JP2011256910A - Universal joint and uniaxial eccentric screw pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a universal joint which can be easily dismantled and can reduce the problem of deterioration with time and the like due to abnormal wear accompanying local concentration of stress and to provide a uniaxial eccentric screw pump provided with the universal joint.SOLUTION: The universal joint 80 is formed by pivotally supporting and connecting first and second connection parts 82 and 84 by pins A and B. A shaft insertion hole 98 in which the pin B can be inserted is provided in the nearly center part of the pin A. The pin A is inserted in first pin A insertion holes 90a and 90b and a second pin A insertion hole 94 and the pin B is inserted in first pin B insertion parts 92a and 92b, a second pin B insertion hole 96 and the shaft insertion hole 98 formed in the pin A to form a connection structure.

Description

  The present invention relates to a joint and a uniaxial eccentric screw pump.

  Conventionally, a universal joint as disclosed in Patent Document 1 below is provided. The universal joint of Patent Document 1 is formed by inserting three pins through a cross frame interposed between a left and right fork formed on the front body and an upper and lower fork formed on the rear body. It is a thing. Specifically, the left and right pins are inserted so as to penetrate the front main body and the cross frame in the left and right directions, and the vertical pins are inserted into the front end bifurcations formed on the upper and lower sides of the rear main body. It is formed by screwing the direction pin into the cross frame.

  Conventionally, a universal joint 150 as shown in FIG. 8 is used in a uniaxial eccentric screw pump. This universal joint has a first connecting portion 152 formed at the shaft end of the first shaft and a second connecting portion 154 formed at the shaft end of the second shaft, and a connecting pin 156 is provided over both of them. It is connected so that rotational force can be transmitted by being inserted. The second connection portion 152 is provided with a through hole 158 for inserting the connecting pin 156 described above. The through hole 158 is tapered and has a shape such that the opening diameter increases from the center toward both outer sides. The connecting pin 156 can swing inside the through hole 146.

JP-A-2005-344587

  Since the universal joint disclosed in Patent Document 1 described above is formed by screwing the vertical pin into the cross piece, it cannot be easily disassembled or cleaned. Therefore, this universal joint requires a considerable amount of labor for maintenance, and has a problem that it is not suitable for devices that handle foods that must be disassembled and cleaned on a daily basis.

  Further, when the universal joint 150 shown in FIG. 8 is used in a state where the shaft is eccentrically rotated like a uniaxial eccentric screw pump, a large stress acts locally due to the behavior shown in FIG. There is a possibility that the pin and the insertion hole through which the pin is inserted will be abnormally worn. Specifically, the universal joint used in the single-shaft eccentric screw pump is subjected to a load in the radial direction due to torque and a load in the thrust direction due to discharge pressure, and is also restricted by being an eccentric shaft. As shown in FIGS. 9A and 9B, when a load in the radial direction (indicated by an arrow in FIG. 9A) acts, the pin and the insertion hole come into line contact. As a result, a large surface pressure acts on the portion indicated by the thick line in FIG. 9A and the portion indicated by the black circle in FIG. 9B. When a load in the thrust direction is applied, a large stress is locally applied by rotation at the apex portion (portion indicated by a black dot in the drawing) of the tapered insertion hole as shown in FIG. 9C. As a result, problems such as abnormal wear, breakage, and deformation of the pins and the insertion holes are caused, and it becomes difficult to disassemble and clean the universal joint, which may deteriorate the maintenance characteristics.

  Therefore, the present invention provides a universal joint that can reduce the contact surface pressure between the pivot and the shaft insertion hole through which the pivot is inserted, and can significantly reduce abnormal wear due to local concentration of stress, and a uniaxial eccentric including the universal joint. The purpose was to provide a screw pump.

