Screw machinery

Abstract

An extruder includes a pair of connecting parts. The pair of connecting parts coaxially connect the ends of a pair of output shafts of a speed reduction part and the ends of a pair of screws respectively. The connecting part has: a coupling member having an insertion hole into which the end of the screw and the shaft part of the output shaft are inserted; a locking part which is installed at the end of the output shaft and has an outer diameter larger than that of the end of the output shaft. The coupling member has: a first accommodating part which accommodates the end of the output shaft; a second accommodating part which has an inner diameter larger than that of the first accommodating part and accommodates the locking part; a stepped part which is formed between the first accommodating part and the second accommodating part. The stepped part of the insertion hole is locked to the locking part, thereby restricting the relative movement of the coupling member with respect to the output shaft.

Description

Technical Field

[0001] The present invention relates to a screw machine. Background Art

[0002] In Japanese Patent Laid-Open Publication No. 2008-168459, a twin-screw kneading extruder having two screws is disclosed. In this twin-screw kneading extruder, the two screws are respectively connected to the output shaft of a speed reducer via shaft joints, and the speed reducer is connected to an electric motor. Summary of the Invention

[0003] Regarding the connecting portion (joint) that connects the screw and the output shaft of the speed reducer, it is required to connect the screw and the output shaft in a manner that does not move relative to each other in the axial direction. As a structure of the above connecting portion, for example, there is a structure in which a connector provided over the screw and the output shaft is threadedly fastened to the screw and the output shaft by a nut.

[0004] On the other hand, for screw machines, there is a requirement for increasing the torque of the driving torque of the screw. In order to increase the driving torque of the screw, it is necessary to increase the diameter of the output shaft of the reduction portion that transmits the torque of the driving portion to the screw. When the diameter of the output shaft is increased, the nut of the connecting portion is also increased accordingly.

[0005] Here, in a screw machine (extruder) having a pair of screws disclosed in Japanese Patent Laid-Open Publication No. 2008-168459, the axial distance between the pair of screws is determined according to the screw shape and the like, and there is a limit to the space between the screws.

[0006] Therefore, when the connecting portions that respectively connect the two screws and the output shaft of the speed reducer are of a structure in which a nut fastens the connector and the output shaft, interference may occur between the nuts that connect the screw and the output shaft of the speed reducer. Therefore, in the structure of the connecting portion in which the connector and the output shaft are fastened by a nut, there is a limit to increasing the diameter of the output shaft of the speed reducer.

[0007] An object of the present invention is to provide a screw machine that miniaturizes the connecting portion that connects the screw and the output shaft of the reduction portion.

[0008] According to an aspect of the present invention, a screw machine includes: a pair of screws that are arranged in parallel and mesh with each other; a drive unit that rotates and drives the pair of screws around their respective axes; a reduction unit that reduces the rotation of the drive unit and outputs it via a pair of output shafts; a pair of connection units that coaxially connect the ends of the pair of output shafts of the reduction unit and the ends of the pair of screws; the ends of the output shafts have an outer diameter larger than that of the connected ends of the screws, and the connection unit includes: a coupling member having an insertion hole into which the end of the screw and the shaft portion of the output shaft are inserted; a fixing unit that fixes the coupling member and the end of the screw; a locking unit that is mounted on the end of the output shaft and is composed of a plurality of divided pieces divided in the circumferential direction and has an outer diameter larger than that of the end of the output shaft, and the coupling member includes: a first accommodating portion that accommodates the end of the output shaft; a second accommodating portion having an inner diameter larger than that of the first accommodating portion and accommodating the locking unit; a stepped portion that is formed between the first accommodating portion and the second accommodating portion, and the stepped portion of the insertion hole is locked to the locking unit, thereby restricting the relative movement of the coupling member relative to the output shaft in the axial direction of the screw toward the screw. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 FIG. is a plan view showing the overall structure of an extruder according to an embodiment of the present invention.

[0010] Figure 2 FIG. is a cross-sectional view showing the structure around the connection portion of the extruder according to an embodiment of the present invention.

[0011] Figure 3 FIG. is a front view of the locking portion of the extruder according to an embodiment of the present invention.

[0012] Figure 4A FIG. is a view for explaining the assembling method of the connection structure of the extruder according to an embodiment of the present invention, and is a front view of the locking portion as viewed from the A arrow of Figure 2 FIG.

