JP2006226280A - Uniaxial eccentric screw-pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a uniaxial eccentric screw-pump of a 2/3 thread type in which a rotor is almost free of overhang as compared with a pump having a connection structure of a flange type, the entire length of the pump is made short, the pump casing is shortened to have a comparatively small bore, and miniaturization accompanied by weight reduction is achieved. <P>SOLUTION: One end of a flexible rod 6 is formed to have a tapered end part 61 having a gradually reduced outside-diameter in the direction of the tip end. A tapered hole 21b is made in correspond with the tapered end part 61 at the end of the center shaft of the rotor 21. The tapered end part 61 of the flexible rod 6 is inserted in the tapered hole 21b. A tension bolt 7 is inserted from the other end of the rotor through the through hole 21a bored in the center shaft of the rotor 21. The tip end thread 71 of the tension bolt 7 is screwed down in a threaded hole 62 made in the center shaft of the tapered end part 61 of the flexible rod 6. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a structure in which a metal flexible rod and a rotor or a drive shaft of a drive device are connected mainly in a single-shaft eccentric screw pump. The present invention relates to a single-shaft eccentric screw pump including a pump body having a stator having a three-thread female screw hole having an approximately equilateral triangular opening cross section, and a flexible rod that connects a drive shaft of a driving device and the rotor.

  A uniaxial eccentric screw pump is usually a two-thread female screw type stator having a cross-sectionally oblong hole that is continuous in a screw shape in the longitudinal direction, and is fitted into the female screw hole of this stator so as to be slidably rotatable. The pump body has a single-thread male screw type rotor whose pitch is 1/2 of the screw hole, and the rotor revolves in the opposite direction while rotating in one direction and is eccentric about the rotation center axis in the stator. The pumping action is demonstrated by rotating. For this reason, a universal joint is interposed between the drive shaft of the drive unit and the coupling rod that connects the rotor, or the rotor is eccentrically rotated by using a flexible and relatively long coupling rod. Generally, a means for allowing the above is adopted.

  When a metal flexible rod is used for the coupling rod, the connection between the pump rotor and drive shaft and the flexible rod is formed in a tapered shape with the diameter of the flexible rod gradually reduced with the end of the flexible rod facing the tip. A taper hole corresponding to the taper end is provided in the connecting casing having a flange projecting, and the taper end of the flexible rod is fitted into the taper hole, and a bolt penetrating from the end of the connection casing is flexibly provided. The flexible rod and the connecting casing are integrally coupled by screwing and tightening the threaded portion of the rod end. Then, an inward flange provided on the distal end side of the joint case is locked to the flange portion of the connection casing, and the tightening ring on the proximal end side is connected to the step portion formed on the rotor end portion or the drive shaft end portion. A so-called flange method (refer to the connection structure on the flexible rod 6 and drive shaft 42 side in FIG. 4) is proposed or adopted in which the connection is performed by fitting, supporting, and tightening.

As a prior art related to a single-shaft eccentric screw pump in which a rotor and a drive shaft are connected using a flexible rod made of engineering plastic, when connecting the flexible rod and the drive shaft, the end of the flexible rod is formed into a tapered shape, and the drive shaft It is shown that it is inserted into a tapered hole provided at the end and bonded with an adhesive, or a key and a key groove are provided between them (for example, see Patent Document 1).
JP-A-9-264264 (paragraphs 0013, 0016, 0018 and FIGS. 8, 9)

  In the conventional uniaxial eccentric screw pump described above, the flange or the drive shaft connected to the flexible rod has the following problems.

  1. Since the connection casing with flange and the joint case with flange are used, the number of parts is large and the structure is complicated.

2. Disassembling and assembling are complicated because it is necessary to remove the bearing in the bearing casing when inspecting and replacing the mechanical seal and the like.

  3. Due to the flange, the entire device is lengthened.

  4). To connect the flexible rod to the rotor, the tension bolt penetrates from the other end of the rotor, and the taper end of the flexible rod is inserted into the taper hole provided at the end of the rotor to flex the tip threaded portion of the tension bolt. A method of screwing and fastening to the taper end of the rod is conceivable. In this case, in the above-described general 1/2 strip type single-shaft eccentric screw pump, the rotor is long and the eccentric amount is large. Since the diameter of the through hole for the tension bolt that can be drilled in is limited to be small, the screw strength necessary for connection with the flexible rod cannot be sufficiently ensured, which is difficult to implement.