  The universal joint of the present invention provided to solve the above-described problem includes a first connection portion provided at the shaft end of the first shaft, a second connection portion provided at the shaft end of the second shaft, A pivot A pivotally supports the first connection portion so as to be pivotable, and a pivot B pivotally supports the second connection portion so as to be pivotable. In the universal joint of the present invention, the pivots A and B are each constituted by a pin, and the pin forming one of the pivots A and B penetrates in a direction intersecting the axial direction in the axial intermediate portion. A connecting structure is provided in which a shaft insertion hole is provided, and the pivots A and B are connected in a freely rotatable manner by inserting a pin forming the other of the pivots A and B into the shaft insertion hole. Is formed.

  In the universal joint of the present invention, the gap formed between the inner peripheral surface of the shaft insertion hole and the outer peripheral surface of the pin inserted through the shaft insertion hole is at any position in the axial direction of the pin. It is desirable that it is substantially constant. In the universal joint of the present invention, the first connection portion and the second connection portion are provided with pin insertion holes into which the pins forming the pivots A and B can be inserted, and the inner peripheral surface of the pin insertion hole It is desirable that a gap formed between the pin insertion hole and the outer peripheral surface of the pin inserted into the pin insertion hole is substantially constant at any position in the pin insertion direction.

  More specifically, the universal joint of the present invention will be described. The first pin A can be inserted through the first connection part, and the pin B can be inserted through the first connection part. A first pin B insertion portion formed so as to cross and communicate with the A insertion portion may be provided. Further, the second pin A insertion portion through which the pin A can be inserted and the pin B can be inserted into the second connection portion, and intersect and communicate with the second pin A insertion portion. The second pin B insertion portion formed as described above can be provided. Further, the shaft insertion hole may be formed so as to penetrate in a direction intersecting the axial direction at an axially intermediate portion of the pin A. In this configuration, the universal joint of the present invention inserts the pin A across the first pin A insertion portion and the second pin A insertion portion, and the first pin B insertion portion and the second pin. By inserting the pin B over the B insertion part and the shaft insertion hole, the first connection part and the second connection part can be connected. In addition, a part or all of the first pin A insertion portion, the second pin A insertion portion, the first pin B insertion portion, and the second pin B insertion portion described above can be formed by a through hole. It is. Further, when these insertion portions are formed by through holes, the opening diameter is substantially the same as the diameter of the circumscribed circle of the pins A and B, and the opening diameter is any portion in the insertion direction of the pins A and B. It is desirable that they are substantially the same.

  The universal joint of the present invention may be one in which a fluid can enter and exit at a portion where the connection structure is formed. Moreover, it is preferable that the universal joint of this invention is equipped with the cover in the part in which the said connection structure was formed.

  The uniaxial eccentric screw pump of the present invention can be inserted through the above-described universal joint of the present invention, a male screw type rotor driven by rotational power transmitted through the universal joint, and the rotor. And a stator having an inner peripheral surface formed in a female screw shape.

  As described above, the universal joint according to the present invention pivotally supports the first connecting portion and the second connecting portion by the pivots A and B including two pins, and the pivots A and B can be rotated with respect to each other. It is formed by connecting. Specifically, in the universal joint of the present invention, the first connecting portion is freely rotatable with respect to the pivot A, and the second connecting portion is freely rotatable with respect to the pivot B. Yes. Further, the other pin is inserted into the shaft insertion hole provided in the axially intermediate portion of the pin constituting one of the pivots A and B, so that the pivots A and B can freely rotate with respect to each other. It is connected. Therefore, the universal joint of the present invention can be assembled and disassembled simply by inserting or removing the pins forming the pivots A and B, and maintenance such as cleaning can be easily performed.

  In the universal joint of the present invention, the first connecting portion and the second connecting portion can freely rotate both in the direction around the axis of the pivot A and in the direction around the axis of the pivot B. Therefore, even if the first shaft and the second shaft rotate eccentrically, stress is applied to the entire pin, so stress concentration on a specific part is unlikely to occur and the abnormal wear is unlikely to occur as in the conventional universal joint. It hardly occurs. In addition, problems such as deterioration of members such as the first connection portion, the second connection portion, and the pivots A and B, and the accompanying deterioration in maintenance characteristics are also solved.