[0013] Figure 4B FIG. is a view for explaining the assembling method of the connection structure of the extruder according to an embodiment of the present invention, and is a front view of the locking portion as viewed from the A arrow of Figure 2 FIG.

[0014] Figure 4C FIG. is a view for explaining the assembling method of the connection structure of the extruder according to an embodiment of the present invention, and is a front view of the locking portion as viewed from the A arrow of Figure 2 FIG.

[0015] Figure 4D FIG. is a view for explaining the assembling method of the connection structure of the extruder according to an embodiment of the present invention, and is a front view of the locking portion as viewed from the A arrow ofFigure 2 The front view of the locking part observed from arrow A.

[0016] Figure 4E The figure for explaining the assembling method of the connecting structure of the extruder related to the embodiment of the present invention, and it is the front view of the locking part observed from arrow A. Figure 2 The front view of the locking part observed from arrow A. Detailed Embodiment

[0017] Hereinafter, with reference to the drawings, the screw machine related to the embodiment of the present invention will be described. In addition, in each drawing, for the convenience of explanation, the scale of each structure is appropriately changed and is not necessarily strictly illustrated. In addition, for a plurality of identical structures, only a part of them are labeled, and sometimes the symbols for other parts are omitted.

[0018] The screw machine of the present embodiment is an extruder that kneads while conveying granular or powdery materials supplied into the threaded holes 21 of the barrel 20 by the screws 10a and 10b, and extrudes the kneaded materials from the discharge port 23 of the barrel 20 to form. Hereinafter, the screw machine of the present embodiment will be described as the "extruder 100".

[0019] As Figure 1 shown, the extruder 100 includes: a pair of screws 10a and 10b; a barrel 20 having threaded holes 21 into which the pair of screws 10a and 10b are inserted; an electric motor 30 as a driving part that rotates the pair of screws 10a and 10b in the threaded holes 21; and a reduction part 40 that decelerates the rotation of the electric motor 30 and transmits it to the pair of screws 10a and 10b. In this way, the extruder 100 is a so-called twin-screw kneading extruder having a pair of screws 10a and 10b.

[0020] The barrel 20 is a cylindrical member formed to extend in one direction and having screw holes 21 formed along its long side direction.

[0021] At one end in the long side direction of the barrel 20, a supply port 22 for supplying materials into the screw holes 21 is formed to open in the screw holes 21. At the other end in the long side direction of the barrel 22, a discharge port 23 for discharging the kneaded material generated from the melted and kneaded materials is formed to open in the screw holes 21. Hereinafter, the side of the supply port 22 in the screw holes 21 ( Figure 1 the right side in Figure 1 the figure) is also referred to as the "upstream" of the screw holes 21, and the side of the discharge port 23 (

[0022] In addition, although not shown in the drawings, in the barrel 20, there are provided a heating device for heating the barrel 20, a cooling device for cooling the barrel 20, a vacuum device for volatilization, a temperature sensor for detecting the temperature of the barrel 20, and the like.

[0023] A pair of screws 10a and 10b have the same shape as each other and are arranged so as to extend parallel to each other with a predetermined interval between their central axes. The pair of screws 10a and 10b are inserted into the screw holes 21 of the barrel 20 in a state of being engaged with each other. The pair of screws 10a and 10b are rotated in the same direction around their respective central axes (axes) by an electric motor 30. That is, the pair of screws 10a and 10b rotate synchronously with each other. Hereinafter, the pair of screws 10a and 10b will be simply referred to as "screw 10" in a general sense, and the specific structure will be described.

[0024] The screw 10 is a shaft member that is arranged from the base end connected to the electric motor 30 toward the tip end along the long side direction of the barrel 20 via a reduction unit 40. The base end of the screw 10 is located upstream of the screw hole 21, and the tip end is located downstream of the screw hole 21.

[0025] The screw 10 has a spiral flight 11 (screw blade) on its outer periphery. The material supplied from the supply port 22 to the screw hole 21 is transferred toward the downstream side by the rotating screw 10. The material transferred toward the downstream side is melted and kneaded by a kneading unit (not shown) provided on the screw 10 and composed of a plurality of kneading discs or the like. The material melted by the kneading unit is extruded from the discharge port 23 and ejected outside the barrel 20.