  In addition, in the connection structure described in the above publication, sufficient connection strength cannot be obtained even when a connecting means such as adhesion or key engagement is used when a metal flexible rod is used.

  The present invention has been made in view of the above points. Instead of the above-described general single-shaft eccentric screw pump, the 2 / 3-row single-shaft eccentric screw pump in which the stator has three female screws and the rotor has two male screws. By adopting, the length of the rotor can be shortened because the pressure resistance is improved, and the eccentric amount is also small, so the diameter of the through hole for the tension bolt that can be drilled in the rotor can be increased The screw strength to be fastened with the tension bolt can be sufficiently secured. Furthermore, compared to the flange type connection structure, there is almost no rotor overhang, the pump overall length can be shortened, the pump casing length can be shortened to reduce the diameter, the mechanical seal can be easily disassembled and assembled, and it is compact and lightweight. 2/3 provided with at least one of the flexible rods with a taper-stop tension bolt type connection structure that provides greater mechanical strength than a connection structure using adhesion or key engagement. It is an object of the present invention to provide a strip type single-shaft eccentric screw pump.

  In order to solve the above-mentioned object, a uniaxial eccentric screw pump according to the present invention has a two-thread male screw rotor having an oval cross section and a stator having a three-thread female thread hole having a substantially equilateral triangular opening section into which the rotor is fitted. A uniaxial eccentric screw pump comprising a pump body, a pump casing, a drive shaft connected to a drive device, and a flexible rod for connecting the rotor, wherein at least one end of the flexible rod faces an outer diameter. Is formed in a taper shape that gradually decreases, a taper hole corresponding to the taper end portion is provided in a central shaft portion of the rotor or the drive shaft, and the taper end portion of the flexible rod is inserted into the taper hole. In addition, the tension is passed from the other end of the rotor through the through hole formed in the central shaft portion of the rotor or the drive shaft. And inserting the screw bolt into the screw hole provided in the central shaft portion of the tapered end portion of the flexible rod and fastening the screw to the rotor or the drive shaft and the flexible rod. Is connected.

According to the single-shaft eccentric screw pump according to the present invention having the above-described configuration, the pump main body having a two-thread male screw rotor and a three-thread female thread stator is used. Compared to the male threaded rotor, the length can be shortened, and the diameter of the through hole for the tension bolt drilled in the center of the rotor can be increased, so that sufficient screw strength can be secured at the threaded portion of the tension bolt and rotor. , Not only the drive shaft side but also the rotor side can be connected by the taper tension bolt method, and it is necessary to provide a protrusion to attach the flange to the rotor end or drive shaft end compared to the conventional flange method And there is almost no overhang on the rotor or drive shaft. In particular the bending moment of the rotor can be minimized, thereby improving the discharge performance of the pump is that. Further, since there is no flange and there is no need to provide a projection or the like that engages with the flange, the structure becomes simple, the mechanical seal can be easily disassembled and inspected, and the size and weight can be easily reduced.

  According to a second aspect of the present invention, both end portions of the flexible rod are formed in a tapered shape whose outer diameter gradually decreases toward the tip, and the central end portion of the rotor and the drive shaft corresponds to the tapered end portion. A taper hole is formed, and the taper end of the flexible rod is fitted into the taper hole, and the through hole formed in the central shaft of the rotor and the drive shaft passes through the other end of the rotor. By inserting a tension bolt and screwing and fastening the threaded end of the tension bolt into the screw hole provided in the central shaft of the tapered end of the flexible rod, the rotor and the drive shaft and the flexible The rod can be connected.

  According to the uniaxial eccentric screw pump according to claim 2, since the both ends of the flexible rod and the connection side of the drive shaft and the rotor are each made of a taper tension bolt system, no flange is required on the drive shaft side or the rotor side. Thus, the structure is simplified, the pump casing can be made smaller in diameter, and the size and weight can be easily reduced.

  According to a third aspect of the present invention, it is preferable that a cover that covers a nut that is screwed into the threaded portion of the tension bolt is attached to an end of the rotor opposite to the flexible rod.

