JP2016121673A - Turbo pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a turbo pump in which even if the pump generates a high axial thrust force, its main shaft does not drop off, a main shaft showing a high general purpose for use in connecting with a shaft coupling can be used and a replacement work with a mechanical seal can be easily carried out.SOLUTION: This invention relates to a turbo pump in which a main shaft 4 for supporting an impeller 3 has a mechanical seal 5 at a part passing through a pump casing and the main shaft 4 and a motor shaft 7 of a motor are connected by a pump side shaft joint 10, a motor side shaft joint 11 and a spacer 12 present between both shaft joints. An outer peripheral surface of the main shaft 4 is provided with a groove 4G, the pump side shaft joint 10 is provided with a female thread 10s, and a bolt 20 is engaged with the female thread 10s to fit the extremity end of the bolt 20 into the groove 4G.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a turbo pump, and more particularly, to a turbo pump having a mechanical seal at a portion where a main shaft supporting an impeller penetrates a pump casing.

In the turbo type pump that gives energy to the liquid by rotating the impeller in the pump casing, a mechanical seal is often used as a shaft seal device in a portion where the main shaft supporting the impeller penetrates the pump casing. .
Some centrifugal pumps, which are a kind of such a turbo-type pump, employ a split coupling structure and provide a mechanical seal replacement space in order to replace the mechanical seal without removing the motor during maintenance. (Patent Document 1).

  The split split coupling structure is lengthened and weighted to increase rigidity. However, the large output model is heavy and the workability and assemblability deteriorate. In addition, the split coupling is difficult to achieve concentricity and perpendicularity, which increases the manufacturing cost. If a split coupling is manufactured at a realistic manufacturing cost, the concentricity and squareness will not be sufficient, and pump vibration and noise will increase due to insufficient concentricity and squareness. Further, when a split coupling is adopted due to an overhang of the pump impeller, an underwater bearing structure is required at the tip of the main shaft.

As described above, the split coupling structure described in Patent Document 1 has various problems from the viewpoints of workability, assemblability, and performance.
There are few problems like the above-mentioned split coupling structure, and as a structure in which the mechanical seal can be replaced without removing the motor at the time of maintenance, in Patent Document 2, the pump side shaft joint is fixed to the pump shaft that supports the impeller A pump in which a motor side shaft joint is fixed to a motor shaft of a motor and a spacer is interposed between the pump side shaft joint and the motor side shaft joint is described.

JP 2007-205360 A JP 59-138794 A

As a result of repeated studies on a coupling structure in which a spacer is interposed between the motor-side shaft coupling and the pump-side shaft coupling described in Patent Document 2, the present inventors listed the following. I found that there is a problem to do.
(1) Since the shaft coupling and the main shaft are not fixed with a set screw, etc., when used with a pump that generates a large axial thrust, the main shaft may be pulled out in the axial direction, causing the pump to become inoperable. There is.
(2) Since a special main shaft is used for coupling with the shaft coupling on both the motor side and the pump side, the cost of manufacturing parts increases. In addition, since a motor cannot be used as a general-purpose product and a dedicated motor has to be used, the manufacturing cost of the pump may increase.
(3) When removing the spacer in the middle part, the main shaft must be dropped more than the fit between the spacer and shaft coupling. Therefore, the space for the rotating body (rotor) including the main shaft and impeller due to the pump structure This coupling structure cannot be used with pumps that cannot afford them.

  The present invention has been made in view of the above-described circumstances. Even if the pump generates a large axial thrust force, the main shaft does not fall off, and a highly versatile main shaft is used for connection with a shaft coupling. An object of the present invention is to provide a turbo pump that can perform mechanical seal replacement work easily.

In order to achieve the above object, a first aspect of the turbo pump according to the present invention includes a mechanical seal in a portion where the main shaft supporting the impeller passes through the pump casing, and pumps the main shaft and the motor shaft of the motor. A turbo pump connected by a side shaft joint, a motor side shaft joint, and a spacer interposed between both shaft joints, wherein a groove is provided on the outer peripheral surface of the main shaft, a female screw is provided on the pump side shaft joint, and a bolt Is screwed into the female screw and the tip of the bolt is inserted into the groove.
According to the present invention, the pump side shaft joint and the main shaft are fixed in the axial direction by using bolts and grooves, so that the main shaft can be prevented from falling off, and even in a pump that receives a high axial thrust force, the pump side shaft The present coupling structure composed of a joint, a motor side shaft joint and a spacer can be employed. That is, when the bolt is fitted into the groove of the main shaft and the bolt is hooked (or engaged) with the upper end portion of the main shaft groove, the main shaft can be prevented from falling off due to the axial thrust force. The number of bolts may be increased by the axial thrust force, or the bolt size may be increased.

In a preferred aspect of the present invention, the groove is a circumferential groove extending in a circumferential direction of the main shaft.
In a preferred aspect of the present invention, the groove includes a circular groove having a circular cross section or an elliptical cross section, or a polygonal groove having a polygon cross section.
According to the round groove of the present invention, the contact area between the groove and the fixing screw / bolt is increased and the surface pressure can be reduced, so that a larger axial thrust force can be received.

In a preferred aspect of the present invention, the front end of the bolt is in contact with the bottom of the groove.
According to the present invention, since the tip of the bolt contacts the bottom of the groove when fixed, it is possible to prevent damage to the outer diameter surface of the main shaft. Therefore, when the pump side shaft joint is attached to and detached from the main shaft, twisting is prevented, and the pump side shaft joint can be easily and repeatedly attached and detached.

In a preferred aspect of the present invention, a counterbore hole is formed in a portion of the pump side shaft joint provided with the female screw so that the head of the bolt can be accommodated in the counterbore hole.
In a preferred aspect of the present invention, when the front end of the bolt is brought into contact with the bottom of the groove, the outer surface of the pump side shaft joint that surrounds the end surface of the head of the bolt and the periphery of the counterbore The surface is substantially flush with the surface.
According to the present invention, when the front end of the bolt is not inserted into the groove of the pump shaft, that is, when the bolt is not accurately inserted into the groove, the end surface of the bolt head is the outer peripheral surface of the pump side shaft joint. It sticks out (protrudes). Therefore, the operator can easily recognize the poor assembly state between the pump shaft and the pump side shaft joint. Therefore, it is possible to prevent the assembly failure between the pump shaft and the pump side shaft joint.

In a preferred aspect of the present invention, the tip of the bolt to be fitted into the groove has a smooth cylindrical shape without a screw.
When the axial thrust force acts on the pump shaft and the axial thrust force cannot be supported only by the frictional force of the front end surface of the bolt, the upper end surface of the groove and the front end portion of the bolt come into contact with each other. In this case, when the bolt is a full screw, deformation of the screw shape due to the contact can be considered. Moreover, when it is going to remove a bolt in the state of contact, there is a concern about the twisting of the bolt and the female screw of the pump side shaft joint. According to the present invention, since the smooth outer peripheral surface at the tip of the bolt is in contact with the upper end surface of the groove, the above deformation and twisting are prevented.

In a preferred aspect of the present invention, the inlet side corner of the groove is chamfered or tapered.
According to the present invention, since the corner portion on the inlet side of the groove is chamfered or tapered, the bolt can be easily inserted into the groove.
In a preferred aspect of the present invention, the corner of the tip of the bolt is chamfered or tapered.
According to the present invention, since the corner portion of the tip of the bolt is chamfered or tapered, the bolt can be easily inserted into the female screw.