[0026] The operation of the electric motor 30 is controlled by a controller (not shown). The motor shaft 31 of the electric motor 30 is connected to the reduction unit 40, and the rotation of the motor shaft 31 is transmitted to the pair of screws 10a and 10b via the reduction unit 40. Thereby, the pair of screws 10a and 10b are rotationally driven by the electric motor 30.

[0027] The reduction unit 40 includes a pair of output shafts 41a and 41b, and reduces the rotation of the motor shaft 31 of the electric motor 30 through a gear mechanism (not shown) composed of a plurality of gears and outputs it via the pair of output shafts 41a and 41b. The pair of output shafts 41a and 41b rotate synchronously with each other in the same direction. Since the structure of the gear mechanism of the reduction unit 40 can adopt a known structure, detailed description and illustration are omitted.

[0028] The pair of output shafts 41a and 41b of the reduction unit 40 are coaxially connected to the pair of screws 10a and 10b respectively through a pair of connecting parts 50a and 50b.

[0029] Hereinafter, the connection structure of the pair of screws 10a, 10b and the pair of output shafts 41a, 41b will be specifically described. In addition, the connection structure between one screw 10a and one output shaft 41a and the connection structure between the other screw 10b and the other output shaft 41b are the same structure. Therefore, hereinafter, the pair of screws 10a, 10b will be collectively referred to as "screw 10", the pair of output shafts 41a, 41b will be collectively referred to as "output shaft 41", and the pair of connection parts 50a, 50b will be collectively referred to as "connection part 50", so as to describe the connection structure between the screw 10 and the output shaft 41.

[0030] As Figure 2 shown, the screw 10 and the output shaft 41 are coaxially connected through the connection part 50. A spline 42a is formed on the outer periphery of the end 42 of the output shaft 41 connected to the connection part 50. A spline 12a is formed on the outer periphery of the end 12 of the screw 10 connected to the connection part 50. In the present embodiment, the outer diameter of the end 42 of the output shaft 41 is formed to be larger than the outer diameter of the end 12 of the screw 10.

[0031] The connection part 50 has: a coaxial coupling member 51 having an insertion hole 51a for inserting the end 12 of the screw 10 and the end 42 of the output shaft 41; a fixing part 60 for fixing the coupling member 51 and the end 12 of the screw 10; a locking part 70 mounted on the end 42 of the output shaft 41; and a stopper 80 mounted on the end 42 of the output shaft 41 and capable of abutting against the end 12 of the screw 10 in the axial direction.

[0032] The insertion hole 51a of the coupling member 51 is a through hole opening at both axial ends of the coupling member 51 and is formed coaxially with the screw 10 and the output shaft 41. The coupling member 51 has: a first accommodating part 52 for accommodating the end 42 of the output shaft 41; a second accommodating part 53 having a larger inner diameter than the first accommodating part 52 and accommodating the locking part 70; and a third accommodating part 54 for accommodating the end 12 of the screw 10. The first accommodating part 52, the second accommodating part 53, and the third accommodating part 54 are arranged in sequence from the reduction part 40 side toward the screw 10 side ( Figure 2 from the right side to the left side in

[0033] The inner peripheral surface 52a of the first housing portion 52 is spline-coupled to the spline 42a of the end portion 42 of the output shaft 41. Thus, the rotating force of the output shaft 41 is transmitted to the coupling member 51 via the spline coupling, and the coupling member 51 rotates along with the rotation of the output shaft 41.

[0034] A part of the inner peripheral surface 54a of the third housing portion 54 is spline-coupled to the spline 12a of the end portion 12 of the screw 10. Thus, the rotating force of the coupling member 51 is transmitted to the screw 10 via the spline coupling, and further, the rotating force of the output shaft 41 is transmitted to the screw 10, and the screw 10 rotates along with the rotation of the output shaft 41.

[0035] The inner diameter D2 of the second housing portion 53 is formed to be larger than the inner diameter D1 of the first housing portion 52, and further larger than the inner diameter D3 of the third housing portion 54 (D2 > D1 > D3). In addition, the outer diameter of the end portion 42 of the output shaft 41 is substantially the same as the inner diameter D1 of the first housing portion 52. The outer diameter of the locking portion 70 is substantially the same as the inner diameter D2 of the second housing portion 53. The outer diameter of the end portion 12 of the screw 10 is substantially the same as the inner diameter D3 of the third housing portion 54. Thus, hereinafter, they are also referred to as "the outer diameter D1 of the end portion 42 of the output shaft 41", "the outer diameter D2 of the locking portion 70", and "the outer diameter D3 of the end portion 12 of the screw 10".

