screw SQ is denoted as valley diameter d (mm). The imaginary line DE is an imaginary circle whose diameter is the effective diameter of the screw SR.

[0027] "Mountain section M" is the part located radially outside the screw SQ with respect to the imaginary line DE when viewed in a cross section (XZ section) perpendicular to the axial direction of the screw SQ. "Valley section V" is the part located radially inside the screw SQ with respect to the imaginary line DE.

[0028] "Mountain diameter D" is the distance D between the center C and the position PA, where PA is the position on the outer surface of the mountain peak M when the distance from the center C to the outer surface of the mountain peak M is maximum when viewed in an XZ cross-section.

[0029] "Valve diameter d" is the distance d between the center C and the position PB on the outer surface of the valley V when the distance from the center C to the outer surface of the valley V is minimized when viewed in the XZ section.

[0030] <<Upstream Screw>> As shown in Figure 1, the upstream screw 52 includes, for example, a shaft 52A, a progressive flight 54 as an example of a conveying section, a progressive kneading 56 as an example of a mixing section, and a progressive flight 58 as an example of a conveying section.

[0031] <<<Sequential Flights>>> The progressive flight 54 and the progressive flight 58 convey the resin material P downstream in the Y direction as they rotate. The length of the progressive flight 54 in the Y direction is longer than the length of the progressive flight 58 in the Y direction. The progressive flight 54 and the progressive flight 58 have the same configuration except for their length in the Y direction. Therefore, the description of the progressive flight 54 will be explained below, and the description of the progressive flight 58 will be omitted.

[0032] As shown in Figure 4A, the rotation direction of the upstream screw 52 is set to the clockwise direction indicated by the arrow CW. As shown in Figure 4B, the forward flight 54 is formed in a right-hand thread shape with helical peaks 54A and valleys 54B so that the resin material P (Figure 1) moves in the Y direction (forward direction). As shown in Figure 4A, a fixing hole 54C is provided at the rotation center of the forward flight 54 through which the shaft 52A (Figure 1) is inserted. The shaft 52A is serrated-fitted to the fixing hole 54C to enable large torque transmission.

[0033] <<<Sequential Kneading>>> As shown in Figure 1, the progressive kneading machine 56 kneads the resin material P as it rotates. The progressive kneading machine 56 also has the function of conveying the resin material P downstream while kneading it.

[0034] As shown in Figures 5A and 5B, the progressive kneading 56 is formed in a spiral shape with multiple peaks 56A and valleys 56B arranged so that the resin material P (Figure 1) is kneaded and conveyed in the Y direction (forward direction). A fixing hole 56C (Figure 5A) through which a shaft 52A (Figure 1) is inserted is provided at the rotational center of the progressive kneading 56. The shaft 52A is serrated-fitted to the fixing hole 56C to enable large torque transmission.

[0035] <<Downstream Screw>> As shown in Figure 1, the downstream screw 62 includes a shaft 52A and progressive kneading sections 64, 65, and 66 as an example of a kneading section, and progressive flights 72, 73, and 74 as an example of another conveying section. The progressive kneading sections 64, 65, and 66 and the progressive flights 72, 73, and 74 are arranged alternately along the Y direction.

[0036] <<<Sequential Kneading>>> The progressive kneading 64 is located downstream in the Y direction from the progressive flight 58. The progressive kneading 64, 65, and 66 knead the resin material P as they rotate. The progressive kneading 64, 65, and 66 also have the function of conveying the resin material P downstream while kneading it. The progressive kneading 64, 65, and 66 are components with an external shape similar to the progressive kneading 56, but their dimensions are different. The progressive kneading 64, 65, and 66 are fixed to the shaft 52A, just like the progressive kneading 56.

[0037] <<<Sequential Flights>>> The forward feed flights 72, 73, and 74 transport the resin material P downstream in the Y direction as they rotate. The lengths of the forward feed flights 72, 73, and 74 in the Y direction are all different. The forward feed flights 72, 73, and 74 are components with an external shape similar to the forward feed flight 54, but their dimensions are different. The forward feed flights 72, 73, and 74 are fixed to the shaft 52A, just like the forward feed flight 54.

