KR102439444B1 - Single-shaft eccentric screw pump - Google Patents

Abstract

Even when a flexible connecting member is used for the power transmission mechanism part, the object is to minimize the reduction of the pressure feeding performance due to the collapse of the rotor posture due to the influence of the restoring force (reaction force) of the connecting member.
The uniaxial eccentric screw pump 10 includes a rotor 30 , a stator 20 provided with a through hole 22 , and a power transmission mechanism unit 50 . The power transmission mechanism unit 50 is provided with a connecting member 62 constituted by a flexible rod or the like. The connecting member 62 can rotate the rotor 30 eccentrically so that the rotor 30 revolves along the inner peripheral surface of the stator 20 while rotating inside the stator 20 . The through hole 22 is opened so as to constitute an elliptical opening region in a cross section transverse to the axis of the stator 20 . In addition, the stator 20 has a bulging part which swells inward in the transverse direction of an opening region in the longitudinal middle part of an opening region.

Description

Single Shaft Eccentric Screw Pump {SINGLE-SHAFT ECCENTRIC SCREW PUMP}

The present invention relates to a uniaxial eccentric screw pump in which a connecting member having flexibility in a direction crossing with respect to the axial direction of the rotor is employed in a power transmission mechanism for transmitting rotational power input from a drive source to a rotor.

Conventionally, like the uniaxial eccentric screw pump disclosed in the following patent document 1, what provided the connection member which has flexibility, such as a flexible rod and a flexible wire, in the power transmission mechanism part is provided. In the uniaxial eccentric screw pump of patent document 1, rotation power input from a drive source can be transmitted to a rotor via a connection member. Thereby, while rotating a rotor inside a stator, it can eccentrically rotate so that it may revolve so that it may follow the inner peripheral surface of a stator.

Japanese Patent Laid-Open No. 2012-154215

However, as described above, when a connecting member such as a flexible rod is employed in the power transmission mechanism portion, the posture of the rotor collapses due to the restoring force (reaction force) of the connecting member. Referring to FIG. 8 , when the rotor 120 connected to the connecting member 100 is inserted into the stator 110 and rotated, the restoring force of the connecting member 100 acts on the rotor 120 . By the action of this restoring force, the rotor 120 tries to change its posture so as to follow the connecting member 100 such as a flexible rod and to be arranged in a straight line. However, the movement of the rotor 120 is regulated by the stator 110 . Therefore, the rotor 120 does not become in the posture arranged in a straight line with the connecting member 100 .

Here, for example, if the stator 110 is a rigid body such as a metal, the rotor 120 does not move and has the posture as shown in FIG. 8A . Specifically, even if the restoring force due to the deformation of the connecting member 100 acts, if the stator 110 is a rigid body, the movement of the rotor 120 is completely regulated by the stator 110 , so the rotor 120 is the stator. There is no inclination to (110).

However, the generally used stator 110 is made of an elastic body such as rubber, and is elastically deformed. Therefore, when the restoring force of the connecting member 100 acts on the rotor 120, the proximal end side (power source side: right side in the drawing) of the rotor 120 as shown in the example shown in FIG. It becomes an inclined posture so as to be lower than the left side in the drawing).

Here, in the uniaxial eccentric screw pump, when the rotor 120 is in line contact in the stator 110 , a space (cavity) through which the fluid to be pressure-feed passes is formed in the stator 110 . When a break occurs in the line contact portion (seal line) of the rotor 120 and the stator 110 constituting the cavity, there is a risk that the fluid flows backward from the high pressure discharge side toward the low pressure suction side. In addition, if the rotor 120 deviates from the geometrically ideal motion, it may cause deterioration of the pressure feeding performance or pulsation of the fluid. Therefore, in the uniaxial eccentric screw pump, preventing the rotor 120 from being inclined with respect to the stator 110 may become an important task in stabilizing the discharge performance.