[0036] As Figure 3 shown, the locking portion 70 is configured as an annular shape having a central hole 70a by a plurality of divided pieces divided in the circumferential direction. The locking portion 70 has an outer diameter D2 larger than the outer diameter D1 of the end portion 42 of the output shaft 41, and a part of the radially outer side thereof faces the stepped portion 55 of the coupling member 51.

[0037] As Figure 2 shown, the locking portion 70 is mounted on the top end of the output shaft 41 by a limiting member 80. The limiting member 80 has: a cylindrical convex column portion 81 that is inserted through the central hole 70a of the locking portion 70; and a flange portion 82 that is provided at the end of the convex column portion 81 and has an outer diameter larger than that of the convex column portion 81. The end portion of the convex column portion 81 opposite to the flange portion 82 abuts against the end face of the output shaft 41. The outer diameter of the flange portion 82 is smaller than the inner diameter of the insertion hole 51a in the third housing portion 54. That is, the outer diameter of the flange portion 82 is smaller than the outer diameter D2 of the locking portion 70.

[0038] The limiting member 80 is mounted on the end portion 42 of the output shaft 41 by a bolt (not shown). Thereby, the locking portion 70 is clamped between the end face of the output shaft 41 and the flange portion 82 of the limiting member 80 and is mounted on the output shaft 41. The locking portion 70 and the flange portion 82 may be configured to always abut, or a gap may be provided between the locking portion 70 and the flange portion 82. The end face of the flange portion 82 is formed as a circular flat surface and faces the end face of the screw 10.

[0039] AsFigure 3 As shown, the locking portion 70 is composed of a plurality of divided pieces obtained by dividing an annular ring member having a predetermined plate thickness in the circumferential direction. In the present embodiment, the locking portion 70 is composed of three divided pieces, namely, a first divided piece 71, a second divided piece 72, and a third divided piece 73.

[0040] The first divided piece 71, the second divided piece 72, and the third divided piece 73 are formed in a substantially fan shape, and each has: outer peripheral arc portions 71a, 72a, 73a, which form a part of the circular outer peripheral surface of the locking portion 70; inner peripheral arc portions 71b, 72b, 73b, which form a part of the inner peripheral surface of the central hole 70a of the locking portion 70. The dimensions L1, L2, L3 of the first divided piece 71, the second divided piece 72, and the third divided piece 73 with respect to the chords of the respective outer peripheral arc portions 71a, 72a, 73a are formed to be equal to or less than the inner diameter D3 of the third accommodating portion 54 (L1≤D3, L2≤D3, L3≤D3). In other words, the maximum dimensions L1, L2, L3 in the outer shapes of the first divided piece 71, the second divided piece 72, and the third divided piece 73 are formed to be equal to or less than the inner diameter D3 of the third accommodating portion 54. Thereby, the first divided piece 71, the second divided piece 72, and the third divided piece 73 can be accommodated in the insertion hole 51a from the screw 10 side in a posture where the central axis of the central hole 70a of the locking portion 70 and the central axis of the insertion hole 51a of the coupling member 51 are parallel.

[0041] The first divided piece 71 and the second divided piece 72 are formed in the same shape as each other. The dimension L3 of the third divided piece 73 with respect to the chord of the outer peripheral arc portion 73a is smaller than the dimensions L1, L2 of the chords of the first divided piece 71 and the second divided piece 72 (L1 = L2>L3). The third divided piece 73 has a pair of parallel portions 73c, 73d that are arranged in parallel with each other at a distance smaller than the inner diameter of the central hole 70a of the locking portion 70. That is, the dimension L3 of the third divided piece 73 with respect to the chord of the outer peripheral arc portion 73a is smaller than the inner diameter D4 of the central hole 70a of the locking portion 70 (D4>L3). The pair of parallel portions 73c, 73d are planes opposed to the first divided piece 71 and the second divided piece 72, and connect the outer peripheral arc portion 73a and the inner peripheral arc portion 73b of the third divided piece 73.