According to a second aspect of the turbo pump of the present invention, the main shaft that supports the impeller includes a mechanical seal in a portion that passes through the pump casing, and the main shaft and the motor shaft of the motor are connected to the pump side shaft joint and the motor side shaft joint. And a spacer interposed between both shaft joints, wherein the main shaft is provided with a female screw in a direction perpendicular to the axial direction of the main shaft, a through hole is provided in the pump side shaft joint, and a bolt is provided. The bolt is inserted into the through hole and screwed into the female screw.
According to the present invention, the pump side shaft joint and the motor can be prevented from falling off by fixing the pump side shaft joint and the main shaft in the axial direction using bolts, even in a pump that receives a high axial thrust force. The present coupling structure composed of a side shaft joint and a spacer can be employed. That is, since the main shaft and the pump side shaft joint are fastened by bolts, the axial thrust force can be received by a high-strength bolt, so that the main shaft can be prevented from falling off.

According to a third aspect of the turbo pump of the present invention, the main shaft that supports the impeller includes a mechanical seal in a portion that passes through the pump casing, and the main shaft and the motor shaft of the motor are connected to the pump side shaft joint and the motor side shaft joint. And a spacer interposed between both shaft joints, wherein the main shaft is provided with a through hole in a direction perpendicular to the axial direction of the main shaft, the pump side shaft joint is provided with a through hole, and a pin Is inserted into both the through holes.
According to the present invention, the pump side shaft joint and the motor can be prevented from falling off by fixing the pump side shaft joint and the main shaft in the axial direction by using a pin, even in a pump that receives a high axial thrust force. The present coupling structure composed of a side shaft joint and a spacer can be employed. That is, since the main shaft and the pump side shaft joint are connected by inserting (or press-fitting) the pin, the axial thrust force can be received by the high-strength pin, so that the main shaft can be prevented from falling off. .

In a preferred aspect of the present invention, a key is interposed between the pump side shaft coupling and the main shaft.
In a preferred aspect of the present invention, a key is interposed between the motor side shaft coupling and the motor shaft.

According to a preferred aspect of the present invention, at least one of the pump side shaft coupling and the motor side shaft coupling is provided with a female screw at a position corresponding to the key, and a bolt is screwed to the female screw so that a tip of the bolt is used as the key. It is made to contact | abut.
According to the present invention, the bolt is screwed into the female screw of the pump side shaft joint or the motor side shaft joint, and the bolt is tightened so that the tip of the bolt comes into contact with the key with a strong force. The side shaft joint is fixed so as not to move in the axial direction with respect to the main shaft or the motor shaft. In addition, since it is comprised so that the front-end | tip of a volt | bolt may contact | abut to a key, the damage to the outer-diameter surface of a main shaft or a motor shaft can be prevented at the time of fixation.

  In a preferred aspect of the present invention, a retaining ring for positioning the pump side shaft joint is attached to the main shaft.

In a preferred aspect of the present invention, a split ring for positioning the pump side shaft joint is attached to the main shaft, and a retaining ring is fitted on the cylindrical portion of the pump side shaft joint and the split ring. It is characterized by that.
According to the present invention, during operation, the retaining ring is fitted onto the split ring, so that the outer peripheral surface of the split ring is in close contact with the inner peripheral surface of the stop ring. Is fixed by a retaining ring. At the time of disassembly, the split ring becomes free by sliding the stop ring upward along the cylindrical portion of the pump side shaft joint. Since the split ring is split in half, even if there is no space, it can be easily removed radially outward. After removing the split ring, the spacer can be removed by sliding the pump side shaft joint downward along the main shaft, and the cartridge mechanical seal can be removed without removing the motor side shaft joint.

In a preferred aspect of the present invention, the cylindrical portion of the pump-side shaft joint is provided with a female screw in a direction orthogonal to the axial direction of the main shaft, a through hole is provided in the retaining ring, a bolt is inserted into the through hole, and the bolt is It is characterized by being screwed into a female screw.
According to the present invention, the retaining ring can be fixed to the pump side shaft joint using a bolt.

In a preferred aspect of the present invention, a step portion is formed on the inner peripheral side of the pump side shaft joint, a plate is placed on the step portion, a bolt extending in the axial direction of the main shaft is inserted into the through hole of the plate, and the bolt is It is characterized by being screwed into a female screw formed at the upper end of the main shaft.
According to the present invention, a plate is placed on the inner peripheral side of the pump side shaft joint, and a bolt extending in the axial direction of the main shaft is inserted into the through hole of the plate, and the bolt is screwed to the female screw at the upper end portion of the main shaft. I am letting. Therefore, it is possible to receive axial force with the bolt and plate, so that the main shaft can be prevented from falling off, and even pumps under conditions that receive high axial thrust force are composed of a pump side shaft joint, a motor side shaft joint and a spacer. The present coupling structure can be adopted.

In a preferred aspect of the present invention, a fitting portion between at least one of the pump side shaft coupling and the motor side shaft coupling and the spacer is formed radially inward from the outermost diameter portion.
According to the present invention, the fitting portion of the component does not become the outermost diameter portion, and when the component is stored alone, it is difficult to accidentally scratch or dent the fitting portion.

In a preferred aspect of the present invention, at the time of replacement of the mechanical seal, the fastening of a fastener including a screw connecting the spacer and the pump side shaft joint is released, and the impeller, the main shaft, and the pump side shaft joint are released. The rotating body is dropped, and after replacing the mechanical seal, the rotating body is raised by a fastening operation of the fastener and returned to a normal position.
According to the present invention, the rotating body including the impeller, the main shaft, and the pump side shaft joint can be raised and returned to the normal position only by the operation of fastening fasteners such as bolts and nuts after replacement of the mechanical seal. Therefore, workability is extremely excellent.

The present invention has the following effects.
(1) The mechanical seal can be replaced by removing only the pump side shaft joint and the intermediate spacer without removing the motor and the motor side shaft joint.
(2) Because the shaft coupling and the main shaft (pump shaft) are fixed with set screws, bolts or pins, etc., even if the pump generates a large axial thrust force, the main shaft will not drop off, which is caused by the main shaft dropping off. There is no fear of the pump being unable to operate.
(3) A highly versatile spindle can be used for coupling with the shaft coupling on both the motor side and the pump side. Moreover, a general-purpose product can be used for the motor, and the manufacturing cost of the pump can be reduced.
(4) When removing the spacer at the intermediate part of the shaft coupling on the motor side and pump side, ensure that there is an amount equivalent to the fit between the spacer and shaft coupling, and that the spacer can be removed laterally with a margin. (Pump shaft) can be dropped and the pump side shaft joint can be shifted downward, so even if the pump has no allowance for the drop space of the rotating body (rotor) including the main shaft and impeller, This coupling structure composed of a motor side shaft joint and a spacer can be employed.
(5) When the shaft coupling is fixed to the main shaft (pump shaft), the surface of the outer diameter of the main shaft is prevented from being damaged, and the shaft coupling can be easily removed, so that the mechanical seal can be easily replaced.
(6) The pump-side shaft coupling and the main shaft are firmly coupled by the plate and the bolt, and can withstand an excessive axial load.
(7) By fixing the lower end of the pump side shaft joint with a split ring, attachment and removal are simplified. That is, during operation, since the retaining ring is fitted onto the split ring, the outer peripheral surface of the split ring is in close contact with the inner peripheral surface of the retaining ring. It is fixed by. At the time of disassembly, the split ring becomes free by sliding the stop ring upward along the cylindrical portion of the pump side shaft joint. Since the split ring is split in half, even if there is no space, it can be easily removed radially outward. After removing the split ring, if the pump side shaft coupling is slid down, the spacer can be removed, and the cartridge mechanical seal can be removed without removing the motor side shaft coupling.
(8) When the tip of the bolt is not inserted into the groove of the pump shaft, that is, when the bolt is not correctly inserted into the groove, the end surface of the bolt head protrudes from the outer peripheral surface of the pump side shaft joint ( Stick out). Therefore, the operator can easily recognize the poor assembly state between the pump shaft and the pump side shaft joint. Therefore, it is possible to prevent the assembly failure between the pump shaft and the pump side shaft joint.