[0038] [Valley and peak diameters of forward flight] As shown in Figure 6, the forward flight 54 in the upstream screw 52 has peaks 54A and valleys 54B. Peaks 54A refer to the portion located radially outside the virtual circle whose diameter is the effective diameter of the upstream screw 52. Valleys 54B refer to the portion located radially inside the virtual circle whose diameter is the effective diameter of the upstream screw 52. In Figure 6, for comparison, the forward flight 54 is shown with a solid line, and the forward flight 72, which will be described later, is shown with a dashed line.

[0039] The peak diameter D1 (mm) of the forward flight 54 is the distance between the center C and position P1, where P1 is the position on the outer surface of the peak 54A when the distance from the center C to the outer surface of the peak 54A is maximized when viewed in the XZ cross section.

[0040] The valley diameter d1 (mm) of the forward flight 54 is the distance between the center C and position P2, where P2 is the position on the outer surface of the valley portion 54B at which the distance from the center C to the outer surface of the valley portion 54B is minimized when viewed in the XZ cross section.

[0041] Furthermore, let the radius of cylinder 36 be D3 (mm). Here, let R1 (=D1 / d1) be the ratio of the peak diameter D1 to the valley diameter d1. Also, let R3 (=D3 / d1) be the ratio of the radius D3 of cylinder 36 to the valley diameter d1. The illustration of ratios R1 and R3 is omitted.

[0042] As shown in Figure 7, in the downstream screw 62, the forward flight 72 has peaks 72A and valleys 72B. Peaks 72A refer to the portion located radially outside the virtual circle whose diameter is the effective diameter of the downstream screw 62. Valleys 72B refer to the portion located radially inside the virtual circle whose diameter is the effective diameter of the downstream screw 62.

[0043] The peak diameter D2 (mm) of the forward flight 72 is the distance between the center C and position P3, where P3 is the position on the outer surface of the peak 72A when the distance from the center C to the outer surface of the peak 72A is maximized when viewed in the XZ cross section.

[0044] The valley diameter d2 (mm) of the forward flight 54 is the distance between the center C and the position P4 on the outer peripheral surface when the distance from the center C to the outer peripheral surface of the valley portion 72B is minimized, as viewed in the X-Z cross section.

[0045] Furthermore, let the radius of the cylinder 42 be D4 (mm). Here, let the ratio of the peak diameter D2 to the valley diameter d2 be R2 (= D2 / d2). Also, let the ratio of the radius D4 of the cylinder 42 to the valley diameter d2 be R4 (= D4 / d2). The illustration of the ratios R2 and R4 is omitted.

[0046] As shown in Fig. 6, when comparing the forward flight 54 and the forward flight 72, the relationship D1 / d1 < D2 / d2 holds, and the relationship D3 / d1 < D4 / d2 also holds. In other words, the ratio R1 is smaller than the ratio R2, and the ratio R3 is smaller than the ratio R4.

[0047] 〔Valley diameter and peak diameter of forward kneading〕 As shown in Fig. 8, in the upstream screw 52, the forward kneading 56 has a peak portion 56A and a valley portion 56B. The peak portion 56A means a portion located radially outside the virtual circle having the effective diameter of the upstream screw 52 as the diameter. The valley portion 56B means a portion located radially inside the virtual circle having the effective diameter of the upstream screw 52 as the diameter.

[0048] The peak diameter D5 (mm) of the forward kneading 56 is the distance between the center C and the position P5 on the outer peripheral surface when the distance from the center C to the outer peripheral surface of the peak portion 56A is maximized, as viewed in the X-Z cross section.

[0049] The valley diameter d5 (mm) of the forward kneading 56 is the distance between the center C and the position P6 on the outer peripheral surface when the distance from the center C to the outer peripheral surface of the valley portion 56B is minimized, as viewed in the X-Z cross section.

[0050] Here, the ratio of the peak diameter D5 to the valley diameter d5 is defined as R5 (=D5 / d5). Also, the ratio of the radius D3 to the valley diameter d5 is defined as R6 (=D3 / d5). The illustration of ratios R5 and R6 is omitted. In this embodiment, as an example, R5=R1 and R6=R3.