[0042] In addition, on the first split piece 71 and the second split piece 72, a flat portion 71c, 72c and a chamfered portion 71d, 72d are respectively provided, wherein the flat portions 71c, 72c are in surface contact with the parallel portions 73c, 73d of the third split piece 73; the chamfered portions 71d, 72d are formed perpendicular to the flat portions 71c, 72c in a manner intersecting the flat portions 71c, 72c. By providing the chamfered portions 71d, 72d, it is possible to prevent the generation of stress concentration without making the end of one of the first split piece 71 and the second split piece 72 into a sharpened shape (so-called pin angle). In addition, by providing the chamfered portions 71d, 72d, the dimensions L1, L2 with respect to the chords of the outer peripheral arc portions 71a, 72a are shortened, and thus, it is easy to insert the first split piece 71 and the second split piece 72 into the insertion hole 51a.

[0043] As Figure 2 shown, the fixing portion 60 has: a split collar 61 which is mounted on an annular recess 12b formed on the outer periphery of the end portion 12 of the screw 10; a nut 62 which connects the end portion 12 of the screw 10 and the connector 51 via the split collar 61.

[0044] The split collar 61 is a ring member having a shape divided in the circumferential direction and capable of expanding and contracting in the radial direction. The split collar 61 is configured to have an outer diameter larger than the outer diameter D3 of the end portion 12 of the screw 10 in a state of being mounted on the outer periphery of the end portion 12 of the screw 10. The split collar 61 is axially locked with respect to the recess 12b of the screw 10.

[0045] On the outer periphery of the third receiving portion 54 of the connector 51, an external thread portion 54b that engages with the nut 62 is formed. On the inner periphery of the nut 62, a seating portion 63 that abuts axially with respect to the split collar 61 is formed. By screwing the nut 62 with the external thread portion 54b of the connector 51 in a state where the seating portion 63 of the nut 62 abuts against the split collar 61 and tightening with a predetermined tightening force, the screw 10 and the connector 51 are threadedly fastened via the nut 62 and the split collar 61. In this way, the screw 10 is fixed to the connector 51 by the fixing portion 60.

[0046] Next, mainly with reference to Figures 4A to 4E , a method of connecting the screw 10 and the output shaft 41 in the present embodiment will be described. In addition, in Figures 4A to 4E , the up-and-down direction in the drawing represents the up-and-down direction in the vertical direction. In addition, Figures 4A to 4E the dashed line in

[0047] In order to connect the screw 10 and the output shaft 41, first, the end 42 of the output shaft 41 is inserted into the first receiving portion 52 of the coupling member 51, and the output shaft 41 and the coupling member 51 are spline-coupled.

[0048] Next, the locking portion 70 is received in the second receiving portion 53 of the coupling member 51. Specifically, as Figure 4A and Figure 4B shown, in a state where the opening for arranging the third split piece 73 faces downward relatively, the first split piece 71 and the second split piece 72 are inserted into the insertion hole 51a from the other side (the screw 10 side). At this time, the maximum dimensions L1 and L2 of the first split piece 71 and the second split piece 72 are smaller than the inner diameter D3 of the third receiving portion 54. Therefore, as Figure 4A shown, in a state where it is received in the second receiving portion 53 (the posture Figure 2 shown), it can be easily inserted into the insertion hole 51a from the screw 10 side.

[0049] Next, as Figure 4C shown, in the insertion hole 51a, the first split piece 71 and the second split piece 72 are rotated 180° around the central axis of the insertion hole 51a, and the opening for arranging the third split piece 73 is arranged upward relatively. In this state, the flat portions 71c and 72c of the first split piece 71 and the second split piece 72 are arranged along the vertical direction. In addition, the third split piece 73 is inserted into the insertion hole 51a and arranged between the first split piece 71 and the second split piece 72, thereby forming an annular locking portion 70.

[0050] Here, a pair of parallel portions 73c and 73d are provided on the third split piece 73, and flat portions 71c and 72c are provided on the first split piece 71 and the second split piece 72. Therefore, first, as Figure 4D shown, the third split piece 73 is inserted between the first split piece 71 and the second split piece 72 from near the radial center of the insertion hole 51a, and then the third split piece 73 is moved radially outward ( Figure 4D the upper side in the figure), so that it can be arranged between the first split piece 71 and the second split piece 72. In this way, by inserting the third split piece 73 into the insertion hole 51a once from near the center of the insertion hole 51a and then moving the third split piece 73 in the radial direction, the third split piece 73 can be arranged at a predetermined position, and the locking portion 70 having an outer diameter larger than the inner diameters of the first receiving portion 52 and the third receiving portion 54 can be easily formed.

