JP5838462B2 - Uniaxial eccentric screw pump - Google Patents

Description

  The present invention relates to a uniaxial eccentric screw pump capable of transferring a fluid by rotating a female screw type rotor (outer rotor) in conjunction with rotation of a male screw type rotor (inner rotor).

  Conventionally, as disclosed in Patent Documents 1 to 3 below, a uniaxial eccentric screw pump in which a female screw type rotor (outer rotor) rotates in conjunction with rotation of a male screw type rotor (inner rotor) is a food. It is provided for pumping high viscosity fluids (fluids) such as raw materials, chemical raw materials, and sewage sludge. In the uniaxial eccentric screw pump of Patent Document 1, a seal member is provided so as to seal both ends of a portion where the self-lubricating bearing and the outer rotor slide so that the outer rotor and the bearing portion can be cleaned. In addition, an inlet and an outlet are provided on the suction side and the discharge side, and both are communicated with each other via a communication path.

  In the uniaxial eccentric screw pump of Patent Document 2, in order to prevent deterioration of the pumping performance due to liquid leakage from the high pressure side to the low pressure side, a labyrinth-like seal member or the like is provided to discharge the self-lubricating bearing and the outer rotor. The structure which sealed the sliding part end of the side is employ | adopted. In addition, in the single-shaft eccentric screw pump of Patent Document 3, between the self-lubricated bearing and the outer rotor, in order to suppress deterioration of the pumping performance due to liquid leakage from the high pressure side to the low pressure side while maintaining the lubrication performance of the bearing. In addition, a communication path is provided along the axial direction, and a dividing portion is provided in the communication path, so that the suction side and the discharge side are not in a direct communication state.

JP 2009-293529 A JP 2010-209731 A JP 2010-209732 A

  Here, in general, in a single-shaft eccentric screw pump, the discharge pressure tends to be higher than the suction pressure. Therefore, in a uniaxial eccentric screw pump that can rotate not only for the inner rotor but also for the outer rotor, the outer rotor may be displaced in the axial direction due to the effect of the differential pressure between the discharge pressure and the suction pressure. In order to eliminate such positional deviation of the outer rotor, in the above-described conventional single-shaft eccentric screw pump, a large-diameter portion projecting radially outward is provided at a substantially central portion in the axial direction of the outer rotor, and a large-diameter portion is provided in the casing. The structure which provided the enlarged diameter part which can be inserted is adopted. However, in the case of such a structure, the apparatus configuration becomes complicated, and there is a problem that manufacturing and maintenance are difficult.

  Even when a structure like the prior art is adopted, the outer rotor may be displaced in the axial direction due to the influence of the discharge pressure or the suction pressure, and the enlarged diameter portion and the large diameter portion may be in close contact with each other. There is sex. When the operation is performed in a state where the outer rotor is displaced in this manner, the outer rotor rotates with the large diameter portion pressed against the enlarged diameter portion, which causes a large power loss and heat generation problem. There is a possibility that the diameter portion or the diameter-expanded portion is worn.

  Accordingly, the present invention provides a single-shaft eccentric screw pump in which the outer rotor rotates in conjunction with the rotation of the inner rotor, prevents a large power loss, prevents the outer rotor from being displaced in the axial direction, and The object was to reliably prevent wear of the outer rotor or the like due to displacement in the direction.

  The uniaxial eccentric screw pump of the present invention provided to solve the above-described problem is constituted by a drive machine capable of outputting rotational power via a drive shaft, and a male screw-like shaft body connected to the drive shaft. An inner rotor, a cylindrical body having an inner peripheral surface formed into a female screw type, and an outer rotor having a through hole into which the inner rotor can be inserted from a base end side forming one end toward a tip end side forming the other end; A casing having a housing space capable of housing the outer rotor so as to be rotatable, the outer rotor having a flange portion projecting radially outward, and the casing includes the outer rotor. A first opening provided on the distal end side relative to the outer rotor, a second opening provided on the proximal end side with respect to the outer rotor, and a flange accommodating portion capable of accommodating the flange portion And the outer rotor rotates in the casing in conjunction with the rotation of the inner rotor, thereby sucking in fluid from one of the first opening and the second opening, It can be discharged from the other side of the first opening and the second opening.

  In the uniaxial eccentric screw pump of the present invention, between the outer rotor and the casing, a first space facing a tip surface provided on a tip side of the outer rotor and communicating with the first opening, The second space that faces the base end surface provided on the base end side of the outer rotor and communicates with the second opening, and is provided separately from the second space, faces the base end surface, and A third space that communicates with the fourth space that is provided on the distal end side of the flange portion in the outer rotor and communicates with the second space is formed. The uniaxial eccentric screw pump according to the present invention is configured such that the tip surface of the outer rotor is in a state where a fluid is introduced into the first space, the second space, the third space, and the fourth space. The pressure B acting from the side toward the base end face side and the pressure F acting from the base end face side toward the tip end face side can be balanced.

