Synchromesh triangular rotor plasticizing transportation method and device

Abstract

The invention provides a synchromesh triangular rotor plasticizing transportation method and device. According to the method, a material conveying volume formed by two or three triangular rotors with spiral structures and the inner surface of the machine barrel is periodically separated and folded in the radial direction and is periodically compressed and released and forcibly propelled in the axial direction, and mass and heat transfer, melting plasticizing and positive displacement conveying of materials are achieved in the meshing rotation process of the triangular rotors. The device is composed of two or three triangular rotors, a machine barrel and a power assembly, each triangular rotor is composed of a triangular rotor shaft and a triangular rotor body, each triangular rotor body is of a spiral structure with the cross section being a Reuleaux triangle, and the screw pitches of the axial corresponding positions of the two or three triangular rotor bodies are equal; an inner cavity of the machine barrel is a straight hole without a spiral structure, the two or three triangular rotor bodies are meshed in the inner cavity of the machine barrel, and the triangular rotor shafts are respectively connected with the power assembly. According to the invention, radial and axial normal stress effects can be applied to materials, and a positive displacement conveying effect is provided, so that the materials can be quickly compacted, exhausted, subjected to mass and heat transfer, fused and plasticized, and finally quantitatively and forcibly discharged.

Description

Technical Field

[0001] This invention relates to the field of polymer plasticizing and transporting technology, and more specifically, to a method and apparatus for plasticizing and transporting synchronously meshing triangular rotors. Background Technology

[0002] Compared to single-screw plasticizing and conveying methods, twin-screw and triple-screw plasticizing and conveying methods have better mixing, blending, degassing, and plasticizing effects. They have significant advantages in the blending of polymer materials, especially in the blending of filler-filled polymer composite systems. Therefore, twin-screw and triple-screw plasticizing and conveying methods play an important role and hold a significant position in the field of polymer material processing.

[0003] In the field of advanced manufacturing, fused deposition modeling (FDM) technology in additive manufacturing (3D printing) has been widely used in the molding of polymer materials, especially in the molding of complex structural products, and has significant advantages and application prospects in the field of customization. Currently, FDM technology is relatively mature, using filament as raw material. The filament is melt-deposited in the extruder head and then extruded from the nozzle and stacked to form the final product. However, the preparation process of filament, especially polymer composite filament, is complex, requires large equipment, and consumes a lot of energy, resulting in high prices and limiting the development of FDM technology in the molding of polymer products. Furthermore, the short residence time of filament, especially high-viscosity polymer filament, in the extruder head prevents it from fully melting, leading to poor adhesion between printed layers and consequently affecting the performance of the printed product.

[0004] In the future, the direct output of molten and plasticized material from the extruder into the 3D printing extruder head, eliminating the need for filament preparation and achieving one-stop 3D printing from resin to finished product, will be an inevitable trend in the field of FDM technology. This will not only save on filament preparation costs but also reduce the overall molding cycle from resin to finished product in 3D printing technology. However, current twin-screw and triple-screw extruders cannot meet the needs of one-stop 3D printing technology. On the one hand, the screw plasticizing method relies on the dragging and shearing action generated by the screw rotation to achieve material melting, plasticizing, and conveying, which suffers from poor dispersion and mixing effects, slow mass and heat transfer, long thermomechanical paths, and high energy consumption, and is highly dependent on the viscoelasticity of polymer materials. On the other hand, the screw conveying method relies on viscous dragging action and lacks positive displacement conveying and metering output capabilities. These problems hinder the realization of one-stop 3D printing technology.

[0005] To address the current shortcomings in the field of polymer material processing and the development needs of the 3D printing field, this study aims to develop a plasticizing and transporting method and device with short thermomechanical process, low energy consumption, and precise metering output. This method will significantly improve the mixing efficiency and dispersion effect of polymer material composite systems, promote the realization of one-stop 3D printing technology in the field of advanced manufacturing, and has important significance for the development of the polymer material processing and molding field. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, the purpose of this invention is to provide a synchronous meshing triangular rotor plasticizing and conveying method and apparatus to solve the problems of long thermomechanical process, high energy consumption, poor dispersion effect and weak conveying capacity in traditional twin-screw and triple-screw plasticizing and conveying methods.

[0007] To achieve the above objectives, the present invention adopts the following technical solution.