[0051] As shown in Figure 9, in the downstream screw 62, the progressive kneading 64 has peaks 64A and valleys 64B. Peaks 64A refer to the portion located radially outside the virtual circle whose diameter is the effective diameter of the downstream screw 62. Valleys 64B refer to the portion located radially inside the virtual circle whose diameter is the effective diameter of the downstream screw 62.

[0052] The crest diameter D6 (mm) of the progressive kneading 64 is the distance between the center C and position P7, where P7 is the position on the outer surface of the crest portion 64A at which the distance from the center C to the outer surface of the crest portion 64A is maximum when viewed in the XZ cross section.

[0053] The root diameter d6 (mm) of the progressive kneading 64 is the distance between the center C and position P8, where P8 is the position on the outer surface of the root portion 64B at which the distance from the center C to the outer surface of the root portion 64B is minimized when viewed in the XZ section.

[0054] Here, let R7 (=D6 / d6) be the ratio of the peak diameter D6 to the valley diameter d6. Also, let R8 (=D4 / d6) be the ratio of the radius D4 to the valley diameter d6. The illustration of ratios R7 and R8 is omitted. In this embodiment, as an example, R7=R2 and R8=R4. In other words, in the forward kneading 56 (Figure 8) and forward kneading 64, the ratio R5 is smaller than the ratio R7, and the ratio R6 is smaller than the ratio R8. Thus, the same relationship as in the forward flights 54 and 72 (Figure 1) holds for the forward kneading 56 and 64.

[0055] As described above, in the extruder 10, when the valley diameter d1 and the peak diameter D1 of the upstream screw 52 are set, and the valley diameter d2 and the peak diameter D2 of the downstream screw 62 are set, D1 / d1 < D2 / d2 holds. Further, when the radius D3 of the cylinder 36 and the radius D4 of the cylinder 42 are set, D3 / d1 < D4 / d2 holds. In the extruder 10, each value is set such that D1 / d1 is less than 1.5. In other words, each value is set such that D2 / d2 is 1.5 or more.

[0056] [Operation of Embodiment 1] Referring to FIGS. 1 to 9, the operation of the extruder 10 of Embodiment 1 will be described. In the extruder 10, the ratio R1 (= D1 / d1) of the upstream screw 52 in the upstream zone K1 is smaller than the ratio R2 (= D2 / d2) of the downstream screw 62 in the downstream zone K2. Therefore, the space volume in the upstream zone K1 becomes smaller than the space volume in the downstream zone K2, and the pressure boosting ability in the upstream zone K1 becomes higher. Thus, even if the length of the upstream zone K1 in the Y direction is set to a short length, the required pressure in the upstream zone K1 can be obtained. As a result, compared with a configuration in which D1 / d1 ≧ D2 / d2 holds, the size of the extruder 10 in the conveying direction (Y direction) can be reduced.

[0057] Since the space volume in the upstream zone K1 becomes smaller and the pressure boosting ability becomes higher, the filling rate of the resin material P in the upstream zone K1 becomes higher, and the conveying ability of the resin material P also becomes higher. Therefore, since the resin pressure and the volatile gas generated during kneading in the downstream zone K2 are suppressed from flowing back to the upstream zone K1, the continuous operation of the extruder 10 can be stably performed.

[0058] Here, let the length in the Y direction of the upstream zone K1 be L1 (mm) (Fig. 1). If the length L1 is too short, the pressure boosting ability may be insufficient. The required pressure boosting ability in the upstream zone K1 depends on the internal pressure of the downstream zone K2, but as the ratio RA of the length L1 to the inner diameter of the cylinder 36 (= 2 × radius D3), it is necessary that RA (= L1 / (2 × D3)) is 1.5 or more. The ratio RA is preferably 7.0 or more.

