Uniaxial eccentric screw pump

Abstract

[Problem] To provide a uniaxial eccentric screw pump which facilitates adjustment of the interference or clearance between a rotor and a stator, and which can also be automated. [Solution] A uniaxial eccentric screw pump 1 comprises: an input shaft 3 rotated by the motive power of a drive machine; a rotor 5 connected to the input shaft 3 so as to be eccentrically rotatable; and a stator 12 into which the rotor 5 can be inserted. The uniaxial eccentric screw pump 1 comprises a movement mechanism 50, which is capable of shaping the outer diameter of the rotor 5 and / or the inner diameter of an inner hole 12a of the stator 12 so as to decrease proceeding from one end toward the other end and / or changing the amount of eccentricity of the rotor 5, and which moves the stator 12 closer to or farther from the rotor 5 in an axial direction. A stator casing 10 comprises a first stator casing 14 that supports the stator 12 and a second stator casing 16 that holds the first stator casing 14 so as to allow for relative movement in the axial direction.

Description

Single-axis eccentric screw pump

[0001] The present invention relates to a single-axis eccentric screw pump. More specifically, for example, it relates to a single-axis eccentric screw pump that can adjust the tightening clearance or gap between a rotor and a stator according to the volume change due to the temperature change of the stator or according to the wear of the stator.

[0002] Conventionally, a single-axis eccentric screw pump is known in which a male screw type rotor is inserted into the inner hole of a female screw type stator, and the rotor rotates to discharge the fluid sucked from the suction port from the discharge port (for example, Patent Document 1).

[0003] The single-axis eccentric screw pump described in Patent Document 1 is formed such that the outer diameter of the rotor decreases and the inner diameter of the inner hole of the stator decreases as it goes from one corresponding end of the rotor and the stator to the other end. It has a moving mechanism for relatively moving the stator in the direction of the central axis of the inner hole with respect to the rotor. Further, the moving mechanism constituting the single-axis eccentric screw pump described in Patent Document 1 includes a moving casing provided with the stator, a fixed casing provided with the rotor, and a screw portion connecting the moving casing and the fixed casing to each other. By rotating the moving casing in the screw direction of the screw portion, the stator is relatively moved in the direction of the central axis of the inner hole with respect to the rotor. Thus, the invention described in Patent Document 1 above is supposed to adjust the tightening clearance or gap (simply referred to as tightening clearance etc. for both together) between the rotor and the stator.

[0004] Japanese Patent No. 5320849

[0005] By the way, in recent years, in the single-axis eccentric screw pump as described in Patent Document 1 above, there are demands for simplifying the adjustment of the tightening clearance etc. between the rotor and the stator and for automation in the adjustment of the tightening clearance etc. However, the single-axis eccentric screw pump described in Patent Document 1 cannot fully satisfy these demands.

[0006] Therefore, the present invention aims to provide a single-screw eccentric pump that allows for simple adjustment of the overlap or gap between the rotor and stator, and also enables automation.

[0007] (1) The single-screw eccentric pump of the present invention, provided to solve the above-mentioned problems, comprises an input shaft that rotates by the power of a drive machine, a rotor that is eccentrically rotatable with respect to the input shaft and is composed of a male screw-type shaft body, and a stator formed in the shape of a female screw through which the rotor can be inserted, wherein it is possible to form either or both of the outer diameter of the rotor and the inner diameter of the inner bore of the stator to decrease from one end to the other, or to change the amount of eccentricity of the rotor, and the pump is provided with a movement mechanism that moves the stator closer to and further away from the rotor along the axial direction of the input shaft.

[0008] In the single-screw eccentric pump of the present invention, either the outer diameter of the rotor and / or the inner diameter of the inner bore of the stator are formed to decrease from one end to the other, or the amount of eccentricity of the rotor can be changed, or both can be changed. Therefore, in the single-screw eccentric pump of the present invention, even if the rotor and stator change in volume due to temperature changes or wear out, there is no need to replace the rotor or stator, and the overlap or gap (collectively referred to as overlap, etc.) of the rotor and stator can be easily adjusted.

[0009] Furthermore, the single-screw eccentric pump of the present invention allows the stator to be moved closer to and further away from the rotor by a moving mechanism. This simplifies the structure compared to moving the rotor, which is a rotating component, and also facilitates adjustment of the tension between the rotor and stator.

[0010] (2) The uniaxial eccentric screw pump of the present invention described above is provided with a stator casing that houses the stator and is formed to extend along the axial direction, wherein the stator casing comprises a first stator casing that supports the stator so that it cannot move relative to it in the axial direction, and a second stator casing that holds the first stator casing so that it can move relative to it in the axial direction, and the moving mechanism is characterized by moving the first stator casing and the second stator casing relative to each other in the axial direction.

[0011] The single-screw pump of the present invention, with this configuration, allows the first stator casing to move relative to the second stator casing, thereby allowing the first stator casing and stator to move closer to and further away from the rotor. As a result, the single-screw pump of the present invention can have a simpler structure compared to when the rotor side, which is a rotating component, is moved, and adjustments such as the tension between the rotor and stator can be easily made. Here, the first stator casing and the second stator casing are preferably configured to be able to move relative to each other in the axial direction by means of splines, keys, rails, etc., provided along the axial direction.

[0012] (3) In the single-screw eccentric pump of the present invention described above, the moving mechanism is preferably characterized in that the second stator casing comprises a moving groove formed along the axial direction and an operating part that is integral with the first stator casing and can move along the moving groove, and the first stator casing and the second stator casing are moved relative to each other along the axial direction by moving the operating part along the moving groove.

[0013] The single-screw eccentric pump of the present invention allows the first stator casing to be moved integrally with the stator along the axial direction by moving the operating unit along the axial direction of the input shaft (hereinafter also simply referred to as the axial direction). As a result, the single-screw eccentric pump of the present invention allows adjustment of the rotor and stator's tension by operating the operating unit. Therefore, the single-screw eccentric pump of the present invention allows for easy adjustment of the rotor and stator's tension by easily operating the operating unit from the outside of the main body.

[0014] (4) The single-screw eccentric pump of the present invention described above is characterized in that the moving groove is formed in the second stator casing in a helical shape at a predetermined pitch and angle such that the helical shaft extends along the axial direction, and the first stator casing and the second stator casing are moved relative to each other along the axial direction by rotating the operating part along the moving groove.

[0015] The single-screw eccentric pump of the present invention, with this configuration, allows the stator to be moved axially relative to the rotor, integrally with the first stator casing, by operating the operating unit. As a result, the single-screw eccentric pump of the present invention can reduce the resistance to the movement of the operating unit, even when resistance occurs to the movement of the rotor relative to the stator. That is, the operating unit can be operated axially by utilizing the principle of leverage, the principle of inclined planes, and the thrust force of the screw. Therefore, the single-screw eccentric pump of the present invention can reduce the burden on the operator and advantageously advance the automation of adjustments such as the tightening allowance of the rotor and stator.

[0016] (5) In the single-screw eccentric pump of the present invention as described above, the operating unit is switchable between a fixed state in which relative movement of the first stator casing and the second stator casing in the axial direction is impossible, and an unfixed state in which relative movement of the first stator casing and the second stator casing in the axial direction is permitted, and in the unfixed state, the operating unit is moved along the moving groove by the moving mechanism, thereby moving the first stator casing and the second stator casing relative to each other in the axial direction, and in the fixed state, the first stator casing and the second stator casing are positioned and fixed at predetermined positions in the axial direction.

[0017] The single-screw eccentric pump of the present invention allows the first stator casing and the second stator casing to be moved relative to each other in the axial direction by operating the operating unit, which is in an unfixed state. Furthermore, the single-screw eccentric pump of the present invention allows the first stator casing (stator) and the second stator casing to be positioned and fixed at predetermined positions in the axial direction by fixing the operating unit. Therefore, the single-screw eccentric pump of the present invention allows for easy adjustment of the tension between the rotor and stator by operating the operating unit, and maintains the axial position of the rotor and stator after adjustment.

[0018] (6) The single-screw eccentric pump of the present invention described above is preferably characterized by having a locking part that tightens the first stator casing and the second stator casing so that they approach each other radially around the axis, and the locking part can be switched between a tightened state and an untightened state.

[0019] The single-screw eccentric pump of the present invention, with this configuration, can reduce the gap between the first and second stator casings when they are tightened together. As a result, the single-screw eccentric pump of the present invention can suppress vibrations during operation. The locking part can also suppress relative rotation and relative movement of the first and second stator casings by, for example, clamping and tightening the outer circumference of the second stator casing. Furthermore, the locking part should be configured to allow switching between a tightened state and an untightened state by, for example, rotational operation using a knob or handle.

[0020] (7) In the single-screw eccentric pump of the present invention as described above, the moving groove has at least one engagement hole at a predetermined position along the moving groove that engages with the operating part to suppress the movement of the operating part, and the moving mechanism moves the operating part along the moving groove and engages the operating part with the engagement hole to position and fix the first stator casing and the second stator casing at predetermined positions in the axial direction.

[0021] The single-screw eccentric pump of the present invention allows the operating part to be fixed at the position where the engagement hole is formed by forming an engagement hole in the moving groove. Therefore, the single-screw eccentric pump of the present invention allows the relative amount of axial movement of the first stator casing and the second stator casing to be easily adjusted by the position where the engagement hole is formed. Here, the engagement hole can preferably be a counterbore, for example. When the engagement hole is formed as a counterbore, for example, the counterbore can be formed as a screw hole, and a screw portion provided on one end of the operating part can be screwed into the counterbore. In this configuration, the operating part can be fixed and released by rotating the operating part. Also, when the engagement hole is formed as a counterbore, for example, the operating shaft of the operating part can be provided with a small diameter portion that can pass through the moving groove and a large diameter portion that engages with the counterbore, and the small diameter portion and large diameter portion of the operating shaft can be selectively switched using a spring or the like.

[0022] (8) The single-screw eccentric pump of the present invention described above is characterized in that the operating section is fixed to the first stator casing so as not to rotate relative to it, and has a plurality of handle shafts formed in the direction around the axis so as to extend in a direction intersecting the axial direction, a plurality of the moving grooves are formed in the direction around the axis corresponding to the handle shafts, the plurality of handle shafts are inserted so as to be movable along the plurality of the moving grooves provided corresponding to each of them, and by rotating the plurality of handle shafts in the same direction along the plurality of the moving grooves provided corresponding to each of them, the first stator casing and the operating section move integrally with respect to the second stator casing in the axial direction.

[0023] The single-screw pump of the present invention has a pair of handle shafts in the operating section that are formed to intersect symmetrically in the axial direction, so that the pair of handle shafts can be operated using the principles of levers and inclined planes. As a result, the single-screw pump of the present invention can reduce the force required to operate the operating section (handle shafts). Therefore, the single-screw pump of the present invention can reduce the burden on the operator (worker) and facilitate automation. Here, the pair of handle shafts are preferably arranged perpendicular to the axial direction of the input shaft, and are preferably set to an appropriate length that reduces the movement resistance of the first stator casing (stator).

[0024] (9) In the single-screw eccentric pump of the present invention as described above, the second stator casing is provided with a screw member along the axial direction, the first stator casing is supported with a nut member that screws onto the screw member, the nut member is movable integrally with the first stator casing in the axial direction as the screw member rotates, and the moving mechanism moves the screw position of the nut member by rotating the screw member, thereby moving the first stator casing and the second stator casing relative to each other in the axial direction.

[0025] The single-screw eccentric pump of the present invention, with this configuration, allows the screw position of the screw member to be moved, thereby allowing the first stator casing and the second stator casing to move relative to each other in the axial direction. As a result, the single-screw eccentric pump of the present invention allows for easy adjustment of the rotor and stator overlap by adjusting the tightening of the screw member. By configuring the screw member to be accessible from the outside of the single-screw eccentric pump, the rotor and stator overlap can be easily adjusted without disassembling the single-screw eccentric pump. Various types of screw members can be used, such as triangular screws, trapezoidal screws, and ball screws.

[0026] (10) The single-screw eccentric pump of the present invention described above is equipped with a switching mechanism that switches between a relative rotation-impossible state in which the first stator casing and the second stator casing are made unable to rotate relative to each other, and a relative rotation-allowed state in which relative rotation of the first stator casing and the second stator casing is permitted, wherein the moving mechanism is equipped with a first screw portion formed on the outer circumference side of the first stator casing along the axial direction, and a second screw portion formed on the inner circumference side of the second stator casing along the axial direction and screwed into the first screw portion, wherein in the relative rotation-allowed state, the rotor is rotated to screw the first screw portion and the second screw portion together, thereby allowing the first stator casing and the second stator casing to move relative to each other in the axial direction, and in the relative rotation-impossible state, relative movement of the first stator casing and the second stator casing in the axial direction is suppressed.