FIG. 1 is a cross-sectional view showing a turbo pump according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing an example of a structure for fixing a motor shaft and a motor side shaft joint in the turbo pump shown in FIG. FIG. 3 is a schematic cross-sectional view showing an example of a structure for fixing the pump shaft and the pump side shaft joint in the turbo pump shown in FIG. 4 is a schematic cross-sectional view showing another example of a structure for fixing a pump shaft and a pump side shaft joint in the turbo pump shown in FIG. FIG. 5 is a schematic cross-sectional view showing still another example of a structure for fixing a pump shaft and a pump side shaft joint in the turbo pump shown in FIG. 6 is a schematic cross-sectional view showing still another example of a structure for fixing a pump shaft and a pump side shaft joint in the turbo pump shown in FIG. 7 (a), (b), (c), and (d) are diagrams showing details of the groove formed in the pump shaft shown in FIG. 6, and FIG. 7 (a) is a front view showing an example of the groove. FIG. 7B is a cross-sectional view showing another example of the groove, and FIGS. 7C and 7D are views taken along the arrow A in FIG. 7B. FIG. 8 is a schematic cross-sectional view showing details of a fitting portion between a motor side shaft joint and a spacer in the turbo pump shown in FIG. FIG. 9 is a schematic cross-sectional view showing details of a fitting portion between the motor side shaft coupling and the spacer in the turbo pump shown in FIG. FIG. 10A is a schematic cross-sectional view showing an initial state (regular state) before exchanging the mechanical seal, and FIG. 10B shows fixing of the pump side shaft joint and the spacer in the mechanical seal replacement procedure. It is typical sectional drawing which shows the process of canceling | releasing. Fig.11 (a) is typical sectional drawing which shows the process of removing a spacer in the replacement procedure of a mechanical seal, FIG.11 (b) is typical sectional drawing which shows the process of removing a pump side shaft coupling from a pump shaft. is there. FIG. 12 is a schematic cross-sectional view illustrating a process of removing the mechanical seal from the pump shaft in the mechanical seal replacement procedure. FIG. 13A is a schematic cross-sectional view showing a process of mounting the mechanical seal on the pump shaft in the mechanical seal replacement procedure, and FIG. 13B shows a process of mounting the pump-side shaft joint on the pump shaft. It is a typical sectional view shown. FIG. 14A is a schematic cross-sectional view showing a process of fixing the pump-side shaft joint and the pump shaft in the mechanical seal replacement procedure, and FIG. 14B is a plan view of the spacer on the pump-side shaft joint and the motor-side shaft. It is typical sectional drawing which shows the process integrated between joints. FIG. 15A is a schematic cross-sectional view illustrating a process of fixing the motor side shaft joint and the spacer in the mechanical seal replacement procedure, and FIG. 15B illustrates a process of coupling the pump side shaft joint and the spacer. It is a typical sectional view shown. FIG. 16A is a schematic plan view of a C-shaped retaining ring, and FIGS. 16B and 16C are schematic sectional views showing an operation process for removing the C-shaped retaining ring from the pump shaft. FIG. 17A is a schematic cross-sectional view showing an example of a structure in which a split ring for positioning the pump side shaft coupling with respect to the axial direction of the pump shaft is provided on the pump side shaft coupling. (B) is a figure which shows a split ring and a stop ring for fixing a split ring. 18 (a) and 18 (b) are schematic cross-sections showing the operating and disassembled states in the pump side shaft joint positioning structure using the split ring configured as shown in FIG. 17 (a). FIG. 18 (a) shows the time of operation, and FIG. 18 (b) shows the time of disassembly. FIG. 19A is a schematic cross-sectional view showing a proper assembled state of the pump shaft and the pump side shaft joint, and FIG. 19B shows the pump shaft because the fixing bolt is not in the groove of the pump shaft. It is typical sectional drawing which shows the state which has a poor assembly | attachment with a pump side shaft coupling. FIG. 20 is a schematic cross-sectional view showing an example of a fixing bolt used in the embodiment shown in FIGS. 19 (a) and 19 (b). FIGS. 21A and 21B are views showing an example of the groove of the pump shaft used in the embodiment shown in FIGS. 19A and 19B. FIG. It is typical sectional drawing which shows a pump side shaft coupling, FIG.21 (b) is a side view of the pump shaft provided with the groove | channel.

Hereinafter, an embodiment of a turbo pump according to the present invention will be described with reference to FIGS. 1 to 21, the same or corresponding components are denoted by the same reference numerals, and redundant description is omitted.
FIG. 1 is a cross-sectional view showing a turbo pump according to an embodiment of the present invention. As shown in FIG. 1, the turbo pump includes a casing 1 having a suction port 1 a and a discharge port 1 b, and a casing cover 2 fixed to the casing 1. An impeller 3 is arranged in a pump casing constituted by the casing 1 and the casing cover 2.

  As shown in FIG. 1, the impeller 3 is supported by a pump shaft (main shaft) 4. A mechanical seal 5 is provided as a shaft seal device at a portion where the pump shaft 4 penetrates the casing cover 2 constituting the pump casing. A motor base 6 for supporting a motor (not shown) is provided above the casing cover 2. In FIG. 1, the motor is not shown, but the motor shaft 7 of the motor is shown. Liner rings 8 and 8 are provided in the gap between the upper and lower ends of the impeller 3 and the pump casing.

  As shown in FIG. 1, a pump side shaft joint 10 is fixed to a pump shaft 4 that supports an impeller 3, a motor side shaft joint 11 is fixed to a motor shaft 7 of the motor, and the pump side shaft joint 10 and the motor side shaft are fixed. A spacer 12 is interposed between the joint 11. That is, the coupling structure that couples the pump shaft 4 of the pump and the motor shaft 7 of the motor includes the pump side shaft joint 10, the motor side shaft joint 11, and the spacer 12. The pump side shaft joint 10 and the spacer 12 are coupled by a fastener such as a bolt and a nut, and the motor side shaft joint 11 and the spacer 12 are coupled by a fastener such as a bolt and a nut. According to this coupling structure, the mechanical seal 5 can be inspected and replaced only by removing the pump side shaft joint 10 and the spacer 12 without moving any heavy motor. The motor base 6 is formed with a working window (not shown) when the mechanical seal 5 is inspected and replaced.