[0051] Next, as Figure 4EAs shown, the first split piece 71, the second split piece 72, and the third split piece 73 are rotated 180° about the central axis of the insertion hole 51a, and the third split piece 73 is relatively disposed below. Thereby, even without support, the first split piece 71, the second split piece 72, and the third split piece 73 do not disperse, and the shape of the annular locking portion 70 can be maintained.

[0052] Next, the stopper 80 is inserted into the insertion hole 51a, and the stud portion 81 of the stopper 80 is inserted into the central hole 70a of the locking portion 70 (refer to Figure 2 ). In this state, the stopper 80 is attached to the output shaft 41 by a bolt. Thereby, the locking portion 70 is attached to the output shaft 41 by the stopper 80.

[0053] Next, the nut 62 is inserted into the outer periphery of the end portion 12 of the screw 10, and then the snap ring 61 is attached to the outer periphery of the end portion 12 of the screw 10. The end portion 12 of the screw 10 having the nut 62 and the snap ring 61 attached to its outer periphery is inserted into the insertion hole 51a of the coupling member 51 until it abuts against the stopper 80, and the screw 10 and the coupling member 51 are spline-coupled.

[0054] Next, the nut 62 is threadedly fastened to the coupling member 51 with a predetermined tightening force, thereby fixing the screw 10 and the coupling member 51.

[0055] As described above, the screw 10 and the output shaft 41 are connected by the connecting portion 50. Thereby, the movement of the screw 10 in the axial direction toward the output shaft 41 is restricted by the abutment of the screw 10 against the stopper 80. In addition, the movement of the screw 10 in the direction away from the output shaft 41 is restricted by the step portion 55 of the coupling member 51 being caught by the outer periphery of the locking portion 70 attached to the output shaft 41. In this way, the screw 10 and the output shaft 41 are connected by the connecting portion 50 so as not to relatively move in the axial direction. Thereby, it is possible to prevent deviations in the meshing of the pair of screws 10a and 10b and interference between the screws 10a and 10b due to the relative movement of the screws 10a and 10b in the axial direction.

[0056] In addition, since the screw 10 and the output shaft 41 are axially locked by the step portion 55 inside the coupling member 51 and the locking portion 70 housed in the coupling member 51, it is possible to suppress the radial enlargement of the connecting portion 50. Therefore, in order to increase the driving torque of the screw 10 to a high torque, it is easy to increase the diameter of the output shaft 41.

[0057] In addition, in the present embodiment, the outer diameter D1 of the end portion 42 of the output shaft 41 of the decelerating portion 40 is larger than the outer diameter D3 of the end portion 12 of the screw 10. Therefore, in order to engage the stepped portion 55 and the engaging portion 70 on the inner circumference of the coupling member 51, the outer diameter D2 of the engaging portion 70 is set to be larger than the outer diameter D1 of the end portion 42 of the output shaft 41, and thus larger than the outer diameter D3 of the end portion 12 of the screw 10 (D2 > D1 > D3). In contrast, since the engaging portion 70 has a shape formed by a plurality of segmented pieces divided in the circumferential direction, even when the outer diameter of the engaging portion 70 is larger than the outer diameter D3 (inner diameter D3 of the third accommodating portion 54) of the end portion 12 of the screw 10, it can be easily inserted into the insertion hole 51a and easily assembled.

[0058] Next, a modified example of the present embodiment will be described. The following modified examples are also within the scope of the present invention, and the structures of the following modified examples can be combined with those of the above-described embodiment or the following modified examples can be combined with each other. In addition, in each modified example, the same reference numerals are given to the same structures as those in the above-described embodiment, and the description thereof is omitted.

[0059] In the above-described embodiment, the screw machine is a so-called twin-screw kneading extruder including a pair of screws 10a and 10b. In contrast, the screw machine only needs to include at least a pair of screws, and may be a multi-screw extruder including three or more screws.