  In the uniaxial eccentric screw pump of the present invention, with the fluid being pumped, the tip of the fluid is introduced into the first space, the second space, the third space, and the fourth space with respect to the outer rotor. The pressure B acting from the surface side toward the proximal end surface side and the pressure F acting from the proximal end surface side toward the distal end surface side are in a balanced state. In other words, the uniaxial eccentric screw pump of the present invention is intended to eliminate the positional deviation of the outer rotor by balancing the pressure acting in the axial direction of the outer rotor. Is different. Therefore, in the single-shaft eccentric screw pump of the present invention, the pressure B and the pressure F acting in the axial direction on the outer rotor are canceled when the fluid is pumped, and the positional deviation of the outer rotor in the axial direction is offset. Does not occur.

  In the uniaxial eccentric screw pump of the present invention, since the outer rotor is not displaced in the axial direction when the fluid is pumped, it can be prevented from rotating while being pressed against the casing. Thereby, abrasion of an outer rotor can be prevented and the effort of maintenance etc. can be suppressed to the minimum.

  In the uniaxial eccentric screw pump of the present invention described above, the third space and the fourth space are formed in a first gap formed between the front end side flange surface of the flange portion and the flange accommodating portion of the casing. The second space and the third space are communicated with a second gap formed between the second space and the third space and a base end surface of the outer rotor. Under the influence of the fluid introduced into the first space and the second space, the pressure acting on the outer rotor from the front end surface side to the base end surface side is defined as b1, and the second space The pressure acting on the outer rotor from the base end surface side to the front end surface side is defined as f1 due to the influence of the fluid introduced into the outer rotor, and is introduced into the third space through the communication path. The pressure acting on the outer rotor from the base end face side to the tip end face side is defined as f2, and the outer rotor is affected by the fluid introduced into the fourth space. The pressure acting on the rotor from the front end surface side toward the base end surface side is defined as b2, and the fluid introduced from the third space side in the first gap and the fourth space side Introduced fluid shadow The pressure acting on the flange portion from the distal end surface side toward the proximal end surface side is defined as b3, and the fluid introduced from the second space and the fluid introduced from the third space side When the pressure acting from the second gap to the flange portion from the base end face side to the tip end face side is defined as f3, the sum of the pressures b1, b2, b3, It is desirable to have a configuration that can balance the sum of the pressures f1, f2, and f3.

  In the uniaxial eccentric screw pump of the present invention, the shaft is moved relative to the outer rotor due to the influence of the fluid flowing into the third space and the fourth space and the slight fluid introduced into the first gap and the second gap. The pressure related to the sum of the pressures b1, b2, and b3 acting in the direction cancels out with the sum of the pressures f1, f2, and f3 acting toward the opposite side in the axial direction. Therefore, in the uniaxial eccentric screw pump of the present invention, it is possible to prevent the outer rotor from being displaced in the axial direction due to the influence of the pressure acting on the outer rotor in the axial direction when the fluid is pumped. In addition, according to the present invention, the outer rotor is prevented from rotating while being pressed against the casing by a strong force acting in the axial direction, and the wear of the outer rotor and maintenance work are minimized. it can.

  In the uniaxial eccentric screw pump of the present invention described above, it is desirable that the flange portion is provided on the base end side.

  According to such a configuration, the structure of the outer rotor and the casing can be simplified, and the manufacturing cost and the like can be minimized. In addition, by providing the flange portion on the base end side of the outer rotor, it is easy to attach and detach the outer rotor for maintenance or the like.

  Further, in the uniaxial eccentric screw pump of the present invention, a gap is formed between the outer peripheral surface of the outer rotor and the inner peripheral surface of the housing space, and the fluid can pass through the gap. preferable.

  According to such a configuration, the fluid is interposed in the gap between the inner peripheral surface of the housing space in the casing and the outer peripheral surface of the outer rotor, and the outer rotor is smoothly smoothed as if supported by the so-called fluid bearing. Can be rotated.

  In the uniaxial eccentric screw pump of the present invention, a bearing that rotatably supports the outer rotor accommodated in the accommodation space may be provided integrally with the casing or as a separate body.

  According to this configuration, the outer rotor can be smoothly rotated by the bearing, and power loss can be suppressed to a minimum.

