TW201621172A - Turbopump - Google Patents

Abstract

A turbopump which can use a main shaft having high general versatility for connection with a shaft coupling without causing the main shaft to drop even in a pump in which a large axial thrust force is generated, and can facilitate replacement work of a mechanical seal is disclosed. The turbopump includes a mechanical seal provided in a portion where the main shaft passes through a pump casing, and a pump-side shaft coupling, a motor-side shaft coupling, and a spacer which are configured to connect the main shaft and a motor shaft of a motor, the spacer being interposed between the pump-side shaft coupling and the motor-side shaft coupling. A groove is formed in an outer circumferential surface of the main shaft, a female screw is formed in the pump-side shaft coupling, and a bolt is screwed into the female screw to fit a tip end of the bolt into the groove.

Description

Turbo pump

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a turbo pump, and more particularly to a turbopump having a mechanical seal in a portion that supports a main shaft of the impeller through the pump casing.

In a turbo pump that energizes a liquid in a pump casing by rotating an impeller, a mechanical seal is often used as a shaft seal device in a portion that supports a main shaft of the impeller through the pump casing.

One of the turbo pumps is a centrifugal pump. In order to replace the mechanical seal without disassembling the motor during maintenance, the coupling structure is divided into two, and the space for replacing the mechanical seal is provided (patent Document 1).

The coupling structure that is divided into two is often long, large, and heavy in order to exhibit rigidity, and the large output type is inferior in workability and combination because of the heavy weight of the coupling. In addition, the two-part coupling is less likely to form concentricity and straight angle, and the manufacturing cost is high. When the coupling is divided into two at the actual manufacturing cost, the concentricity and the straight angle are not accurate enough, and the vibration and noise of the pump become large due to the lack of concentricity and straight angle. In addition, when the pump impeller is overhanged, when the coupling is divided into two, the front end of the main shaft needs to adopt a submerged bearing structure.

As described above, the coupling structure described in Patent Document 1 has various problems in terms of workability, combination, and performance.

There is little problem in the structure of the coupling that is divided into two as described above, and the structure of the mechanical seal can be replaced without disassembling the motor during maintenance. Patent Document 2 describes a pump that supports the blade. The pump side coupling is fixed on the pump shaft of the wheel, and the motor side coupling is fixed on the motor shaft of the motor, and a spacer is interposed between the pump side coupling and the motor side coupling.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2007-205360

[Patent Document 2] Japanese Laid-Open Patent Publication No. 59-138794

The present inventors have reviewed the results of the review of the coupling structure in which the spacer is interposed between the motor-side coupling and the pump-side coupling of Patent Document 2, and found that the structure has the following problems.

(1) Since the coupling and the spindle are not fixed by using a set screw or the like, when the pump that generates a large axial thrust is used, the spindle is axially stretched and falls off, which may cause the pump to be inoperable.

(2) Since the special spindle for coupling to the coupling is used on both the motor side and the pump side, the manufacturing cost of parts is improved. In addition, since the motor cannot use the general-purpose product and a dedicated motor must be used, the manufacturing cost of the pump may increase.

(3) When the spacer of the intermediate portion is removed, since the main shaft must be dropped above the fitting portion between the spacer and the coupling, the structure of the pump is not provided for the rotating body (rotor) including the main shaft and the impeller to fall. The pump of the margin space cannot be constructed with this coupling.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a spindle having high versatility for coupling with a coupling even if a pump that generates a large axial thrust does not fall off, and can be easily mechanically sealed. Turbine pump for replacement work.

In order to achieve the above object, the first state of the turbo pump of the present invention is provided with a mechanical seal in a portion of the main shaft supporting the impeller penetrating the pump casing, and is provided by the pump side coupling, the motor side coupling, and the The spacer between the coupling joints is coupled to the motor shaft of the spindle and the motor, and the turbo pump is characterized in that: a groove is arranged on the outer surface of the spindle, and a female thread is arranged on the pump side coupling to make the bolt and the bolt The aforementioned female screw is screwed so that the front end of the bolt is fitted into the groove.

When the invention is used, the pump side 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. Even if the pump is subjected to high axial thrust, the pump side coupling can be used. The coupling structure of the motor side coupling and the spacer. That is, by inserting the bolt into the groove of the main shaft, the bolt catches (engages) the upper end portion of the groove of the main shaft, thereby preventing the axial thrust from causing the main shaft to fall off. The number of bolts can also be increased depending on the axial thrust, or the bolt size can be increased.

Preferably, the groove is formed by a circumferential groove extending in the circumferential direction of the main shaft.

A preferred aspect of the invention is characterized in that the groove is formed by a circular groove having a circular cross section or an elliptical cross section or a polygonal groove having a polygonal cross section.