[0027] The single-screw pump of the present invention, with this configuration, allows the first threaded portion (first stator casing) and the second threaded portion (second stator casing) to be screwed together as the rotor rotates in a relative rotation-permissible state. As a result, the single-screw pump of the present invention allows the first stator casing and the second stator casing to move relative to each other in the axial direction as the rotor rotates in a relative rotation-permissible state. In other words, the single-screw pump of the present invention can automatically adjust the tightening tolerance of the rotor and stator by utilizing the rotation of the rotor.

[0028] On the other hand, with the single-screw pump of the present invention, by having such a configuration, relative movement of the first stator casing and the second stator casing in the axial direction is suppressed when relative rotation is impossible. Therefore, if adjustments such as the overlap between the rotor and stator are not made, the rotor and stator can be positioned at a predetermined position in the axial direction. Thus, the single-screw pump of the present invention can be easily automated by, for example, providing an actuator to switch between allowing relative rotation or preventing relative rotation between the first stator casing and the second stator casing. In other words, since the single-screw pump of the present invention can utilize the power source of the drive machine that drives the input shaft for adjusting the overlap between the rotor and stator, the adjustment of the overlap between the rotor and stator can be automated simply by providing an actuator to switch between a state where relative rotation is impossible and a state where relative rotation is permitted. Therefore, cost reductions can be expected when automating the process.

[0029] (11) In the single-screw eccentric pump of the present invention described above, the first stator casing is provided so as to be movable in the axial direction relative to the second stator casing, the second stator casing has a cylinder chamber into which fluid can be introduced, and the moving mechanism moves the first stator casing by introducing fluid into the cylinder chamber and thereby biasing it in any direction along the axial direction.

[0030] The single-screw eccentric pump of the present invention, with this configuration, allows for automatic adjustment of the rotor and stator tension, etc., with a simple structure. Here, it is preferable that the cylinder chamber can selectively introduce fluid from both sides along the axial direction of the second stator casing. Furthermore, the fluid introduced into the cylinder chamber can flow in either direction along the axial direction and can bias the first stator casing in either direction along the axial direction. Here, various fluids can be used, such as gases like air, or liquids like oil and water.

[0031] (12) In the single-screw eccentric pump of the present invention described above, the first stator casing is provided so as to be movable in the axial direction relative to the second stator casing, and the moving mechanism has an actuator for moving the first stator casing in the axial direction.

[0032] The single-screw pump of the present invention, with this configuration, allows the first stator casing to be moved axially by the drive of the actuator. This enables the single-screw pump of the present invention to automatically adjust the overlap between the rotor and stator. Various power sources such as air cylinders, hydraulic cylinders, air actuators, and servo actuators can be used as the actuator. Furthermore, in the single-screw pump of the present invention, for example, when using an air cylinder, an elastic member such as a spring can be provided in the operating axis direction, allowing the biasing force from the elastic member to be used for pressurization adjustment at the start of operation of the air cylinder. This reduces the load on the air cylinder, thus enabling miniaturization of the air cylinder. In addition, in the single-screw pump of the present invention, when using an air cylinder, an air port can be provided, for example, to supply air through the air port when disassembling the single-screw pump. This eliminates the need for overlap between the rotor and stator when disassembling the single-screw pump of the present invention, thus improving disassembly.

[0033] (13) In the single-screw eccentric pump of the present invention described above, the movement of the first stator casing by the actuator is preferably characterized in that it is performed while the rotor is being rotated, or while the rotor is stopped, or both.

[0034] The single-screw eccentric pump of the present invention, with this configuration, can automatically adjust the tension between the rotor and stator, whether the rotor is rotating or stopped. Therefore, the single-screw eccentric pump of the present invention can stably discharge fluids with high precision.

[0035] (14) The single-screw eccentric pump of the present invention described above comprises a stator casing that houses the stator and is formed to extend along the axial direction, a pump casing arranged along the axial direction relative to the stator, and a discharge nozzle provided on the tip side of the stator, wherein the stator casing is integrally arranged with the stator and movable in the axial direction relative to at least one of the discharge nozzle and the pump casing, and the moving mechanism comprises at least one movable member provided on at least one end of the stator in the axial direction and movable integrally with the stator in the axial direction, and at least one adjustment bolt, wherein the movable member has a first bolt hole formed through it along the axial direction into which the adjustment bolt is screwed, and the discharge nozzle and front At least one side of the pump casing has a second bolt hole formed along the axial direction for fastening the adjustment bolt, and the adjustment bolt comprises an outer bolt portion having a first threaded portion formed on its outer circumference and a hollow hole, and an inner bolt portion inserted into the hollow hole so as to be rotatable relative to the outer bolt portion and having a second threaded portion formed on at least a part of its outer circumference, wherein the tip of the outer bolt portion can abut against the outer circumference of the second bolt hole when screwed into the first bolt hole, and the tip of the inner bolt portion fastens either the movable member and the discharge nozzle, or the movable member and the pump casing, or both, when screwed into the second bolt hole, and the axial distance of the stator can be adjusted according to the degree of tightening of the outer bolt portion.

[0036] The single-screw eccentric pump of the present invention, with this configuration, allows the degree of tightening of the adjustment bolt to change the screw position between the first threaded portion and the first bolt hole on the outer bolt portion, thereby moving (moving forward and backward) in the axial direction. As a result, the moving member moves forward and backward along the axial direction, causing the stator casing (stator) to move toward and away from the rotor in conjunction with the moving member. In other words, the single-screw eccentric pump of the present invention can adjust the overlap between the rotor and stator. Here, at least one adjustment bolt is sufficient, but two or more adjustment bolts may be provided. When two or more adjustment bolts are provided, for example, a pair of adjustment bolts should be provided on both the discharge nozzle side and the pump casing side of the stator casing so that their directions of movement are opposite to each other. Also, when two or more adjustment bolts are provided, it is good to arrange each adjustment bolt evenly around the axis of the moving member. As a result, the single-screw eccentric pump of the present invention can adjust the overlap between the rotor and stator with high precision.

[0037] According to the present invention, it is possible to provide a single-screw eccentric pump that allows for simple adjustment of the overlap or gap between the rotor and stator, and that can also be automated.

[0038] (a) is a front cross-sectional view of a single-screw eccentric pump according to one embodiment of the present invention. (a) is an enlarged front cross-sectional view of the main part of Figure 1, and (b) is a right side view of (a). (a) is a plan view of a single-screw eccentric pump according to the first modified example of the present invention, (b) is a view of the cross-sectional arrow in the C-C direction of (a), and (c) is a front view of a part of the components constituting the operating section in (a). This is a partially cutaway plan cross-sectional view of Figure 3(a). (a) is an enlarged front cross-sectional view of the main part of a single-screw eccentric pump according to the second modified example of the present invention, and (b) is a right side view of (a). (a) to (c) are enlarged front cross-sectional views of the main part of a single-screw eccentric pump according to the third modified example of the present invention, and are explanatory diagrams for adjusting the tightening allowance, etc., and (d) is a right side view of (a) to (c). This is an enlarged front cross-sectional view of the main part of a single-screw eccentric pump according to the fourth modified example of the present invention. This is an enlarged front cross-sectional view of the main part of a single-screw eccentric pump according to the fifth modification of the present invention. (a) is a front cross-sectional view showing the state of a single-screw eccentric pump according to the sixth modification of the present invention before adjustment of the tightening allowance, etc., and (b) is a front cross-sectional view showing the state of the single-screw eccentric pump of (a) after adjustment of the tightening allowance, etc., and (a) is a partially omitted view of Figure 9(a) taken along the A-A arrow, and (b) is a partially omitted view of Figure 9(a) taken along the B-B arrow.

[0039] The following describes in detail a single-screw eccentric pump 1 according to one embodiment of the present invention, with reference to the drawings. Note that the figures are schematic representations for ease of understanding and may differ from the actual shape, size, and arrangement of components. Also note that hatching in the cross-section may be omitted in some figures. In Figure 1, the left side may be described as the front side and the right side as the rear side. Unless otherwise specified, the axial direction of the input shaft 3 may simply be referred to as the axial direction. Also note that the drive unit 2 is omitted in all figures except Figure 4.

[0040] As shown in Figure 1, the single-screw eccentric pump 1 includes an input shaft 3 that transmits the driving force of the drive unit 2 (see Figure 4), a male screw-type rotor 5 (also referred to as rotor 5), a female screw-type stator 12 (also referred to as stator 12), and a moving mechanism 50. In addition to the above, the single-screw eccentric pump 1 also includes a stator casing 10, a pump casing 20, a bearing housing 30, a bearing 32 that rotatably supports the input shaft 3, and a shaft seal casing 40, etc.

[0041] The single-screw eccentric pump 1 is a rotary positive displacement pump. The single-screw eccentric pump 1 can transfer or fill any fluid, from low viscosity to high viscosity, with high precision by having a rotor 5 inserted through the inner bore 12a of the stator 12 rotate relative to the stator 12. Here, the fluid includes liquids, gases, and fluids such as slurries and granular materials.

[0042] The rotor 5 is composed of a male screw-type shaft body with n (in this embodiment, n=1) threads (leaves), and its longitudinal cross-sectional shape is formed to be approximately circular. The helical pitch is set to be the same as the pitch of the inner bore 12a of the stator 12. The rotor 5 is made of a metal such as stainless steel and is inserted through the inner bore 12a of the stator 12. A connecting shaft 7 is integrally provided at the rear end of the rotor 5. The connecting shaft 7 is eccentrically rotatable to the input shaft 3 via a connecting part 9 such as a pin joint, universal joint, gear joint, Oldham joint, or flexible rod. Therefore, the rotor 5 (connecting shaft 7) can rotate eccentrically with respect to the input shaft 3. Note that multiple connecting parts 9 may be provided as needed.

[0043] Further, both the outer diameter of the rotor 5 and the inner diameter of the stator 12 described later are formed so as to decrease from one end portion toward the other end portion. In the present embodiment, both the outer diameter of the rotor 5 and the inner diameter of the inner hole 12a of the stator 12 are formed so as to decrease from one end portion on the side of the connecting shaft 7 (right side in the drawing) of the rotor 5 toward the other end portion on the tip side (left side in the drawing) of the rotor 5. Note that the direction in which the outer diameter of the rotor 5 and the inner diameter of the inner hole 12a of the stator 12 are decreased can be changed according to the usage state. Further, it is sufficient that either one or both of the outer diameter of the rotor 5 and the inner diameter of the inner hole 12a of the stator 12 are formed so as to change from one end portion toward the other end portion.

[0044] Further, in the uniaxial eccentric screw pump 1 according to the present embodiment, instead of the changes in the outer diameter of the rotor 5 and the inner diameter of the stator 12, or together with the above changes, the eccentricity of the rotor 5 can also be changed.

[0045] The input shaft 3 is formed of a metal shaft, and in the present embodiment, it is formed so as to extend from the rear end side of a bearing housing 30 described later to the inside of a pump casing 20. The input shaft 3 is rotatably supported by a pair of bearings 32, 32 (bearings 32, 32) provided at intervals in the bearing housing 30, and a connection portion 60 for connecting a drive shaft (not shown) of a drive machine 2 (see FIG. 4) is provided at the rear end side (right side in the drawing). The input shaft 3 is connected to the drive machine 2 via the connection portion 60. Therefore, the input shaft 3 can be rotationally driven by the power of the drive machine 2. Here, for example, an electric motor such as a stepping motor or a servo motor is used as the drive machine 2.

[0046] The stator 12 is formed in a female screw type into which the rotor 5 can be inserted. The stator 12 is mounted in a stator casing 10 in a sealed state so as not to relatively rotate. The stator 12 has, for example, an inner hole 12a having a female screw shape with two threads (leaves) and is formed in a substantially cylindrical shape. The inner hole 12a is formed such that its longitudinal cross-sectional shape is an ellipse. The inner hole 12a is formed by being twisted with a lead twice that of the rotor 5 in the direction of its central axis 3a.