In the uniaxial eccentric screw pump of the present invention, a region facing the first space on the distal end surface of the outer rotor is defined as a first region, and a surface facing the second space on a proximal end side surface of the flange portion. A region that is defined as a second region, a region that faces the third space in the flange portion is defined as a third region, and the region of the fourth space that is formed on a tip side surface of the flange portion. When the opening region is defined as the fourth region, it is preferable that the first region, the second region, the third region, and the fourth region are each axially symmetric or annular.

  According to such a configuration, it is possible to apply a pressure substantially uniformly in the circumferential direction to the first region, the second region, the third region, and the fourth region, and the outer rotor is caused by the pressure acting from the fluid. It is possible to prevent the occurrence of the positional deviation more reliably.

  According to the present invention, in the uniaxial eccentric screw pump of the type in which the outer rotor rotates in conjunction with the rotation of the inner rotor, the outer rotor is displaced in the axial direction, and wear of the outer rotor or the like due to this is caused. It becomes possible to prevent reliably.

It is sectional drawing which shows the uniaxial eccentric screw pump which concerns on one Embodiment of this invention. It is a disassembled perspective view which shows the casing employ | adopted in the uniaxial eccentric screw pump of FIG. It is a perspective view which shows the main-body part of the casing shown in FIG. 2, (a) shows the state seen from the front end side, (b) shows the state seen from the base end side. It is a perspective view which shows the end stud of the casing shown in FIG. 2, (a) shows the state seen from the front end side, (b) shows the state seen from the base end side. It is a perspective view which shows the outer rotor employ | adopted in the uniaxial eccentric screw pump of FIG. It is the enlarged view to which the 3rd space vicinity in FIG. 1 was expanded. It is sectional drawing which shows the modification of the uniaxial eccentric screw pump shown in FIG. It is sectional drawing which shows the modification of the uniaxial eccentric screw pump shown in FIG.

  Next, a uniaxial eccentric screw pump 10 that is an embodiment of the present invention will be described in detail with reference to the drawings. In the following description, unless otherwise specified, a side close to the drive unit 50 that is a power source is described as a base end side, and a side opposite to the base end side is described as a front end side. The uniaxial eccentric screw pump 10 of the present embodiment is a so-called rotary displacement pump, and has a configuration in which a driving machine 50, an inner rotor 60, an outer rotor 70, and the like are accommodated in the casing 20, as shown in FIG. Has been.

  As shown in FIG. 2, the casing 20 is roughly divided into a main body portion 22, an end stud 24, an intermediate portion 26, and a drive unit accommodating portion 28, and these are integrally connected. As shown in FIG. 1, the casing 20 has an internal space 30 in a region from the end stud 24 to the intermediate portion 26. The casing 20 also has a first opening 32 in the end stud 24 and a second opening 34 in the outer peripheral portion of the intermediate portion 26.

  The internal space 30 of the casing 20 is roughly divided into an outer rotor accommodating space 36, a first space 38, and a second space 40. The outer rotor accommodating space 36 is a space in which the outer rotor 70 is accommodated, and is formed to extend in the longitudinal direction (axial direction) of the casing 20. The first space 38 is a space provided at a position adjacent to the outer rotor accommodating space 36 on the first opening 32 side. The first space 38 communicates with the first opening 32 and faces a tip surface 70 a that forms one end (tip) of the outer rotor 70.

  The second space 40 is a space provided at a position adjacent to the outer rotor accommodating space 36 on the second opening 34 side. The second space 40 communicates with the second opening 34 and faces the base end surface 70 b that forms the base end of the outer rotor 70. Further, in the second space 40, the drive shaft 52 of the drive machine 50 protrudes from the drive machine housing portion 28 side, and the inner rotor 60 protrudes from the outer rotor housing space 36 side. The drive shaft 52 and the inner rotor 60 are directly connected and integrated in the second space 40.

  In addition to the internal space 30 described above, the casing 20 is provided with a third space 42, first and third space communication passages 44, and a flange accommodating portion 46. The third space 42 faces the base end surface 70 b of the outer rotor 70 and is a space provided separately from the second space 40. The third space 42 communicates with the first space 38 via the first / third space communication passage 44. The flange accommodating portion 46 is for accommodating the flange portion 72 of the outer rotor 70 accommodated in the main body portion 22 of the casing 20, and is provided on the base end side of the main body portion 22.

  The structure of the casing 20 will be described in more detail. As shown in FIGS. 1 to 3, the main body portion 22 is provided with a protruding portion 22 a. The protruding portion 22 a is formed so as to protrude in the axial direction on the distal end side of the main body portion 22. An outer rotor accommodating space 36 is opened at a substantially central portion of the protruding portion 22a.