  According to the uniaxial eccentric screw pump according to claim 3, since the base end side screw portion of the tension bolt at the rotor end portion and the nut screwed to this are covered with the cover, there is no contact with the liquid to be transferred, and the nut Corrosion of the part can be prevented, and stable use over a long period of time becomes possible.

  The connection position between the end portion of the flexible rod and the rotor central shaft portion or the drive shaft central shaft portion may be any position between the front end position and the base end position of the rotor. Or it can be made into the arbitrary positions between the front-end | tip position of a drive shaft, and a base end position.

  5. The single-shaft eccentric screw pump according to claim 4, wherein the load acting on the stator from the flexible rod on the rotor side is obtained when the connecting position of the flexible rod, the rotor, and the drive shaft is set to an intermediate position in the longitudinal direction of the rotor and the drive shaft, respectively. Since it is applied to the central portion of the stator in the longitudinal direction, the addition to the stator is equalized, leading to a longer life of the stator 22, and on the drive shaft side, the flexible rod acts on the end of the drive shaft. Since the bending moment is supported in the vicinity of the bearing, the load on the drive shaft is reduced. Furthermore, the length of the pump casing, and hence the total length of the pump, is shortened, and space saving is achieved. Furthermore, the total length of the pump can be further shortened by connecting the flexible rod, the rotor, and the drive shaft to the ends of the rotor and the drive shaft opposite to the pump casing, respectively. The position of the connection with the flexible rod is between the tip position and the base end position of the rotor or between the tip position and the base end position of the drive shaft. The most advantageous position is set according to

As described above, the uniaxial eccentric screw pump according to the present invention uses a two-thread male screw type rotor and a three-thread female thread type stator in the pump body, so that when the pump discharge flow rate is the same, the conventional ½ thread type is used. The length of the through hole for the tension bolt drilled in the center of the rotor can be shortened compared to the single-threaded eccentric screw pump rotor of the single-shaft eccentric screw pump. When connecting the tension bolt and the rotor, the screw strength of the screwed part can be secured sufficiently, and not only the drive shaft side but also the rotor side can be connected by the taper tension bolt method, and compared to the flange method There is no need to provide flange mounting flanges at the rotor end or drive shaft end. As a result, the rotor or drive shaft overhang is almost eliminated, so the bending moment of the rotor or drive shaft received from the flexible rod is minimized and the discharge performance is improved. is there.

  Embodiments of a uniaxial eccentric screw pump according to the present invention will be described below with reference to the drawings.

  1 is a cross-sectional view showing an embodiment of a uniaxial eccentric screw pump, FIG. 2 is an enlarged cross-sectional view showing one end portion of the rotor of FIG. 1, and FIG. 3 is a view taken in the direction of arrow A in FIG.

  As shown in FIG. 1, a uniaxial eccentric screw pump 1 of this example includes a uniaxial eccentric screw pump body 2 on one side (left side in the figure), and a pump casing 3, a bearing device 4 and a drive motor (not shown) are sequentially arranged. And a drive motor 42 (not shown) is connected to a drive shaft 42 that partially protrudes on the other side to drive the pump 1.

  The main part of the uniaxial eccentric screw pump main body 2 is composed of a double male screw rotor 21 having an oval cross section and a stator 22 having a substantially equilateral triangular opening cross section and a screw hole 23 having a three female thread shape. The rotor center point O rotates in the reverse direction (counterclockwise in FIG. 5) around the center axis N of the stator 22 while rotating in one direction (clockwise in FIG. 5) around the center point O of the rotor 21 in the screw hole 23. ), And the center point O of the rotor 21 rotates eccentrically about the center axis N (see FIG. 5). At this time, in the screw hole 23, the object to be transferred is transferred to one side by a pump action through the space part x (gap part: FIG. 5) with the rotor 21. The eccentric amount e of the center point O with respect to the central axis N when the rotor 21 rotates is smaller than that of the conventional general 1 / 2-strip type single-shaft eccentric screw pump, and is 2/3 of the eccentric amount. Further, the pump discharge flow rate is about 1.5 times that of a ½ strip type uniaxial eccentric screw pump having the same outer diameter (the same length).