FIG. 2 is a schematic cross-sectional view showing an example of a structure for fixing the motor shaft 7 and the motor side shaft coupling 11 in the turbo pump shown in FIG. As shown in FIG. 2, a key 13 is interposed between the motor shaft 7 and the motor side shaft coupling 11, and the motor side shaft coupling 11 is configured to rotate integrally with the motor shaft 7. The motor side shaft coupling 11 is formed with a plurality (two in the figure) of female threads, and bolts 14 are screwed onto the female threads of the motor side shaft coupling 11. By tightening the bolt 14 so that the tip of the bolt 14 abuts against the key 13 with a strong force, the motor side shaft coupling 11 is fixed to the motor shaft 7 so as not to move in the axial direction. In addition, since it is comprised so that the front-end | tip of the volt | bolt 14 may contact | abut to the key 13, the damage to the outer diameter surface of the motor shaft 7 can be prevented at the time of fixation.
In this way, by fixing the motor shaft 7 and the motor side shaft joint 11 in the axial direction using the bolts 14, it is possible to prevent the motor side shaft joint 11 from falling off the motor shaft 7, and a high axial thrust force is achieved. Even in a pump under the receiving condition, the present coupling structure including the pump side shaft joint 10, the motor side shaft joint 11, and the spacer 12 can be employed. In addition, the motor side shaft coupling 11 can be prevented from falling off by fixing the motor side shaft coupling 11 and the motor shaft 7 by shrink fitting (or press fitting).

  FIG. 3 is a schematic cross-sectional view showing an example of a structure for fixing the pump shaft 4 and the pump side shaft joint 10 in the turbo pump shown in FIG. As shown in FIG. 3, a circumferential groove 4g is formed at a predetermined position of the pump shaft 4, and a C-type retaining ring 16 is attached to the circumferential groove 4g. The C-type retaining ring 16 is used for positioning the pump side shaft joint 10 with respect to the axial direction of the pump shaft 4. Note that screws, bolts or pins can be used in place of the C-type retaining ring 16.

FIG. 4 is a schematic cross-sectional view showing another example of a structure for fixing the pump shaft 4 and the pump side shaft joint 10 in the turbo pump shown in FIG. As shown in FIG. 4, a female screw 4 s is formed at a predetermined position of the pump shaft 4, and a through hole 10 h is formed in the cylindrical portion of the pump side shaft joint 10. The pump side shaft joint 10 and the pump shaft 4 can be fixed by inserting the bolt 18 through the through hole 10h and screwing the bolt 18 into the female screw 4s.
In this way, by fixing the pump side shaft joint 10 and the pump shaft 4 in the axial direction using the bolts 18, the pump shaft 4 can be prevented from falling off, and even in a pump that receives a high axial thrust force, The present coupling structure composed of the shaft coupling 10, the motor side shaft coupling 11, and the spacer 12 can be employed.

FIG. 5 is a schematic cross-sectional view showing still another example of a structure for fixing the pump shaft 4 and the pump side shaft joint 10 in the turbo pump shown in FIG. As shown in FIG. 5, a through hole 4 h is formed at a predetermined position of the pump shaft 4, and a through hole 10 h is also formed in the cylindrical portion of the pump side shaft joint 10. The pump side shaft joint 10 and the pump shaft 4 can be fixed by inserting the pin 19 through the through hole 10 h of the pump side shaft joint 10 and the through hole 4 h of the pump shaft 4.
Thus, by fixing the pump side shaft joint 10 and the pump shaft 4 in the axial direction using the pin 19, the pump shaft 4 can be prevented from falling off, and even in a pump that receives a high axial thrust force, The present coupling structure composed of the shaft coupling 10, the motor side shaft coupling 11, and the spacer 12 can be employed.

FIG. 6 is a schematic cross-sectional view showing still another example of a structure for fixing the pump shaft 4 and the pump side shaft joint 10 in the turbo pump shown in FIG. As shown in FIG. 6, a key 13 is interposed between the pump shaft 4 and the pump side shaft joint 10, and the pump shaft 4 and the pump side shaft joint 10 are configured to rotate integrally. . A groove 4G is formed at a predetermined position of the pump shaft 4, and a female screw 10s is formed in the cylindrical portion of the pump side shaft joint 10. Then, the bolt 20 is screwed into the female screw 10s of the pump side shaft joint 10, and the tip of the bolt 20 is fitted into the groove 4G. The pump-side shaft joint 10 and the pump shaft 4 can be fixed by tightening the bolt 20 so that the tip of the bolt 20 abuts against the bottom of the groove 4G of the pump shaft 4 with a strong force.
Thus, by fixing the pump side shaft joint 10 and the pump shaft 4 in the axial direction by using the bolt 20 and the groove 4G, the pump shaft 4 can be prevented from falling off, and the pump is subjected to a high axial thrust force. However, the present coupling structure including the pump side shaft coupling 10, the motor side shaft coupling 11, and the spacer 12 can be employed.

Further, since the tip of the bolt 20 abuts against the bottom of the groove 4G when fixed, it is possible to prevent the outer surface of the pump shaft 4 from being damaged. Therefore, when the pump side shaft joint 10 is attached to and detached from the pump shaft 4, the pump side shaft joint 10 can be easily and repeatedly attached and detached.
According to the combination of the bolt 20 and the groove 4G shown in FIG. 6, the bolt 20 is caught (or engaged) with the upper end of the groove 4G of the pump shaft 4, thereby preventing the pump shaft 4 from dropping off due to the axial thrust force. be able to. The number of bolts may be increased by the axial thrust force, or the bolt size may be increased.

FIGS. 7A, 7B, 7C and 7D are diagrams showing details of the groove 4G formed in the pump shaft 4 shown in FIG. 7A is a front view showing an example of the groove 4G, FIG. 7B is a cross-sectional view showing another example of the groove 4G, and FIGS. 7C and 7D are views of FIG. FIG.
The groove 4G shown in FIG. 7A is composed of a circumferential groove formed over the entire circumference of the pump shaft 4 in the circumferential direction. The width of the circumferential groove is set to be slightly larger than the outer diameter of the bolt 20.
Grooves 4G shown in FIGS. 7B and 7C are configured by round grooves provided at intervals in the circumferential direction of the pump shaft 4. The round groove includes a circular cross section or an elliptic cross section. The inner diameter of the round groove is set slightly larger than the outer diameter of the bolt 20. Moreover, the groove | channel 4G shown in FIG.7 (d) is comprised from the polygonal groove | channel provided in the circumferential direction of the pump shaft 4 at intervals. The polygonal groove includes a polygonal cross section such as a quadrangular cross section or a hexagonal cross section. The distance between the opposite sides of the polygonal groove is set to be slightly larger than the outer diameter of the bolt 20.
7 (b), 7 (c), and 7 (d), the contact area between the groove and the fixing screw / bolt is increased, and the surface pressure can be reduced. There is a feature that can receive thrust force. In the illustrated example, two round grooves or polygonal grooves are formed in the circumferential direction of the pump shaft 4, but the number of round grooves or polygonal grooves is appropriately changed according to the axial thrust force applied to the pump shaft 4. .

8 and 9 are schematic cross-sectional views showing details of a fitting portion between the motor side shaft coupling 11 and the spacer 12 in the turbo pump shown in FIG.
In the example shown in FIG. 8, the outer diameter of the flange portion of the motor side shaft coupling 11 is made slightly larger than the outer diameter of the flange portion of the spacer 12, and a recess 11 a is formed on the outer peripheral portion of the flange portion of the motor side shaft coupling 11. The outer diameter portion of the spacer 12 is fitted into the recess 11a. That is, the motor side shaft coupling 11 and the spacer 12 are coupled by fitting. A recess may be provided in the flange portion of the spacer 12, and the outer diameter portion of the flange portion of the motor side shaft coupling 11 may be fitted into the recess.