  Here, the universal joint of the present invention can be of a so-called open joint type in which a fluid can enter and exit in a connecting structure forming portion. Therefore, when the universal joint of the present invention adopts an open joint type connection structure and is assumed to be installed in a place exposed to fluids, it has excellent maintenance characteristics such as disassembly, assembly, and cleaning. It is desirable that In particular, maintenance such as cleaning is frequently performed when there is a possibility that the above-described fluid is ingested by the human body, such as food and pharmaceuticals, so that maintenance is required to be performed easily. The universal joint of the present invention can easily perform maintenance such as disassembly, assembly, and cleaning as described above, and is a case where maintenance is frequently performed as in the case of handling food and medicine. Can also be suitably used.

  In the universal joint of the present invention, the gap formed between the inner peripheral surface of the shaft insertion hole and the outer peripheral surface of the pin inserted through the shaft insertion hole is substantially constant at any position in the axial direction of the pin. By configuring so as to be, it is possible to avoid the occurrence of local concentration of stress accompanying the pin contact in the shaft insertion hole portion. That is, the contact pressure between the pin insertion hole and the pin can be made uniform, and the local concentration of stress can be avoided. Therefore, in the universal joint of the present invention, it is possible to reliably prevent abnormal wear that is a concern in the conventional universal joint shown in FIG. In addition, the universal joint of the present invention is less likely to cause deterioration and damage of each member due to abnormal wear, and is superior to the related art in terms of maintenance characteristics such as disassembly, assembly, and cleaning.

  Moreover, based on the same knowledge, when the pin insertion hole which can insert the pin which makes the pivot A and B is provided in said 1st connection part and said 2nd connection part, the inner peripheral surface of a pin insertion hole, and pin insertion It is possible to make the gap formed between the outer peripheral surface of the pin inserted through the hole substantially constant at any position in the pin insertion direction. By adopting such a configuration, the contact surface pressure between the pin insertion hole and the pin can be made uniform, and local concentration of stress accompanying the contact of the pin can be prevented from occurring in the pin insertion hole portion. As a result, abnormal wear can be suppressed, deterioration and damage of each member can be prevented, and a universal joint superior to that of the prior art in terms of maintenance characteristics such as disassembly, assembly, and cleaning can be provided.

  As described above, the universal joint of the present invention has the pivots A and B constituted by pins, and can be disassembled and assembled only by inserting and removing these pins. On the other hand, it is conceivable that the pins forming the pivot axes A and B may be displaced or dropped due to the influence of vibration or the like, and therefore it is preferable to take some measures. From this point of view, it is desirable that the portion where the connecting structure is formed is covered with a cover to prevent the pins forming the pivots A and B from falling off or being displaced.

  Since the uniaxial eccentric screw pump of the present invention includes the above-described universal joint of the present invention, the power from the drive source can be transmitted to the rotor and the rotor can be smoothly eccentrically rotated. Moreover, the uniaxial eccentric screw pump of this invention can maintain a universal joint easily by disassembling, assembling, cleaning, etc. Therefore, the uniaxial eccentric screw pump of the present invention can be suitably used for transporting a fluid that may be ingested by the human body, such as food and medicine.

It is sectional drawing which shows the uniaxial eccentric screw pump which concerns on one Embodiment of this invention. It is a perspective view which shows the universal joint which concerns on one Embodiment of this invention. It is a disassembled perspective view of the universal joint shown in FIG. It is a P direction arrow view of the universal joint shown in FIG. It is QQ sectional drawing of the universal joint shown in FIG. It is a figure which shows an example of a drop-off prevention means, (a) is a disassembled perspective view, (b) is RR sectional drawing of the same (a). It is explanatory drawing which shows an example of a drop-off prevention means. It is a top view which shows the universal joint of a prior art. It is explanatory drawing which shows the relationship between the pin and through-hole in the universal joint of the prior art shown in FIG. 8, (a) is the state where the load to the radial direction acted, (b) is the state to which the load to the thrust direction acted Indicates.