  On the other hand, as shown in FIGS. 1 and 3B, a first step portion 22 b and a second step portion 22 c are formed in the opening portion on the base end side of the main body portion 22. Thereby, the main-body part 22 is made into the shape reduced in diameter in two steps in the base end side. In the main body 22, a region from the opening portion on the base end side to the first step portion 22 b functions as an intermediate portion insertion portion 22 d into which the end portion of the intermediate portion 26 is inserted. Moreover, the area | region from the 1st step part 22b to the 2nd step part 22c functions as a space (flange accommodating part 46) for accommodating the flange part 72 of the outer rotor 70 explained in full detail behind. Further, in the main body portion 22, a communication path constituting portion 44 a that forms a part of the first and third space communication paths 44 is formed at a position that is radially outward from the internal space 30 described above.

  Moreover, as shown in FIG.1 and FIG.4 (b), the recessed part insertion part 24b of the concave shape is provided in the end stud 24, and the protrusion part insertion part 24b is for fitting the protrusion part 22a. It is open to one end (connection end 24a) side of the end stud 24. A groove 24c is provided over the entire circumference on the inner peripheral surface of the protruding portion insertion portion 24b. A sealing member 24d such as an O-ring is fitted in the groove 24c.

  A first space 38 is formed inside the end stud 24. The first space 38 opens to the protruding portion insertion portion 24b side, and the opening shape and size thereof are substantially the same as the opening of the outer rotor accommodating space 36 formed in the protruding portion 22a of the outer rotor accommodating space 36. It is said that. The opening area of the first space 38 is reduced in a tapered shape in a portion (a reduced diameter portion 38a) extending from the connection end 24a side to the axially intermediate portion of the end stud 24. Further, the first space 38 is provided with a communication path constituting portion 44 b that forms part of the first and third space communication paths 44. The communication path constituting portion 44 b communicates with the inclined surface forming the reduced diameter portion 38 a of the first space 38, and opens to the connection end 24 a side of the end stud 24.

  The main body 22 and the end stud 24 are connected by inserting the protrusion 22a into the protrusion insertion part 24b described above. In addition, the communication path components 44 a and 44 b are in communication with each other, and the first and third space communication paths 44 that connect the first space 38 and the second space 40 are formed. Thereby, the fluid discharged from the front end side of the outer rotor 70 is in a state where the first space 38, the first / third space communication passage 44, and the third space 42 are filled.

  As shown in FIG.1 and FIG.2, as for the intermediate part 26, the one end side (tip side) is formed in the step shape. Specifically, the first step portion 26a and the second step portion 26b are formed on one end side of the intermediate portion 26, and the diameter is reduced in two steps toward the distal end side (main body portion 22 side). Yes. In the intermediate portion 26, the portion on the tip side of the first step portion 26 a is a portion that functions as the insertion portion 26 c that is inserted into the intermediate portion insertion portion 22 d of the main body portion 22 described above.

  The outer diameter of the insertion part 26c is substantially the same as the inner diameter of the intermediate part insertion part 22d described above. A circumferential groove 26d is provided on the outer peripheral surface of the insertion portion 26c over the entire circumference, and a sealing member 26e such as an O-ring is fitted in the circumferential groove 26d. Accordingly, the insertion portion 26c is sealed by being inserted into the intermediate portion insertion portion 22d, and the main body portion 22 and the intermediate portion 26 are connected so that the fluid does not leak out.

  Further, when the insertion portion 26c of the intermediate portion 26 is inserted into the intermediate portion insertion portion 22d of the main body portion 22, an annular third space 42 is formed in a portion corresponding to the second step portion 26b. The third space 42 is connected to first and third space communication paths 44 formed in the main body portion 22. Accordingly, the third space 42 is in a state of communicating with the first space 38 formed on the end stud 24 side via the first / third space communication passage 44.

  The drive machine 50 is comprised by the conventionally well-known motor, and is accommodated in the drive machine accommodating part 28 of the casing 20 mentioned above. The drive shaft 52 of the drive machine 50 protrudes into the second space 40 of the intermediate portion 26 and is connected to the end portion of the inner rotor 60.

  The inner rotor 60 is a shaft body made of a metal such as stainless steel or titanium, a resin such as engineering plastic, ceramics, or the like, and is rotatable about the axial center position L1 as the drive unit 50 is operated. Yes. The inner rotor 60 has n-1 threads (n is a natural number) and has a single-stage or multi-stage female screw shape. In the example of the present embodiment, the inner rotor 60 is multi-stage with one line. The inner rotor 60 is formed so that its cross-sectional shape is substantially a perfect circle when viewed in cross section at any position in the longitudinal direction.