[0047] The stator 12 has an inner cylinder portion into which the inner peripheral rotor 5 is inserted, which is formed of, for example, a synthetic resin including engineering plastics such as synthetic rubber, Teflon (registered trademark), polyacetal, and cast nylon. By forming the stator 12 of synthetic rubber or synthetic resin, it is possible to ensure the liquid tightness (sealing property) of the space 13 formed by the outer surface of the rotor 5 and the inner surface of the inner hole 12a of the stator 12. The stator 12 has a stator outer cylinder 12b formed of metal or the like fixed to the outer peripheral portion by adhesion or the like, and the inner cylinder portion and the stator outer cylinder are integrally housed in the stator casing 10. Note that the stator outer cylinder 12b and the stator casing 10 may be integrally formed.

[0048] The stator casing 10 is configured to house the stator 12 therein in a non-rotatable manner. The stator casing 10 is formed in a cylindrical shape of, for example, a metal such as stainless steel. Further, a discharge nozzle 18 (also referred to as an end stud 18) is provided on the tip side (front end side) of the stator casing 10. The discharge nozzle 18 has a fluid discharge port 18b formed to open on the tip side. Note that the discharge nozzle 18 may be integrally formed with the stator casing 10. In the present embodiment, the stator casing 10 includes a first stator casing 14 and a second stator casing 16. Further, a moving mechanism 50 is provided in the stator casing 10.

[0049] The second stator casing 16 is formed in a cylindrical shape along the axial direction, and the first stator casing 14 is inserted therein. The second stator casing 16 is configured to hold the first stator casing 14 so as to be relatively movable (slidable) in the axial direction. The second stator casing 16 has a discharge nozzle 18 provided on the tip side. The rear end side of the second stator casing 16 is connected, for example, by being inserted into the front end side of a pump casing 20 described later. Further, a moving groove 54 for moving an operation unit 52 described later is formed in a spiral shape on the outer periphery of the second stator casing 16. The second stator casing 16 is configured to form a part of the moving mechanism 50 described later.

[0050] The first stator casing 14 is designed to support the stator 12 so that it cannot move relative to it in the axial direction. In this embodiment, the first stator casing 14 is divided into two parts in the axial direction. The first stator casing 14 is integrated with the stator 12 by sandwiching the stator 12 from both sides in the axial direction and fastening them with bolts. In addition to the above, the first stator casing 14 and the stator 12 can be integrated by various means such as bonding and engagement. Furthermore, in this embodiment, the first stator casing 14 is inserted inside the second stator casing 16, which will be described later, and can move relative to the second stator casing 16 in the axial direction. In this embodiment, the first stator casing 14 is designed to slide along the axial direction of the second stator casing 16. The first stator casing 14 is designed to constitute a part of the moving mechanism 50, which will be described later. An operating part 52, which will be described later, is connected to the outer circumference of the first stator casing 14. Therefore, by rotating the operating unit 52 in a spiral motion along the movable groove 54, the first stator casing 14 can move axially while rotating relative to the second stator casing 16.

[0051] The pump casing 20 is positioned between the stator casing 10 and the bearing housing 30, which will be described later. The pump casing 20 is formed in a substantially cylindrical shape using a material such as metal (stainless steel, etc.). The pump casing 20 is connected to the rear end of the stator casing 10. In other words, the pump casing 20 is provided along the axial direction of the input shaft 3. In this embodiment, the pump casing 20 is positioned adjacent to the bearing housing 30 in the axial direction of the input shaft 3. The pump casing 20 may be positioned adjacent to the bearing housing 30, or a portion of it may overlap with it. In addition, other components may be interposed between the pump casing 20 and the bearing housing 30.

[0052] The pump casing 20 has a supply port 22 (suction port 22) formed on a part of its outer circumference for drawing in fluid. In this embodiment, the area around the suction port 22 is formed to protrude cylindrically radially outward from the pump casing 20, and a flange 22a for connecting piping or the like is formed at the protruding end. One end portion of the input shaft 3, the connecting portion 9, and the connecting shaft 7 are rotatably inserted inside the pump casing 20. The input shaft 3 is also rotatably supported at the rear end of the pump casing 20 (opposite the stator casing 10) via a shaft seal casing 40. The pump casing 20 is connected to the bearing housing 30 via a rectangular flange 24 formed on the rear end.

[0053] The pump casing 20 can deliver (transfer) the fluid drawn in from the suction port 22 toward the inner bore 12a of the stator 12 as the rotor 5 rotates. The fluid delivered to the stator 12 is discharged from the discharge port 18b as the rotor 5 rotates.

[0054] The bearing housing 30 is connected to the pump casing 20 via a shaft seal casing 40. The bearing housing 30 is formed in a substantially cylindrical shape using a material such as metal (stainless steel). The front end of the bearing housing 30 is connected to the flange 24 of the pump casing 20 via bolts or the like. Inside the bearing housing 30, a pair of bearings 32, 32 are housed at a predetermined distance apart so as not to rotate relative to each other. The input shaft 3 is inserted through the bearing housing 30, and the input shaft 3 is rotatably supported by the bearings 32, 32. In other words, the input shaft 3 is rotatably supported by the bearing housing 30.

[0055] A shaft seal casing 40 is connected to the front end (pump casing 20 side) of the bearing housing 30 so as not to rotate relative to it. The bearing housing 30 is provided with a support portion 36 on its lower end for support on a machine base (not shown) or the like. The bearing housing 30 is detachably fixed to the machine base (not shown) via bolts (not shown) or the like. The bearing housing 30 also houses the bearings 32, 32 so as not to move relative to them.

[0056] The shaft seal casing 40 is provided between the bearing housing 30 and the pump casing 20. The shaft seal casing 40 is formed in a cylindrical shape using a material such as metal (stainless steel). The shaft seal casing 40 has an inner diameter that is approximately the same as or slightly larger than the outer diameter of the input shaft 3, allowing the input shaft 3 to be inserted through it. The shaft seal casing 40 is provided with a shaft seal 42 on its inner circumference, which keeps the space between the input shaft 3 and the shaft seal casing 40 (around the input shaft 3) sealed when the input shaft 3 is inserted. As a result, the shaft seal 42 can prevent fluid from inside the pump casing 20 from entering the bearing housing 30. Here, for example, a gland packing is used for the shaft seal 42. In addition to gland packing, various sealing members such as lip seals (lip packings) and mechanical seals can be used for the shaft seal 42. The rear end of the shaft seal casing 40 is coupled to the inner circumference of the front end of the bearing housing 30.

[0057] The front end of the shaft seal casing 40 is fitted onto the rear end of the pump casing 20. In other words, at least a portion of the shaft seal casing 40 overlaps with the pump casing 20. The space between the shaft seal casing 40 and the pump casing 20 is sealed with an appropriate O-ring to prevent fluid from leaking out of the pump casing 20.

[0058] The moving mechanism 50 moves the stator 12 closer to and further away from the rotor 5 along the axial direction of the input shaft 3. The details of the moving mechanism 50 in this embodiment will be described below with reference to Figures 1 and 2.

[0059] The moving mechanism 50 includes a helical moving groove 54 formed on the outer circumference of the second stator casing 16 such that a helical axis extends along the axial direction of the input shaft 3, and an operating part 52 that can move integrally with the first stator casing 14 along the moving groove 54. In this embodiment, the moving mechanism 50 includes the first stator casing 14 and the second stator casing 16, as described above.

[0060] As shown in Figure 2(a), the movable groove 54 is formed spirally in the second stator casing 16 at a predetermined pitch and angle such that the spiral axis extends along the axial direction of the input shaft 3. In this embodiment, the movable groove 54 is formed spirally over 180 degrees on the upper outer circumference of the second stator casing 16. Here, in this embodiment, the movable groove 54 is provided on the outer circumference of the second stator casing 16, but it is not limited to this, and the movable groove 54 can be provided at various locations on the second stator casing 16. Considering the ease of forming the movable groove 54 and the operability of the operating part 52, the movable groove 54 can preferably be formed on the outer circumference of the second stator casing 16.

[0061] The operating part 52 is formed, for example, as a knob that protrudes radially outward from the second stator casing 16. As shown in Figure 1, the base end of the operating part 52 is fixed to the first stator casing 14.

[0062] The operating unit 52 can switch between a fixed state, which prevents relative movement of the first stator casing 14 and the second stator casing 16 in the axial direction, and an unfixed state, which allows relative movement of the first stator casing 14 and the second stator casing 16 in the axial direction.

[0063] In this embodiment, the switching between the fixed and unfixed states of the operating unit 52 can be performed, for example, through the engagement hole 54a formed in the movable groove 54. This will be explained in detail below.

[0064] The movable groove 54 has at least one engagement hole 54a (three in this embodiment) formed therein. The engagement hole 54a corresponds to a so-called counterbore and serves to fix the operating part 52. The engagement hole 54a is formed to be able to engage with the operating part 52 at a predetermined position along the movable groove 54. By engaging with the operating part 52, the engagement hole 54a is intended to suppress the movement of the operating part 52. In other words, the engagement of the engagement hole 54a and the operating part 52 makes it impossible for the first stator casing 14 and the second stator casing 16 to move relative to each other in the axial direction (also referred to as a fixed state).

[0065] In this embodiment, the engagement holes 54a are formed along the path of the movable groove 54 at positions of 0 degrees, 90 degrees, and 180 degrees around the axis of the input shaft 3. Therefore, in this embodiment, by moving the operating part 52 along the movable groove 54 in 90-degree increments, the operating part 52 engages with each engagement hole 54a and is fixed in place. In other words, when the operating part 52 is moved along the movable groove 54, the engagement holes 54a engage with the operating part 52, thereby positioning and fixing the first stator casing 14 and the second stator casing 16 at predetermined positions in the axial direction. In this embodiment, the engagement holes 54a are formed, for example, as counterbore holes.

[0066] Furthermore, in this embodiment, for example, a counterbore hole is formed as a screw hole, and a screw portion (not shown) provided on one end of the operating part 52 is screwed into the counterbore hole. With this configuration, the operating part 52 can be fixed and unlocked by rotating the operating part 52. Although not shown, for example, the operating part 52 may be provided with a small diameter portion that can move along the movable groove 54 and a larger diameter portion that engages with the engagement hole 54a, and the engagement state between the operating part 52 and the engagement hole 54a can be switched by switching the height positions of the small diameter portion and the large diameter portion of the operating part 52 by biasing force such as a spring. This allows the operating part 52 to switch between a fixed state and an unfixed state.

[0067] Here, as shown in Figures 1 and 2(a), the moving mechanism 50 can move the first stator casing 14 and the second stator casing 16 relative to each other along the axial direction by rotating the operating part 52 along the moving groove 54 when the operating part 52 is not fixed. In this embodiment, the first stator casing 14 can be moved axially relative to the second stator casing 16 by moving the operating part 52 along the moving groove 54. As a result, the moving mechanism 50 can adjust the tightening allowance and gap (also referred to as tightening allowance, etc.) of the rotor 5 and the stator 12.

[0068] Furthermore, in this embodiment, as shown in Figures 2(a) and 2(b), the single-screw eccentric pump 1 is provided with a pair of locking parts 56, 56.

[0069] The locking parts 56, 56 are designed to tighten the first stator casing 14 and the second stator casing 16 so that they move closer to each other in the radial direction around their axes. The locking parts 56, 56 can be switched between a tightened state and an untightened state. This allows the locking parts 56, 56 to suppress vibrations during operation of the single-screw eccentric pump 1. Specifically, as shown in Figure 2(b), the locking part 56 is equipped with an operating handle 56a, etc. Since the locking parts 56, 56 are provided symmetrically in the front-to-back direction along the axial direction, only the description of one locking part 56 will be given, and the description of the other locking part 56 will be omitted.

[0070] A notch, known as a split 57, is formed on the outer circumference of the second stator casing 16 along the axial direction. The second stator casing 16 can be tightened radially by tightening the split 57. The split 57 can be switched between a tightened state and an untightened state by the rotational operation of the operating handle 56a, which will be described later. Specifically, the locking portion 56 is provided with a pair of flanges 56b, 56b that protrude radially and face each other. The pair of flanges 56b, 56b have, for example, female threads (not shown) formed on them.

[0071] The operating handle 56a is provided with an operating shaft 56c in a direction intersecting the operating handle 56a. The operating shaft 56c has, for example, a male screw (not shown) formed at its tip. The operating shaft 56c is positioned to intersect the axial direction of the input shaft 3, and the tip of the operating shaft 56c is screwed into a pair of flanges 56b, 56b. Therefore, by rotating the operating handle 56a, it is possible to switch between a tightened state (tightened state of the split 57) and an untightened state (untightened state of the split 57).