However, when the stator 110 is elastically deformed, the restoring force caused by the deformation of the connecting member 100 changes the posture of the rotor 120 as shown in FIG. There is a fear that breakage may occur or that the rotor 120 may perform an operation deviating from the geometrically ideal movement. Accordingly, when the connecting member 100 such as a flexible rod is employed in the power transmission mechanism, problems such as reverse flow of the fluid or pulsation of the fluid may occur.

Therefore, in the present invention, even when a flexible connecting member such as a flexible rod or a flexible wire is employed in the power transmission mechanism portion, the attitude collapse of the rotor due to the influence of the restoring force (reaction force) of the connecting member, and the resulting An object of the present invention is to provide a single-axis eccentric screw pump capable of minimizing the deterioration of the pressure feeding performance and the pulsation of the fluid.

Here, generally, as shown in FIGS. For this reason, the rotor contacts the stator in the through hole, and a force acts from the rotor to the stator in the radial direction outward of the stator. The influence is small at both ends in the longitudinal direction of the opening region of the through hole, and is large at the middle in the longitudinal direction. Under this assumption, the present inventors found that, in the longitudinal middle portion of the opening region of the through hole, if the force acting from the rotor toward the stator in the short direction outward of the opening region can be supported, the restoring force (reaction force) of the connecting member By suppressing the attitude collapse of the rotor due to the influence of

The uniaxial eccentric screw pump of the present invention provided based on the above knowledge includes a rotor constituted by a male-threaded shaft, and a stator made of an elastic body having a female-threaded through hole into which the rotor can be inserted; and a power transmission mechanism for transmitting input rotational power to the rotor, wherein the power transmission mechanism includes a connecting member having flexibility in a direction crossing the axial direction of the rotor, the stator It is possible to rotate the rotor eccentrically so as to revolve along the inner circumferential surface of the stator while rotating inside of In the longitudinal middle portion of the opening region, a bulging portion that swells inward in the transverse direction of the opening region is formed in at least a part of the region in the axial direction of the stator.

The uniaxial eccentric screw pump of the present invention has a bulge that bulges inward in the transverse direction of an opening region of a through hole formed in the stator in at least a part of the region in the axial direction of the stator. By setting it as such a structure, the force which acts toward the outer side in the transverse direction of a through hole with respect to a stator from a rotor can be supported by a bulging part. Thereby, the attitude collapse of the rotor due to the influence of the restoring force (reaction force) of the connecting member can be suppressed, and the deterioration of the pressure feeding performance and the pulsation of the fluid can be minimized.

In the uniaxial eccentric screw pump of the present invention described above, it is preferable that the connecting member is constituted by a flexible rod or a flexible wire.

In the uniaxial eccentric screw pump of this invention, it can suppress to the minimum that the attitude|position of a rotor collapses under the influence of the restoring force of the connecting member comprised with a flexible rod or a flexible wire. Accordingly, it is possible to minimize the decrease in the pressure feeding performance and the pulsation of the fluid due to the collapse of the rotor attitude.

Here, as the present inventors intensively studied, when the restoring force of the connecting member acts on the rotor, the movement of the rotor is restricted by the rigidity of the stator at the end (tip end) located on the opposite side to the driving source side, It was found that the rotor tends to be in a state in which the rotor is lowered toward the base end side with

In the uniaxial eccentric screw pump of the present invention provided based on this knowledge, the stator has a proximal end positioned on the drive source side and a tip end positioned on the opposite side to the drive source, and the bulging portion is at least a portion of the stator. It is formed in the area|region on the side of the said base end part.

With such a configuration, it is possible to minimize the state in which the rotor is lowered from the front end side toward the base end side, that is, the state where the rotor is inclined with respect to the stator. Thereby, the uniaxial eccentric screw pump which can suppress the fall of the pressure-feeding performance and the pulsation of a fluid to a minimum can be provided.