[0059] In the extruder 10, in addition to the relationship D1 / d1 < D2 / d2 holding, the relationship D3 / d1 < D4 / d2 also holds. Therefore, based on not only the radius of the screw 50 but also the radius of the cylinder unit 34, the space volume is set within a preferable range. Thereby, it is possible to further suppress the backflow of the resin pressure and volatile gas generated during kneading in the downstream zone K2 to the upstream zone K1.

[0060] In the extruder 10, the downstream screw 62 includes forward feeding kneadings 64, 65, 66. Thereby, compared with a configuration in which the downstream screw 62 has only forward feeding flights 72, 73, 74, the resin material P can be heated by the heat generated due to the shearing action accompanying the rotation of the screw 50.

[0061] In the extruder 10, the downstream screw 62 includes forward feeding flights 72, 73, 74. Thereby, compared with a configuration in which the downstream screw 62 has only forward feeding kneadings 64, 65, 66, the conveying ability of the resin material P can be enhanced.

[0062] In the extruder 10, the upstream screw 52 includes forward feeding kneading 56. Thereby, compared with a configuration in which the upstream screw 52 has only forward feeding flight 54, the resin material P can be heated by the heat generated due to the shearing action accompanying the rotation of the screw 50.

[0063] [Embodiment 2] An extruder 80 according to Embodiment 2 of this disclosure will be described with reference to the drawings. Components that are the same as or similar to those in the extruder 10 of Embodiment 1 are denoted by the same reference numerals and their description is omitted.

[0064] Figure 10 shows a portion of the extruder 80 in the Y direction. Extruder 80 differs from extruder 10 (Figure 1) in that an adapter 82 is added to the cylinder 36. Except for the length of the screw 50 in the Y direction, the configuration is the same as that of extruder 10 (Figure 1).

[0065] The adapter 82 is provided at the downstream end of the cylinder 36 in the direction of transport (Y direction) of the resin material P. The adapter 82 is an example of an enlarged diameter section. The adapter 82 has a hole 83 that forms part of the transport path for the resin material P. The XZ cross-sectional shape of the hole 83 is circular. The radius of the upstream end of the hole 83 in the Y direction is D3. The radius of the downstream end of the hole 83 in the Y direction is D4. In the hole 83, the radius increases continuously from D3 to D4 toward the cylinder 42. In other words, in the hole 83, the inner diameter increases continuously toward the cylinder 42.

[0066] In the extruder 80, the radius of the adapter 82 increases continuously from D3 to D4. In other words, no steps are formed. This prevents some of the resin material P being conveyed in the Y direction from getting stuck in the stepped portion, allowing the resin material P to be smoothly conveyed from cylinder 36 to cylinder 42.

[0067] [Embodiment 3] An extruder 90 according to Embodiment 3 of this disclosure will be described with reference to the drawings. Components identical or similar to those in the extruder 10 of Embodiment 1 are denoted by the same reference numerals and their description is omitted.

[0068] Figure 11 shows the extruder 90. The extruder 90 differs from the extruder 10 (Figure 1) in that progressive flights 92 and 94 are added to the downstream screw 62, a flow path 93 is provided in the first block 43 (cylinder 42), and a pressure adjustment section 96 is provided in place of the discharge section 46 (Figure 1).

[0069] The channel 93 penetrates the block 43 in the Z direction and communicates with the downstream transport channel 44. Water W is supplied to the channel 93 as an example of a liquid material. As an example of a liquid material, liquid resin or the like may be used instead of water W.

[0070] The pressure regulating section 96 is located downstream of the cylinder 42. For example, the pressure regulating section 96 has a hole 97 with a radius smaller than radius D3 (Figure 6). The hole 97 extends along the Y direction. The pressure regulating section 96 can adjust the pressure inside the cylinder 42 by changing the radius (inner diameter) of the hole 97.

[0071] In the extruder 90, resin material P is supplied in the upstream zone K1, and water W is supplied in the downstream zone K2. In the upstream zone K1, the relationship between the peak diameter and valley diameter described above is met, thereby increasing the pressurization capacity. As a result, the sealing performance in the upstream zone K1 is improved against the resin material P, water W, and gas generated by kneading present in the downstream zone K2, thus suppressing backflow from the downstream zone K2 to the upstream zone K1. Furthermore, since it is not necessary to increase the number of blocks 37 to suppress backflow, the size of the extruder 90 in the conveying direction (Y direction) can be reduced.