[0072] Here, the moving groove 54 can be formed in a straight line, for example. However, considering the resistance to movement of the operating part 52, it is desirable to form it as a helical groove having a predetermined pitch and angle. Specifically, by rotating the operating part 52 in a helical direction, the lever principle and the inclined plane principle can be utilized, thereby improving the operability of the operating part 52. On the other hand, when the single-axis eccentric screw pump 1 is driven, the operating part 52 comes into contact with the moving groove 54 due to the discharge pressure, so unintended movement of the stator 12 and the operating part 52 can be suppressed. Furthermore, by forming the moving groove 54 as a helical groove, the operating part 52 can be moved using rotational thrust in the helical direction, thus reducing the operating force of the operating part 52.

[0073] The above describes the configuration of one embodiment of the single-screw eccentric pump 1 of the present invention. Next, the operation and effects of the single-screw eccentric pump 1 according to this embodiment will be described. The single-screw eccentric pump 1 according to the above embodiment can be configured as follows, for example, and this configuration can produce the following unique effects.

[0074] (a) The single-screw eccentric pump 1 of the present invention described above comprises an input shaft 3 that rotates by the power of a drive unit 2, a rotor 5 that is eccentrically rotatable with respect to the input shaft 3 and is composed of a male screw-type shaft body, and a stator 12 that is formed in the shape of a female screw through which the rotor 5 can be inserted, and is characterized in that either or both of the outer diameter of the rotor 5 and the inner diameter of the inner bore 12a of the stator 12 are formed to decrease from one end to the other, or the amount of eccentricity of the rotor 5 is changed, and is provided with a moving mechanism 50 that moves the stator 12 closer to and further away from the rotor 5 along the axial direction of the input shaft 3.

[0075] In the single-screw eccentric pump 1 of the present invention, either the outer diameter of the rotor 5 or the inner diameter of the inner bore 12a of the stator 12, or both, are formed to decrease from one end to the other, or the eccentricity of the rotor 5 can be changed, or both. Therefore, in the single-screw eccentric pump 1 of the present invention, even if the rotor 5 and stator 12 change in volume due to temperature changes or wear out, there is no need to replace the rotor 5 or stator 12, and the overlap or gap (collectively referred to as overlap, etc.) of the rotor 5 and stator 12 can be easily adjusted.

[0076] Furthermore, the single-screw eccentric pump 1 of the present invention allows the stator 12 to move closer to and further away from the rotor 5 by the moving mechanism 50. This simplifies the structure compared to moving the rotor 5, which is a rotating component, and also facilitates adjustment of the tension between the rotor 5 and the stator 12.

[0077] (b) The single-screw eccentric pump 1 of the present invention described above is provided with a stator casing 10 that houses a stator 12 and is formed to extend along the axial direction, the stator casing 10 comprising a first stator casing 14 that supports the stator 12 so that it cannot move relative to it in the axial direction, and a second stator casing 16 that holds the first stator casing 14 so that it can move relative to it in the axial direction, and the moving mechanism 50 is characterized by moving the first stator casing 14 and the second stator casing 16 relative to each other in the axial direction.

[0078] The single-screw eccentric pump 1 of the present invention, with this configuration, allows the first stator casing 14 to move relative to the second stator casing 16, thereby allowing the first stator casing 14 and stator 12 to move closer to and further away from the rotor 5. As a result, the single-screw eccentric pump 1 of the present invention can have a simpler structure compared to when the rotor 5, which is a rotating component, is moved, and adjustments such as the tension between the rotor 5 and stator 12 can be easily made.

[0079] (c) In the single-screw eccentric pump 1 of the present invention described above, the moving mechanism 50 comprises a moving groove 54 formed along the axial direction in the second stator casing 16, and an operating part 52 that can move integrally with the first stator casing 14 along the moving groove 54, and is characterized in that the first stator casing 14 and the second stator casing 16 are moved relative to each other along the axial direction by moving the operating part 52 along the moving groove 54.

[0080] The single-screw eccentric pump 1 of the present invention allows the first stator casing 14 to be moved integrally with the stator 12 along the axial direction by moving the operating unit 52 along the axial direction of the input shaft 3 (hereinafter also simply referred to as the axial direction). As a result, the single-screw eccentric pump 1 of the present invention allows adjustment of the tightening tolerance of the rotor 5 and stator 12 by operating the operating unit 52. Therefore, the single-screw eccentric pump 1 of the present invention allows for easy adjustment of the tightening tolerance of the rotor 5 and stator 12 by easily operating the operating unit 52 from the outside of the main body.

[0081] (d) The single-screw eccentric pump 1 of the present invention described above is characterized in that the movable groove 54 is formed in the second stator casing 16 in a helical shape at a predetermined pitch and angle such that the helical axis extends along the axial direction, and the first stator casing 14 and the second stator casing 16 are moved relative to each other along the axial direction by rotating the operating unit 52 along the movable groove 54.

[0082] The single-screw eccentric pump 1 of the present invention, with this configuration, allows the stator 12 to be moved axially relative to the rotor 5 in conjunction with the first stator casing 14 by operating the operating unit 52. As a result, the single-screw eccentric pump 1 of the present invention can reduce the resistance to movement of the operating unit 52 even when resistance is generated when the rotor 5 moves relative to the stator 12. That is, the operating unit 52 can be operated axially by utilizing the principle of leverage, the principle of inclined planes, and the thrust force of the screw. Therefore, the single-screw eccentric pump 1 of the present invention can reduce the burden on the operator and advantageously advance the automation of adjustments such as the tightening allowance of the rotor 5 and stator 12.

[0083] (e) In the single-screw eccentric pump 1 of the present invention described above, the operating unit 52 is switchable between a fixed state in which relative movement of the first stator casing 14 and the second stator casing 16 in the axial direction is impossible, and an unfixed state in which relative movement of the first stator casing 14 and the second stator casing 16 in the axial direction is permitted. In the unfixed state, the operating unit 52 is moved along the moving groove 54 by the moving mechanism 50, thereby moving the first stator casing 14 and the second stator casing 16 relative to each other along the axial direction. In the fixed state, the first stator casing 14 and the second stator casing 16 are positioned and fixed at predetermined positions in the axial direction.

[0084] The single-screw eccentric pump 1 of the present invention allows the first stator casing 14 and the second stator casing 16 to be moved relative to each other in the axial direction by operating the operating unit 52, which is in an unfixed state. Furthermore, the single-screw eccentric pump 1 of the present invention allows the first stator casing 14 (stator 12) and the second stator casing 16 to be positioned and fixed at predetermined positions in the axial direction by fixing the operating unit 52. Therefore, the single-screw eccentric pump 1 of the present invention allows for easy adjustment of the tension between the rotor 5 and the stator 12 by operating the operating unit 52, and maintains the axial position of the rotor 5 and the stator 12 in the adjusted position.

[0085] (f) The single-screw eccentric pump 1 of the present invention described above is equipped with a locking part 56 that tightens the first stator casing 14 and the second stator casing 16 so that they approach each other in the radial direction around the axis, and is characterized in that the locking part 56 can be switched between a tightened state and an untightened state.

[0086] The single-screw eccentric pump 1 of the present invention, with this configuration, can reduce the gap between the first stator casing 14 and the second stator casing 16 when the first stator casing 14 and the second stator casing 16 are tightened. As a result, the single-screw eccentric pump 1 of the present invention can suppress vibrations during operation. The locking part 56 can also suppress relative rotation and relative movement of the first stator casing 14 and the second stator casing 16 by, for example, clamping and tightening the outer circumference of the second stator casing 16. Furthermore, the locking part 56 should be configured to allow switching between a tightened state and an untightened state by, for example, rotational operation using a knob or handle.

[0087] (g) In the single-screw eccentric pump 1 of the present invention described above, the moving groove 54 has at least one engagement hole 54a at a predetermined position along the moving groove 54 that engages with the operating part 52 to suppress the movement of the operating part 52, and the moving mechanism 50 moves the operating part 52 along the moving groove 54 and engages the operating part 52 with the engagement hole 54a to position and fix the first stator casing 14 and the second stator casing 16 at predetermined positions in the axial direction.

[0088] The single-screw pump 1 of the present invention allows the operating unit 52 to be fixed at the position where the engagement hole 54a is formed, by forming an engagement hole 54a in the moving groove 54. Therefore, the single-screw pump 1 of the present invention allows the relative amount of axial movement of the first stator casing 14 and the second stator casing 16 to be easily adjusted by the position where the engagement hole 54a is formed. Here, the engagement hole 54a can preferably be a counterbore, for example. When the engagement hole is formed as a counterbore, for example, the counterbore can be formed as a screw hole, and a screw portion (not shown) provided on one end of the operating unit 52 can be screwed into the counterbore. With this configuration, the operating unit 52 can be fixed and released by rotating the operating unit 52. Furthermore, if the engagement hole 54a is formed as a counterbore, for example, the shaft of the operating part 52 may be provided with a small-diameter portion that can pass through the movable groove 54 and a large-diameter portion that engages with the counterbore, and the small-diameter portion and the large-diameter portion of the shaft of the operating part 52 may be selectively switched using a spring or the like.

[0089] The above describes the configuration and operation and effects of one embodiment of the single-screw eccentric pump 1 of the present invention. Next, an embodiment of the single-screw eccentric pump 100 according to the first modified example of the present invention will be described below with reference to Figures 3 and 4.

[0090] <First Modification> The single-axis eccentric screw pump 100 according to the first modification has the same configuration as the embodiment described above, except for the configuration of the moving mechanism 50. Therefore, a description of the configuration similar to that of the embodiment described above will be omitted. Also, please note that the same reference numerals are used for the same components as in the embodiment described above.

[0091] As shown in Figure 3(a), the single-screw eccentric pump 100 according to the first modified example is designed to improve the operability of the operating section 52 in the embodiment described above.

[0092] The operating section 152 is fixed to the first stator casing 14 so as not to rotate relative to it, and has multiple handle shafts 152a (one pair in the first modification) in the direction around the axis, which are formed to extend in a direction intersecting the axial direction (orthogonal in the first modification). Specifically, as shown in Figure 3(c), the operating section 152 is provided with a sleeve 153 along the axial direction of the input shaft 3, and the handle shafts 152a, 152a are supported on the sleeve 153 so as to be perpendicular to the axial direction.

[0093] As shown in Figures 3(b) and 3(c), the sleeve 153 has a rotation stopper 153a for the stator 12 (first stator casing 14) at its axial front end. The sleeve 153 is integrated with the first stator casing 14 by tightening the rotation stopper 153a. Furthermore, as shown in Figure 4, the part of the sleeve 153 rearward of the rotation stopper 153a is inserted into the front end of the second stator casing 16 in a nested structure with respect to the second stator casing 16. The sleeve 153, together with the first stator casing 14 and the stator 12, can move relative to the second stator casing 16 in the axial direction.

[0094] In the single-screw eccentric pump 100, a plurality of movable grooves 154 (a pair in the first modified example) are formed spirally around the axis of the input shaft 3, corresponding to the handle shafts 152a, 152a. The pair of movable grooves 154, 154 are formed symmetrically on the circumferential surface of the second stator casing 16 in the direction of the axis of the input shaft 3. Each of the movable grooves 154, 154 is formed over at least 180 degrees around its axis.

[0095] Furthermore, in the first modified example of the single-axis eccentric screw pump 100, stay bolts 102, 102 are provided on both sides of the main body so as to be symmetrical with respect to the axis of the input shaft 3. The stay bolts 102, 102 are used to fasten the end stud 18 and the pump casing 20 together, thereby sandwiching and fixing the stator 12 between them.

[0096] As shown in Figure 3(a), a pair of handle shafts 152a, 152a are inserted through a pair of movable grooves 154, 154, respectively. The handle shafts 152a, 152a can move axially while rotating spirally along the movable grooves 154, 154. Here, the stay bolts 102, 102 are removed when the handle shafts 152a, 152a are rotated. The handle shafts 152a, 152a can reduce resistance during rotational operation by the principle of leverage.