In the example shown in FIG. 9, the recess 12 a is formed in the flange portion of the spacer 12, the projection 11 b is formed in the flange portion of the motor side shaft coupling 11, and the recess 12 a and the projection 11 b are fitted. . In addition, a convex part may be formed in the flange part of the spacer 12, and a concave part may be formed in the flange part of the motor side shaft coupling 11. In the example shown in FIG. 9, the fitting portion between the motor side shaft coupling 11 and the spacer 12 is formed radially inward from the outermost diameter portions of the motor side shaft coupling 11 and the spacer 12. In the example shown in FIG. 9, the fitting portion of the part is not the outermost diameter portion, and when the component is stored alone, it is less likely that the fitting portion is erroneously scratched or dented.
As shown in FIGS. 8 and 9, high concentricity and squareness can be obtained by coupling the motor side shaft coupling 11 and the spacer 12 by fitting. The fitting of the pump side shaft joint 10 and the spacer 12 is also the same as the example shown in FIGS.

  In the above-described embodiment, with respect to the fastening method of the pump shaft 4 and the pump side shaft joint 10 and the motor shaft 7 and the motor side shaft joint 11, a reamer bolt is used to prevent the bolt from being broken by an impact load, or It is preferable that the fit between the bolt holes is a clearance fit or an intermediate fit to reduce the gap between the bolt and the bolt hole.

Next, the replacement procedure of the mechanical seal 5 in the turbo pump shown in FIG. 1 will be described with reference to FIGS. 10 to 15, only main components related to the replacement of the mechanical seal 5 are illustrated. That is, the casing 1 shows only the part holding the liner ring 8, and the casing cover 2 and the motor base 6 are not shown.
FIG. 10A is a schematic cross-sectional view showing an initial state (normal state) before the mechanical seal 5 is replaced after the mechanical seal 5 is mounted on the pump shaft 4. As shown in FIG. 10A, the pump shaft 4 and the pump side shaft joint 10 are fixed by fitting bolts 20 into the grooves 4G of the pump shaft 4 and tightening them. The pump side shaft joint 10 and the spacer 12 are fixed by fastening bolts 21 and nuts 22, and the motor side shaft joint 11 and the spacer 12 are fastened by bolts 21 and nuts 22. It is fixed by. Instead of using the nut 22, a female thread may be formed in the flange portion of the pump side shaft joint 10, and a female screw may be formed in the upper flange portion of the spacer 12.

  FIG. 10B is a diagram illustrating a first step of the replacement procedure of the mechanical seal 5, and is a schematic cross-sectional view illustrating a process of releasing the fixing of the pump side shaft joint 10 and the spacer 12. As shown by the arrow in FIG. 10B, by removing the bolt 21 and the nut 22 that fix the pump side shaft joint 10 and the spacer 12, the fixation of the pump side shaft joint 10 and the spacer 12 is released, The entire rotor (the impeller 3, the pump shaft 4, the mechanical seal 5, and the pump side shaft joint 10) falls on the liner ring 8 held by the casing 1. Accordingly, the impeller 3 and the liner ring 8 come into contact with each other.

FIG. 11A is a diagram illustrating a second step of the replacement procedure of the mechanical seal 5 and is a schematic cross-sectional view illustrating a process of removing the spacer 12. 11A, the bolt 21 and the nut 22 that fix the motor side shaft coupling 11 and the spacer 12 are removed, and the bolt 20 is removed as shown by the lower right arrow, and the pump side is removed. The shaft coupling 10 is shifted downward to bring the lower end of the pump side shaft coupling 10 into contact with the mechanical seal 5 to ensure a sufficient space below the spacer 12. Next, the spacer 12 is removed as indicated by the arrow at the center of FIG. At this time, since there is a sufficient space between the lower end of the spacer 12 and the upper end of the pump shaft 4, the spacer 12 can be removed laterally with a margin.
FIG. 11B is a diagram illustrating a third step of the replacement procedure of the mechanical seal 5, and is a schematic cross-sectional view illustrating a process of removing the pump side shaft joint 10 from the pump shaft 4. The pump-side shaft coupling 10 is removed from the pump shaft 4 as indicated by the upper right arrow in FIG. Even if the bolt 20 is not removed from the pump-side shaft joint 10, the pump-side shaft joint 10 can be removed from the pump shaft 4 if the bolt 20 is retracted to a state where the tip of the bolt 20 is not in the groove 4G.

  FIG. 12 is a diagram showing a fourth step of the procedure for replacing the mechanical seal 5, and is a schematic cross-sectional view showing a process of removing the mechanical seal 5 from the pump shaft 4. The mechanical seal 5 is removed from the pump shaft 4 as indicated by the arrow in FIG. Thus, the disassembling process shown in FIGS. 10B to 12 is completed.

FIG. 13A is a diagram illustrating a fifth step of the replacement procedure of the mechanical seal 5, and is a schematic cross-sectional view illustrating a process of mounting the mechanical seal 5 on the pump shaft 4. The mechanical seal 5 to be replaced is attached to the pump shaft 4 as indicated by the arrow in FIG.
FIG. 13B is a diagram showing a sixth step of the replacement procedure of the mechanical seal 5, and is a schematic cross-sectional view showing a process of mounting the pump side shaft joint 10 to the pump shaft 4. As shown by the arrow in FIG. 13 (b), the pump side shaft joint 10 is attached to the pump shaft 4.

FIG. 14A is a diagram illustrating a seventh step of the replacement procedure of the mechanical seal 5, and is a schematic cross-sectional view illustrating a process of fixing the pump side shaft joint 10 and the pump shaft 4. As shown in FIG. 14A, the pump-side shaft coupling 10 is mounted on the pump shaft 4, the pump-side shaft coupling 10 is shifted downward, and the lower end of the pump-side shaft coupling 10 is brought into contact with the mechanical seal 5 so that the pump shaft A sufficient space above 4 is secured.
FIG. 14B is a diagram illustrating an eighth step of the replacement procedure of the mechanical seal 5, and is a schematic cross-sectional view illustrating a process of incorporating the spacer 12 between the pump-side shaft coupling 10 and the motor-side shaft coupling 11. . As shown by the arrow in FIG. 14B, the spacer 12 is assembled between the motor side shaft coupling 11 and the pump shaft 4. At this time, since there is a sufficient space between the motor side shaft coupling 11 and the pump shaft 4, the spacer 12 can be inserted with a margin.

FIG. 15A is a diagram illustrating a ninth step of the replacement procedure of the mechanical seal 5, and is a schematic cross-sectional view illustrating a process of fixing the motor side shaft coupling 11 and the spacer 12. As shown by the arrow at the upper right of FIG. 15A, the bolt 21 and the nut 22 are fastened (fastened 1) to fix the motor side shaft joint 11 and the spacer 12. At this time, as shown in FIGS. 8 and 9, high concentricity and squareness can be obtained by coupling the motor side shaft coupling 11 and the spacer 12 by fitting.
Next, after the pump side shaft joint 10 is shifted upward, the bolt 20 is screwed into the female screw 10s of the pump side shaft joint 10 as shown by the lower right arrow in FIG. The pump side shaft joint 10 and the pump shaft 4 are fixed by fastening the bolt 20 (fastening 2) so as to be in contact with the bottom of the groove 4G of the pump shaft 4.