[0072] [Embodiment 4] Figures 12A and 12B show an embodiment 4 of the present disclosure in which a reverse feed flight 102 and a reverse feed kneading 106 are added to the extruder 10. Figures 13A and 13B show the reverse feed flight 102. Figures 14A and 14B show the reverse feed kneading 106. For configurations that are the same as or similar to those of the extruder 10 in embodiment 1, please refer to Figure 1, and the figure numbers will be omitted, along with the same reference numerals and descriptions.

[0073] As shown in Figures 13A and 13B, the reverse feed flight 102 is formed in a screw shape with spiral peaks 102A and valleys 102B so that when the rotation direction is indicated by arrow CW (Figure 13A), the resin material P moves in the direction of arrow Y (reverse direction). The reverse feed flight 102 is an example of a reverse conveying section. In addition, a fixing hole 102C (Figure 13A) is provided at the rotational center of the reverse feed flight 102 through which the shaft 52A is inserted. The shaft 52A is serrated-fitted to the fixing hole 102C to enable large torque transmission.

[0074] As shown in Figure 12A, the reverse feed flight 102 is, for example, provided at the upstream end in the Y direction of the upstream screw 52. In addition, a discharge port 103 is provided at the upstream end of the upstream zone K1 of the extruder 10. Here, as the upstream screw 52 rotates, the reverse feed flight 102 rotates, allowing the resin material P that has accumulated upstream of the supply port 37A to be discharged from the discharge port 103.

[0075] As shown in Figures 14A and 14B, the reverse feed kneading 106 is formed in a shape in which multiple peaks 106A are arranged spirally so that when the rotation direction is indicated by arrow CW (Figure 14A), the resin material P is kneaded and conveyed in the direction of arrow Y (reverse direction). The reverse feed kneading 106 is an example of both a kneading section and a reverse conveying section. The reverse feed kneading 106 also has multiple valleys 106B. Furthermore, a fixing hole 106C (Figure 14A) is provided at the rotation center of the reverse feed kneading 106 through which a shaft 52A is inserted. The shaft 52A is serrated-fitted to the fixing hole 106C to enable large torque transmission.

[0076] As shown in Figure 12B, the reverse feed kneading 106 is, for example, provided at the downstream end of the downstream screw 62 in the Y direction. In addition, a discharge port 107 is provided in a part of the downstream zone K2 of the extruder 10. Here, as the downstream screw 62 rotates, the reverse feed kneading 106 rotates, allowing the resin material P that has accumulated upstream of the discharge section 46 (Figure 1) in the downstream zone K2 to be discharged from the discharge port 107. Thus, an extruder 10 equipped with a reverse feed flight 102 and a reverse feed kneading 106 may be used.

[0077] [Embodiment 5] Figure 15A shows a progressive flight 112 as Embodiment 5 of the present disclosure. Components that are the same as or similar to those in the extruder 10 of Embodiment 1 are denoted by the same reference numerals and their descriptions are omitted.

[0078] The progressive flight 112 is an example of a conveying section. The progressive flight 112 constitutes a single-screw type screw 111 and is equipped with a peak 112A and a valley 112B. In the progressive flight 112, the valley 112B having a valley diameter d7 and the peak 112A having a peak diameter D7 are arranged radially on the screw 111. A fixing hole 112C through which a shaft 52A (Figure 1) is inserted is provided at the rotational center of the progressive flight 112.

[0079] The peak portion 112A refers to the part located radially outside the virtual circle whose diameter is the effective diameter of the screw 111. The valley portion 112B refers to the part located radially inside the virtual circle whose diameter is the effective diameter of the screw 111.

[0080] The peak diameter D7 (mm) of the forward flight 112 is the distance between the center C and position P9, where P9 is the position on the outer surface of the peak 112A when the distance from the center C to the outer surface of the peak 112A is maximum when viewed in the XZ cross section.