[0097] In the first modified example, the handle shafts 152a, 152a (operating section 152) are integrated with the first stator casing 14 (stator 12) via the sleeve 153. Therefore, by rotating the handle shafts 152a, 152a spirally along the movable grooves 154, 154, they can be moved axially relative to the second stator casing 16 together with the sleeve 153 (stator 12, first stator casing 14). In other words, the moving mechanism 50 can move the first stator casing 14 and the operating section 152 together axially relative to the second stator casing 16 by rotating the pair of handle shafts 152a, 152a in the same direction along their respective movable grooves 154, 154.

[0098] In this first modified example, the single-screw eccentric pump 100 can be automated, for example, by performing the rotational movement of the handle shafts 152a, 152a using actuators or the like. In the first modified example, a pair of handle shafts 152a, 152a are provided, but the invention is not limited to this, and two or more pairs or three or more handle shafts 152a may be provided. It is desirable that the handle shafts 152a be provided at equal intervals in the direction of the axis from the viewpoint of even operation. Furthermore, it is desirable that the handle shafts 152a be provided in pairs, taking into consideration operability, cost, ease of manufacturing, etc. The length and shape of the handle shafts 152a can be changed as appropriate.

[0099] The single-screw eccentric pump 100 according to the first modified example can be configured as follows, for example, and this configuration can produce the following unique effects.

[0100] (h) The single-screw eccentric pump 100 of the present invention described above is characterized in that the operating unit 152 is fixed to the first stator casing 14 so as not to rotate relative to it, and has a plurality of handle shafts 152a formed to extend in a direction intersecting the axial direction in the direction of the axis, a plurality of movable grooves 154 are formed in the direction of the axis corresponding to the handle shafts 152a, the plurality of handle shafts 152a are inserted so as to be movable along the plurality of movable grooves 154 provided corresponding to each of them, and by rotating the plurality of handle shafts 152a in the same direction along the plurality of movable grooves 154 provided corresponding to each of them, the first stator casing 14 and the operating unit 52 move integrally with respect to the second stator casing 16 in the direction of the axis.

[0101] In the single-screw eccentric pump 100 of the present invention, the pair of handle shafts 152a, 152a in the operating section 152 are formed to intersect symmetrically in the axial direction, so that the pair of handle shafts 152a, 152a can be operated using the principles of levers and inclined planes. As a result, the single-screw eccentric pump 100 of the present invention can reduce the force required to operate the operating section 152 (handle shafts 152a). Therefore, the single-screw eccentric pump 100 of the present invention can reduce the burden on the operator (worker) and facilitate automation. Here, the pair of handle shafts 152a are preferably arranged perpendicular to the axial direction of the input shaft 3, and are preferably set to an appropriate length that reduces the movement resistance of the first stator casing 14 (stator 12).

[0102] The above describes the configuration and operation and effects of the single-screw eccentric pump 100 according to the first modified example of the present invention. Next, an embodiment of the single-screw eccentric pump 200 according to the second modified example of the present invention will be described below with reference to Figure 5. Note that in Figure 5, only the main parts related to the moving mechanism 50 are shown.

[0103] ≪Second Modification≫ The single-axis eccentric screw pump 200 according to the second modification has the same configuration as the embodiment described above, except for the configuration of the moving mechanism 50. Therefore, a description of the configuration similar to that of the embodiment described above will be omitted. Also, please note that the same reference numerals are used for the same components as in the embodiment described above.

[0104] As shown in Figure 5(a), in the second modified single-screw pump 200, relative axial movement of the first stator casing 14 and the second stator casing 16 is performed via a screw member 214 provided along the axial direction of the second stator casing 16. The details of the second modified single-screw pump 200 will be described below.

[0105] The second stator casing 16 has a large-diameter section 210 in its middle portion. A recess 212 is formed on the inner wall of the large-diameter section 210 so as to extend along the axial direction. Furthermore, a threaded member 214 constituting a moving mechanism 50 is provided on the outer circumference of the recess 212 of the second stator casing 16, extending along the axial direction. The threaded member 214 is screwed onto a nut member 216, which will be described later. Various bolts can be used for the threaded member 214. The threaded member 214 is rotatably supported relative to the second stator casing 16, and one end of the threaded member 214 is positioned to be accessible from a notch 217 formed in the second stator casing 16. Therefore, by rotating the threaded member 214 through the notch 217, the stator 12 can be moved axially integrally with the nut member 216.

[0106] The first stator casing 14 has a nut member 216, which constitutes the moving mechanism 50, supported in the axial middle portion of its outer circumference. The nut member 216 is positioned to be axially movable along a recess 212 of the second stator casing 16. The nut member 216 has a screw hole (not shown) in the axial direction and can be screwed into a screw member 214. As the screw member 214 rotates, the nut member 216 can move axially integrally with the first stator casing 14 (stator 12). In other words, the moving mechanism 50 can move the first stator casing 14 and the second stator casing 16 relative to each other in the axial direction by rotating the screw member 214 and moving the screwed position of the nut member 216. As a result, the single-screw eccentric pump 200 can adjust the tightening allowance of the rotor 5 and the stator 12.

[0107] Furthermore, as shown in Figure 5(b), the single-screw eccentric pump 200 is provided with a locking portion 56, similar to the embodiment described above. Therefore, by tightening the locking portion 56, the gap between the first stator casing 14 and the second stator casing 16 is reduced, and vibrations during operation of the single-screw eccentric pump 200 are suppressed.

[0108] Here, for example, if a scale or the like that can identify the position of the nut member 216 is provided around the nut member 216 of the second stator casing 16, the tightening allowance of the rotor 5 and stator 12 can be easily and accurately adjusted. Furthermore, the single-axis eccentric screw pump 200 according to the second modified example can be automated by driving the screw member 214 and the locking part 56 with an actuator such as a motor.

[0109] The single-screw eccentric pump 200 according to the second modified example can be configured as follows, for example, and this configuration can produce the following unique effects.

[0110] (i) In the single-screw eccentric pump 200 of the present invention described above, a screw member 214 is provided on the second stator casing 16 along the axial direction, a nut member 216 that screws onto the screw member 214 is supported on the first stator casing 14, the nut member 216 is movable integrally with the first stator casing 14 in the axial direction as the screw member 214 rotates, and the moving mechanism 50 moves the screw position of the nut member 216, thereby moving the first stator casing 14 and the second stator casing 16 relative to each other in the axial direction.

[0111] The single-screw eccentric pump 200 of the present invention, with this configuration, allows the screw position of the screw member 214 to be moved, thereby allowing the first stator casing 14 and the second stator casing 16 to move relative to each other in the axial direction. As a result, the single-screw eccentric pump 200 of the present invention allows for easy adjustment of the tightening allowance of the rotor 5 and stator 12 by adjusting the tightening of the screw member 214. By configuring the screw member 214 to be accessible from the outside of the single-screw eccentric pump 200, the tightening allowance of the rotor 5 and stator 12 can be easily adjusted without disassembling the single-screw eccentric pump 200. Various types of screw members such as triangular screws, trapezoidal screws, and ball screws can be used for the screw member 214.

[0112] The above describes the configuration and operation and effects of the single-screw eccentric pump 200 according to the second modified example of the present invention. Next, an embodiment of the single-screw eccentric pump 300 according to the third modified example of the present invention will be described below with reference to Figure 6. Note that in Figure 6, only the main parts related to the moving mechanism 50 are shown.

[0113] ≪Third Modification≫ The single-axis eccentric screw pump 300 according to the third modification has the same configuration as the second modification described above, except for the configuration of the moving mechanism 50. Therefore, a description of the configuration similar to that of the above-described embodiment will be omitted. Also, please note that the same reference numerals are used for the same components as in the above-described embodiment.

[0114] As shown in Figure 6(a), the single-screw eccentric pump 300 has a moving mechanism 50 that includes a first screw portion 310 and a second screw portion 312, etc. The single-screw eccentric pump 300 also includes a switching mechanism 320 (corresponding to the lock portion 56, see Figure 6(c)) as in the above embodiment. In the third modified example, the first stator casing 14 is divided into two parts in the axial direction, and the divided pieces are joined together.

[0115] The first threaded portion 310 is formed along the axial direction on at least a portion of the outer circumference of the first stator casing 14. That is, the first threaded portion 310 is formed as a male thread on the outer circumference of the first stator casing 14.

[0116] The second threaded portion 312 is formed along the axial direction on at least a portion of the inner circumference of the second stator casing 16. That is, the second threaded portion 312 is formed as an internal thread on the inner circumference of the second stator casing 16. Furthermore, the second threaded portion 312 is screwed into the first threaded portion 310. Therefore, by screwing the first threaded portion 310 and the second threaded portion 312 together, the first stator casing 14 and the second stator casing 16 move relative to each other in the axial direction.

[0117] Here, the threading direction of the first threaded portion 310 and the second threaded portion 312 is set, for example, in the same direction as the rotation direction (fluid delivery direction) of the rotor 5. As the rotor 5 rotates, it experiences rotational resistance with the stator 12. Therefore, if relative rotation between the first stator casing 14 and the second stator casing 16 is permitted, the stator 12 (first stator casing 14) rotates together with the rotor 5 as it rotates. Consequently, as the rotor 5 rotates, the stator 12 (first stator casing 14) rotates together with the rotor 5 in the direction of rotation, and the first stator casing 14 moves forward in the axial direction, as shown in Figure 6(b).

[0118] On the other hand, if the rotor 5 rotates in the opposite direction to the fluid delivery direction, the stator 12 rotates with it, and the first stator casing 14 moves to the rearward side in the axial direction, as shown in Figure 6(c).

[0119] As shown in Figure 6(d), the switching mechanism 320 switches between a relative rotation-impossible state in which the first stator casing 14 and the second stator casing 16 cannot rotate relative to each other, and a relative rotation-allowed state in which the first stator casing 14 and the second stator casing 16 can rotate relative to each other. Since the switching mechanism 320 has the same configuration as the locking part 56 in the above-described embodiment and the second modified example, some of the detailed explanation will be omitted.

[0120] The switching mechanism 320 (locking part 56) can switch to a relative rotation-impossible state (corresponding to a locked state) which prevents the first stator casing 14 and the second stator casing 16 from rotating relative to each other, and can switch to a relative rotation-allowed state (corresponding to an unlocked state) which allows the first stator casing 14 and the second stator casing 16 to rotate relative to each other. In other words, in the relative rotation-allowed state (unlocked state), the single-screw eccentric pump 300 can rotate the rotor 5 to screw in the first screw part 310 and the second screw part 312, thereby moving the first stator casing 14 and the second stator casing 16 in the axial direction. On the other hand, in the relative rotation-impossible state (locked state), the single-screw eccentric pump 300 can suppress the relative movement of the first stator casing 14 and the second stator casing 16 in the axial direction.

[0121] The single-screw eccentric pump 300 according to the third modified example can be configured as follows, for example, and this configuration can produce the following unique effects.

[0122] (j) The single-screw eccentric pump 300 of the present invention described above is equipped with a switching mechanism 320 that switches between a relative rotation-non-state in which the first stator casing 14 and the second stator casing 16 are unable to rotate relative to each other, and a relative rotation-allowed state in which relative rotation of the first stator casing 14 and the second stator casing 16 is permitted. The moving mechanism 50 is equipped with a first screw portion 310 formed on the outer circumference of the first stator casing 14 along the axial direction, and a second screw portion 312 formed on the inner circumference of the second stator casing 16 along the axial direction and screwed into the first screw portion 310. In the relative rotation-allowed state, the rotor 5 is rotated to screw the first screw portion 310 and the second screw portion 312 together, thereby allowing the first stator casing 14 and the second stator casing 16 to move relative to each other in the axial direction. In the relative rotation-non-state, relative movement of the first stator casing 14 and the second stator casing 16 in the axial direction is suppressed.

[0123] The single-screw eccentric pump 300 of the present invention, with this configuration, allows the first threaded portion 310 (first stator casing 14) and the second threaded portion 312 (second stator casing 16) to be screwed together as the rotor 5 rotates in a relative rotation-permitted state. As a result, the single-screw eccentric pump 300 of the present invention allows the first stator casing 14 and the second stator casing 16 to move relative to each other in the axial direction as the rotor 5 rotates in a relative rotation-permitted state. In other words, the single-screw eccentric pump 300 of the present invention can automatically adjust the tightening tolerance of the rotor 5 and the stator 12 by utilizing the rotation of the rotor 5.