Here, in the uniaxial eccentric screw pump of the present invention described above, from the viewpoint of stabilizing the attitude of the rotor, the expansion amount of the bulging portion may be substantially uniform throughout the axial direction of the stator. However, in order to take into consideration problems such as an increase in torque due to the formation of the bulge and an increase in abrasion rate accompanying deterioration of lubrication properties, it is desirable to further optimize the amount of swelling of the bulge.

Based on these findings, the present inventors have intensively studied, and in some locations in the axial direction of the stator, the effect of improving the discharging performance and suppression of pulsation by configuring a configuration in which no bulge is formed or by reducing the amount of bulge in the bulge. While obtaining the effect, it was found that the effect such as reduction of the wear rate could also be achieved at the same time. Further, as described above, when the restoring force of the connecting member acts on the rotor, the rotor tends to be lowered toward the base end with the tip side of the stator as a supporting point. Therefore, it is preferable that the amount of swelling of the bulging portion is adjusted so that the effect by the bulging portion is expressed in the region on the base end side rather than the region on the tip end portion side.

In the uniaxial eccentric screw pump of the present invention provided based on this knowledge, the stator has a proximal end positioned on the drive source side and a tip end positioned on the opposite side to the drive source, and the amount of expansion of the bulging portion is It is larger in the area|region on the said base-end side than the area|region on the front-end|tip side side.

By setting it as such a structure, effects, such as prevention of torque increase and reduction of abrasion rate, are acquired while suppressing the influence which the restoring force of a connection member has on the attitude|position of a rotor to a minimum.

Further, in the uniaxial eccentric screw pump of the present invention provided based on the same knowledge, the stator has a proximal end positioned on the drive source side and a tip end positioned on the opposite side to the drive source, and the amount of expansion of the bulging portion This gradually increases from the front end side toward the base end side.

By setting it as such a structure, the influence of the restoring force of a connection member on the attitude|position of a rotor can be suppressed to the minimum. Further, in addition to the effect of improving the discharge performance and suppressing pulsation, effects such as the effect of reducing the wear rate can be obtained.

According to the present invention, even when a flexible connecting member such as a flexible rod or a flexible wire is employed in the power transmission mechanism portion, the rotor loses its posture under the influence of the restoring force (reaction force) of the connecting member, and this It is possible to provide a single-axis eccentric screw pump capable of minimizing a decrease in the pressure-feeding performance and pulsation of the fluid.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing of the uniaxial eccentric screw pump which concerns on one Embodiment of this invention.
Fig.2 (a) is a front view which shows an example of a stator, (b) is a left side view, (c) is A1-A1 sectional drawing, (d) is a right side view. Since the rear view, the top view, and the bottom view appear the same as the front view, they are not shown and are abbreviate|omitted.
Fig. 3(a) is a BB cross-sectional view of Fig. 2(c), (b) is a CC-sectional view of Fig. 2(c).
Fig. 4 is an explanatory view of the postures of the rotor and the connecting member during operation of the uniaxial eccentric screw pump of Fig. 1;
Fig. 5 (a) is a front view of the stator showing the first modification, (b) is a left view, (c) is a cross-sectional view A2-A2, (d) is a right view. Since the rear view, the top view, and the bottom view appear the same as the front view, they are not shown and are abbreviate|omitted.
Fig.6 (a) is a front view which shows the 2nd modified example of a stator, (b) is a left view, (c) is a sectional view A3-A3, (d) is a right view. Since the rear view, the top view, and the bottom view appear the same as the front view, it is not shown and abbreviate|omitted.
Fig.7 (a) is a front view which shows the 3rd modified example of a stator, (b) is a left side view, (c) is A4-A4 sectional drawing, (d) is a right side view. Since the rear view, the top view, and the bottom view appear the same as the front view, they are not shown and are abbreviate|omitted.
Fig. 8 (a) is an explanatory diagram regarding the postures of the rotor and the connecting member when the stator is a rigid body, (b) is an explanatory view regarding the postures of the rotor and the connecting member in the prior art, (c) ) is a left side view of (b), (d) is a PP cross-sectional view of (b), (e) is a right side view of (b).