  An endstat 24 is attached to the tip of the stator 22 and serves as a discharge port 24a (this example) or a suction port. On the other hand, a cylindrical stator casing 25 is provided around the stator 22, and the stator casing 25 is sandwiched between the end stud 24 and the pump casing 3.

  The other end side of the pump casing 3 is extended and formed in a bearing casing 41. On the upper surface of the pump casing 3, close to the bearing casing 41, the suction port 31 is formed upward or left and right, and an outward flange 32 is integrally provided around the suction port 31. The drive shaft 42 is rotatably supported in the bearing casing 41 by a pair of left and right bearings 43 and 44, and a part of the drive shaft 42 protrudes outward. The outer diameter of the drive shaft 42 is expanded in three stages from the right side to the left side in FIG. 1, and is formed into a large diameter part 42L, a medium diameter part 42M, and a small diameter part 42S in order from the left side. One end (the bearing casing 41 side) of the pump casing 3 is open, and an annular support housing 11 is fitted around the large diameter portion 42 </ b> L in the open end 33. A mechanical seal 12 is mounted around the large-diameter portion 42L across the support housing 11 to prevent leakage of liquid to be transferred from the pump casing 3 to the bearing casing 41 side.

The rotor 21 and the drive shaft 42 are connected by a metal flexible rod 6. In this example, the flexible rod 6 is made of a metal rod made of titanium alloy or stainless steel. As shown in FIG. 1, the flexible rod 6 is formed in tapered end portions 61 and 61 whose both end portions are formed to be slightly thick and then gradually reduced in diameter toward the tip. Further, a screw hole 62 is provided in the end surface central shaft portion of each tapered end portion 61. These screw holes 62 correspond to the tip screw portion 71 of the tension bolt 7 described later.

  In the case of this example, the flexible rod 6 and the rotor 21 and the flexible rod 6 and the drive shaft 42 are connected by a taper tension bolt. That is, a through hole 21a for the tension bolt 7 is drilled in the central axis portion of the rotor 21 in the longitudinal direction, and a through hole for the tension bolt 7 'is also penetrated in the central axis portion of the drive shaft 42 in the longitudinal direction. 42a is perforated. The tension bolts 7 and 7 ′ have a structure in which small-diameter screw portions 71 and 71 ′ are provided at the distal ends, and screw portions 72 and 72 ′ having slightly larger outer diameters are provided at the proximal ends. 72 and 72 'also have a smaller outer diameter than the tension bolts 7 and 7'.

  A tapered hole 21b corresponding to the tapered end 61 of the flexible rod 6 is formed at the end of the rotor 21 on the pump casing 3 side, and the tapered end 61 of the flexible rod 6 is inserted into the tapered hole 21b. Has been. On the other hand, the tension bolt 7 is inserted from the opposite end portion of the rotor 21, and the tip screw portion 71 is screwed into the screw hole 62 of the flexible rod 6 via the washer 8 to be tightened and connected integrally.

  On the other hand, as shown in FIG. 2, the nut 10 is attached to the base end side screw portion 72 of the tension bolt 7 through a washer 9 integrally provided with a flange portion 9 b on a small diameter portion 9 a that can be inserted into the through hole 21 a. By screwing and tightening the nut 10, the rotor 21 and the flexible rod 6 are integrally fastened. In addition, a bowler cap 26 is attached to the end of the rotor 21 with a plurality of set screws 27, and the nut 10 is covered with the washer 9. Both side portions 21c at the end of the rotor 21 are formed to be lower by one step, and a pair of locking holes 21d for mounting a detent tool (not shown) on each lower step portion 21c as shown in FIG. Is provided.

  Similarly, a tapered hole 42b corresponding to the tapered end 61 of the flexible rod 6 is formed at the end of the drive shaft 42 on the pump casing 3 side. The tapered end of the flexible rod 6 is formed in the tapered hole 42b. The part 61 is inserted. On the other hand, the tension bolt 7 ′ is inserted from the opposite end of the rotor 42, and the tip screw portion 71 ′ is screwed into the screw hole 62 of the flexible rod 6 via the washer 8 to be tightened and connected integrally. . On the other hand, the nut 10 is screwed to the proximal thread portion 72 ′ of the tension bolt 7 ′ via a washer 9 integrally provided with a flange 9b on a small diameter portion 9a that can be inserted into the through hole 42a. The drive shaft 42 and the flexible rod 6 are integrally fastened by tightening the nut 10, but the nut 10 and the washer 9 are not covered unlike the rotor 21. This is because the nut 10 and the like on the drive shaft 42 side are open to the atmosphere and do not come into contact with the liquid to be transferred. Note that a key 42c for connection with a drive motor (not shown) projects from the end of the drive shaft 42 that protrudes outward.