[0124] On the other hand, with the single-screw eccentric pump 300 of the present invention, by having such a configuration, relative movement of the first stator casing 14 and the second stator casing 16 in the axial direction is suppressed when relative rotation is impossible. Therefore, if adjustments such as the tightening allowance of the rotor 5 and stator 12 are not made, the rotor 5 and stator 12 can be positioned at a predetermined position in the axial direction. Thus, with the single-screw eccentric pump 300 of the present invention, for example, adjustments such as the tightening allowance can be easily automated by providing an actuator that switches the first stator casing 14 and the second stator casing 16 between allowing relative rotation and not allowing relative rotation. In other words, with the single-screw eccentric pump 300 of the present invention, the power source of the drive unit 2 that drives the input shaft 3 can be used for adjusting the tightening allowance of the rotor 5 and stator 12. Therefore, by simply providing an actuator to switch between a state where relative rotation is impossible and a state where relative rotation is allowed, the adjustments such as the tightening allowance of the rotor 5 and stator 12 can be automated. As a result, cost reductions can be expected when automating the process.

[0125] The above describes the configuration and operation and effects of the single-screw eccentric pump 300 according to the third modified example of the present invention. Next, an embodiment of the single-screw eccentric pump 400 according to the fourth modified example of the present invention will be described below with reference to Figure 7. Note that in Figure 7, only the essential parts related to the moving mechanism 50 are shown.

[0126] ≪Fourth Modification≫ The single-axis eccentric screw pump 400 according to the fourth modification has the same configuration as the embodiment described above, except for the configuration of the moving mechanism 50. Therefore, a description of the configuration similar to that of the embodiment described above will be omitted. Also, please note that the same reference numerals are used for the same components as in the embodiment described above.

[0127] The fourth modified example of the single-axis eccentric screw pump 400, as shown in Figure 7, is characterized in that the moving mechanism 50 is equipped with a cylinder 420 (also referred to as an actuator 420) that is operated by hydraulic or pneumatic pressure.

[0128] The second stator casing 16 has a large-diameter portion 410, similar to the second modified example. Inside the large-diameter portion 410, a cylinder chamber 422 is formed, which constitutes a cylinder 420, extending in the axial direction. A first air port 424 is formed in the cylinder chamber 422 on the axially forward side, communicating with the cylinder chamber 422. A second air port 426 is also formed in the cylinder chamber 422 on the axially rear side, communicating with the cylinder chamber 422. In the single-screw eccentric pump 400 according to the fourth modified example, the cylinder chamber 422 is formed radially as a plurality of spline grooves. The number of spline grooves can be changed as appropriate, from one to multiple. The cylinder chamber 422 may also be formed as a keyway or a rail instead of spline grooves.

[0129] A movable member 430, which constitutes part of the moving mechanism 50, is attached to the outer circumference of the first stator casing 14. The movable member 430 can move axially within the cylinder chamber 422 in conjunction with the first stator casing 14 by a biasing force such as hydraulic or pneumatic pressure.

[0130] The first air port 424 and the second air port 426 can introduce a liquid such as oil or a gas such as air (both collectively referred to as oil, etc.) into the cylinder chamber 422. The timing of the introduction of the oil, etc. into the first air port 424 and the second air port 426 can be controlled by appropriate control means. By applying pressure such as hydraulic pressure to the first air port 424, the first stator casing 14 retracts axially together with the movable member 430. This adjusts the tension between the rotor 5 and the stator 12.

[0131] On the other hand, by applying pressure such as hydraulic pressure to the second air port 426, the first stator casing 14 moves forward axially, integrally with the movable member 430. This adjusts the tension between the rotor 5 and the stator 12. Although not shown in the figures, the single-axis eccentric screw pump 400 according to the fourth modified example is provided with a locking mechanism 56, similar to the second modified example. Alternatively, instead of the locking mechanism 56, a locking mechanism that can fix the movable member 430 in an appropriate position may be provided.

[0132] Furthermore, the single-screw eccentric pump 400 can improve disassembly by eliminating the need for tightening when disassembling the rotor 5 and stator 12, for example, by introducing oil or the like into the first air port 424 or the second air port 426 to adjust the pressure. In addition, the single-screw eccentric pump 400 can adjust the pre-pressure of the cylinder 420 by providing, for example, a spring member that biases the movable member 430 in the axial direction.

[0133] Thus, in the fourth modified example, the single-axis eccentric screw pump 400 has a cylinder 420 (also referred to as actuator 420) formed by a cylinder chamber 422 and a moving member 430. Here, the movement of the first stator casing 14 by the cylinder 420 can be performed while the rotor 5 is being rotated, or while the rotor 5 is stopped, or both.

[0134] The above is an example of the configuration of the single-screw eccentric pump 400 according to the fourth modified example. The single-screw eccentric pump 400 according to the fourth modified example can be configured as follows, for example, and this configuration can produce the following unique effects.

[0135] (k) In the single-screw eccentric pump 400 of the present invention described above, the first stator casing 14 is provided so as to be movable in the axial direction relative to the second stator casing 16, the second stator casing 16 has a cylinder chamber 422 into which fluid can be introduced, and the moving mechanism 50 moves the first stator casing 14 by introducing fluid into the cylinder chamber 422 and thereby biasing it in any direction along the axial direction.

[0136] The single-screw eccentric pump 400 of the present invention, with this configuration, can automatically adjust the tightening allowance of the rotor 5 and stator 12 with a simple configuration. Here, it is preferable that the cylinder chamber 422 can selectively introduce fluid from both sides along the axial direction of the second stator casing 16. Furthermore, it is sufficient that the fluid introduced into the cylinder chamber 422 can flow in either direction along the axial direction and bias the first stator casing 14 in either direction along the axial direction. Here, various fluids can be used, such as gases such as air, or liquids such as oil and water.

[0137] The above describes the configuration and operation and effects of the single-axis eccentric screw pump 400 according to the fourth modification of the present invention. Next, the configuration of the single-axis eccentric screw pump 500 according to the fifth modification, in which the actuator 420 related to the moving mechanism 50 is changed in the single-axis eccentric screw pump 400 according to the fourth modification, will be described below with reference to Figure 8. Note that only the main parts related to the moving mechanism 50 are shown in Figure 8.

[0138] ≪Fifth Modification≫ The single-axis eccentric screw pump 500 according to the fifth modification has the same configuration as the fourth modification described above, except for the configuration of the moving mechanism 50, so the explanation of the configuration which is the same as that of the above-described embodiment will be omitted. Also, please note that the same reference numerals are used for the same components as in the above-described embodiment.

[0139] As shown in Figure 8, in the fifth modified example of the single-screw eccentric pump 500, the cylinder 520 (also referred to as the actuator 520) is provided on the outside (outer circumference) of the second stator casing 16. In the fifth modified example, a large-diameter portion 510 is provided on the second stator casing 16, similar to the fourth modified example and the like.

[0140] A recess 512 is formed on the inner circumference of the large-diameter portion 510, extending along the axial direction. In addition, a movable member 514, which constitutes part of the moving mechanism 50, is provided on the outer circumference of the first stator casing 14. The movable member 514 can move along the recess 512 in the axial direction integrally with the stator 12 (first stator casing 14).

[0141] The cylinder 520 is designed to be operated by hydraulics, pneumatics, or the like. The cylinder 520 is equipped with a piston shaft 522 that can move back and forth in the axial direction. The tip of the piston shaft 522 is connected to the movable member 530 via bolts or the like. Therefore, by operating the cylinder 520 by hydraulics or the like, the first stator casing 14 can be moved in the axial direction via the movable member 530. This allows the single-axis eccentric screw pump 500 to adjust the tension between the rotor 5 and the stator 12.

[0142] Furthermore, although not shown in the illustration, the single-axis eccentric screw pump 500 according to the fifth modified example is provided with a locking mechanism 56, similar to the third modified example. Alternatively, instead of the locking mechanism 56, a locking mechanism (for example, a cylinder with a locking mechanism) that can fix the movable member 530 in an appropriate position may be provided. Also, while the single-axis eccentric screw pump 500 according to the fifth modified example uses a cylinder 520 as the actuator 520, the actuator 520 is not limited to a cylinder 520; various drive sources can be used. For example, a servo actuator using a servo motor or the like can also be used as the actuator 520.

[0143] The above are examples of the configurations of the single-screw eccentric pumps 400 and 500 according to the fourth and fifth modified examples. The single-screw eccentric pump 400 according to the fourth modified example and the single-screw eccentric pump 500 according to the fifth modified example can be configured as follows, for example, and this configuration can produce the following specific effects.

[0144] (l) In the single-screw eccentric pumps 400 and 500 of the present invention described above, the first stator casing 14 is provided so as to be movable in the axial direction relative to the second stator casing 16, and the moving mechanism 50 has actuators 420 and 520 for moving the first stator casing 14 in the axial direction.

[0145] The single-axis eccentric screw pumps 400 and 500 of the present invention, with this configuration, can move the first stator casing 14 in the axial direction by driving the actuators 420 and 520. This allows the single-axis eccentric screw pumps 400 and 500 of the present invention to automatically adjust the tightening allowance of the rotor 5 and stator 12. Various power sources such as air cylinders, hydraulic cylinders, air actuators, and servo actuators can be used for the actuators 420 and 520. Furthermore, in the single-axis eccentric screw pumps 400 and 500 of the present invention, for example, when using an air cylinder, an elastic member such as a spring can be provided in the operating axis direction, allowing the biasing force from the elastic member to be used for pressurization adjustment at the start of operation of the air cylinder. As a result, the single-axis eccentric screw pumps 400 and 500 of the present invention can reduce the load on the air cylinder, and thus a miniaturization of the air cylinder can be expected. Furthermore, in the case where an air cylinder is used in the single-screw eccentric pump 400 of the present invention, an air port is provided so that, for example, when disassembling the single-screw eccentric pump 400, air can be supplied through the air port. As a result, the single-screw eccentric pump 400 of the present invention can eliminate the need for tightening the rotor 5 and stator 12 when disassembling it, and thus an improvement in disassembly can be expected.

[0146] (m) In the single-axis eccentric screw pumps 400 and 500 of the present invention described above, the movement of the first stator casing 14 by the actuators 420 and 520 is characterized in that it is performed while the rotor 5 is being rotated, or while the rotor 5 is stopped, or both.

[0147] The single-screw eccentric pumps 400 and 500 of the present invention, with this configuration, can automatically adjust the tension between the rotor 5 and the stator 12, whether the rotor 5 is rotating or stopped. Therefore, the single-screw eccentric pumps 400 and 500 of the present invention can stably discharge fluids with high precision.

[0148] The above describes the configuration and operation and effects of the single-screw eccentric pumps 400 and 500 according to the fourth and fifth modifications of the present invention. Next, an embodiment of the single-screw eccentric pump 600 according to the sixth modification of the present invention will be described below with reference to Figures 9 and 10.

[0149] <<Sixth Modification>> The single-axis eccentric screw pump 600 according to the sixth modification has the same configuration as the embodiment described above, except for the configuration of the moving mechanism 50, so the explanation of the configuration similar to the embodiment described above will be omitted. Also, please note that the same reference numerals are used for the same components as in the embodiment described above.

[0150] In the sixth modified example of the single-screw eccentric pump 600, as shown in Figure 9(a), the insertion portion 10a at the rear end of the stator casing 10 is inserted into the front end of the pump casing 20. In other words, the single-screw eccentric pump 600 is configured such that the stator casing 10 and the pump casing 20 are nested together.

[0151] The stator casing 10 is formed to house the stator 12 in a manner that prevents relative rotation and extends along the axial direction. The stator casing 10 is provided with a forward-side movable member 630f (also referred to as movable member 630) that is enlarged in diameter at the axial front end. The forward-side movable member 630f can abut against the nozzle-side flange 18a, which will be described later. A first bolt hole (not shown) is formed through the forward-side movable member 630f along the axial direction. The forward-side movable member 630f is considered to constitute part of the movable mechanism 50.

[0152] An insertion portion 10a is formed at the rear end of the stator casing 10, with a diameter reduced to allow insertion into the opening at the front end of the pump casing 20. The insertion portion 10a is formed to extend behind the rear end of the stator 12 and is configured to be movable in the axial direction relative to the pump casing 20. In other words, the stator casing 10 is arranged integrally with the stator 12 so as to be movable in the axial direction relative to the pump casing 20.