[0060] In addition, in the above-described embodiment, the screw machine is an extruder 100 that kneads and extrudes materials. In contrast, the screw machine may also be a multi-screw material feeder (side feeder) that supplies materials to the extruder 100. The screws of the material feeder do not have a kneading portion and transfer the materials without kneading and melting them.

[0061] In addition, in the above-described embodiment, the pair of screws 10a and 10b rotate in the same direction with respect to each other. In contrast, the pair of screws 10a and 10b may rotate in opposite directions with respect to each other.

[0062] In addition, in the above-described embodiment, the engaging portion 70 is formed by three segmented pieces and is configured as an annular shape in which the entire circumference in the circumferential direction contacts the coupling member 51. In contrast, the engaging portion 70 may be formed by two segmented pieces or four or more segmented pieces. In addition, the engaging portion 70 may also have the following structure, that is, for example, it is formed in a shape having a gap between the circumferences of the segmented pieces, and only a part of the circumference contacts the coupling member 51. In addition, although in the above-described embodiment, the engaging portion 70 is formed by three segmented pieces and the third segmented piece 73 has a different shape from the first segmented piece 71 and the second segmented piece 72, each segmented piece may also be formed in the same shape as each other to form the engaging portion 70.

[0063] Next, the effects of this embodiment will be described.

[0064] The extruder 100 includes: a pair of screws 10 that are arranged in parallel and mesh with each other; an electric motor 30 that rotatably drives each of the pair of screws 10 about an axis; a reduction unit 40 that reduces the rotation of the electric motor 30 and outputs it via a pair of output shafts 41; a pair of connection units 50 that coaxially connect the ends 42 of the pair of output shafts 41 of the reduction unit 40 and the ends 12 of the pair of screws 10; the end 42 of the output shaft 41 has an outer diameter larger than that of the end 12 of the connected screw 10, and the connection unit 50 includes: a coupling member 51 having an insertion hole 51a into which the end 12 of the screw 10 and the shaft portion 42 of the output shaft 41 are inserted; a fixing unit 60 that fixes the coupling member 51 and the end 12 of the screw 10; a locking unit 70 that is mounted on the end 42 of the output shaft 41 and is composed of a plurality of divided pieces divided in the circumferential direction and has an outer diameter larger than that of the end 42 of the output shaft 41, and the coupling member 51 includes: a first housing portion 52 that houses the end 42 of the output shaft 41; a second housing portion 53 that has an inner diameter larger than that of the first housing portion 52 and houses the locking unit 70; a stepped portion 55 that is formed between the first housing portion 52 and the second housing portion 53, and the stepped portion 55 of the insertion hole 51a is locked to the locking unit 70, thereby restricting the relative movement of the coupling member 51 with respect to the output shaft 41 in the direction of the axis of the screw 10 toward the screw 10.

[0065] In addition, in the extruder 100, the connection unit 50 further includes a stopper 80 that is mounted on the end 42 of the output shaft 41 and faces the end 12 of the screw 10, and the locking unit 70 is clamped by the stopper 80 and the end 42 of the output shaft 41 and is mounted on the output shaft 41.

[0066] According to such an extruder 100, the locking unit 70 composed of a plurality of divided pieces has an outer diameter larger than that of the output shaft 41. By inserting the locking unit 70 into the insertion hole 51a of the coupling member 51 and locking it to the stepped portion 55 of the insertion hole 51a, the relative movement of the output shaft 41 and the coupling member 51 in the direction toward the screw 10 is restricted. In this way, since the structure for restricting the relative movement of the output shaft 41 and the coupling member 51, and further restricting the relative movement of the output shaft 41 and the screw 10 is formed inside the coupling member 51, the structure of the connection unit 50 can be miniaturized.

[0067] In addition, in the extruder 100, the locking unit 70 is formed in a ring shape and is locked to the stepped portion 55 of the coupling member 51 so as to cover the entire circumference of the output shaft 41.

[0068] In this structure, the contact area between the locking portion 70 and the stepped portion 55 of the insertion hole 51a can be sufficiently ensured, so that the locking portion 70 and the stepped portion 55 can be more reliably locked.

[0069] In addition, in the extruder 100, the locking portion 70 is configured as an annular shape having a central hole 70a by three split pieces, namely, a first split piece 71, a second split piece 72, and a third split piece 73.