  Next, the uniaxial eccentric screw pump 10 and the universal joint 80 according to an embodiment of the present invention will be described in detail with reference to the drawings. The uniaxial eccentric screw pump 10 is characterized by the universal joint 80. In the following description, the entire structure will be described prior to the description of the universal joint 80.

≪Overall structure of uniaxial eccentric screw pump 10≫
The uniaxial eccentric screw pump 10 is a so-called rotary displacement pump, and has a configuration in which a stator 20, a rotor 30, a power transmission mechanism 50, and the like are accommodated in a casing 12 as shown in FIG. 1. The casing 12 is a metal-made cylindrical member, and a first opening 14a is provided in a disc-shaped end stud 12a attached to one end in the longitudinal direction. Further, a second opening 14 b is provided in the outer peripheral portion of the casing 12. The second opening 14 b communicates with the internal space of the casing 12 at an intermediate portion 12 d located at the intermediate portion in the longitudinal direction of the casing 12.

  The first and second openings 14a and 14b are portions that function as a suction port and a discharge port of the uniaxial eccentric screw pump 10, respectively. More specifically, in the uniaxial eccentric screw pump 10 of the present embodiment, the first opening 14a functions as a discharge port and the second opening 14b functions as a suction port by rotating the rotor 30 in the forward direction. It is possible to pump a fluid (fluid) into the pipe. On the contrary, the uniaxial eccentric screw pump 10 rotates the rotor 30 in the reverse direction so that the first opening 14a functions as a suction port and the second opening 14b functions as a discharge port. Can be pumped. The uniaxial eccentric screw pump 10 of the present embodiment operates so that the first opening 14a functions as a discharge port and the second opening 14b functions as a suction port.

  The stator 20 is a member made of an elastic body typified by rubber, resin, or the like and having a substantially cylindrical appearance. The material of the stator 20 is appropriately selected according to the type and properties of the fluid that is the object to be transferred using the uniaxial eccentric screw pump 10. The stator 20 is accommodated in the stator attachment portion 12b in the casing 12 at a position adjacent to the first opening 14a. The outer diameter of the stator 20 is substantially the same as the inner diameter of the stator attachment portion 12b. Therefore, the stator 20 is mounted such that the outer peripheral surface thereof is in close contact with the inner peripheral surface of the stator mounting portion 12b. The stator 20 is fixed by sandwiching a flange portion 20a on one end side by an end stud 12a at an end portion of the casing 12, and attaching and tightening a stay bolt 16 across the end stud 12a and the main body portion of the casing 12. ing. Therefore, the stator 20 does not cause a position shift or the like in the stator attachment portion 12b of the casing 12. As shown in FIGS. 1 and 2, the inner peripheral surface 24 of the stator 20 is formed in a multistage female screw shape with two strips.

  The rotor 30 is a metal shaft, and has a single-stage multi-stage male screw shape. The rotor 30 is formed so that the cross-sectional shape thereof is almost a perfect circle when viewed in cross section at any position in the longitudinal direction. The rotor 30 is inserted into the through hole 22 formed in the stator 20 described above, and can be freely rotated eccentrically inside the through hole 22.

  When the rotor 30 is inserted into the stator 20, the outer peripheral surface 32 of the rotor 30 and the inner peripheral surface 24 of the stator 20 are in contact with each other over the tangent line therebetween. In this state, a fluid conveyance path 40 is formed between the inner peripheral surface 24 of the stator 20 forming the through hole 22 and the outer peripheral surface of the rotor 30. The fluid conveyance path 40 has a length d times the reference length S of the lead in the axial direction of the stator 20 or the rotor 30 when the length L of the lead of the stator 20 or the rotor 30 is set as the reference length S. It is a multistage (d stage) flow path.