[0153] Furthermore, the stator casing 10 is provided with a rearward moving member 630r (also referred to as moving member 630) at the boundary between the stator 12 and the insertion portion 10a. The rearward moving member 630r is enlarged in diameter and can abut against the pump casing side flange 20a, which will be described later. Similar to the frontward moving member 630f, a first bolt hole (not shown) is formed through the rearward moving member 630r along the axial direction. The rearward moving member 630r is considered to constitute part of the moving mechanism 50. The frontward moving member 630f and the rearward moving member 630r are fastened together by a stay 638 that extends along the axial direction to maintain a predetermined distance between them.

[0154] A pump casing 20 is connected to the axial rear end of the stator casing 10. An enlarged pump casing side flange 20a is formed on the front end of the pump casing 20. A second bolt hole (not shown) is formed along the axial direction of the pump casing side flange 20a, opposite to the first bolt hole (not shown) of the rear movable member 630r.

[0155] Furthermore, a discharge nozzle 18 (also referred to as an end stud 18) is provided at the tip of the stator 12, spaced apart from the stator 12. The discharge nozzle 18 can move relative to the stator 12 in the axial direction. The discharge nozzle 18 has a nozzle-side flange 18a that is enlarged at the rear end. A second bolt hole (not shown) is formed in the nozzle-side flange 18a along the axial direction, opposite to the first bolt hole (not shown) in the front-side movable member 630f.

[0156] The moving mechanism 50 is equipped with a pair of adjustment bolts 640. Each adjustment bolt 640 has an outer bolt portion 642 and an inner bolt portion 644. The adjustment bolt 640 constitutes a so-called double bolt.

[0157] The outer bolt portion 642 consists of a flange 642b formed on one end and a cylindrical portion (not shown) having a hollow hole and a first threaded portion 642a formed on its outer circumference. The outer bolt portion 642 is screwed into a first bolt hole provided in the front movable member 630f, and its tip is made capable of contacting the outer circumference of a second bolt hole provided in the nozzle-side flange 18a of the discharge nozzle 18.

[0158] The inner bolt portion 644 is inserted through a hollow hole (not shown) in the outer bolt portion 642, and a second threaded portion 644a is formed on its outer circumference. The inner bolt portion 644 is screwed into the second bolt hole to fasten the front moving member 630f and the nozzle-side flange 18a, and the rear moving member 630r and the pump casing-side flange 20a. A nut 644b is screwed onto the head of the inner bolt portion 644. When the nut 644b is tightened, it comes into contact with the head of the outer bolt portion 642, suppressing the movement (rotation) of the inner bolt portion 644 (fixing the inner bolt portion 644). On the other hand, by loosening the nut 644b, the fixing of the inner bolt portion 644 is released, and the movement (rotation) of the outer bolt portion 642 is permitted.

[0159] The moving mechanism 50 according to the sixth modified example is configured as described above. Next, the adjustment operation of the rotor 5 and stator 12 by the moving mechanism 50 will be explained with reference to Figures 9(a) and 9(b).

[0160] As shown in Figures 9(a) and 9(b), the moving mechanism 50 can adjust the distance between the stator 12 and the pump casing 20, and between the stator 12 and the discharge nozzle 18, depending on the degree of tightening of the outer bolt portion 642. Specifically, first, prior to adjustment, the nut 644b of the inner bolt portion 644 is loosened, releasing the fixation by the inner bolt portion 644 and enabling operation of the outer bolt portion 642. Next, from the state shown in Figure 9(a), as the outer bolt portion 642 of the rear moving member 630r is tightened, the first threaded portion 642a screws into the first bolt hole of the rear moving member 630r and contacts the outer circumference of the second bolt hole (not shown) of the pump casing side flange 20a, pressing against the pump casing side flange 20a (pump casing 20). As a result, as shown in Figure 9(b), the distance between the rear moving member 630r and the pump casing 20 increases (they separate). Furthermore, the rearward moving member 630r moves integrally with the stator 12 and the stator casing 10, so that the stator 12 moves away from the rotor 5. In other words, adjustments such as the tightening allowance of the rotor 5 and the stator 12 are made. After the adjustments such as the tightening allowance of the rotor 5 and the stator 12 are made, the nut 644b is tightened to fix the inner bolt portion 644 and the outer bolt portion 642.

[0161] On the other hand, by loosening the nut 644b of the inner bolt portion 644 to release the fixing by the inner bolt portion 644, and then loosening the outer bolt portion 642 of the front moving member 630f from the state shown in Figure 9(a), the first threaded portion 642a is loosened from the first bolt hole (not shown) of the front moving member 630f, and the inner bolt portion 644 is pulled. As a result, the front moving member 630f moves closer to the nozzle-side flange 18a, and the distance between the nozzle-side flange 18a and the front moving member 630f decreases (they get closer). Also, since the front moving member 630f moves integrally with the stator 12 and the stator casing 10, the stator 12 moves closer to the rotor 5. In other words, adjustments such as the tightening allowance of the rotor 5 and the stator 12 are made. After adjusting the tightening allowance of the rotor 5 and stator 12, the nut 644b is tightened to fix the inner bolt portion 644 and the outer bolt portion 642. Furthermore, by providing appropriate scales on the stator casing 10, pump casing 20, discharge nozzle 18, etc., it becomes easier to adjust the amount of movement (travel distance) of the stator casing 10 (stator 12).

[0162] Furthermore, although details are omitted here, to change from the state in Figure 9(b) to the state in Figure 9(a), the opposite operation should be performed on the rear moving member 630r and the front moving member 630f. That is, to change from the state in Figure 9(b) to the state in Figure 9(a), the first threaded portion 642a of the rear moving member 630r is loosened to bring the rear moving member 630r closer to the pump casing side flange 20a, while the first threaded portion 642a of the front moving member 630f is tightened to separate the stator casing 14 from the nozzle side flange 18a. This adjusts the tightening allowance of the rotor 5 and stator 12.

[0163] Although not shown in the diagram, the adjustment of the adjustment bolt 640 by the moving mechanism 50 can be automated, for example, by driving the adjustment bolt 640 with an actuator or the like.

[0164] The above is an example of the configuration of the single-screw eccentric pump 600 according to the sixth modified example. The single-screw eccentric pump 600 according to the sixth modified example can be configured as follows, for example, and this configuration can produce the following unique effects.

[0165] (n) The single-screw eccentric pump 600 of the present invention described above comprises a stator casing 10 that houses a stator 12 and is formed to extend along the axial direction, a pump casing 20 arranged along the axial direction relative to the stator 12, and a discharge nozzle 18 provided on the tip side of the stator 12, wherein the stator casing 10 is integrally arranged with the stator 12 and movable in the axial direction relative to at least one of the discharge nozzle and the pump casing 20, and the moving mechanism 50 comprises at least one moving member 630 provided on at least one end side of the stator 12 in the axial direction and movable integrally with the stator 12 in the axial direction, and at least one adjustment bolt 640, wherein a second bolt hole for screwing the adjustment bolt 640 is formed through the moving member 630 along the axial direction, and the discharge nozzle 18 and the pump casing 20 At least one side of the pump casing 20 has a second bolt hole formed along the axial direction for fastening an adjustment bolt 640. The adjustment bolt 640 comprises an outer bolt portion 642 having a first threaded portion 642a formed on its outer circumference and a hollow hole, and an inner bolt portion 644 inserted into the hollow hole so as to be rotatable relative to the outer bolt portion 642, with a second threaded portion 644a formed on at least a part of its outer circumference. The outer bolt portion 642 can be screwed into the second bolt hole so that its tip can abut against the outer circumference of the second bolt hole, and the inner bolt portion 644 can be screwed into the second bolt hole so that its tip fastens either the movable member 630 and the discharge nozzle 18, or the movable member 630 and the pump casing 20, or both. The axial movement distance of the stator 12 can be adjusted according to the degree of tightening of the outer bolt portion 642.

[0166] The single-screw eccentric pump 600 of the present invention, with this configuration, allows the degree of tightening of the adjustment bolt 640 to move (move forward and backward) the screw position between the first threaded portion 642a and the second bolt hole in the outer bolt portion 642 in the axial direction. As a result, the moving member 630 moves forward and backward along the axial direction, and the stator casing 10 (stator 12) moves toward and away from the rotor 5 integrally with the moving member 630. In other words, the single-screw eccentric pump 600 of the present invention can adjust the tightening tolerance of the rotor 5 and the stator 12. Here, it is sufficient to provide at least one adjustment bolt 640, and two or more adjustment bolts 640 may be provided. When two or more adjustment bolts 640 are provided, for example, a pair of adjustment bolts 640, 640 may be provided on both the discharge nozzle 18 (end stud 18) side and the pump casing 20 side of the stator casing 10 so that their directions of movement are opposite to each other. Furthermore, if two or more adjustment bolts 640 are provided, it is preferable to arrange each adjustment bolt 640 evenly around the axis of the movable member. This allows the single-axis eccentric screw pump 600 of the present invention to adjust the tightening allowance of the rotor 5 and stator 12 with high precision.

[0167] The above describes the configuration and operation and effects of the single-screw eccentric pump according to embodiments and modifications of the present invention. However, the single-screw eccentric pumps 1, 100, 200, 300, 400, 500, and 600 of the present invention are not limited to the embodiments or modifications described above, and various modifications can be made within the scope of the invention. For example, the single-screw eccentric pumps 1, 100, 200, 300, 400, 500, and 600 may not have some or all of the configurations described in (b) to (m) above, or they may have some or all of the configurations described in (b) to (m) above, along with other configurations.

[0168] In this embodiment, the input shaft 3 is connected to the rotor 5 via a connecting shaft 7. However, various forms of input shaft 3 can be used, such as one that is connected to the rotor 5 without a connecting shaft 7, or one or more connecting shafts 7 and connecting parts 9. When the input shaft 3 is directly connected to the rotor 5, it is preferable to connect it in such a way that the rotor 5 can rotate eccentrically. In this embodiment, the rotor 5 is formed as a single groove, but various numbers of grooves can be used for the rotor 5. The shape, size, and material of the rotor 5 can also be changed to various types depending on the type of fluid, etc. In addition, various numbers of grooves can be used for the stator 12 depending on the number of grooves of the rotor 5. The shape, size, and material of the stator 12 can also be used depending on the shape, size, and material of the rotor 5.

[0169] Furthermore, the shape and size of the main body of the single-screw eccentric pump 1 can be various shapes and sizes within the scope of the present invention. In addition, although a shaft seal casing 40 is provided in this embodiment, the shaft seal casing 40 may be provided only as needed, and it is also possible to omit the shaft seal casing 40. In such cases, various means such as sealing members that can seal the space between the input shaft 3, the bearing housing 30, and the pump casing 20 can be used.

[0170] In this embodiment, the outer diameter of the rotor 5 and the inner diameter of the inner bore 12a of the stator 12 are formed to decrease from the rear end to the front end. However, the present invention is not limited to this, and it is sufficient if either or both of the outer diameter of the rotor 5 and the inner diameter of the inner bore 12a of the stator 12 decrease from one end to the other. It is also possible for the inner diameters of the rotor 5 and the inner bore 12a of the stator 12 to not change from one end to the other, but this makes it difficult to adjust the tightening allowance, etc., by moving the rotor 5 relative to the stator 12. Therefore, it is sufficient if either or both of the inner diameters of the rotor 5 and the inner bore 12a of the stator 12 decrease from one end to the other, or if it is possible to change the eccentricity of the rotor 5, or both.

[0171] In this embodiment, the stator 12 is housed in the stator casing 10 in a manner that prevents relative rotation. However, the stator casing 10 can be of various forms, sizes, and shapes, not only those that directly house the stator 12, but also those that indirectly house the stator 12. Furthermore, in this embodiment, the stator casing 10 is divided into a first stator casing 14 and a second stator casing 16, with the first stator casing 14 being held to be axially movable relative to the second stator casing 16. However, the invention is not limited to this. As long as the stator 12 is axially movable relative to the rotor 5, the stator casing 10 may not be divided into a first stator casing 14 and a second stator casing 16. Also, in this embodiment, the first stator casing 14 in the stator casing 10 is inserted into the interior of the second stator casing 16, forming a so-called nested structure. However, the first stator casing 14 and the second stator casing 16 can also be nested in a manner where the inside and outside are reversed. In such cases, it is advisable to provide an adapter or the like at the end of the stator 12 to increase the diameter.

[0172] In this embodiment, a helical moving groove 54 is provided as the moving mechanism 50, but the moving groove 54 is not limited to a helical shape and may be, for example, linear. The moving groove 54 can be formed with various forming angles, forming ranges, number of turns, etc. Furthermore, the operating part 52 can be formed with various sizes, shapes, and rotation angles depending on the form of the moving groove 54.