  As shown in FIG. 5, the outer rotor 70 is a cylindrical member made of an elastic body typified by rubber or resin. The outer rotor 70 has a substantially cylindrical outer shape, and has a flange portion 72 projecting radially outward on the proximal end side as shown in FIGS. 1 and 5. The material of the outer rotor 70 is appropriately selected according to the type and properties of the fluid that is the conveyed object. The outer rotor 70 is inserted into the internal space 30 of the casing 20 described above, and the flange portion 72 is housed in the flange housing portion 46. In this state, a gap 74 is formed between the outer peripheral surface of the outer rotor 70 and the inner peripheral surface of the internal space 30 and the inner peripheral surface of the flange accommodating portion 46 so that a small amount of fluid can flow. .

  The outer rotor 70 has a through hole 76 penetrating from the proximal end side toward the distal end side. The inner peripheral surface 76a of the outer rotor 70 has a single-stage or multi-stage female screw shape with n strips (n is a natural number). In the present embodiment, as shown in FIG. 1 and FIG. The inner rotor 60 is inserted into the through hole 76 from the proximal end side toward the distal end side. Further, the outer rotor 70 is accommodated so as to be rotatable around an axial center position L2 that deviates in the radial direction with respect to the axial center position L1 of the inner rotor 60.

  The outer rotor 70 is provided with a fourth space communication path 78 that connects the through hole 76 and the distal end side surface 72 a (flange surface) on the distal end side of the flange portion 72. The fourth space communication passage 78 is inclined so as to extend outward in the radial direction from the upstream side (base end side) in the flow direction of the fluid flowing into the through hole 76 toward the downstream side (tip end side). And connected to an annular groove (hereinafter referred to as “fourth space 48”) formed in the front end side surface 72a. The fourth space 48 is formed so as to be substantially concentric with the outer rotor 70 at the base portion of the outer rotor 70. The fourth space communication path 78 opens into the fourth space 48. Therefore, the fluid introduced into the through hole 76 can be introduced into the fourth space 48 via the fourth space communication path 78, and the pressure in the fourth space 48 can be changed to the pressure in the second space 40. Can be the same. Further, the front end side surface 72 a of the flange portion 72 faces the surface (opposing surface 46 a) that constitutes the flange accommodating portion 46 in the casing 20. In addition, a base end side surface 72 b formed on the opposite side (base end side) of the front end side surface 72 a in the flange portion 72 corresponds to the base end surface 70 b of the outer rotor 70, and faces the second space 40 and the third space 42. doing.

  In the uniaxial eccentric screw pump 10, the inner rotor 60 rotates about the axial center position L1 by operating the drive unit 50. Further, in conjunction with the rotation of the inner rotor 60, the outer rotor 70 is driven and rotated about the axial center position L2. Thereby, the fluid introduced into the second space 40 from the second opening 34 is pumped and discharged from the first opening 32 through the through hole 76 of the outer rotor 70 and the first space 38 at a predetermined discharge pressure. Is done.

  Here, in the uniaxial eccentric screw pump 10 of this embodiment, the base end side surface 72b faces the second space 40 due to the influence of the fluid sucked into the second space 40 from the second opening 34 and pumped. The pressure f1 acts on the second region 73b. Further, the fluid that has flowed into the through hole 76 of the outer rotor 70 further flows into the fourth space 48 formed of the annular groove via the fourth space communication passage 78, and the fourth space 48 is filled with the fluid. As a result, the pressure b <b> 2 in the direction from the distal end side to the proximal end side acts from the fourth space 48 on the distal end side surface 72 a of the flange portion 72.

  Further, as shown in FIG. 1, the uniaxial eccentric screw pump 10 forms a region (first region 73 a) facing the first space 38 on the tip surface 70 a of the outer rotor 70 and a cavity for fluid pressure feeding. Pressure b1 (discharge pressure) acts on the inner peripheral surface 76a of the through hole 78 in a direction from the distal end side toward the proximal end side. On the other hand, a part of the fluid flowing out from the front end side of the outer rotor 70 and flowing into the first space 38 flows into the third space 42 via the first / third space communication passage 44. As a result, as shown in FIGS. 1 and 6, the pressure f <b> 2 is applied to the third region 73 c facing the third space 42 in the flange portion 72 of the outer rotor 70 in the direction from the proximal end side toward the distal end side. Works.

  In the uniaxial eccentric screw pump 10, the first gap 62 formed between the front end side surface 72 a of the flange portion 72 and the flange accommodating portion 22 e of the casing 20 is connected to the outer peripheral surface of the flange portion 72 from the third space 42. A small amount of fluid that has flowed in through a gap between the inner wall surfaces of the main body portion 22 is introduced and supplied to the fourth space 48 formed of an annular groove, whereby the flange portion 72 is proximal to the proximal side. The pressure b3 acts toward Further, a small amount of fluid flows from the third space 42 to the second space 40 in the second gap 64 formed between the second space 40 and the third space 42 and the base end side surface 72 of the outer rotor. Thus, the pressure f3 acts on the flange portion 72 from the proximal end side toward the distal end side.