[0008] A synchronous meshing triangular rotor plasticizing and conveying method: The material conveying volume formed by two or three triangular rotors with helical structures and the inner surface of the barrel is periodically separated and closed radially, and periodically compressed and released and forcibly propelled axially. During the meshing and rotation of the triangular rotors, the material achieves mass transfer and heat transfer, melting and plasticizing, and positive displacement conveying.

[0009] A synchronous meshing triangular rotor plasticizing and conveying device for implementing the above method: comprising two or three triangular rotors, a barrel, and a power assembly; each triangular rotor consists of a triangular rotor shaft and a triangular rotor body; each triangular rotor body has a Reuleaux triangular cross-section and a helical structure; the pitch of the helical rotors at corresponding axial positions of the two or three triangular rotor bodies is equal; the inner cavity of the barrel is a straight hole without a helical structure; the two or three triangular rotor bodies mesh in the inner cavity of the barrel; and the triangular rotor shafts are respectively connected to the power assembly.

[0010] The straight line formed by the centers of the circumcircles of the Reuleaux triangles of all cross sections of the triangular rotor body is collinear with the axis of the triangular rotor shaft, and is also the central axis of rotation of the triangular rotor.

[0011] Preferably, the acute angle vertices of the triangular rotor are rounded.

[0012] The pitch of the helical structure of the triangular rotor body varies along the axial direction.

[0013] Preferably, the pitch of the helical structure of the triangular rotor body gradually decreases along the axial direction.

[0014] The meshing between the triangular rotor bodies is the contact between the vertex of one triangular rotor body and the arc edge of another triangular rotor body.

[0015] Preferably, there are two triangular rotors: a front triangular rotor and a rear triangular rotor. The front and rear triangular rotor bodies are synchronously meshed in opposite directions within the inner cavity of the barrel. The helical structures at corresponding axial positions of the front and rear triangular rotor bodies rotate in opposite directions, with a phase difference of 30°. The distance between the rotation center axes of the front and rear triangular rotors is equal to the radius of the arc of the triangular rotor body. times.

[0016] Preferably, there are two triangular rotors, namely a first triangular rotor and a second triangular rotor. The bodies of the first triangular rotor and the second triangular rotor are engaged synchronously in the inner cavity of the barrel in the same direction. The spiral structures of the corresponding axial positions of the first triangular rotor and the second triangular rotor have the same direction of rotation and no phase difference. The distance between the rotation center axis of the first triangular rotor and the rotation center axis of the second triangular rotor is equal to the radius of the arc of the triangular rotor body.

[0017] Preferably, there are three triangular rotors: a left triangular rotor, a middle triangular rotor, and a right triangular rotor. The bodies of the left, middle, and right triangular rotors are aligned in a straight line and mesh synchronously in the inner cavity of the barrel. The spiral structures at the corresponding axial positions of the left, middle, and right triangular rotors have the same rotation direction and no phase difference. The distance between the rotation center axes of the left and middle triangular rotors is equal to the radius of the arc of the triangular rotor body, and the distance between the rotation center axes of the middle and right triangular rotors is also equal to the radius of the arc of the triangular rotor body.

[0018] Preferably, there are three triangular rotors: an upper triangular rotor, a lower left triangular rotor, and a lower right triangular rotor. The upper, lower left, and lower right triangular rotor bodies are arranged in a triangle and mesh synchronously in the inner cavity of the barrel. The spiral structures at corresponding axial positions of the upper, lower left, and lower right triangular rotor bodies have the same rotation direction and no phase difference. The distance between the rotation center axes of the upper and lower left triangular rotors is equal to the radius of the arc of the triangular rotor body. The distance between the rotation center axes of the upper and lower right triangular rotors is also equal to the radius of the arc of the triangular rotor body. The distance between the rotation center axes of the lower left and lower right triangular rotors is also equal to the radius of the arc of the triangular rotor body.