[0070] In addition, in the extruder 100, the coupling member 51 further has a third housing portion 54 that is connected to the second housing portion 53 and houses the end portion 12 of the screw 10. The first split piece 71, the second split piece 72, and the third split piece 73 each have outer peripheral arc portions 71a, 72a, and 73a that form a part of the circular outer peripheral surface of the locking portion 70, and the dimensions L1, L2, and L3 with respect to the chords of the outer peripheral arc portions 71a, 72a, and 73a are formed to be equal to or less than the inner diameter of the third housing portion 54. The first split piece 71 and the second split piece 72 have the same shape as each other. The third split piece 73 has: an inner peripheral arc portion 73b that forms a part of the inner peripheral surface of the central hole 70a of the locking portion 70; and a pair of parallel portions 73c, 73d that are parallel to the central axis of the central hole 70a and are arranged in parallel with each other at an interval smaller than the inner diameter of the central hole 70a, and connect the outer peripheral arc portion 73a and the inner peripheral arc portion 73b.

[0071] In this structure, since the third split piece 73 has a pair of parallel portions 73c, 73d, first, the first split piece 71 and the second split piece 72 are inserted into the insertion hole 51a, and then, after the third split piece 73 is inserted into the insertion hole 51a, the third split piece 73 is moved radially outward along the parallel portions 73c, 73d to form the locking portion 70. According to this structure, the locking portion 70 having a larger outer diameter than the output shaft 41 can be easily assembled in the insertion hole 51a.

[0072] The embodiments of the present invention have been described above. However, the above embodiments merely represent a part of the application examples of the present invention, and do not mean to limit the technical scope of the present invention to the specific structures of the above embodiments.

[0073] This application claims priority based on Japanese Patent Application No. 2020-211738 filed with the Japan Patent Office on December 21, 2020, and the entire contents of this application are incorporated herein by reference.

Claims

1. A screw machine, comprising: A pair of screws, which are arranged in parallel and mesh with each other; A drive unit for rotationally driving the pair of screws around their respective axes; A reduction unit that reduces the rotation of the drive unit and outputs it via a pair of output shafts; A pair of connecting parts that coaxially connect the ends of the pair of output shafts of the reduction unit and the ends of the pair of screws respectively; The end of the output shaft has an outer diameter larger than that of the end of the connected screw; The connecting part has: A coupling member having an insertion hole into which the end of the screw and the shaft part of the output shaft are inserted; A fixing part for fixing the coupling member and the end of the screw; A locking part, which is installed at the end of the output shaft and is composed of a plurality of divided pieces divided in the circumferential direction, and has an outer diameter larger than that of the end of the output shaft; The coupling member has: A first accommodating part for accommodating the end of the output shaft; A second accommodating part having an inner diameter larger than that of the first accommodating part and for accommodating the locking part; A stepped part formed between the first accommodating part and the second accommodating part; The stepped part of the insertion hole is locked to the locking part, thereby restricting the relative movement of the coupling member relative to the output shaft in the direction of the axis of the screw towards the screw.

2. The screw machine according to claim 1, wherein, The connecting part further has a limiting member installed at the end of the output shaft and opposed to the end of the screw, The locking part is clamped by the limiting member and the end of the output shaft and is installed on the output shaft.

3. The screw machine according to claim 1, wherein, The locking part is formed in a ring shape and is locked to the stepped part of the coupling member over the entire circumference of the output shaft.

4. The screw machine according to claim 3, wherein, The locking part is formed into a circular ring shape with a central hole by the three divided pieces, namely the first divided piece, the second divided piece, and the third divided piece.

5. The screw machine according to claim 4, wherein, The coupling member further has a third accommodating part connected to the second accommodating part and for accommodating the end of the screw, The first divided piece, the second divided piece, and the third divided piece respectively have an outer circumferential arc part that constitutes a part of the circular outer circumferential surface of the locking part, and the dimension relative to the chord of the outer circumferential arc part is formed to be equal to or less than the inner diameter of the third accommodating part, The first divided piece and the second divided piece have the same shape, The third divided piece has: An inner circumferential arc part that constitutes a part of the inner circumferential surface of the central hole of the locking part; A pair of parallel parts that are parallel to the central axis of the central hole and are arranged parallel to each other with a distance smaller than the inner diameter of the central hole, and connect the outer circumferential arc part and the inner circumferential arc part.

Images