  Here, the radius of the main body portion of the outer rotor 70 is ro, the radius of the proximal end side surface 72b of the flange portion 72 is ra, and the opening region of the fourth space 48 formed in an annular shape on the distal end side surface 72a of the flange portion 72 (first The radius of the four regions 73d) is defined as rb, and the radius of the open region facing the proximal side surface 72b in the second space 40 is defined as ri. Further, the pressure of the fluid discharged from the outer rotor 70 is defined as Po, and the pressure of the fluid introduced into the outer rotor 70 is defined as Pi. In this case, the pressures f1, f2, f3 and the pressures b1, b2, b3 described above can be derived from the following (Formula 1) to (Formula 6).

  In addition, in the following (Expression 3) and (Expression 6), Px and Py can be derived based on experimental results and the like, but are derived based on, for example, the following (Expression 7) and (Expression 8). It is possible. Note that K1 in (Expression 7) and K2 in (Expression 8) are coefficients. The coefficients K1 and K2 can be set in consideration of the pressure distribution of the fluid in the first merge region 62a and the second merge region 64a, the structure of these regions 62a, 64a, and the like. In the uniaxial eccentric screw pump 10 of the present embodiment, the pressure acting in the first merge region 62a is assumed to be equivalent to the average pressure of the pressures Po and Pi on average, and therefore the coefficient K1 is set to about 0.5. It is possible to set. Further, since the pressure acting on the second merge region 64a is assumed to be slightly lower than the average pressure of the pressures Po and Pi on average, the coefficient K2 is set to a positive number smaller than 0.5.

  Further, in the uniaxial eccentric screw pump 10 of the present embodiment, the pressures f1, f2, and f3 acting in the direction from the proximal end side toward the distal end side with respect to the outer rotor 70 when the fluid is pumped, and the proximal end from the distal end side. The area b of the first region 73a, the second region 73b, the third region 73c, and the fourth region 73d so that the pressures b1, b2, b3 acting in the direction toward the side are substantially balanced and offset, and The sizes of the first gap 62 and the second gap 64 are adjusted. That is, the area of each part is adjusted so that the following relationship (Formula 9) is satisfied.

  Of the above-described pressures f1, f2, f3 and pressures b1, b2, b3, those that are negligibly small compared to the other pressures may not be considered in the relationship of (Expression 9).

  As described above, in the uniaxial eccentric screw pump 10 of the present embodiment, the pressure acting on the outer rotor 70 from the distal end side toward the proximal end side in a state where the fluid flows into each part when the fluid is pumped. B (B = b1 + b2 + b3) and the pressure F (F = f1 + f2 + f3) acting from the base end side toward the front end side are substantially balanced and are in a state of being canceled out. In addition, the first region 73a, the second region 73b, the third region 73c, the fourth region 73d, the fourth space 48, the first gap 62, and the second gap 64, which are main regions on which pressure acts, are all. Since they are formed concentrically and annularly, the pressures f1, f2, f3 and the pressures b1, b2, b3 all act substantially uniformly in the circumferential direction. Therefore, the uniaxial eccentric screw pump 10 is not affected by the pressures f1 and b2. Therefore, the uniaxial eccentric screw pump 10 can prevent the positional displacement of the outer rotor 70 in the axial direction. It is possible to prevent the outer rotor 70 from being worn by rotating while being pressed against the casing 20, and to minimize the troubles such as maintenance. Note that the first region 73a, the second region 73b, the third region 73c, the fourth region 73d, the fourth space 48, the first gap 62, and the second gap 64 are not necessarily concentric and annular as described above. However, it is possible to have an axisymmetric shape, and the same effect can be obtained.

  As described above, in the uniaxial eccentric screw pump 10, the flange portion 72 is provided on the proximal end side of the outer rotor 70. Thereby, compared with the case where the flange part 72 is provided in the axial direction intermediate part of the outer rotor 70 like the thing of a prior art, an apparatus structure can be made simple and manufacturing cost etc. can be suppressed to the minimum. In addition, in the example of this embodiment, although the structure which provided the flange part 72 in the base end side of the outer rotor 70 was illustrated, this invention is not necessarily limited to this and the flange part 72 of the outer rotor 70 is provided. You may provide in an axial direction intermediate part.