[0081] The valley diameter d7 (mm) of the forward flight 112 is the distance between the center C and position P10, where P10 is the position on the outer surface of the valley portion 112B at which the distance from the center C to the outer surface of the valley portion 112B is minimized when viewed in the XZ section.

[0082] Furthermore, the ratio R9 (=D7 / d7) of the peak diameter D7 to the valley diameter d7 in the progressive flight 112 is smaller than the ratio R2 of the downstream screw 62 (Figure 7). This allows the size of the extruder 10 to be reduced even when using a single-strand progressive flight 112. The illustration of the ratio R9 is omitted.

[0083] [Embodiment 6] Figure 15B shows a progressive flight 114 as Embodiment 6 of the present disclosure. Components that are the same as or similar to those in the extruder 10 of Embodiment 1 are denoted by the same reference numerals and their descriptions are omitted.

[0084] The progressive flight 114 is an example of a conveying section. The progressive flight 114 constitutes a single-screw type 113 and is equipped with a peak 114A and a valley 114B. A fixing hole 114C is provided at the rotational center of the progressive flight 114 through which a shaft 52A (Figure 1) is inserted.

[0085] The peak portion 114A refers to the part located radially outside the virtual circle whose diameter is the effective diameter of the screw 113. The valley portion 114B refers to the part located radially inside the virtual circle whose diameter is the effective diameter of the screw 113. The valley portion 114B is provided in an annular shape when viewed from the axial direction (Y direction) of the screw 113. The peak portion 114A is a projection-like part that protrudes radially outward from a part of the circumferential direction of the valley portion 114B.

[0086] The peak diameter D8 (mm) of the forward flight 114 is the distance between the center C and position P11, where P11 is the position on the outer surface of the peak 114A when the distance from the center C to the outer surface of the peak 114A is maximum when viewed in the XZ cross section.

[0087] The valley diameter d8 (mm) of the forward flight 114 is the distance between the center C and position P12, where P12 is the position on the outer surface of the valley portion 114B at which the distance from the center C to the outer surface of the valley portion 114B is minimized when viewed in the XZ section.

[0088] The ratio R10 (=D8 / d8) of the crest diameter D8 to the valley diameter d8 in the progressive flight 114 is smaller than the ratio R2 of the downstream screw 62 (Figure 7). This allows the size of the extruder 10 to be reduced even when using a single-strand progressive flight 114. The illustration of the ratio R10 is omitted.

[0089] [Embodiment 7] Figure 15C shows a progressive flight 116 as Embodiment 7 of the present disclosure. Components that are the same as or similar to those in the extruder 10 of Embodiment 1 are denoted by the same reference numerals and their descriptions are omitted.

[0090] The forward feed flight 116 is an example of a conveying section. The forward feed flight 116 constitutes a three-groove screw 115, which has three peaks 116A and three valleys 116B. The three peaks 116A and three valleys 116B are arranged in the circumferential direction of the screw 115. In other words, there are multiple peaks 116A and valleys 116B in the circumferential direction of the screw 115. A fixing hole 116C is provided at the rotational center of the forward feed flight 116 through which a shaft 52A (Figure 1) is inserted.

[0091] The peak portion 116A refers to the part located radially outside the virtual circle whose diameter is the effective diameter of the screw 115. The valley portion 116B refers to the part located radially inside the virtual circle whose diameter is the effective diameter of the screw 115.

[0092] The peak diameter D9 (mm) of the forward flight 116 is the distance between the center C and position P13, where P13 is the position on the outer surface of the peak 116A when the distance from the center C to the outer surface of the peak 116A is maximum when viewed in the XZ cross section.

[0093] The valley diameter d9 (mm) of the forward flight 116 is the distance between the center C and position P14, where P14 is the position on the outer surface of the valley portion 116B at which the distance from the center C to the outer surface of the valley portion 116B is minimized when viewed in the XZ section.

[0094] The ratio R11 (=D9 / d9) of the peak diameter D9 to the valley diameter d9 in the progressive flight 116 is smaller than the ratio R2 of the downstream screw 62 (Figure 7). This allows for a reduction in the size of the extruder 10 (Figure 1) even when using a three-strand progressive flight 116. The illustration of the ratio R11 is omitted.