  The fluid conveyance path 40 extends in a spiral shape in the longitudinal direction of the stator 20 and the rotor 30. Further, when the rotor 30 is rotated in the through hole 22 of the stator 20, the fluid conveyance path 40 advances in the longitudinal direction of the stator 20 while rotating in the stator 20. Therefore, when the rotor 30 is rotated, the fluid is sucked into the fluid conveyance path 40 from one end side of the stator 20, and the fluid is confined in the fluid conveyance path 40 toward the other end side of the stator 20. It is possible to transport and discharge at the other end side of the stator 20. That is, when the rotor 30 is rotated in the forward direction, the fluid sucked from the second opening 14b can be pumped and discharged from the first opening 14a. Further, when the rotor 30 is rotated in the reverse direction, the fluid sucked from the first opening 14a can be discharged from the second opening 14b.

  The power transmission mechanism 50 is provided for transmitting power from the power source (not shown) such as a motor provided outside the casing 12 to the rotor 30 described above. The power transmission mechanism 50 includes a power connection portion 52 and an eccentric rotation portion 54. The power connection portion 52 is one end side in the longitudinal direction of the casing 12, more specifically, the side opposite to the end stud 12a and the stator mounting portion 12b described above (hereinafter also simply referred to as “base end side”). It is provided in the shaft accommodating part 12c provided in the. Moreover, the eccentric rotation part 54 is provided in the intermediate part 12d formed between the shaft accommodating part 12c and the stator attachment part 12b.

  The power connection portion 52 has a drive shaft 56 that is supported by two bearings 58a and 58b so as to be freely rotatable. The drive shaft 56 is taken out from the closed portion on the proximal end side of the casing 12 and connected to a power source. Therefore, the drive shaft 56 can be rotated by operating the power source. A shaft seal device 60 made of, for example, a mechanical seal or a gland packing is provided between the shaft housing portion 12c provided with the power connection portion 52 and the intermediate portion 12d, whereby the shaft housing is accommodated from the intermediate portion 12d side. The fluid which is a conveyed product is made into the structure which does not leak to the part 12c side.

  The eccentric rotating portion 54 is a portion that connects the drive shaft 56 and the rotor 30 described above so that power can be transmitted. The eccentric rotating part 54 has a pivot 62 and two universal joints 80 and 80. The pivot 62 is constituted by a conventionally known coupling rod, screw rod, or the like. The universal joints 80, 80 connect the pivot shaft 62 and the rotor 30, and the pivot shaft 62 and the drive shaft 56, respectively. The universal joints 80, 80 transmit the rotational power transmitted through the drive shaft 56 to the rotor 30 and can rotate the rotor 30 eccentrically.

≪About the structure of universal joint 80≫
Next, the structure of the universal joint 80 will be described in detail. The universal joint 80 that connects the rotor 30 and the pivot shaft 62 and the universal joint 80 that connects the pivot shaft 62 and the drive shaft 56 are the same, but in the following description, unless otherwise specified. An example in which the rotor 30 and the pivot 62 are connected will be described.

  The universal joint 80 has a first connecting portion 82 and a second connecting portion 84, and these are connected and pivotally supported by a connecting structure constituted by pins A and B. The 1st connection part 82 and the 2nd connection part 84 are provided in the edge part of the rotor 30 (1st shaft) and the pivot 62 (2nd shaft), respectively.

  The first connection part 82 is configured to include a space 88 into which the second connection part 84 can be inserted between the peripheral wall parts 86a and 86b having an arc shape when viewed from the front. Moreover, the 1st connection part 82 has 1st pin A insertion part 90a, 90b in surrounding wall part 86a, 86b. Further, the first connection portion 82 includes first pin B insertion portions 92a and 92b formed by a gap existing between both end portions of the peripheral wall portions 86a and 86b (up and down in the illustrated state).