  In the uniaxial eccentric screw pump 10, a gap 74 is formed between the outer peripheral surface of the outer rotor 70 and the inner peripheral surface of the outer rotor accommodating space 36, and the fluid can pass through the gap 74. It is possible. Thereby, the outer rotor 70 can be smoothly rotated in the same manner as that supported by the fluid bearing. In addition, in the example of this embodiment, the structure which supported the outer rotor 70 so that rotation was possible by interposing the fluid in the clearance gap 74 was illustrated, However, It is good also as a structure which provided the bearing etc. separately.

  Specifically, as shown in FIG. 7, a slide bearing 90 may be provided in the outer rotor accommodating space 36 of the casing 20 and the outer rotor 70 may be rotatably supported. With this configuration, the rotational resistance of the outer rotor 70 can be further reduced, and power loss can be minimized. The sliding bearing 90 may be integrally attached to the inner peripheral surface of the casing 20 or may be attached as a separate body from the casing 20.

  In the uniaxial eccentric screw pump 10 of the present embodiment, the outer rotor 70 rotates without being displaced, so that a gap 74 is secured between the outer rotor 70 and the casing 20. Therefore, the uniaxial eccentric screw pump 10 can rotate the outer rotor 70 without causing friction with the casing 20 or the like, prevents wear of the outer rotor 70 due to friction with the casing 20, and the outer rotor 70. Maintenance work such as replacement can be minimized.

  Further, as shown in FIG. 8, the uniaxial eccentric screw pump 10 has a discharge path in one or both of the gap 74 formed between the outer rotor 70 and the casing 20 and the first and third space communication paths 44. 92 and 94 may be connected, and the valves 96 and 98 may be provided in the middle of the discharge paths 92 and 94. In such a configuration, by opening the valves 96 and 98, it is possible to smoothly discharge the fluid and cleaning liquid present in the gap 74 or the first and third space communication passages 44. Maintenance characteristics are improved.

  The uniaxial eccentric screw pump 10 illustrated in the present embodiment is merely an example of the embodiment of the present invention, and can be appropriately changed in design without departing from the spirit of the present invention. Specifically, in the uniaxial eccentric screw pump 10, the drive shaft 52 and the inner rotor 60 are directly connected and integrated in the second space 40, but a coupling is provided between the drive shaft 52 and the inner rotor 60. Alternatively, the connection may be made indirectly, for example, by interposing.

  Further, the first space 38 described above has a reduced diameter portion 38a formed so that the opening region is reduced in a tapered shape, and the communication path constituting portion 44b communicates with an inclined surface forming the reduced diameter portion 38a. However, the reduced diameter portion 38a may be omitted. Further, the communication location of the communication path constituting portion 44b is not necessarily the inclined surface forming the reduced diameter portion 38a, and the communication path constituting portion 44b may be communicated at a place other than the reduced diameter portion 38a.

  The casing 20 is not limited to the shape and assembly structure described above, and can be appropriately changed in design. Specifically, the casing 20 is roughly divided into four parts, that is, a main body part 22, an end stud, an intermediate part 26, and a drive machine accommodating part 28, but the number of constituent parts is limited to this. It is not a thing. Further, the connection form of each part is not limited to the above-described one.

  In the outer rotor 70, the fourth space 48 is formed so as to communicate with the through hole 76, but the fourth space 48 may be communicated with the second opening 34. In addition, the number, position, size, shape, and the like of the fourth space communication passage 78 connected to the fourth space 48 on the distal end side surface 72a can be appropriately changed in design.

  The flange portion 72 of the outer rotor 70 illustrated in the present embodiment has a simple disk shape, but the present invention is not limited to this and is formed so that the outer diameter changes in multiple stages. It is possible to have a multi-stage disk shape. With this configuration, the number of first gaps 62 and second gaps 64 can be increased. Further, the flange portion 72 can be formed to have a tapered cross-sectional shape. With this configuration, the first gap 62 and the second gap 64 can be tapered.

  The above-described (Equation 1) to (Equation 9) show an example of an equation used to substantially balance the pressures B and F acting on the outer rotor 70 in the uniaxial eccentric screw pump 10 of the present embodiment. As long as the gist of the present invention is not deviated, it can be replaced by other mathematical expressions. The design change such as changing the cross-sectional shape of the flange portion 72 described above is intended to position the outer rotor 70 by substantially balancing the pressures B and F acting on the outer rotor 70. As long as it does not deviate from the above, it can be carried out as appropriate. At this time, considering the design change, the pressures B and F acting on the outer rotor 70 are substantially balanced by replacing some or all of (Formula 1) to (Formula 9) with different ones. Thus, the position of the outer rotor 70 can be stabilized.