When the circular groove of the present invention is used, since the contact area between the groove and the fixing screw and the bolt is increased, the contact surface pressure can be reduced, so that a larger axial thrust can be withstood.

A preferred aspect of the invention is characterized in that the front end of the bolt abuts against the bottom of the groove.

According to the present invention, since the front end of the bolt abuts against the bottom of the groove when being fixed, damage to the outer diameter surface of the main shaft can be prevented. Therefore, when the pump side coupling is attached and detached from the spindle, it can be prevented The pump side coupling can be bitten and the pump side coupling can be easily reversed.

Preferably, the pump side coupling is provided with a female thread to form a countersunk hole, and the head of the bolt can be received in the counterbore.

Preferably, when the front end of the bolt abuts against the bottom of the groove, an end surface of the head of the bolt and an outer peripheral surface of the pump-side coupling surrounding the counterbore are substantially same plane.

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 properly inserted into the groove, the end surface of the bolt head protrudes (projects) from the outer peripheral surface of the pump side coupling. Therefore, the operator can easily understand the assembly failure state of the pump shaft and the pump side coupling. Therefore, it is possible to prevent assembly failure of the pump shaft and the pump side coupling.

A preferred aspect of the invention is characterized in that the front end of the bolt embedded in the groove forms a smooth cylindrical shape without a thread.

The axial thrust acts on the pump shaft, and when the axial thrust is not supported by the frictional force of the front end surface of the bolt, the upper end surface of the groove contacts the front end portion of the bolt. At this time, if the bolt is a full thread, the thread shape may be deformed due to contact. In addition, when the bolt is to be removed in the contact state, the female thread of the bolt and the pump side coupling may be bitten. According to the present invention, since the outer peripheral surface of the bolt is smooth and the outer peripheral surface is in contact with the upper end surface of the groove, the above deformation or biting is prevented.

A preferred aspect of the invention is characterized in that the entrance side corner of the groove is chamfered or tapered.

In the case of the present invention, since the entrance side corner portion of the groove forms a chamfered or tapered shape, the bolt is easily inserted into the groove.

A preferred aspect of the invention is characterized in that the corners of the front end of the bolt are chamfered or tapered. shape.

According to the present invention, since the corner portion of the front end of the bolt is chamfered or tapered, the bolt is easily inserted into the female thread.

The second aspect of the turbo pump of the present invention is provided with a mechanical seal in a portion of the main shaft supporting the impeller penetrating the pump casing, and is provided between the pump side coupling, the motor side coupling and the two coupling sections. a spacer is coupled to the motor shaft of the spindle and the motor, wherein the turbo pump is provided with a female thread in a direction orthogonal to the axial direction of the spindle, and a through hole is formed in the pump side coupling A bolt is inserted into the through hole to screw the bolt with the female screw.

According to the invention, the pump side joint and the main shaft can be fixed in the axial direction by using bolts, so that the main shaft can be prevented from falling off, and even if the pump is subjected to high axial thrust, the pump side coupling and the motor side can be used. The coupling structure of the coupling and the spacer. That is, since the main shaft and the pump side coupling are fastened by bolts, the axial thrust can be received by the bolt having high strength, so that the main shaft can be prevented from coming off.

The third aspect of the turbo pump of the present invention has a mechanical seal on a portion of the main shaft supporting the impeller that penetrates the pump casing, and is connected between the pump-side coupling, the motor-side coupling, and between the two couplings. The spacer is coupled to the motor shaft of the spindle and the motor, and the turbo pump is characterized in that a through hole is provided in a direction orthogonal to the axial direction of the main shaft, and a through hole is provided in the pump side coupling, and the pin is inserted Inserted into the aforementioned two through holes.

According to the invention, the pump side joint and the main shaft can be fixed in the axial direction by using the bolt, so that the main shaft can be prevented from falling off. Even if the pump is subjected to high axial thrust, the pump side coupling and the motor side can be used. The coupling structure of the coupling and the spacer. That is, since the main shaft and the pump side coupling are coupled by inserting (or pressing in) the plug, the axial direction can be supported by the high-strength pin. Thrust, thus preventing the spindle from falling out.

A preferred aspect of the invention is characterized in that a key is inserted between the pump side coupling and the aforementioned spindle.

A preferred aspect of the invention is characterized in that a key is inserted between the motor side coupling and the motor shaft.

According to a preferred aspect of the present invention, at least one of the pump side coupling and the motor side coupling is provided with a female thread at a position corresponding to the key to screw the bolt with the female thread. The front end of the bolt is abutted against the aforementioned key.