  The first pin A insertion portions 90a and 90b pass through the axial center position of the first connection portion 82, and the pin A can be inserted in a direction substantially orthogonal to the axial direction of the first connection portion 82, that is, in the radial direction. Through hole. The opening diameters of the first pin A insertion portions 90a and 90b are substantially the same as the diameter of the circumscribed circle of the pin A. The opening diameters of the first pin A insertion portions 90a and 90b are substantially constant in any part in the insertion direction of the pin A. Further, the first pin B insertion portions 92 a and 92 b are configured by a gap through which the pin B can be inserted in the radial direction of the first connection portion 82.

  The second connection portion 84 is a cylindrical portion having a size that fits in a space 88 formed between the peripheral wall portions 86 a and 86 b of the first connection portion 82. The second connection portion 84 includes a second pin A insertion portion 94 and a second pin B insertion portion 96. The second pin A insertion portion 94 and the second pin B insertion portion 96 each pass through the axial center position of the second connection portion 84 and are substantially orthogonal to the axial direction of the second connection portion 84, that is, in the radial direction. The inner diameter of the through hole is substantially constant regardless of the portion. The opening diameter of the second pin A insertion portion 94 is substantially the same as the diameter of the circumscribed circle of the pin A, and the opening diameter of the second pin B insertion portion 96 is substantially the same as the diameter of the circumscribed circle of the pin B. Yes. The second pin A insertion portion 94 and the second pin B insertion portion 96 are formed so as to be substantially orthogonal to each other and communicate with each other.

  The pin A is a cylindrical member having an outer diameter substantially the same as the opening diameter of the first pin A insertion portions 90a and 90b and the opening diameter of the second pin A insertion portion 94 described above. As described above, since the opening diameters of the first pin A insertion portions 90a and 90b and the opening diameter of the second pin A insertion portion 94 are substantially constant regardless of the portions, when the pin A is inserted, these insertion portions The inner peripheral surfaces of 90a, 90b, and 94 and the outer peripheral surface of the pin A are in surface contact. The pin A has a shaft insertion hole 98 at a substantially central portion in the axial direction. The shaft insertion hole 98 is formed so as to penetrate in a direction substantially orthogonal to the axial direction of the pin A, that is, in the radial direction of the pin A. The opening diameter of the shaft insertion hole 98 is substantially the same as the diameter of the circumscribed circle of the pin B, and is substantially constant regardless of the part. Therefore, when the pin B is inserted into the shaft insertion hole 98, the inner peripheral surface of the shaft insertion hole 98 and the outer peripheral surface of the pin B are in surface contact. The pin B is a member having a columnar appearance.

  The universal joint 80 of the present embodiment is obtained by connecting the first connection portion 82 and the second connection portion 84 by the connection structure 100 configured using the pins A and B described above. Specifically, in the connection structure 100, the second connection portion 84 is inserted into the space 88 formed in the first connection portion 82, and spans the first pin A insertion portions 90 a and 90 b and the second pin A insertion portion 94. The pin B is inserted through the second pin B insertion portion and the shaft insertion hole 98 through the gap between the first pin B insertion portions 92a and 92b. . Thereby, the pins A and B are connected in a substantially cross shape, and the first connection portion 82 and the second connection portion 84 are connected so as to be freely rotatable around the pins A and B.

  Further, as shown by a one-dot chain line in FIG. 4, a drop prevention means 99 for preventing the pin A and the pin B from dropping is provided at the portion where the connection structure 100 is formed. Therefore, even if vibration is applied to the universal joint 80, the state in which the first connection portion 82 and the second connection portion 84 are connected can be maintained without the pins A and B dropping off.

  As described above, the universal joint 80 of the present embodiment is connected by the connecting structure 100 configured by the two pins A and B functioning with the first connecting portion 82 and the second connecting portion 84 as pivots. . In the universal joint 80, the first connection portion 82 can freely rotate with respect to the pin A, and the second connection portion 84 can freely rotate with respect to the pin B. Further, a pin B is inserted into a shaft insertion hole 98 provided in an intermediate portion in the axial direction of the pin A, and the pins A and B are connected so as to be freely rotatable with respect to each other. Therefore, the universal joint 80 can freely rotate the first connection portion 82 and the second connection portion 84 about the pins A and B.