[0095] [Differentiation] The present disclosure is not limited to each of the above embodiments, and it is needless to say that various modifications can be made without departing from the gist thereof. For example, in each of the above embodiments, a "twin-screw extruder" equipped with two (a pair) of screws 50 was shown, but the present disclosure is not limited to this, and it can also be applied to a single-screw type extruder (single-screw extruder).

[0096] In the extruder 10, a configuration may be adopted in which only the relationship D1 / d1 < D2 / d2 holds and the relationship D3 / d1 < D4 / d2 does not hold.

[0097] As shown in FIG. 16, in the extruder 10 or the like, a temperature changing unit 122 may be provided in the block 37 (cylinder 36) and the block 43 (cylinder 42), respectively. The temperature changing unit 122 includes at least one of a cooling unit that cools the resin material P and a heating unit that heats the resin material P. The number of the cooling units and the number of the heating units may each be either singular or plural. As an example of the cooling unit, a pipe through which a liquid such as water flows may be provided, and cooling may be performed by performing heat exchange with the pipe. As an example of the heating unit, a heater may be provided, and heating may be performed by heat generation due to energization.

[0098] Also, the temperature changing unit 122 may be provided only in the cylinder 36. The temperature changing unit 122 may be provided only in the cylinder 42.

[0099] In the extruder 10, only the forward flight 54 may be provided in the upstream zone K1. Only the forward flight 72 may be provided in the downstream zone K2. Only the forward kneading 64 may be provided in the downstream zone K2. Only the forward flight 54 may be provided in the upstream zone K1 and only the forward flight 72 may be provided in the downstream zone K2. Only the forward flight 54 may be provided in the upstream zone K1 and only the forward kneading 64 may be provided in the downstream zone K2.

[0100] In the upstream zone K1, only the forward flight 54 may be provided, while in the downstream zone K2, both the forward kneading 64 and the forward flight 72 may be provided. In the upstream zone K1, only the forward flight 54 and the forward kneading 56 may be provided.

[0101] An adapter 82 may be added to the extruder 90.

[0102] Furthermore, the material, shape, dimensions, number, and installation location of each component in each of the above embodiments are arbitrary as long as they can achieve the disclosure, and are not limited to the above embodiments or modifications. [Explanation of Symbols]

[0103] 10 Extruder, 12 Base, 20 Drive unit, 22 Electric motor, 24 Reducer, 26 Gear mechanism, 30 Kneading section, 32 Hopper, 34 Cylinder unit, 36 Cylinder, 37 Block, 37A Supply port, 39 Upstream conveying path, 42 Cylinder, 43 Block, 44 Downstream conveying path, 45 Step, 46 Discharge section, 50 Screw, 52 Upstream screw, 52A Shaft, 54 Progressive flight (example of conveying section), 54A Peak section, 54B Valley section, 54C Fixing hole, 56 Progressive kneading (example of kneading section), 56A Peak section, 56B Valley section, 56C Fixing hole, 58 Progressive flight (example of conveying section), 62 Downstream screw, 64 Progressive kneading (example of kneading section), 64A Peak section, 64B Valley section, 65 Progressive kneading (example of mixing section), 66 Progressive kneading (example of mixing section), 72 Progressive flight (example of other conveying section), 72A Peak section, 72B Valley section, 73 Progressive flight (example of other conveying section), 74 Progressive flight (example of other conveying section), 80 Extruder, 82 Adapter (example of diameter expansion section), 83 Hole section, 90 Extruder, 92 Progressive flight, 93 Flow path, 94 Progressive flight, 96 Pressure adjustment section, 102 Reverse flight (example of reverse conveying section), 102A Peak section, 102B Valley section, 102C Fixing hole, 103 Discharge port, 106 Reverse kneading (example of mixing section and example of other reverse conveying section), 106A Peak section, 106B Valley section, 106C Fixing hole, 107 Discharge port, 111 Screw, 112 Forward flight (example of conveying section), 112A Peak section, 112B Valley section, 112C Fixing hole, 113 Screw, 114 Forward flight (example of conveying section), 114A Peak section, 114B Valley section, 114C Fixing hole, 115 Screw, 116 Forward flight (example of conveying section), 116A Peak section, 116B Valley section, 116C Fixing hole, 122 Temperature change section, A1 Range, A2 Range, C Center, CW Rotation direction, d Valley diameter, d1 Valley diameter, d2 Valley diameter, d5 Valley diameter, d6 Valley diameter, D Peak diameter, D1 Peak diameter, D2 Peak diameter, D3 Radius, D4 Radius, D5 Peak diameter, D6 Peak diameter, DE Virtual line, FL Installation floor, K1 Upstream zone, K2 Downstream zone, L1 length, M peak, MR molten resin, P resin material, P1 position, P2 position, P3 position, P4 position, P5 position, P6Position, P7 position, P8 position, P9 position, P10 position, P11 position, P12 position, P13 position, P14 position, PA position, PB position, PR resin paste, R1 ratio, R2 ratio, R3 ratio, R4 ratio, R5 ratio, R6 ratio, R7 ratio, R8 ratio, R9 ratio, R10 ratio, R11 ratio, S1 cross-sectional area, S2 cross-sectional area, SQ scrubber, V valley section, W water, Y conveying direction, Z vertical direction