In the case of the present invention, by screwing the bolt with the female thread of the pump side coupling or the motor side coupling, the bolt is screwed into the bolt at the front end of the bolt, and the pump side coupling or the motor side is connected. The shaft joint does not move axially to the spindle or motor shaft. In addition, since the bolt end is abutted against the key, it is possible to prevent damage to the outer diameter surface of the main shaft or the motor shaft during fixing.

According to a preferred aspect of the present invention, the spindle is provided with the buckle of the pump side coupling for positioning.

Preferably, the spindle is provided with the pump-side coupling for positioning and dividing into two rings, and the cylindrical portion of the pump-side coupling and the aforementioned two-divided ring. Upper snap ring.

According to the present invention, in the operation, the ring is fitted to the two divided rings, and the outer peripheral surface of the two divided rings is in close contact with the inner peripheral surface of the buckle, and the two divided rings are fixed by the buckle. At the time of disassembly, the ring is loosened by sliding the buckle up along the cylindrical portion of the pump-side coupling. Since the two ring systems are divided into two, even if there is no space, it can be easily removed in the radial direction. After disassembling the two rings, you can slide the pump side coupling down the main shaft. The spacer is removed and the cartridge mechanical seal can be removed without disassembling the motor side coupling.

Preferably, the cylindrical portion of the pump-side coupling is provided with a female thread in a direction orthogonal to the axial direction of the main shaft, and a through hole is formed in the buckle, and the bolt is inserted The bolt is screwed to the aforementioned female thread through the through hole.

With the present invention, the buckle can be secured to the pump side coupling using bolts.

Preferably, a step is formed on an inner circumferential side of the pump-side coupling, a plate is mounted on the step, and a bolt extending in the axial direction of the main shaft is inserted into the through hole of the plate. The bolt is screwed to a female thread formed at an upper end portion of the aforementioned main shaft.

According to the present invention, the stepped portion is mounted on the inner peripheral side of the pump side joint, and the 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 thread of the upper end portion of the main shaft. Therefore, since the bolt and the plate can be subjected to the axial force, the spindle can be prevented from falling off, and even the pump under high axial thrust can be used with the pump side coupling, the motor side coupling, and the spacer. The configuration of the coupling is constructed.

According to a preferred aspect of the present invention, at least one of the pump side coupling and the motor side coupling and the fitting portion of the spacer are formed radially inward of 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 separately stored, it is difficult to inadvertently damage or scratch the fitting portion.

Preferably, when the mechanical seal is replaced, the fastening of the fastener having the screw connecting the spacer and the pump side coupling is released to include the impeller, the main shaft and the pump side The rotating body of the shaft joint is dropped; after replacing the mechanical seal, by The fastening operation of the fastener causes the rotating body to rise and return to a normal position.

According to the present invention, after the mechanical seal is replaced, since the rotating body including the impeller, the main shaft and the pump-side coupling is raised by merely tightening the fastener such as a bolt or a nut, the normal return can be returned. The position is excellent, so workability is excellent.

The present invention achieves the effects listed below.

(1) It is not necessary to disassemble the motor and the motor side coupling, and the mechanical seal can be replaced only by disassembling the pump side coupling and the intermediate spacer.

(2) Since the coupling and the main shaft (pump shaft) are fixed by set screws or bolts or bolts, even if the pump generates a large axial thrust, the spindle does not fall off, and the pump cannot be operated due to the spindle falling off.

(3) A highly versatile spindle for coupling to a coupling can be used for both the motor side and the pump side. In addition, the motor can also use general-purpose products, which can reduce the manufacturing cost of the pump.

(4) When the spacer between the motor side and the pump-side coupling intermediate portion is removed, the portion corresponding to the fitting portion between the spacer and the coupling is secured, and the spacer is kept laterally away. The main shaft (pump shaft) can be lowered and the pump side coupling can be moved to the lower side, so even if there is no pump for the remaining space including the rotating body (rotor) of the main shaft and the impeller, the pump side coupling can be used. The coupling structure of the motor side coupling and the spacer.

(5) When the coupling is fixed to the main shaft (pump shaft), it prevents damage to the outer diameter surface of the main shaft, and the coupling can be easily disassembled, and the replacement of the mechanical seal is easy.

(6) The pump-side coupling and the main shaft are strongly coupled with the plate and the bolt, and can also withstand excessive axial load.

(7) Installation and disassembly are simple by fixing the lower end of the pump side coupling with two rings. That is, in the operation, by fitting the buckle to the two divided rings, the outer circumferential surface of the two rings is in close contact with the inner circumferential surface of the buckle, and the two divided rings are fixed by the buckle. At the time of disassembly, the ring is loosened by sliding the buckle up along the cylindrical portion of the pump-side coupling. Since the two ring systems are divided into two, even if there is no space, it can be easily removed in the radial direction. After disassembling the two-part ring and allowing the pump-side coupling to slide downward, the spacer can be removed, and the cylindrical mechanical seal can be removed without disassembling the motor-side coupling.