EMBODIMENT OF THE INVENTION Hereinafter, it demonstrates in detail, referring drawings for the uniaxial eccentric screw pump 10 which is one Embodiment of this invention. The uniaxial eccentric screw pump 10 is a so-called positive displacement pump. As shown in FIG. 1 , the uniaxial eccentric screw pump 10 has a configuration in which a stator 20 , a rotor 30 , a power transmission mechanism unit 50 , and the like are assembled with respect to a casing 12 . The casing 12 is made of metal and is a cylindrical member. A cylindrical end stud 12a is attached to one end side of the casing 12 in the longitudinal direction. A first opening 14a is formed in the end stud 12a. Moreover, the 2nd opening 14b is formed in the outer peripheral part of the casing 12. As shown in FIG. The second opening 14b communicates with the inner space of the casing 12 in the intermediate portion 12d positioned at the middle portion in the longitudinal direction of the casing 12 .

The 1st opening 14a and the 2nd opening 14b are the parts which function as the suction port and the discharge port of the uniaxial eccentric screw pump 10, respectively. More specifically, in the uniaxial eccentric screw pump 10 of the present embodiment, by rotating the rotor 30 in the forward direction, the first opening 14a functions as a discharge port, and the second opening 14b It is possible to pressurize the fluid (fluid) to function as the suction port. Also, contrary to this, the uniaxial eccentric screw pump 10 rotates the rotor 30 in the reverse direction so that the first opening 14a functions as a suction port and the second opening 14b functions as a discharge port. It is possible to pressurize

The stator 20 is made of an elastic body typified by rubber, resin, or the like. For the stator 20, in addition to the cylindrical one, it is possible to use a cylindrical one with a polygonal cross-sectional shape. In this embodiment, as shown in FIG. 2, as the stator 20, what has an external shape of a substantially cylindrical external shape is used. The material of the stator 20 is suitably selected according to the type, property, etc. of the fluid which is a to-be-conveyed object of the uniaxial eccentric screw pump 10. As shown in FIG.

As shown in FIG. 1, the stator 20 is provided in the position adjacent to the end stud 12a. As shown in FIG. 3, the stator 20 arrange|positions the inner cylinder 20t inside 20 s of substantially cylindrical outer cylinders. At the end of the inner cylinder 20t, a protrusion 21 protruding outward in the radial direction is formed. The protrusion 21 protrudes in the longitudinal direction of the stator 20 rather than the end of the outer cylinder 20s, and is in contact with the end of the stator 20 in the longitudinal direction. The inner cylinder 20t has a spot facing shape in the spot facing portion 23 formed near the end portion. In addition, although the example in which the spot facing part 23 was formed in the stator 20 was shown in this embodiment, the stator 20 does not necessarily need to form the spot facing part 23. As shown in FIG.

In the stator 20, the protrusions 21 at both ends are sandwiched between the end studs 12a and the casing 12 at the ends of the casing 12, and the stays span the end studs 12a and the casing 12. It is fixed by attaching and fastening the bolt 16.

In addition, in the stator 20, a through hole 22 for inserting a rotor 30 to be described later is formed so as to extend in the axial direction. The through-hole 22 has a single-stage or multi-stage female thread shape in n sets. In this embodiment, it has become a multistage shape with two sets. As shown in FIG. 2 , the through hole 22 has substantially the same cross-sectional shape when viewed in cross section at any position in the longitudinal direction (axial direction). The cross-sectional shape of the through hole 22 and the opening shape at the end are the direction in which the length in one direction (hereinafter also referred to as "H direction") intersects with respect to the H direction (hereinafter also referred to as "B direction"). It has a long oval shape with respect to the length of the furnace.