Claims

1. Extruders including the following: A first cylinder having a supply port into which resin material is supplied; A first screw located within the first cylinder, including a conveying section for conveying the resin material and a kneading section for kneading the resin material; A second cylinder connected to the first cylinder; and A second screw, located within the second cylinder, includes another conveying section for conveying the resin material and another kneading section for kneading the resin material. Here, If the valley diameter of the aforementioned conveying section is d1 and the peak diameter is D1, and the valley diameter of the other conveying section is d2 and the peak diameter is D2, then the relationship D1 / d1 < D2 / d2 holds true. If the radius of the first cylinder is D3, the radius of the second cylinder is D4, the valley diameter of the kneading section is d5 and the peak diameter is D5, and the valley diameter of the other kneading section is d6 and the peak diameter is D6, then the relationships D5 / d5 < D6 / d6 and D3 / d5 < D4 / d6 hold true.

2. In the extruder according to claim 1, Let D3 be the radius of the first cylinder. If the radius of the second cylinder is D4, The following relationship holds: D3 / d1<D4 / d2.

3. In the extruder according to claim 1, An extruder in which the first cylinder is provided with an enlarged diameter section at its downstream end in the direction of conveying the resin material, such that the inner diameter continuously increases toward the second cylinder.

4. In the extruder according to claim 1, The second cylinder is provided with a channel through which liquid material is supplied. An extruder is provided with a pressure adjustment unit that can adjust the pressure inside the second cylinder, downstream of the second cylinder in the direction of conveying the resin material.

5. In the extruder according to claim 1, An extruder in which a reverse conveying section is provided at the upstream end of the first screw in the direction of conveying the resin material, for conveying the resin material in the opposite direction to the conveying direction.

6. In the extruder according to claim 1, An extruder in which the downstream end of the second screw in the direction of conveying the resin material is provided with another reverse conveying section that conveys the resin material in the opposite direction to the conveying direction.

7. In the extruder according to claim 6, The other reverse conveying unit is an extruder that conveys the resin material while kneading it.

8. In the extruder according to claim 1, An extruder in which at least one of the first cylinder and the second cylinder is provided with a temperature changing unit capable of changing the temperature of the resin material.

9. In the extruder according to claim 1, An extruder in which, in the conveying section, the valley portion having the valley diameter and the peak portion having the peak diameter are arranged in the radial direction of the first screw.

10. In the extruder according to claim 9, The aforementioned valley portion is provided in an annular shape, An extruder in which the aforementioned peaks protrude radially outward from a part of the circumferential direction of the aforementioned valleys.

11. In the extruder according to claim 9, An extruder in which the aforementioned valleys and peaks are provided in multiple locations in the circumferential direction of the first screw.

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