[0019] This invention can improve the mixing effect of polymer materials, realize positive displacement conveying and metering output of materials, and has the following advantages and beneficial effects compared with traditional technologies: 1. In the melting and plasticizing process of the present invention, the material is periodically separated and closed in the radial direction and periodically compressed and released in the axial direction, which improves the mass and heat transfer effect and melting and plasticizing efficiency, shortens the thermomechanical process, and reduces the energy consumption of the melting and plasticizing process; 2. This invention has positive displacement conveying capability, realizing forced propulsion for solid conveying and melt transport, improving conveying efficiency and output stability, and reducing conveying energy consumption; 3. The plasticizing and transporting method of the present invention has low sensitivity to material properties, which is beneficial for processing high-viscosity polymer materials and efficient dispersing and mixing fillers; 4. The plasticizing and conveying device of the present invention is short in length and small in size, and can be directly or indirectly connected to the extrusion head of a 3D printer, making it suitable for one-stop 3D printing molding. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the Reuleaux triangle shape of the triangular rotor body.

[0021] Figure 2 This is a schematic diagram of the principle of the dual-axis synchronous meshing triangular rotor plasticizing and conveying device in Embodiment 1.

[0022] Figure 3 yes Figure 2 AA sectional view.

[0023] Figure 4 This is a schematic diagram of the principle of the dual-axis co-directional synchronous fully meshing triangular rotor plasticizing and conveying device in Embodiment 2.

[0024] Figure 5 yes Figure 4 BB section view.

[0025] Figure 6 This is a schematic diagram of the principle of the plasticizing and conveying device of the three-axis co-directional synchronous fully meshing triangular rotor arranged in a straight line, as described in Embodiment 3.

[0026] Figure 7 yes Figure 6 CC section view.

[0027] Figure 8 This is a schematic diagram of the principle of the triangular arrangement of three axes in the same direction, synchronous and fully meshing triangular rotor plasticizing and conveying device in Embodiment 4.

[0028] Figure 9 yes Figure 8 DD section view.

[0029] Figure 10 yes Figure 8 A schematic diagram showing the change in the volume of the cavity between the bodies of the triangular rotors when the triangular rotors rotate synchronously in the same direction.

[0030] Among them, 1 is the front triangular rotor, 11 is the front triangular rotor shaft, 12 is the front triangular rotor body, 2 is the rear triangular rotor, 21 is the rear triangular rotor shaft, 22 is the rear triangular rotor body, 3 is the opposing barrel, 4 is the first triangular rotor, 41 is the first triangular rotor shaft, 42 is the first triangular rotor body, 5 is the second triangular rotor, 51 is the second triangular rotor shaft, 52 is the second triangular rotor body, 6 is the co-directional barrel, 7 is the left triangular rotor, 71 is the left triangular rotor shaft, 72 is the left triangular rotor body, and 8 is the middle triangular rotor. Rotor, 81 is the middle triangular rotor shaft, 82 is the middle triangular rotor body, 9 is the right triangular rotor, 91 is the right triangular rotor shaft, 92 is the right triangular rotor body, 10 is the straight-line barrel, 11 is the upper triangular rotor, 111 is the upper triangular rotor shaft, 112 is the upper triangular rotor body, 12 is the lower left triangular rotor, 121 is the lower left triangular rotor shaft, 122 is the lower left triangular rotor body, 13 is the lower right triangular rotor, 131 is the lower right triangular rotor shaft, 132 is the lower right triangular rotor body, 14 is the triangular barrel. R The radius of the arc of the triangular rotor body, O The center of the circumcircle of the triangular rotor body, O 1 represents the center axis of rotation of the front triangular rotor. O 2 is the center axis of rotation of the rear triangular rotor. O 4 represents the rotational center axis of the first triangular rotor. O 5 represents the rotation center axis of the second triangular rotor. O 7 represents the center axis of rotation of the left triangular rotor. O 8 represents the central axis of rotation of the middle triangular rotor. O 9 represents the center axis of rotation of the right triangular rotor. O 11 The axis of rotation of the upper triangular rotor O 12 The center axis of rotation of the lower left triangular rotor. O 13 The center axis of rotation of the lower right triangular rotor. L This represents the distance between the rotation center axes of the triangular rotor. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the following text is only used to describe several specific embodiments of the present invention and does not strictly limit the scope of protection specifically claimed by the present invention.