  The present invention can be applied to a single-shaft eccentric screw pump capable of transferring a fluid by rotating an outer rotor in conjunction with rotation of an inner rotor, and is particularly suitable for applications that require downsizing.

DESCRIPTION OF SYMBOLS 10 Uniaxial eccentric screw pump 20 Casing 30 Internal space 32 1st opening 34 2nd opening 36 Outer rotor accommodating space 38 1st space 40 2nd space 42 3rd space 44 Communication path 46 Flange accommodating part 46a Opposite surface 50 Drive machine 52 Drive Shaft 60 Inner rotor 70 Outer rotor 70a Tip surface 70b Base end surface 72 Flange 72a Tip side surface (flange surface)
72b Base end side surface 73a First region 73b Second region 73c Third region 73d Fourth region 74 Gap 76 Through hole 78 Fourth space communication passage 90 Slide bearing

Claims (6)

A drive capable of outputting rotational power via a drive shaft;
An inner rotor constituted by a male screw-like shaft connected to the drive shaft;
An outer rotor having a through-hole into which the inner rotor surface can be inserted from a base end side forming one end toward a tip end side forming the other end;
A casing having a housing space capable of housing the outer rotor in a rotatable manner;
The outer rotor is
It has a flange portion projecting radially outward,
The casing is
A first opening provided on the tip side with respect to the outer rotor;
A second opening provided on the base end side with respect to the outer rotor;
A flange housing portion capable of housing the flange portion,
When the outer rotor rotates inside the casing in conjunction with the rotation of the inner rotor, fluid is sucked from one side of the first opening and the second opening, and the first opening and the first opening It is possible to discharge from the other side of the two openings,
Between the outer rotor and the casing,
A first space facing the tip surface provided on the tip side of the outer rotor and communicating with the first opening;
A second space facing a base end surface provided on the base end side of the outer rotor and communicating with the second opening;
A third space provided separately from the second space, facing the base end surface and communicating with the first space;
In the outer rotor, provided on the tip side of the flange portion, a fourth space communicating with the through hole is formed,
In a state in which a fluid is introduced into the first space, the second space, the third space, and the fourth space, from the distal end surface side to the proximal end surface side with respect to the outer rotor. A uniaxial eccentric screw pump characterized by being able to balance the acting pressure B and the pressure F acting from the base end surface side toward the distal end surface side. The third space and the fourth space are in communication with a first gap formed between the front end side flange surface of the flange portion and the flange housing portion of the casing,
The second space and the third space communicate with a second gap formed between the second space and the third space, and a base end surface of the outer rotor,
Under the influence of the fluid introduced into the first space, the pressure acting on the outer rotor from the distal end surface side toward the proximal end surface side is defined as b1,
Under the influence of the fluid introduced into the second space, the pressure acting on the outer rotor from the base end surface side toward the front end surface side is defined as f1,
Under the influence of the fluid introduced into the third space, the pressure acting on the outer rotor from the base end surface side toward the front end surface side is defined as f2,
Under the influence of the fluid introduced into the fourth space, the pressure acting on the outer rotor from the distal end surface side toward the proximal end surface side is defined as b2,
Due to the influence of the fluid introduced from the third space side and the fluid introduced from the fourth space side in the first gap, the front end surface side is directed to the base end surface side with respect to the flange portion. The pressure acting is defined as b3,
Of the second gap, the fluid introduced from the second space and the fluid introduced from the third space side are directed from the base end surface side to the tip surface side with respect to the flange portion. Is defined as f3,
The single-shaft eccentric screw pump according to claim 1, wherein the sum of the pressures b1, b2, and b3 and the sum of the pressures f1, f2, and f3 can be balanced.   The uniaxial eccentric screw pump according to claim 1 or 2, wherein the flange portion is provided on a proximal end side of the outer rotor. A gap is formed between the outer peripheral surface of the outer rotor and the inner peripheral surface of the housing space,
The uniaxial eccentric screw pump according to any one of claims 1 to 3, wherein a fluid can pass through the gap.   The single-shaft eccentric screw according to any one of claims 1 to 4, wherein a bearing that rotatably supports an outer rotor accommodated in the accommodation space is provided integrally with the casing or as a separate body. pump. A region facing the first space on the tip surface of the outer rotor is defined as a first region.
Prescribe,
A region facing the second space on the proximal side surface of the flange portion is defined as a second region,
A region facing the third space in the flange portion is defined as a third region,
When the opening area of the fourth space formed on the tip side surface of the flange portion is defined as a fourth area,
The uniaxial eccentric screw pump according to any one of claims 1 to 5, wherein each of the first region, the second region, the third region, and the fourth region is annular.

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