  In addition, the connection structure 100 employed in the present embodiment is configured by a combination of pins A and B, and can be disassembled and assembled by simply inserting and removing the pins A and B. No need for special tools. Therefore, the universal joint 80 can easily perform maintenance such as cleaning.

  In the present embodiment, the example in which the drop prevention means 99 is provided to prevent the pins A and B constituting the connection structure 100 from dropping is illustrated, but the present invention is not limited to this, and the cover 99 is provided. It may not be. Further, the drop prevention means 99 may be anything as long as it can prevent the pins A and B from falling off. For example, it can be as shown in FIGS. Specifically, the example shown in FIG. 6 employs a sleeve 99 a as the drop-off preventing means 99. In this example, the peripheral wall portions 86a and 86b of the first connection portion 82 are provided with a paragraph portion 86c so that the sleeve 99a can be attached and the pins A and B are attached to form the coupling structure 100. When the sleeve 99a is moved as shown by an arrow in FIG. 6 (a) and is attached to the portion 86c as a paragraph, the pins A and B are prevented from coming off as shown in FIG. 6 (b).

  In the example shown in FIG. 7, the pin A has a head 99b on one end side, and a retaining ring 99c for retaining the pin A is mounted on the other end side after the pin A is mounted. By adopting such a configuration, the pin A can be kept from being detached. In the example shown in FIG. 7, the pin A is illustrated as being prevented by the drop-off prevention means 99 configured by the head 99b and the retaining ring 99c, but the present invention is not limited to this. B can be prevented from coming off by adopting the same configuration. In the example shown in FIG. 7, an example in which only the pin A is prevented is illustrated. However, only the pin B may be retained, or both the pins A and B may be retained. Good. Further, in the example shown in FIG. 7, an example in which the head 99b is provided on one end side of the pin A (or pin B) and the retaining ring 99c is attached on the other end side is illustrated. It is also possible to adopt a configuration in which both are retained by a retaining ring 99c or the like.

  The universal joint 80 is connected via two pins A and B arranged so that the first connection portion 82 and the second connection portion 84 cross each other, and the direction around the axis of the pin A and the pin B It can be freely rotated in both directions around the axis. The pin A can be rotated while being in surface contact with the first pin A insertion portion 90 and the second pin A insertion portion 94, and the pin B can be rotated through the second pin B insertion portion 96 and the shaft insertion. The hole 98 can be rotated while being in surface contact with the hole 98. The slit-shaped first pin insertion portion 92 is a portion through which the pin B passes during assembly and disassembly of the connection structure, and the pin B is not in contact in use. Therefore, even if the rotor 30 rotates eccentrically, the universal joint 80 does not concentrate stress on a specific portion, and abnormal wear does not occur. Therefore, in the universal joint 80, problems such as deterioration of each member such as deformation and abnormal wear of the first connection portion 82, the second connection portion 84, and the pins A and B, and deterioration of maintenance characteristics hardly occur. Therefore, the uniaxial eccentric screw pump 10 is preferably used even when it is necessary to frequently perform maintenance such as cleaning, such as when handling a fluid such as food or medicine that may be ingested by the human body. it can.

  In the above embodiment, the first pin A insertion portion 90, the second pin A insertion portion 94, the second pin B insertion portion 96, and the shaft insertion hole 98 are in a state where the pins A and B are inserted in use. Although the inner peripheral surface of this has a substantially uniform opening diameter regardless of the part, it is possible to change the design as appropriate without departing from the gist of the present invention. Specifically, the first pin A insertion portion 90, the second pin A insertion portion 94, the second pin B insertion portion 96, and the shaft insertion hole 98 are provided for the purpose of facilitating the attachment and detachment of the pins A and B. The entrance portion may be chamfered to form a portion having a non-uniform opening diameter to the extent that the above-described problem such as abnormal wear due to local concentration of stress does not occur.