As shown in FIG. 2 , the through hole 22 is opened so as to constitute an elliptical opening region in a cross section that crosses the axis of the stator 20 . More specifically, the cross-sectional shape of the through hole 22 is curved portions 22a, 22b curved in an arc shape on both end sides in the H direction, and intermediate portions 22c and 22d connecting between the curved portions 22a and 22b. ) has

In addition, the bulges 22e and 22f are formed in the intermediate portions 22c and 22d (approximately central portions of the intermediate portions 22c and 22d in the present embodiment). The bulges 22e and 22f swell toward the inside of the opening region 22g, respectively. More specifically, the bulges 22e and 22f bulge inward in the transverse direction of the through hole 22, respectively. In the present embodiment, the bulges 22e and 22f are gently curved from both ends of the intermediate portions 22c and 22d toward the substantially central portion, and are formed so as to protrude at the innermost side of the through hole 22 in the approximately central portion, have. Thereby, the opening area|region 22g has a constriction part formed in the substantially central part of the intermediate parts 22c and 22d, so to speak, it is a gourd-like shape.

In addition, the bulges 22e and 22f are formed in at least a part of the region in the axial direction of the stator 20 . In the present embodiment, the bulges 22e and 22f are formed over substantially the entire area in the axial direction of the stator 20 .

The amount of expansion of the bulged portions 22e and 22f toward the opening region 22g may be the same at any position (region) in the axial direction of the stator 20, but the amount of expansion may be different depending on the position. Specifically, it is preferable that the bulges 22e and 22f are preferentially formed in the region on the side of the proximal end 20y rather than the side of the distal end 20x of the stator 20 . In this embodiment, the bulging parts 22e and 22f are formed so that the swelling amount in the area|region on the side of the base end part 20y may become larger than the swelling amount in the front-end|tip part 20x side. Specifically, the bulges 22e and 22f formed on the tip portion 20x side have a shape bulged toward the opening region 22g as shown by the broken line in Fig. 2D. In contrast, the bulged portions 22e and 22f formed on the proximal end portion 20y side bulge more toward the opening region 22g side than the bulge portions 22e and 22f formed on the distal end portion 20x side, as indicated by the solid line in the figure. has been In addition, the swelling amount is adjusted so that the swelling part 22e, 22f may increase gradually from the front-end|tip part 20x side toward the base-end part 20y side.

As shown in FIG. 1 , the rotor 30 is a shaft that is inserted into the through hole 22 of the stator 20 . The rotor 30 is made of a material such as metal, resin, or ceramic, and has a single-stage or multi-stage male screw shape in n-1 sets. In this embodiment, the rotor 30 is multistage in one set. The rotor 30 is a shaft to which a connecting member 62, which will be described in detail later, is connected. The rotor 30 rotates eccentrically by the power transmitted through the connecting member 62 .

More specifically, the rotor 30 revolves along the inner peripheral surface 24 constituting the through hole 22 of the stator 20 while rotating inside the stator 20 . The rotor 30 is formed so that the cross-sectional shape of the rotor 30 may be seen in cross section from any position in the longitudinal direction so that it may become a substantially perfect circle shape. The rotor 30 is inserted through the through hole 22 formed in the stator 20 described above, and is freely eccentrically rotatable inside the through hole 22 .

When the rotor 30 is inserted through the stator 20, the outer circumferential surface 32 of the rotor 30 and the inner circumferential surface 24 of the stator 20 come into contact with the tangent lines of both. Moreover, in this state, the fluid conveyance path 40 is formed between the inner peripheral surface 24 of the stator 20 which forms the through-hole 22, and the outer peripheral surface 32 of the rotor 30. As shown in FIG. The fluid conveying path 40 is multi-stage ( d) is the euro.