[0032] Example 1

[0033] like Figures 1-3As shown, the dual-shaft, opposing synchronous meshing triangular rotor plasticizing and conveying device of this embodiment consists of a front triangular rotor 1, a rear triangular rotor 2, opposing barrels 3, and a power assembly. The cross-section of the triangular rotor body is a Reuleaux triangle. The front triangular rotor shaft 11 and the rear triangular rotor shaft 21 are respectively connected to the power assembly. The front triangular rotor body 12 and the rear triangular rotor body 22 are synchronously meshed in the inner cavity of the opposing barrel 3. The front triangular rotor body 12 and the rear triangular rotor body 22 have a finite number of meshing points. The meshing points and the radial clearance between them and the triangular rotor bodies are spaced apart. The helical structures of the front triangular rotor body 12 and the rear triangular rotor body 22 have opposite rotation directions. The phase difference between the front triangular rotor 1 and the rear triangular rotor 2 is 30°. The rotation center axis of the front triangular rotor 1 is... O 1 and the rotation center axis of the rear triangular rotor 2 O The spacing of 2 is The front triangular rotor body 12 and the rear triangular rotor body 22 form cavities with the opposing barrel 3. When the triangular rotors rotate synchronously in opposite directions, the volume of the cavities corresponding to the front triangular rotor body 12 and the rear triangular rotor body 22 is periodically divided and closed in the radial direction, realizing the mass and heat transfer of materials between the cavities. The radial gap between the triangular rotor bodies exhibits a large-small-large cyclic change, causing the material to be subjected to radial periodic normal stress. The volume of the cavities is compressed in the output direction, causing the material to be subjected to axial normal stress. The spiral structure of the triangular rotor body and the forward movement of the meshing point position form a positive displacement conveying effect.

[0034] In this embodiment, under the action of positive displacement conveying, the material is subjected to radial and axial normal stress, which can be quickly compacted, degassed, transferred mass and heat, melted and plasticized, and finally forcibly discharged in a quantitative manner.

[0035] Example 2

[0036] like Figure 4 , Figure 5 As shown, the dual-axis, co-directional, synchronous, fully meshing triangular rotor plasticizing and conveying device of this embodiment consists of a first triangular rotor 4, a second triangular rotor 5, a co-directional barrel 6, and a power assembly. The first triangular rotor shaft 41 and the second triangular rotor shaft 51 are respectively connected to the power assembly. The first triangular rotor body 42 and the second triangular rotor body 52 are synchronously and fully meshed in the inner cavity of the co-directional barrel 6. The first triangular rotor body 42 and the second triangular rotor body 52 have an infinite number of meshing points, and the line connecting the meshing points is a helix. The structure and installation phase of the first triangular rotor body 42 and the second triangular rotor body 52 are the same. The rotation center axis of the first triangular rotor 4 is... O 4 and the central axis of rotation of the rear triangular rotor 5 O 5 spacing L = RThe first triangular rotor body 42 and the second triangular rotor body 52 form cavities with the co-rotating barrel 6. When the triangular rotors rotate synchronously in the same direction, the cavities corresponding to the first triangular rotor body 42 and the second triangular rotor body 52 are periodically divided, closed, and squeezed in the radial direction. The material is subjected to radial periodic normal stress, which quickly realizes the mass and heat transfer of the material. The cavity volume is compressed in the output direction, so that the material is subjected to axial normal stress. The spiral structure of the triangular rotor body and the forward movement of the meshing point position form a positive displacement conveying effect.

[0037] In this embodiment, under the action of positive displacement conveying, the material is subjected to radial and axial normal stress, which can be quickly compacted, degassed, transferred mass and heat, melted and plasticized, and finally forcibly discharged in a quantitative manner.