  FIG. 15B is a diagram illustrating a tenth step of the replacement procedure of the mechanical seal 5, and is a schematic cross-sectional view illustrating a process of joining the pump side shaft joint 10 and the spacer 12. As shown by the arrow in FIG. 15B, the pump side shaft joint 10 and the spacer 12 are fixed by fastening the bolt 21 and the nut 22 (fastening 3). At this time, using the bolts 21 and nuts 22, the entire rotor (the impeller 3, the pump shaft 4, the mechanical seal 5, and the pump side shaft joint 10) dropped on the liner ring 8 held in the casing 1 and the spacer 12 are connected. Fix it. The entire rotor is gradually raised by fastening the bolt 21 and the nut 22. When the bolt 21 and the nut 22 are completely fastened, the pump-side shaft joint 10 and the spacer 12 are coupled by fitting, and high concentricity and squareness can be obtained. At this time, the entire rotor returns to the initial state (regular state), the contact between the impeller 3 and the liner ring 8 is lost, and the state shown in FIG. Thus, the mechanical seal replacement / reassembly process shown in FIGS. 13A to 15B is completed.

  As shown in FIGS. 10 to 15, according to the replacement procedure of the mechanical seal 5 of the present embodiment, when removing the spacer 12 at the intermediate portion between the motor side shaft joint 11 and the pump side shaft joint 10, the spacer / shaft joint is removed. Since the pump shaft 4 can be dropped and the pump side shaft joint 10 can be shifted downward so as to secure an amount corresponding to the fit between them and allow the spacer 12 to be removed laterally with a margin, the impeller 3, Even in the case of a pump having no allowance for the space where the rotating body (rotor) including the pump shaft 4 and the pump side shaft joint 10 falls, this coupling constituted by the pump side shaft joint 10, the motor side shaft joint 11, and the spacer 12 is used. A structure can be adopted.

Next, as shown in FIG. 3, when a C-shaped retaining ring 16 for positioning the pump side shaft coupling 10 with respect to the axial direction of the pump shaft 4 is provided, a work procedure for removing the C-shaped retaining ring 16. This will be described with reference to FIGS. 16 (a), (b) and (c).
FIG. 16A is a schematic plan view of a C-shaped retaining ring, and FIGS. 16B and 16C are schematic sectional views showing an operation process for removing the C-shaped retaining ring 16 from the pump shaft 4.
As shown in FIG. 16 (a), the C-shaped retaining ring 16 includes tool insertion holes 16h and 16h at both ends of the C-shaped main body.
As shown in FIG. 16B, the lower end surface of the pump side shaft joint 10 is in contact with a C-shaped retaining ring 16 attached to the pump shaft 4. Below the C-shaped retaining ring 16 is the casing cover 2 (see FIG. 1). When removing the C-shaped retaining ring 16 from the pump shaft 4, as shown in FIG. 16 (b), the detaching tool 30 is visually inserted into the gap between the C-shaped retaining ring 16 and the casing cover 2, and FIG. ), The claw portion 30a at the tip of the removal tool 30 is inserted into the tool insertion hole 16h of the C-shaped retaining ring 16. Thereafter, the C-shaped retaining ring 16 is expanded by the removal tool 30, and the C-shaped retaining ring 16 is removed from the pump shaft 4.

  As shown in FIGS. 16 (b) and 16 (c), when the work of removing the C-shaped retaining ring 16 from the pump shaft 4 using the detaching tool 30 is actually performed, the C-shaped retaining ring 16, the casing cover 2, Since the tool insertion hole 16h is not visible from above, it has been found that it is extremely difficult to insert the claw portion 30a of the removal tool 30 into the tool insertion hole 16h of the C-shaped retaining ring 16. It has also been found that the claw portion 30a of the detachable tool 30 is easily detached from the tool insertion hole 16h of the C-shaped retaining ring 16 during work.

Therefore, the present inventors have conceived of using a split ring instead of the C-shaped retaining ring 16.
FIG. 17A is a schematic cross-sectional view showing an example of a structure in which a split ring for positioning the pump side shaft joint 10 with respect to the axial direction of the pump shaft 4 is provided in the pump side shaft joint, FIG. 17B is a diagram showing a split ring and a retaining ring for fixing the split ring.

  As shown in FIG. 17A, a circumferential groove 4g is formed at a predetermined position of the pump shaft 4, and a split ring 31 is attached to the circumferential groove 4g. As shown in the upper perspective view in FIG. 17B, the split ring 31 is a circular ring divided into two. As shown in FIG. 17A, when the split ring 31 is mounted in the circumferential groove 4g, the outer diameter of the split ring 31 is equal to the outer diameter of the cylindrical portion of the pump-side shaft joint 10. Is set to A retaining ring 32 is fitted to the outer periphery of the split ring 31 and the outer periphery of the cylindrical portion of the pump side shaft joint 10. As shown in the lower perspective view in FIG. 17B, the retaining ring 32 has a short cylindrical shape. As shown in FIG. 17 (a), a plurality of (for example, four) female screws 10s are formed at predetermined intervals in the circumferential direction slightly above the lower end of the cylindrical portion of the pump-side shaft coupling 10. The stop ring 32 has a through hole 32h at a position corresponding to the female screw 10s. A disassembling female screw 10Bs is formed above the female screw 10s (described later). The retaining ring 32 can be fixed to the cylindrical portion of the pump side shaft joint 10 by inserting the bolt 33 through the through hole 32h and screwing the bolt 33 into the female screw 10s. When the retaining ring 32 is fixed to the pump-side shaft joint 10, the outer peripheral surface of the split ring 31 comes into close contact with the inner peripheral surface of the retaining ring 32. Thereby, the split ring 31 is fixed by the stop ring 32 in a state where it is mounted in the circumferential groove 4g.

  As shown in FIG. 17A, the inner diameter of the upper side of the pump side shaft joint 10 is set larger than the inner diameter of the lower side of the pump side shaft joint 10, and a step portion 10D is formed on the upper side of the pump side shaft joint 10. Is formed. A disc-shaped plate 35 is placed on the step portion 10D of the pump side shaft coupling 10, and a through hole 35h is formed in the plate 35. A bolt 36 extending in the axial direction of the pump shaft 4 is inserted into the through hole 35 h of the plate 35, and the bolt 36 is screwed into the female screw 4 s at the upper end portion of the pump shaft 4. Accordingly, since the bolt 36 and the plate 35 can receive axial force, the pump shaft 4 can be prevented from falling off, and the pump-side shaft joint 10 and the motor-side shaft can be used even in a pump that receives a high axial thrust force. The present coupling structure including the joint 11 and the spacer 12 can be employed.