The fluid conveying path 40 extends spirally in the longitudinal direction of the stator 20 or the rotor 30 . In addition, when the rotor 30 is rotated in the through hole 22 of the stator 20, the fluid conveyance path 40 advances in the longitudinal direction of the stator 20 while rotating the inside of the stator 20. As shown in FIG. Therefore, when the rotor 30 is rotated, the fluid is sucked into the fluid transport path 40 from the one end side of the stator 20 and the stator 20 is trapped in the fluid transport path 40 . It is possible to transport toward the other end side of the stator 20 and to discharge it in the other end side of the stator 20 . That is, when the rotor 30 is rotated in the forward direction, it is possible to pressurize the fluid sucked in from the second opening 14b and discharge it from the first opening 14a. In addition, when the rotor 30 is rotated in the reverse direction, the fluid sucked in from the first opening 14a can be discharged from the second opening 14b.

The power transmission mechanism unit 50 is provided to transmit power to the rotor 30 described above from a drive source (not shown) such as a motor provided outside the casing 12 . The power transmission mechanism unit 50 includes a power connection unit 52 and an eccentric rotation unit 54 . The power connecting portion 52 is a shaft receiving portion 12c formed on one end side of the casing 12 in the longitudinal direction, more specifically on the opposite side to the one where the above-described stator 20 is installed (hereinafter, simply referred to as "base end side"). ) is formed in Moreover, the eccentric rotation part 54 is formed in the intermediate part 12d formed between the shaft accommodating part 12c and the stator 20. As shown in FIG.

The power connection part 52 has a drive shaft 56, which is supported so that it can rotate freely by two bearings 58a, 58b. The drive shaft 56 is taken out from the closed part on the proximal end side of the casing 12, and is connected to the power source. Thereby, by operating the power source, it is possible to rotate the drive shaft 56 . Between the shaft accommodating part 12c and the intermediate part 12d in which the power connection part 52 is formed, the shaft sealing device 60 which consists of a mechanical seal, a gland packing, etc., for example is provided, and, thereby, the intermediate part 12d ) side to the shaft accommodating part 12c side, it has a structure in which the fluid, which is an object to be transported, does not leak.

The eccentric rotating part 54 is a part connected to the drive shaft 56 and the rotor 30 described above so that power transmission is possible by the connecting member 62 . The connecting member 62 is connected to the drive shaft 56 or the rotor 30 by a connection method such as screw connection or shrink fit. The connecting member 62 may be any type as long as it has flexibility in a direction crossing the axial direction of the rotor 30 . Specifically, a flexible rod or a flexible wire can be used for the connecting member 62 . In the present embodiment, a flexible rod is used as the connecting member 62 . Thereby, the eccentric rotation unit 54 transmits the rotational power transmitted through the drive shaft 56 to the rotor 30 , thereby eccentrically rotating the rotor 30 .

The above-described uniaxial eccentric screw pump 10 operates a driving source made of a motor or the like to rotate the rotor 30 in the forward direction, thereby sucking in the fluid from the base end 20y side and pressurizing the front end portion 20x to the side, It can be discharged from the 1st opening 14a formed in the end stud 12a. Here, in the uniaxial eccentric screw pump 10 as described above, the bulges 22e and 22f are formed in the stator 20 . The bulges 22e and 22f are bulged inward in the transverse direction in the longitudinal middle portion of the opening region 22g of the through hole 22 . By forming the bulging portions 22e and 22f, the restoring force acting on the stator 20 from the connecting member 62 is supported in the bulging portions 22e and 22f, and the attitude collapse of the rotor 30 can be suppressed. can be (see FIG. 4). Therefore, in the uniaxial eccentric screw pump 10, the fall of the pressure feeding performance resulting from the restoring force of the connection member 62 and the pulsation of a fluid can be suppressed to the minimum.