  Next, an operation mode of the uniaxial eccentric screw pump 1 of the first embodiment configured as described above will be described.

In FIG. 1, the drive shaft 42 is rotated in a specific direction by the drive motor, and this rotational force is transmitted to the rotor 21 via the flexible rod 6, and the rotor 21 rotates while being eccentric in the screw hole 23 of the stator 22. The amount of eccentricity at this time is absorbed by the deformation of the flexible rod 6. As a result, a pump action is generated in the pump body 2, and the transferred liquid is sucked into the pump casing 3 from the suction port 31, and the transferred liquid is discharged from the discharge port 24 a on the end stud 24 side through the pump body 2. The If the drive motor (not shown) is rotated in the reverse direction, the discharge port 24a on the end stud 24 side serves as a suction port, and the transferred liquid is sucked into the pump casing 3 through the pump body 2, The suction port 31 serves as a discharge port, and the liquid to be transferred is discharged.

  Although one example of the uniaxial eccentric screw pump of the present invention has been described above, it can be implemented as follows.

  In the uniaxial eccentric screw pump 1 of the above embodiment, only the connection between the flexible rod 6 and the drive shaft 42 can be changed to the flange system. That is, the uniaxial eccentric screw pump 1 ′ of this example is provided with a tapered hole 42b corresponding to the tapered end portion 61 of the flexible rod 6 as shown in FIG. A tightening ring 16 provided with a projecting substantially cylindrical connector 15 and an inward flange 16a on the tip side is used. The tapered end portion 61 is fitted into the tapered hole 15b of the substantially cylindrical connector 16, the short headed tension bolt 17 is inserted from the proximal end side opening 15c, and the distal end screw portion 17a is inserted into the screw hole 62 of the flexible rod 6. The flexible rod 6 and the substantially cylindrical connector 15 are integrally connected by screwing and tightening. Then, with the flange 16a engaged with the flange 15a of the substantially cylindrical connector 15, the tightening ring 16 is tightened around the step portion 42d provided at the end of the drive shaft 42 to drive the flexible rod 6 It can also be connected to the shaft 42 so as to be integrally rotatable. Since other configurations are the same as those in the above embodiment, common members are denoted by the same reference numerals, and description thereof is omitted. In this case, the flange portion becomes long and protrudes outward in the radial direction, but the operation as a pump is common.

  FIG. 6 is a sectional view showing a third embodiment of the uniaxial eccentric screw pump according to the present invention. The uniaxial eccentric screw pump 1-3 of this example is different from the screw pump 1 of the first embodiment in that the connection positions of the tapered end portion 61 of the flexible rod 6 and the rotor 21 and the drive shaft 42 are respectively set in the rotor 21. In addition, the drive shaft 42 is at a substantially intermediate position in the longitudinal direction.

  That is, as shown in FIG. 6, a circular long hole 27 is formed from the center shaft portion of the end surface of the rotor casing 21 on the rotor casing 21 to a substantially intermediate position in the longitudinal direction, and the flexible rod 6 is formed at the bottom end of the long hole 27. A tapered hole 27b corresponding to the tapered end portion 61 is formed, and the tapered end portion 61 of the flexible rod 6 is fitted into the tapered hole 27b. On the other hand, the tension bolt 7 is inserted from the central shaft portion on the opposite end surface of the rotor 21, the tip screw portion 71 is screwed into the screw hole 62 of the flexible rod 6 via the washer 8, and is tightened and integrally connected. Yes.