18 (a) and 18 (b) are schematic views showing states during operation and disassembly in the positioning structure of the pump-side shaft joint 10 using the split ring configured as shown in FIG. 17 (a). 18A is a cross-sectional view, FIG. 18A shows the time of operation, and FIG. 18B shows the time of disassembly.
During operation, as shown in FIG. 18A, the stop ring 32 is in the lowered position, and the stop ring 32 is fixed to the pump-side shaft joint 10 by a bolt 33. The outer peripheral surface of the split ring 31 is in close contact with the inner peripheral surface of the stop ring 32, and the split ring 31 is fixed by the stop ring 32 in a state of being mounted in the circumferential groove 4g.
At the time of disassembly, the bolt 33 is removed and the retaining ring 32 is slid upward along the cylindrical portion of the pump side shaft joint 10, and the bolt 33 is inserted into the through hole 32h as shown in FIG. Is fastened to the cylindrical portion of the pump-side shaft joint 10 by screwing it into the female screw 10Bs for disassembly of the pump-side shaft joint 10. As a result, the split ring 31 becomes free and the split ring 31 is split in two, so that even if there is no space, it can be easily removed radially outward as indicated by the arrows. Thereafter, the pump-side shaft joint 10 can be slid down along the pump shaft 4 to remove the spacer 12.

Thus, according to the positioning structure of the pump side shaft joint 10 using the split ring 31 shown in FIGS. 17 and 18, the plate 35 and the bolt 36, an excessive axial load can be received, And it is possible to carry out decomposition easily. More specifically, it has the characteristics listed below.
(1) The pump side shaft joint 10 and the pump shaft (main shaft) 4 are firmly coupled by the plate 35 and the bolt 36, and can withstand an excessive axial load.
(2) When the lower end of the pump side shaft joint 10 is fixed with the split ring 31, attachment and removal are simplified. That is, when the pump side shaft joint 10 is slid down, the spacer 12 can be removed, and the cartridge mechanical seal can be removed without removing the motor side shaft joint 11.
(3) The retaining ring 32 that can be slid up and down can be slid downward during operation to fix the split ring 31, and can be slid upward during maintenance to remove the split ring 31. .

Next, as shown in FIG. 6, a groove 4G is provided on the outer peripheral surface of the pump shaft 4, a female screw 10s is provided on the pump side shaft joint 10, and a bolt 20 is screwed to the female screw 10s so that the tip of the bolt 20 is formed in the groove 4G. In the embodiment in which the pump side shaft joint 10 is fixed to the pump shaft 4 by being fitted into the pump shaft 4, the assembled state of the pump shaft 4 and the pump side shaft joint 10 is shown in FIGS. Will be described with reference to FIG.
FIG. 19A is a schematic cross-sectional view showing a properly assembled state of the pump shaft 4 and the pump side shaft joint 10. As shown in FIG. 19A, a groove 4 </ b> G is formed at a predetermined position of the pump shaft 4, and a female screw 10 s is formed at the cylindrical portion of the pump side shaft joint 10. Then, the fixing bolt 20 is screwed into the female screw 10s of the pump side shaft coupling 10, and the tip of the fixing bolt 20 is fitted into the groove 4G. The pump-side shaft joint 10 can be fixed to the pump shaft 4 by tightening the bolt 20 so that the tip of the fixing bolt 20 abuts against the bottom of the groove 4G of the pump shaft 4 with a strong force. The pump side shaft joint 10 is provided with a counterbore 10c for accommodating the head 20a of the fixing bolt 20.

  As shown in FIG. 19A, in a properly assembled state of the pump shaft 4 and the pump side shaft joint 10, the bolt 20 is tightened until the tip of the fixing bolt 20 contacts the bottom of the groove 4 </ b> G of the pump shaft 4. And the whole bolt head 20a is accommodated in the counterbore 10c. At this time, the end surface 20e of the bolt head 20a and the outer peripheral surface 10e of the pump side shaft joint 10 surrounding the counterbore 10c are set to be substantially flush with each other. Here, “substantially flush” means that there is no step between the end face 20e of the bolt head 20a and the outer peripheral face 10e of the pump-side shaft joint 10 in the cross-sectional view of FIG. If the state in which the end surface 20e of the head 20a protrudes (projects) from the outer peripheral surface 10e of the pump-side shaft coupling 10 is defined as + (plus), it means that there is a slight step within ± 2 mm. In the illustrated example, a hexagon socket head cap screw is used as the fixing bolt 20, but a hexagon socket head set screw may be used. When a hexagon socket set screw is used, when the tip of the set screw comes into contact with the bottom of the groove 4G of the pump shaft 4, it surrounds the end face of the set screw on the hexagon socket side and the counterbore 10c. The outer peripheral surface 10e of the pump side shaft coupling 10 is substantially flush.

  FIG. 19B is a schematic cross-sectional view showing a state in which the pump shaft 4 and the pump-side shaft joint 10 are in a poorly assembled state because the fixing bolt 20 is not in the groove 4G of the pump shaft 4. As shown in FIG. 19B, when the tip of the fixing bolt 20 is not fitted in the groove 4G of the pump shaft 4, that is, when the fixing bolt 20 is not accurately inserted into the groove 4G, The end face 20e of the bolt head 20a protrudes (protrudes) from the outer peripheral face 10e of the pump side shaft joint 10. Therefore, the operator can easily recognize the state of poor assembly between the pump shaft 4 and the pump side shaft joint 10. When there is an assembly failure, there is a possibility that the displacement of the axial position of the pump shaft 4 (X in FIG. 19B), or the pump shaft 4 is dropped (missed) due to the axial thrust force. However, when there is an assembly failure between the pump shaft 4 and the pump side shaft joint 10, the end surface 20e of the bolt head 20a protrudes (protrudes) from the outer peripheral surface 10e of the pump side shaft joint 10, as shown in FIG. For this reason, it is possible to easily recognize the assembly failure state between the pump shaft 4 and the pump side shaft joint 10, and therefore, it is possible to prevent the assembly failure. The shape of the fixing bolt 20 may be any shape as long as the pump side shaft joint 10 can be fastened to the pump shaft 4 such as a hexagon socket head cap screw or a set screw.

  20 is a schematic cross-sectional view showing an example of the fixing bolt 20 used in the embodiment shown in FIGS. 19 (a) and 19 (b). In the example shown in FIG. 20, the tip 20t of the fixing bolt 20 has a non-screw shape. That is, in the fixing bolt 20 shown in FIG. 20, the tip portion 20t that is a portion to be inserted into the groove 4G of the pump shaft 4 is a non-screw-shaped cylinder having a smaller diameter than the screw portion of the bolt.

  When the axial thrust force acts on the pump shaft 4 and the axial thrust force cannot be supported only by the frictional force of the front end surface of the fixing bolt 20, as shown in FIG. 20, the upper end surface of the groove 4G and the fixing bolt 20 The tip 20t comes into contact. In this case, when the fixing bolt 20 is a full screw, deformation of the screw shape due to the contact can be considered. Moreover, when it is going to remove the fixing bolt 20 in the contact state, there is a concern that the fixing bolt 20 and the female screw 10 s of the pump side shaft joint 10 may be twisted. In the structure shown in FIG. 20, the smooth outer peripheral surface of the tip portion 20t of the fixing bolt 20 is in contact with the upper end surface of the groove 4G.

  FIGS. 21A and 21B are views showing an example of the groove 4G of the pump shaft 4 used in the embodiment shown in FIGS. 19A and 19B. FIG. It is typical sectional drawing which shows the assembly | attachment state of the axis | shaft 4 and the pump side shaft coupling 10, FIG.21 (b) is a side view of the pump axis | shaft 4 provided with the groove | channel 4G. In the example shown in FIGS. 21A and 21B, the groove 4G formed in the pump shaft 4 is a round groove, and the inlet side corner of the groove 4G has a chamfered CH or a tapered shape T. Thus, when the inlet side corner of the groove 4G is chamfered CH or tapered T, the fixing bolt 20 can be easily inserted into the groove 4G. Further, the corner of the tip 20t of the fixing bolt 20 is also chamfered CH or tapered T. This facilitates the insertion of the fixing bolt 20 into the female screw 10s.