In the uniaxial eccentric screw pump 10 described above, the connecting member 62 may be any member as long as it has flexibility in a direction intersecting with the axial direction of the rotor 30 , for example, a flexible rod. or a flexible wire may be appropriately used. In addition to the flexible rod and the like, a coupling having a characteristic capable of suppressing torsion in the circumferential direction of the axis while allowing bending in a direction intersecting the axial direction, such as a so-called bending shaft coupling, is connected to the connecting member 62 It is possible to use it as

In addition, in the uniaxial eccentric screw pump 10 described above, the amount of expansion of the bulged portions 22e and 22f formed in the stator 20 is higher in the region on the base end portion 20y side than in the region on the tip portion 20x side. there is big By setting it as such a structure, while suppressing the influence of the restoring force of the connecting member 62 on the attitude|position of the rotor 30 to a minimum, the bad effect by forming the bulging part 22e, 22f can also be prevented. That is, in the uniaxial eccentric screw pump 10, under the influence of the restoring force of the connecting member 62, the front end portion 20x side of the stator 20 is used as a supporting point toward the base end portion 20y side. In consideration of problems such as a tendency to be in a lowered state, an increase in torque accompanying the formation of the bulges 22e and 22f, and an increase in abrasion rate accompanying deterioration of lubricating properties, the bulged portion 22e , 22f) is adjusted according to the position of the stator 20 in the axial direction. Therefore, in the uniaxial eccentric screw pump 10, not only suppresses problems such as a decrease in the pressure feeding performance due to the restoring force of the connecting member 62 and pulsation of the fluid, but also reduces the wear rate of the stator 20 Effects such as effects are also obtained.

In addition, in the stator 20 shown in this embodiment, the swelling amount of the bulging parts 22e, 22f gradually increases from the front-end|tip part 20x side toward the base-end part 20y side. Therefore, regardless of any position in the axial direction of the stator 20 as a reference, the amount of expansion of the bulged portions 22e and 22f formed in the stator 20 is higher than the area on the tip 20x side, on the base end portion 20y side. large in the area of However, this invention is not limited to this, For example, on the basis of the predetermined position in the axial direction of the stator 20, in the area|region on the side of the front-end|tip part 20x, the swelling amount of the bulge 22e, 22f is fixed amount. It may be such that the relationship of α<β is established by setting α to a constant amount β in the region on the proximal end portion 20y side with reference to the predetermined position. That is, the amount of swelling of the bulging portions 22e and 22f is not limited to changing steplessly as in the present embodiment, and may change stepwise. In addition, when changing the swelling amount of the swelling parts 22e and 22f to the front end 20x side and the base end 20y side with respect to the predetermined position as a reference, the swelling amount is adjusted according to conditions such as liquidity and pressure of the fluid to be handled. It is preferable to appropriately adjust the position to be changed and the amount of change.

In addition, in the present embodiment, by gradually increasing the amount of swelling of the bulges 22e and 22f from the distal end 20x to the proximal 20y side, the proximal end 20y side rather than the distal end 20x side region. Although the example in which the bulged parts 22e and 22f were greatly expanded in the area|region of was shown, this invention is not limited to this.

Specifically, the swelling amount of the bulging portions 22e and 22f may be increased stepwise (discontinuously) for each region from the tip portion 20x side toward the base end portion 20y side. In the case where it is not necessary to consider the increase in torque due to the formation of the bulges 22e and 22f or the increase in the wear rate accompanying the deterioration of the lubricating properties, etc., in the entire axial direction of the stator 20 What made the swelling amount of the bulging part 22e, 22f substantially uniform may be sufficient.

In addition, the above-described bulging portions 22e and 22f protrude in a substantially mountain-shaped shape that gradually protrudes inward of the through hole 22 from both ends of the intermediate portions 22c and 22d toward the approximately central portion, The present invention is not limited thereto. That is, the bulged portions 22e and 22f may be bulged toward the inside of the opening region 22g in the intermediate portions 22c and 22d, respectively.