  Similarly, a circular long hole 45 is formed from the central shaft portion of the end surface on the pump casing 3 side of the drive shaft 42 to substantially the middle position in the longitudinal direction, and the taper of the flexible rod 6 is formed at the bottom end of the long hole 45. A tapered hole 45b corresponding to the shaped end portion 61 is formed, and the tapered end portion 61 of the flexible rod 6 is fitted into the tapered hole 45b. In the case of this example, the tapered end portion 61 (the connection portion between the drive shaft 42 and the flexible rod 6) is the position of the bearing 43. On the other hand, a tension bolt 7 ′ is inserted from the central shaft portion on the opposite end face of the rotor 42, and the tip screw portion 71 ′ is screwed into the screw hole 62 of the flexible rod 6 through the washer 8 and tightened to be connected integrally. Has been. Since other configurations are the same as those in the above embodiment, common members are denoted by the same reference numerals, and description thereof is omitted.

In the uniaxial eccentric screw pump 1-3 of this example, since the load acting on the stator 22 from the flexible rod 6 is applied to the center portion in the longitudinal direction of the stator 22 on the rotor 21 side, the addition to the stator 22 is equalized. As a result, the life of the stator 22 is extended. Further, on the drive shaft 42 side, the bending moment acting on the end of the drive shaft 42 from the flexible rod 6 is directly supported by the bearing 43, so the load on the drive shaft 42 is reduced. Furthermore, with the above configuration, the length of the pump casing 3 and thus the total length of the pump 1-3 are shortened, and space saving is achieved.

  FIG. 7 is a sectional view showing a fourth embodiment of the uniaxial eccentric screw pump according to the present invention. The uniaxial eccentric screw pump 1-4 of this example is different from the screw pump 1-3 of the third embodiment in that the connection positions of the end 61 of the flexible rod 6, the rotor 21 and the drive shaft 42 are respectively pump casings. 3 and that the end 61 of the flexible rod 6 and the rotor 21 are connected to each other by a shrink-fitting method or a screwing method.

  Specifically, as shown in FIG. 7, a circular long hole 25 is formed through the rotor 21 from the central axis portion of the end surface on the pump casing 3 side to the opposite end portion, and inside the end portion 25 a of the long hole 25. The bowl-cap-shaped plug body portion 28 is fitted into the screw hole 29 and screwed into a screw hole 29 a provided in the bowl-hat-shaped plug body portion 28 from the end face of the rotor 21 with a plurality of bolts 29, and is connected by screwing. . It is also possible to provide a female screw portion on the inner peripheral surface of the end portion 25a of the long hole 25, and to connect the male screw portion engraved on the outer peripheral surface of the bowler hat shaped plug body 28 by screwing and tightening. Further, a straight hole 28b corresponding to the cylindrical end 63 of the flexible rod 6 is formed in the central shaft portion of the plug body 28, and the cylindrical end 63 of the flexible rod 6 is shrink-fitted into the straight hole 28b. Fitted and connected together.

  In addition, a circular long hole 45 is similarly formed from the central shaft portion of the end surface on the pump casing 3 side of the drive shaft 42 to the opposite end portion, and the tapered end of the flexible rod 6 is formed at the bottom end of the long hole 45. A tapered hole 45b corresponding to the portion 61 is formed, and the tapered end 61 of the flexible rod 6 is fitted into the tapered hole 45b. On the other hand, the tension bolt 7 ″ is inserted from the central shaft portion on the opposite end face of the drive shaft 42, and the tip screw portion 71 ″ is screwed into the screw hole 62 of the flexible rod 6 through the washer 8 and tightened to be integrated. It is connected. Since other configurations are the same as those in the above embodiment, common members are denoted by the same reference numerals, and description thereof is omitted.

  According to the uniaxial eccentric screw pump 1-4 of this example, the length of the pump casing 3 is further shortened compared with the uniaxial eccentric screw pump 1-3 of the third embodiment, and the overall length of the pump is minimized. Further, since the connection between the rotor 21 and the flexible rod 6 is a shrink-fitting method, the structure is simplified. However, the connection between the flexible rod 6 and the drive shaft 42 is a tension bolt system, and the tension bolt 7 'is tightened so that the rotor 21, the flexible rod 6 and the drive shaft 42 can be reliably connected integrally. .