Next, suitable materials for the motor shaft, shaft coupling (motor side, pump side), and pump shaft will be described.
The material of the motor shaft, shaft coupling (motor side, pump side), and pump shaft can be arbitrarily selected, but the selection shown in Table 1 below is advantageous.

Since the pump shaft and the shaft coupling need to be removed when replacing the mechanical seal, they are fitted in a gap. When the temperature rises as the pump is operated, in the case of the combination of the above materials, the pump shaft has a larger linear expansion coefficient than the shaft coupling, so that the gap in the fitting portion is reduced, and there is no gap depending on the temperature rise value. This works in a direction to prevent the main shaft from being pulled in the axial direction by the axial thrust, and is advantageous.
The motor shaft and the shaft coupling are fixed by shrink fitting or press fitting because they do not need to be removed. For this reason, there is no problem as long as the materials of the two parts are selected to have the same linear expansion coefficient. However, a material having a large linear expansion coefficient (for example, austenitic stainless steel) may be used for the motor shaft in order to enhance the effect of preventing the main shaft from falling off against the axial thrust with the same effect as that on the pump shaft side. However, since it is more advantageous in terms of motor characteristics to use a magnetic material such as S35C, which is a magnetic material, the special steel and austenitic stainless steel are joined by pressure welding or shrink fitting (press fitting). There is a need to.

The present invention can be applied to other types of turbo pumps including single-stage and multi-stage vertical line pumps.
Although the embodiment of the present invention has been described so far, the present invention is not limited to the above-described embodiment, and it is needless to say that the present invention may be implemented in various different forms within the scope of the technical idea.

1 Casing 1a Suction port 1b Discharge port 2 Casing cover 3 Impeller 4 Pump shaft (main shaft)
4g Circumferential groove 4G groove 4h Through hole 4s Female screw 5 Mechanical seal 6 Motor base 7 Motor shaft 8 Liner ring 10 Pump side shaft joint 10c Counterbore 10e Outer peripheral surface 10h Through hole 10s Female screw 10Bs Female screw for disassembly 10D Step part 11 Motor Side shaft coupling 11a Concave portion 11b Convex portion 12 Spacer 12a Concave portion 13 Key 14 Bolt 16 C-type retaining ring 16h Tool insertion hole 18 Bolt 19 Pin 20 Bolt 20a Bolt head 20e End face 20t Tip portion 21 Bolt 22 Nut 30 Removal tool 30a Claw portion 31 Split ring 32 Stop ring 32h Through hole 33 Bolt 35 Plate 35h Through hole 36 Bolt

Claims (20)

The main shaft supporting the impeller is provided with a mechanical seal at a portion passing through the pump casing, and the main shaft and the motor shaft of the motor are connected by a pump side shaft joint, a motor side shaft joint, and a spacer interposed between both shaft joints. Turbo-type pump,
A turbo-type pump, wherein a groove is provided on an outer peripheral surface of the main shaft, a female screw is provided on the pump side shaft joint, a bolt is screwed into the female screw, and a tip of the bolt is fitted into the groove.   2. The turbo pump according to claim 1, wherein the groove is a circumferential groove extending in a circumferential direction of the main shaft.   2. The turbo pump according to claim 1, wherein the groove includes a circular groove having a circular cross section or an elliptical cross section, or a polygon groove having a polygon cross section.   The turbo pump according to any one of claims 1 to 3, wherein a tip end of the bolt is in contact with a bottom portion of the groove.   5. A counterbore hole is formed in a portion of the pump side shaft joint provided with an internal thread so that the head portion of the bolt can be accommodated in the counterbore hole. The turbo type pump described in 1.   When the front end of the bolt is brought into contact with the bottom of the groove, the end surface of the bolt head and the outer peripheral surface of the pump side shaft joint surrounding the counterbore are substantially flush with each other. The turbo pump according to claim 5, wherein   The turbo pump according to any one of claims 1 to 6, wherein a tip end of the bolt to be fitted into the groove has a smooth cylindrical shape without a screw.   The turbo pump according to any one of claims 1 to 7, wherein an inlet side corner portion of the groove is chamfered or tapered.   The turbo pump according to any one of claims 1 to 8, wherein a corner portion of a tip of the bolt is chamfered or tapered. The main shaft supporting the impeller is provided with a mechanical seal at a portion passing through the pump casing, and the main shaft and the motor shaft of the motor are connected by a pump side shaft joint, a motor side shaft joint, and a spacer interposed between both shaft joints. Turbo-type pump,
The main shaft is provided with a female screw in a direction perpendicular to the axial direction of the main shaft, the pump side shaft joint is provided with a through hole, a bolt is inserted into the through hole, and the bolt is screwed into the female screw. Turbo pump. The main shaft supporting the impeller is provided with a mechanical seal at a portion passing through the pump casing, and the main shaft and the motor shaft of the motor are connected by a pump side shaft joint, a motor side shaft joint, and a spacer interposed between both shaft joints. Turbo-type pump,
A turbo-type pump characterized in that a through hole is provided in the main shaft in a direction perpendicular to the axial direction of the main shaft, a through hole is provided in the pump side shaft joint, and a pin is inserted through the both through holes.   The turbo pump according to any one of claims 1 to 11, wherein a key is interposed between the pump side shaft joint and the main shaft.   The turbo pump according to any one of claims 1 to 12, wherein a key is interposed between the motor side shaft coupling and the motor shaft.   At least one of the pump side shaft coupling and the motor side shaft coupling is provided with a female screw at a position corresponding to the key, and a bolt is screwed to the female screw so that a tip of the bolt is brought into contact with the key. The turbo pump according to claim 12 or 13.   The turbo pump according to any one of claims 1 to 14, wherein a retaining ring for positioning the pump side shaft joint is attached to the main shaft.   A split ring for positioning the pump side shaft joint is mounted on the main shaft, and a retaining ring is fitted on the cylindrical portion of the pump side shaft joint and the split ring. The turbo pump according to any one of 1 to 14.   A female screw is provided in the cylindrical portion of the pump side shaft joint in a direction orthogonal to the axial direction of the main shaft, a through hole is provided in the retaining ring, a bolt is inserted into the through hole, and the bolt is screwed into the female screw. The turbo pump according to claim 16.   A step portion is formed on the inner peripheral side of the pump side shaft joint, a plate is placed on the step portion, and a bolt extending in the axial direction of the main shaft is inserted into a through hole of the plate to form a bolt at the upper end portion of the main shaft. The turbo-type pump according to any one of claims 1 to 17, wherein the turbo-type pump is screwed into the formed female screw.   The fitting portion between at least one of the pump side shaft coupling and the motor side shaft coupling and the spacer is formed radially inward from the outermost diameter portion. The turbo pump according to one item.   When replacing the mechanical seal, the fastener including the screw connecting the spacer and the pump side shaft joint is released, and the rotating body including the impeller, the main shaft, and the pump side shaft joint is dropped. The turbo pump according to any one of claims 1 to 19, wherein after the replacement of the mechanical seal, the rotating body is lifted and returned to a normal position by a fastening operation of the fastener.

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