[0038] Example 3

[0039] like Figure 6 , Figure 7 As shown, the plasticizing and conveying device of the three-axis co-rotor in a straight line arrangement in this embodiment consists of a left triangular rotor 7, a middle triangular rotor 8, a right triangular rotor 9, a straight-line barrel 10, and a power assembly. The left triangular rotor shaft 71, the middle triangular rotor shaft 81, and the right triangular rotor shaft 91 are respectively connected to the power assembly. The left triangular rotor body 72, the middle triangular rotor body 82, the middle triangular rotor body 82, and the right triangular rotor body 92 are co-rotor in a straight line and fully meshed in the inner cavity of the co-rotor barrel 10. The left triangular rotor body 72, the middle triangular rotor body 82, the middle triangular rotor body 82, and the right triangular rotor body 92 all have an infinite number of meshing points, and the lines connecting the meshing points are all helical lines. The structure and installation phase of the left triangular rotor body 72, the middle triangular rotor body 82, and the right triangular rotor body 92 are the same, and the rotation center axes of the three triangular rotors are all on the same plane. The rotation center axis of the left triangular rotor 7 is... O 7 and the central axis of rotation of the middle triangular rotor 8 O The spacing of 8, the central axis of rotation of the triangular rotor 8 O 8 and the right triangular rotor 9 rotate along the central axis O The spacing of 9 is L = R The left triangular rotor body 72, the middle triangular rotor body 82, and the right triangular rotor body 92 form cavities with the straight cylinder 10. When the triangular rotors rotate synchronously in the same direction, the volume of the cavities corresponding to the left triangular rotor body 72, the middle triangular rotor body 82, and the right triangular rotor body 92 is periodically divided, closed, and squeezed radially. The material is subjected to radial periodic normal stress, which quickly realizes the mass and heat transfer of the material. The volume of the cavity is compressed along the output direction, so that the material is subjected to axial normal stress. The spiral structure of the triangular rotor body and the forward movement of the meshing point position form a positive displacement conveying effect.

[0040] In this embodiment, under the action of positive displacement conveying, the material is subjected to radial and axial normal stress, which can be quickly compacted, degassed, transferred mass and heat, melted and plasticized, and finally forcibly discharged in a quantitative manner.

[0041] Example 4

[0042] like Figure 8 , Figure 9 As shown, the triangularly arranged, three-axis, co-directional, synchronous, fully meshing triangular rotor plasticizing and conveying device of this embodiment consists of an upper triangular rotor 11, a lower left triangular rotor 12, a lower right triangular rotor 13, a triangular barrel 14, and a power assembly. The upper triangular rotor shaft 111, the lower left triangular rotor shaft 121, and the lower right triangular rotor shaft 131 are respectively connected to the power assembly. The upper triangular rotor body 112 and the lower left triangular rotor body 122, the upper triangular rotor body 112 and the lower right triangular rotor body 132, and the lower left triangular rotor body 122 and the lower right triangular rotor body 132 are also connected. 2. The three triangular rotors are fully meshed in the same direction and synchronously within the inner cavity of the same-direction barrel 14. They are arranged in a triangular pattern. The upper triangular rotor body 112 and the lower left triangular rotor body 122, the upper triangular rotor body 112 and the lower right triangular rotor body 132, and the lower left triangular rotor body 122 and the lower right triangular rotor body 132 all have an infinite number of meshing points. The lines connecting the meshing points are all helical lines. The upper triangular rotor body 112, the lower left triangular rotor body 122, and the lower right triangular rotor body 132 have the same structure and installation phase. The rotation center axis of the upper triangular rotor 11 is the same. O 11 And the rotation center axis of the lower left triangular rotor 12 O 12 The spacing, the rotation center axis of the upper triangular rotor 11 O 11 And the rotation center axis of the lower right triangular rotor 13 O 13 The axis of rotation of the lower left triangular rotor 12 O 12 And the rotation center axis of the lower right triangular rotor 13 O 13 The spacing is L = R , O 11 , O 12 and O 13 The spacing forms a side with a length of R An equilateral triangle; the upper triangular rotor body 112, the lower left triangular rotor body 122, and the lower right triangular rotor body 132 respectively form cavities with the triangular cylinder 14, such as Figure 10As shown, when the triangular rotors rotate synchronously in the same direction, the volume of the cavity between the upper triangular rotor body 112, the lower left triangular rotor body 122, and the lower right triangular rotor body 132 changes periodically. The material is subjected to radial periodic normal stress, which quickly realizes the mass and heat transfer of the material. The cavity volume is compressed along the output direction, so that the material is subjected to axial normal stress. The spiral structure of the triangular rotor body and the forward movement of the meshing point position form a positive displacement conveying effect.

[0043] In this embodiment, under the action of positive displacement conveying, the material is subjected to radial and axial normal stress, which can be quickly compacted, degassed, transferred mass and heat, melted and plasticized, and finally forcibly discharged in a quantitative manner.

[0044] The above description is merely a preferred embodiment of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention. Structures, devices, and operating methods not specifically described or explained in this invention are implemented according to conventional methods in the art unless otherwise specified or limited.