  By the way, it is not restricted to the uniaxial eccentric screw pump 1-3 * 4 of the said 3rd and 4th Example, According to the property (type, viscosity, etc.) of the liquid which it is going to convey with a pump, The connecting position of the end portion and the central shaft portion of the rotor 21 or the central shaft portion of the drive shaft 42 is any position (advantageous position) between the distal end position and the proximal end position of the rotor 21 or the distal end of the drive shaft 42. It can be set to any position (advantageous position) between the position and the base end position. In addition, the connection on the rotor 21 side can be a fitting structure by screwing in addition to shrink fitting. Furthermore, the connection by shrink fitting or screwing is not limited to the rotor 21 side, but can be similarly applied to the drive shaft 42 side. In this case, the rotor 21 side needs to be connected by a tension bolt system.

It is sectional drawing which shows the Example of the uniaxial eccentric screw pump which concerns on this invention. It is sectional drawing which expands and shows the one end part of the rotor of FIG. It is an A direction arrow directional view of FIG. It is sectional drawing which shows 2nd Example of the uniaxial eccentric screw pump which concerns on this invention. FIGS. 5A to 5F are enlarged cross-sectional views sequentially showing the rotational operation (spinning and revolution) of the rotor at a fixed position in the stator of the 2/3 single-shaft eccentric screw pump. It is sectional drawing which shows 3rd Example of the uniaxial eccentric screw pump which concerns on this invention. It is sectional drawing which shows 4th Example of the uniaxial eccentric screw pump which concerns on this invention.

Explanation of symbols

1 · 1 ′ · 1−3 · 4 Single-shaft eccentric screw pump 2 Pump body 3 Pump casing 4 Bearing device 6 Flexible rod 7 · 7 ′ · 7 ”tension bolt 8 · 9 Washer 10 Nut 11 Support housing 12 Mechanical seal 15 Substantially cylindrical 16 Tightening ring 16a flange 17 Headed tension bolt 21 Male threaded rotor 22 Stator 23 Female threaded hole 24 Endstat 24a Discharge port 25 Stator casing 26 Bowler cap lid 27/45 Long hole 28 Bowler hat plug body 31 Suction port 41 Bearing casing 42 Drive shaft 61 Tapered end 62 Tapered hole 63 Cylindrical end (shrink fit)
71, 71 ', 72, 72' thread

Claims (4)

A pump main body having a two-thread male screw rotor having an oval cross-section and a stator having a three-thread female screw hole having an approximately equilateral triangular opening in which the rotor is fitted; a pump casing; a drive shaft connected to a drive device; A uniaxial eccentric screw pump comprising a flexible rod connecting the rotor,
At least one end portion of the flexible rod is formed in a tapered shape whose outer diameter gradually decreases toward the tip, and a tapered hole corresponding to the tapered end portion is provided in a central shaft portion of the rotor or the drive shaft. The taper end of the flexible rod is inserted into the inside, and a tension bolt is inserted from the other end of the rotor through the through-hole drilled in the central shaft of the rotor or the drive shaft. The rotor or the drive shaft and the flexible rod are connected by screwing and fastening the screw portion on the tip side of the screw into a screw hole provided in the central shaft portion of the tapered end portion of the flexible rod. Uniaxial eccentric screw pump. Both end portions of the flexible rod are formed in a tapered shape whose outer diameter gradually decreases toward the tip, and a tapered hole corresponding to the tapered end portion is provided in a central shaft portion of the rotor and the drive shaft. The taper end of the flexible rod is inserted into the inside, and a tension bolt is inserted from the other end of the rotor through the through-hole drilled in the central shaft of the rotor and the drive shaft. The rotor, the drive shaft, and the flexible rod are connected by screwing and tightening a screw portion provided in a central shaft portion of the tapered end portion of the flexible rod. The uniaxial eccentric screw pump according to claim 1. 3. The single-shaft eccentric screw pump according to claim 1, wherein a cover that covers a nut that is screwed onto a proximal-side screw portion of the tension bolt is attached to an end portion of the rotor opposite to the flexible rod. . The connecting position between the end of the flexible rod and the rotor central shaft or the drive shaft central shaft can be any position between the front end position and the base end position of the rotor or the front end position and the base end of the drive shaft. The single-shaft eccentric screw pump according to claim 1, wherein the single-shaft eccentric screw pump is at an arbitrary position between the positions.

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