[0173] In this embodiment, an engagement hole 54a is provided in the movable groove 54, allowing the operating unit 52 to be switched between a fixed state and an unlocked state at a predetermined position. However, various means can be used for the fixing mechanism that fixes the operating unit 52. Furthermore, when providing the engagement hole 54a, it is not limited to the embodiment described above, and various positions, sizes, shapes, and quantities can be provided. In addition, in this embodiment, in addition to the fixing mechanism for the operating unit 52, a locking part 56 is provided to reduce the gap between the first stator casing 14 and the second stator casing 16 by tightening, thereby suppressing vibration. However, the locking part 56 may be provided only as needed. Furthermore, in this embodiment, the locking part 56 tightens radially from the outer circumference of the second stator casing 16, thereby suppressing relative movement and rotation in the axial direction of the first stator casing 14 and the second stator casing 16. However, it is not limited to this. For example, the locking part 56 may be composed of a retractable pin, and the locked state and unlocked state may be switched by the protrusion and retraction of the pin.

[0174] In this embodiment, the moving mechanism 50 is provided only for the function of moving the first stator casing 14 and the second stator casing 16 relative to each other in the axial direction. However, the moving mechanism 50 may also have a function to fix the first stator casing 14 and the second stator casing 16 so that they cannot move relative to each other in the axial direction (for example, an engagement hole 54a or a locking part 56). The mechanism for fixing the relative movement of the first stator casing 14 and the second stator casing 16 in the axial direction is not limited to the engagement hole 54a or a locking part 56, and various means can be used.

[0175] Furthermore, in the first modified example, a configuration in which a handle shaft 152a is provided on the operating section 152 is illustrated, but the direction, number, shape, length, etc. of the handle shafts 152a can be changed as appropriate. For example, there may be one handle shaft 152a or three or more. The handle shaft 152a can preferably be of various forms that utilize the principle of leverage or the thrust of a screw. In addition, although a stay bolt 102 is provided in this embodiment, the stay bolt 102 may be provided only if necessary.

[0176] In the fifth modified example of the single-axis eccentric screw pump 500, a cylinder 520 is used as the actuator 520. However, the actuator 520 is not limited to a cylinder 520; various drive sources can be used. For example, a servo actuator using a servo motor or the like can also be used as the actuator 520. Furthermore, the movement of the first stator casing 14 by the actuator 520 can be performed not only while the rotor 5 is stopped, but also while the rotor 5 is being driven to rotate, or in any case regardless of whether the rotor 5 is rotating or not.

[0177] Furthermore, in the sixth modification, the adjustment bolt 640 (double bolt 640) is screwed from the stator casing 10 side toward the pump casing 20 side and also screwed from the stator casing 10 side toward the discharge nozzle 18 side, but the present invention is not limited thereto. The insertion direction of the adjustment bolt 640 can be set to various directions that allow the stator casing 10 (stator 12) to move relative to it in the axial direction. Various numbers of adjustment bolts 640 can be used, from a single one to multiple adjustment bolts 640. For example, the adjustment bolt 640 may be provided only on one side, either the pump casing 20 side or the discharge nozzle 18 side.

[0178] Furthermore, while it is desirable that the adjustment bolts 640 be arranged evenly or symmetrically around the axial direction so that the stator casing 10 can move smoothly, the arrangement is not limited to this, and various quantities and arrangements can be used. Also, in this embodiment, double bolts 640 are used as adjustment bolts 640, but the arrangement is not limited to this, and various bolts and means that can move the stator casing 10 (stator 12) closer to or further away from the rotor 5 can be used. For example, the adjustment bolts 640 may be composed of a combination of a push screw and a pull screw. In the sixth modification, the stator casing 10 and the pump casing 20, and the discharge nozzle 18 and the stator casing 10 are configured as a nested structure, but other members may be interposed between the stator casing 10 and the pump casing 20 or between the stator casing 10 and the discharge nozzle 18, as long as the stator casing 10 can move relative to the pump casing 20 in the axial direction.

[0179] Furthermore, the automation of adjustments such as the tightening allowance of the rotor 5 and stator 12 in the single-screw eccentric pump according to the above-described embodiments and their respective modifications can be adopted not only in some embodiments and modifications, but in any embodiment and modification.

[0180] The above describes various embodiments and modifications of the single-screw eccentric pump according to the present invention. However, the present invention is not limited to those exemplified in the embodiments and modifications described above, and it will be readily apparent to those skilled in the art that other embodiments may exist in the spirit and teachings thereof, without departing from the scope of the claims.

[0181] The single-screw eccentric pump of the present invention can be used as a pump for transferring various fluids (especially viscous fluids).

[0182] 1: Single-screw eccentric pump 3: Input shaft 5: Rotor (male screw rotor) 10: Stator casing 12: Stator (female screw stator) 12a: Inner bore 14: First stator casing 16: Second stator casing 18: Discharge nozzle 20: Pump casing 50: Moving mechanism 52: Operating section 54: Moving groove 54a: Engagement hole 56: Locking section 100: Single-screw eccentric pump 152: Operating section 152a: Handle shaft 154: Moving groove 200: Single-screw eccentric pump 214: Screw member 216: Nut member 300: Single-screw eccentric pump 310: First screw section 312: Second screw section 320: Switching mechanism 400: Single-screw eccentric pump 420: Actuator 430: Moving member 500: Single-axis eccentric screw pump 514: Moving member 520: Actuator 530: Moving member 600: Single-axis eccentric screw pump 634: First bolt hole 636: Second bolt hole 640: Adjustment bolt (double bolt) 642: Outer bolt section 642a: First threaded section 642b: Flange 644: Inner bolt section 644a: Second threaded section

Claims

An input shaft that rotates due to the power of the drive mechanism, A rotor, which is connected to the input shaft so as to be eccentrically rotatable and is composed of a male screw-type shaft body, A stator formed in the shape of an internal screw through which the rotor can be inserted, Equipped with, It is possible to form either or both of the outer diameter of the rotor and the inner diameter of the inner bore of the stator so that they decrease from one end to the other, or to change the eccentricity of the rotor, A single-screw eccentric pump characterized by having a movement mechanism that moves the stator closer to and further away from the rotor along the axial direction of the input shaft. 　 A stator casing is provided, which houses the stator and is formed to extend along the axial direction. The stator casing is, A first stator casing that supports the stator so as not to move relative to it in the axial direction, A second stator casing holds the first stator casing so as to be movable relative to it in the axial direction, Equipped with, The uniaxial eccentric screw pump according to claim 1, characterized in that the moving mechanism moves the first stator casing and the second stator casing relative to each other in the axial direction. 　 The aforementioned moving mechanism is In the second stator casing, a movable groove formed along the axial direction, An operating section that is integral with the first stator casing and can move along the movable groove, Equipped with, The single-screw eccentric pump according to claim 2, characterized in that the operating unit is moved along the movable groove, thereby causing the first stator casing and the second stator casing to move relative to each other along the axial direction. 　 The movable groove is formed in the second stator casing in a spiral shape at a predetermined pitch and angle such that the spiral axis extends along the axial direction. The single-screw eccentric pump according to claim 3, characterized in that the operating unit is rotated along the movable groove, thereby causing the first stator casing and the second stator casing to move relative to each other along the axial direction. 　 The operating unit is capable of switching between a fixed state, which prevents relative movement of the first stator casing and the second stator casing in the axial direction, and an unfixed state, which allows relative movement of the first stator casing and the second stator casing in the axial direction. In the aforementioned non-fixed state, the operating part is moved along the moving groove by the moving mechanism, thereby causing the first stator casing and the second stator casing to move relative to each other along the axial direction. The single-screw eccentric pump according to claim 3 or 4, characterized in that, in the fixed state, the first stator casing and the second stator casing are positioned and fixed at predetermined positions in the axial direction. 　 The first stator casing and the second stator casing are provided with a locking mechanism that fastens them together so that they approach each other radially around their axis. The uniaxial eccentric screw pump according to any one of claims 2 to 4, characterized in that the locking part is switchable between an untightened state and a tightened state. 　 The moving groove has at least one engagement hole at a predetermined position along the moving groove that engages with the operating part to restrain the movement of the operating part. The single-screw eccentric pump according to claim 3 or 4, characterized in that the moving mechanism moves the operating part along the moving groove and engages the operating part with the engagement hole to position and fix the first stator casing and the second stator casing at predetermined positions in the axial direction. 　 The operating section is fixed to the first stator casing so as not to rotate relative to it, and has a plurality of handle shafts that extend in a direction intersecting the axial direction in the direction of the axis. A plurality of the aforementioned movable grooves are formed in the direction around the axis corresponding to the handle shaft, Multiple handle shafts are inserted so as to be movable along multiple movable grooves provided corresponding to each of them. The single-screw eccentric pump according to claim 4, characterized in that the first stator casing and the operating section move integrally in the axial direction relative to the second stator casing by rotating and moving the multiple handle shafts in the same direction along the multiple corresponding movable grooves. 　 The second stator casing is provided with a threaded member along the axial direction, The first stator casing is supported by a nut member that is screwed onto the threaded member. The nut member is movable in the axial direction integrally with the first stator casing as the screw member rotates. The uniaxial eccentric screw pump according to claim 2, characterized in that the moving mechanism rotates the screw member to move the screwing position of the nut member, thereby moving the first stator casing and the second stator casing relative to each other in the axial direction. 　 The system includes a switching mechanism that switches between a relative rotation-impossible state in which the first stator casing and the second stator casing are unable to rotate relative to each other, and a relative rotation-allowed state in which relative rotation of the first stator casing and the second stator casing is permitted. The aforementioned moving mechanism is The first threaded portion is formed on the outer circumference of the first stator casing along the axial direction, The second stator casing has a second threaded portion formed on its inner circumference along the axial direction and which screws into the first threaded portion, Equipped with, In the relative rotation-permissible state, by rotating the rotor, the first threaded portion and the second threaded portion can be screwed together, thereby allowing the first stator casing and the second stator casing to move relative to each other in the axial direction. The single-screw eccentric pump according to claim 2, characterized in that, in the state in which relative rotation is impossible, the relative movement of the first stator casing and the second stator casing in the axial direction is suppressed. 　 The first stator casing is provided so as to be movable in the axial direction relative to the second stator casing, The second stator casing is equipped with a cylinder chamber into which fluid can be introduced, The single-screw eccentric pump according to claim 2, characterized in that the moving mechanism moves the first stator casing by introducing fluid into the cylinder chamber and thereby biasing it in any direction along the axial direction. 　 The first stator casing is provided so as to be movable in the axial direction relative to the second stator casing, The uniaxial eccentric screw pump according to claim 2, characterized in that the moving mechanism has an actuator for moving the first stator casing in the axial direction. 　 The single-screw eccentric pump according to claim 12, characterized in that the movement of the first stator casing by the actuator is performed while the rotor is being rotated, or while the rotor is stopped, or both. 　 A stator casing that houses the stator and is formed to extend along the axial direction, A pump casing arranged along the axial direction with respect to the stator, A discharge nozzle provided on the tip side of the stator, Equipped with, The stator casing is integrally arranged with the stator and is movable in the axial direction relative to at least one of the discharge nozzle and the pump casing. The aforementioned moving mechanism is At least one movable member provided on at least one end of the stator in the axial direction and movable integrally with the stator in the axial direction, At least one adjustment bolt, Equipped with, The movable member has a first bolt hole formed through it along the axial direction into which the adjustment bolt is screwed. At least one of the discharge nozzle and the pump casing has a second bolt hole formed along the axial direction for fastening the adjustment bolt. The aforementioned adjustment bolt is The outer circumference has a first threaded portion, and the outer bolt portion has a hollow hole, An inner bolt portion is inserted into the hollow hole so as to be rotatable relative to the outer bolt portion, and a second threaded portion is formed on at least a part of its outer circumference, Equipped with, The outer bolt portion is screwed into the first bolt hole so that its tip can abut against the outer circumference of the second bolt hole. The inner bolt portion is screwed into the second bolt hole at its tip to fasten either the movable member and the discharge nozzle, or the movable member and the pump casing, or both. The single-axis eccentric screw pump according to claim 1, characterized in that the distance the stator moves in the axial direction can be adjusted according to the degree of tightening of the outer bolt portion.

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