  The universal joint 80 has a structure (so-called open joint type structure) in which the fluid can freely enter and exit the portion where the coupling structure 100 is formed, and the fluid handled by the uniaxial eccentric screw pump 10 is coupled to the universal joint 80. However, as described above, since abnormal wear due to local concentration of stress is less likely to occur, a problem that wear pieces are mixed into the fluid is less likely to occur. In addition, the universal joint 80 can be configured such that the connection structure 100 is covered with a predetermined cover from the viewpoint of more reliably preventing wear pieces from being mixed into the fluid.

  In this embodiment, although the example which comprised the 1st pin A insertion part 90 by the through-hole and comprised the 1st pin B insertion part 92 by the slit (gap), this invention is not limited to this. Absent. Specifically, the first pin B insertion portion 92 can also be configured by a through hole, the first pin A insertion portion 90 is configured by a through hole, and the first pin B insertion portion 92 is a slit (gap). It is also possible to configure by.

  In this embodiment, the example which provided the 1st connection part 82 in the rotor 30 side and provided the 2nd connection part 84 in the pivot 62 side was illustrated, However, This invention is not limited to this, A 1st connection The part 82 and the second connection part 84 may be arranged opposite to the present embodiment. Similarly, in the case where the universal joint 80 connects the pivot 62 and the drive shaft 56, the first connection portion 82 is provided on either the pivot 62 side or the drive shaft 56 side, and the other The 2nd connection part 84 should just be provided in the side.

  In this embodiment, the example which applied the universal joint 80 to the uniaxial eccentric screw pump 10 was illustrated, However, This invention is not necessarily limited to this, It is used in order to connect shaft bodies in other apparatuses. May be.

DESCRIPTION OF SYMBOLS 10 Uniaxial eccentric screw pump 20 Stator 30 Rotor 80 Universal joint 82 First connection part 84 Second connection part 86a, 86b Peripheral wall part 90a, 90b First pin A insertion hole (pin insertion part)
92a, 92b First pin B insertion part (pin insertion part)
94 Second pin A insertion hole (pin insertion part)
96 2nd pin B insertion hole (pin insertion part)
98 Shaft insertion hole 100 Connection structure A, B Pin (Pivot)

Claims (6)

A first connection provided at the shaft end of the first shaft;
A second connecting portion provided at a shaft end of the second shaft;
A pivot A for pivotally supporting the first connecting portion so as to be rotatable;
A pivot B that pivotally supports the second connection portion so as to be rotatable;
The pivots A and B are each constituted by a pin,
The pin forming one of the pivots A and B is provided with a shaft insertion hole penetrating in a direction intersecting the axial direction at the axial intermediate portion,
By inserting a pin forming the other of the pivots A and B into the shaft insertion hole, a connection structure is formed in which the pivots A and B are connected in a freely rotatable manner. Universal joint.   A gap formed between the inner peripheral surface of the shaft insertion hole and the outer peripheral surface of the pin inserted through the shaft insertion hole is substantially constant at any position in the axial direction of the pin. The universal joint according to claim 1. The first connection part and the second connection part are provided with pin insertion holes into which pins forming the pivot axes A and B can be inserted,
A gap formed between the inner peripheral surface of the pin insertion hole and the outer peripheral surface of the pin inserted through the pin insertion hole is substantially constant at any position in the insertion direction of the pin. The universal joint according to claim 1 or 2.   The universal joint according to any one of claims 1 to 3, wherein a fluid can enter and exit in a portion where the connection structure is formed.   The universal joint according to claim 1, wherein a cover is attached to a portion where the connection structure is formed. A universal joint according to any one of claims 1 to 5,
An externally threaded rotor driven by rotational power transmitted through the universal joint and rotating eccentrically;
A uniaxial eccentric screw pump characterized by comprising a stator through which the rotor can be inserted and whose inner peripheral surface is formed into a female screw type.

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