Specifically, as shown in FIG. 5 , the bulges 22e and 22f may protrude in a semicircular shape toward the inside of the opening region 22g in the substantially central portion of the intermediate portions 22c and 22d. . Moreover, as shown in FIG. 6, the protrusion amount of the bulges 22e, 22f may be substantially uniform toward the substantially central part from the both ends of the intermediate part 22c, 22d. Even if the bulges 22e and 22f have the same shape as in FIG. 5 or FIG. 6 , if the bulges 22e and 22f can support the restoring force of the connecting member 62 acting on the stator 20 , the rotor (30) It is possible to suppress the collapse of the posture, and it is possible to minimize the decrease in the pressure feeding performance due to the restoring force and the pulsation of the fluid.

In addition, in this embodiment, although the example in which the bulged part 22e, 22f was formed in the substantially central part of the intermediate part 22c, 22d was shown, the bulged part 22e at the position deviated from the substantially central part of the intermediate part 22c, 22d. , 22f) may be formed.

In addition, as long as the cross-sectional shape of the through-hole 22 is an oval-shaped thing, the above-mentioned stator 20 may be a thing of any shape. That is, the cross-sectional shape of the through hole 22 is not limited to the track (main circuit) shape connected by the intermediate portions 22c and 22d extending linearly between the oppositely arranged arc shapes 22a and 22b, For example, an oval shape, a platelet shape thing, etc. may be sufficient. More specifically, as shown in FIG. 7 , the stator 20 may be one in which the bulges 22e and 22f are formed in an elliptical through hole 22 , or the like. Even in the case of such a configuration, by supporting the restoring force of the connecting member 62 acting on the stator 20 by the bulging portions 22e and 22f, the attitude collapse of the rotor 30 is suppressed, and the pressure feeding performance is lowered. However, the pulsation of the fluid can be suppressed to a minimum.

The present invention is suitable for general uniaxial eccentric screw pumps in which a connecting member having flexibility in a direction crossing with respect to the axial direction of the rotor is employed in a power transmission mechanism for transmitting rotational power input from a drive source to the rotor. is readily available

10: single shaft eccentric screw pump
20: stator
20x : tip
20y: proximal end
22: through hole
22e, 22f: bulging part
22g: opening area
30: rotor
50: power transmission mechanism part
62: connection member

Claims (5)

A rotor constituted by a male screw type shaft,
a stator made of an elastic body having a female threaded through hole through which the rotor can be inserted;
and a power transmission mechanism for transmitting rotational power input from a driving source to the rotor,
The power transmission mechanism portion is provided with a connecting member having flexibility in a direction crossing the axial direction of the rotor, and the rotor is eccentrically rotated so as to revolve along the inner circumferential surface of the stator while rotating inside the stator. It is possible to rotate
The through hole is opened so as to constitute an elliptical opening region in a cross section transverse to the axis of the stator,
In the longitudinal middle portion of the opening region, a bulge that swells inward in the transverse direction of the opening region is formed in at least a part of the region in the axial direction of the stator,
The connecting member is a flexible rod or a flexible wire,
The single-axis eccentric screw pump, characterized in that the bulging portion suppresses the rotor posture from collapsing under the influence of the restoring force of the flexible rod or flexible wire. The uniaxial eccentric screw pump according to claim 1, wherein the swelling amount of the bulging portion is the same over the whole, or the proximal end is thicker than the distal end. The stator according to claim 1 or 2, wherein the stator has a proximal end located on the side of the drive source and a tip portion located on the opposite side to the drive source,
The said bulging part is formed in the area|region on the said base end side at least of the said stator, The uniaxial eccentric screw pump characterized by the above-mentioned. The stator according to claim 1 or 2, wherein the stator has a proximal end located on the side of the drive source and a tip portion located on the opposite side to the drive source,
The uniaxial eccentric screw pump, characterized in that the swelling amount of the bulging portion is larger in the region on the base end side than in the region on the tip end side. The stator according to claim 1 or 2, wherein the stator has a proximal end located on the side of the drive source and a tip portion located on the opposite side to the drive source,
The uniaxial eccentric screw pump, characterized in that the swelling amount of the bulging portion gradually increases from the tip end side toward the base end side.

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