Claims

1. A synchronized meshing delta rotor plasticating transport method, characterized by, Two or three helical triangular rotors and the material conveying volume formed by the inner surface of the cylinder barrel are periodically separated and closed in the radial direction, periodically compressed and released in the axial direction, and forced to advance, and the material realizes mass and heat transfer, melting and plasticization, and positive displacement conveying during the engagement and rotation of the triangular rotors.

2. A synchronous meshing tri-rotor plasticizing-conveying device for implementing the method of claim 1, characterized in that, The device is composed of two or three triangular rotors, a cylinder barrel, and a power assembly, the triangular rotors are each composed of a triangular rotor shaft and a triangular rotor body, the triangular rotor body is a helical structure with a Lohé triangle cross section, the axial corresponding positions of the two or three triangular rotor bodies have equal helical pitches, the inner cavity of the cylinder barrel is a straight hole without a helical structure, the two or three triangular rotor bodies are engaged in the inner cavity of the cylinder barrel, and the triangular rotor shafts are respectively connected with the power assembly.

3. The apparatus of claim 2, wherein, The straight line formed by the centers of the circumscribed circles of the Lohé triangles of all cross sections of the triangular rotor body is collinear with the axis of the triangular rotor shaft, and is also the center axis of the rotation of the triangular rotor.

4. The apparatus of claim 2, wherein The helical pitch of the helical structure of the triangular rotor body changes in the axial direction.

5. The apparatus of claim 2, wherein, The engagement between the triangular rotor bodies is the contact between the vertex of one triangular rotor body and the arc edge of another triangular rotor body.

6. The device of any one of claims 2-5, wherein, The two triangular rotors are a front triangular rotor and a rear triangular rotor, the front triangular rotor body and the rear triangular rotor body are synchronously engaged in the inner cavity of the barrel, the axial corresponding position helical structures of the front triangular rotor body and the rear triangular rotor body are opposite in rotation direction, the phase difference of the front triangular rotor and the rear triangular rotor is 30°, and the distance between the rotation center axis of the front triangular rotor and the rotation center axis of the rear triangular rotor is 1 / 3 of the arc radius of the triangular rotor body 1 3 + 2 sin 30 ° - a r c sin 1 2 3 .

7. The device of any one of claims 2-5, wherein, The triangular rotors are two, which are a first triangular rotor and a second triangular rotor, the first triangular rotor body and the second triangular rotor body are engaged in the inner cavity of the cylinder barrel in the same direction and synchronously, the axial corresponding positions of the first triangular rotor body and the second triangular rotor body have the same helical direction and no phase difference, and the distance between the center axes of rotation of the first triangular rotor and the second triangular rotor is equal to the arc radius of the triangular rotor body.

8. The device of any one of claims 2-5, wherein, The triangular rotors are three, which are a left triangular rotor, a middle triangular rotor, and a right triangular rotor, the left triangular rotor body, the middle triangular rotor body, and the right triangular rotor body are engaged in the inner cavity of the cylinder barrel in a straight line type, in the same direction and synchronously, the axial corresponding positions of the left triangular rotor body, the middle triangular rotor body, and the right triangular rotor body have the same helical direction and no phase difference, the distance between the center axes of rotation of the left triangular rotor and the middle triangular rotor is equal to the arc radius of the triangular rotor body, and the distance between the center axes of rotation of the middle triangular rotor and the right triangular rotor is also equal to the arc radius of the triangular rotor body.

9. The device of any one of claims 2-5, wherein, The triangular rotors are three, which are an upper triangular rotor, a left lower triangular rotor, and a right lower triangular rotor, the upper triangular rotor body, the left lower triangular rotor body, and the right lower triangular rotor body are engaged in the inner cavity of the cylinder barrel in a triangular shape, in the same direction and synchronously, the axial corresponding positions of the upper triangular rotor body, the left lower triangular rotor body, and the right lower triangular rotor body have the same helical direction and no phase difference, the distance between the center axes of rotation of the upper triangular rotor and the left lower triangular rotor is equal to the arc radius of the triangular rotor body, the distance between the center axes of rotation of the upper triangular rotor and the right lower triangular rotor is also equal to the arc radius of the triangular rotor body, and the distance between the center axes of rotation of the left lower triangular rotor and the right lower triangular rotor is also equal to the arc radius of the triangular rotor body.

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