(8) When the front end of the bolt is not inserted into the groove of the pump shaft, that is, when the bolt is not properly inserted into the groove, the end surface of the bolt head protrudes (projects) from the outer peripheral surface of the pump-side coupling. Therefore, the operator can easily understand the assembly failure state of the pump shaft and the pump side coupling. Therefore, it is possible to prevent assembly failure of the pump shaft and the pump side coupling.

1‧‧‧Shell

1a‧‧‧Inhalation

1b‧‧‧ spitting

2‧‧‧Cabinet cover

3‧‧‧ Impeller

4‧‧‧ pump shaft (spindle)

4g‧‧‧circular groove

4G‧‧‧ trench

4h, 10h, 32h, 35h‧‧‧through holes

4s, 10s‧‧‧ female thread

5‧‧‧Mechanical seals

6‧‧‧Motor seat

7‧‧‧Motor shaft

8‧‧‧ Backing ring

10‧‧‧ pump side coupling

10c‧‧‧ countersink

10e‧‧‧ outer perimeter

10Bs‧‧‧Female thread for decomposition

10D‧‧‧

11‧‧‧Motor-side coupling

11a, 12a‧‧‧ recess

11b‧‧‧ convex

12‧‧‧ spacers

13‧‧‧ keys

14, 18, 20, 21, 33, 36‧‧‧ bolts

16‧‧‧C type buckle

16h‧‧‧Tool insertion hole

19‧‧‧Latch

20a‧‧‧Bolt head

20e‧‧‧ end face

20t‧‧‧ front end

22‧‧‧ Nuts

30‧‧‧Handling tools

30a‧‧‧ claws

31‧‧‧divided into two rings

32‧‧‧ buckle

35‧‧‧ boards

The first figure shows a cross-sectional view of a turbo pump according to an embodiment of the present invention.

The second drawing shows a schematic cross-sectional view showing an example of a structure in which a motor shaft and a motor side coupling are fixed in the turbo pump shown in the first figure.

Fig. 3 is a schematic cross-sectional view showing an example of a structure of a fixed pump shaft and a pump side coupling in the turbo pump shown in Fig. 1 .

The fourth drawing shows a schematic cross-sectional view of another example of the configuration of the fixed pump shaft and the pump side coupling in the turbo pump shown in the first figure.

Fig. 5 is a schematic cross-sectional view showing still another example of the configuration of the fixed pump shaft and the pump side coupling in the turbo pump shown in Fig. 1.

The sixth figure shows the structure of the fixed pump shaft and the pump side coupling in the turbo pump shown in the first figure. A schematic cross-sectional view of another example.

7(a), (b), (c), and (d) are detailed views of the groove formed in the pump shaft shown in Fig. 6, and Fig. 7(a) shows the front of one example of the groove. In the view, the seventh diagram (b) is a cross-sectional view showing another example of the groove, and the seventh diagrams (c) and (d) are the arrow diagrams of the seventh diagram (b).

The eighth drawing shows a detailed schematic cross-sectional view of the fitting portion of the motor-side coupling and the spacer in the turbo pump shown in the first figure.

The ninth drawing shows a detailed schematic cross-sectional view of the fitting portion of the motor-side coupling and the spacer in the turbo pump shown in the first figure.

Figure 10 (a) shows a schematic cross-sectional view of the initial state (normal state) before the mechanical seal is replaced, and the tenth (b) shows that the pump-side coupling and the spacer are released during the mechanical seal replacement process. A schematic cross-sectional view of the fixed process.

Figure 11(a) is a schematic cross-sectional view showing the process of removing the spacer during the replacement of the mechanical seal, and Figure 11(b) is a schematic sectional view showing the process of removing the pump-side coupling from the pump shaft. .

Figure 12 is a schematic cross-sectional view showing the process of removing the mechanical seal from the pump shaft during the replacement of the mechanical seal.

Figure 13 (a) shows a schematic cross-sectional view of the process of installing the mechanical seal on the pump shaft during the replacement of the mechanical seal, and the thirteenth (b) shows the pump side coupling A schematic cross-sectional view of the process of the pump shaft.

Figure 14 (a) is a schematic cross-sectional view showing the process of fixing the pump-side coupling and the pump shaft during the replacement of the mechanical seal, and Figure 14 (b) shows the insertion of the spacer into the pump side. Schematic cross-sectional view of the process between the shaft joint and the motor side coupling.

Figure 15 (a) shows the fixed motor side coupling during the replacement of the mechanical seal A schematic cross-sectional view of the process of the spacer, and fifteenth (b) is a schematic cross-sectional view showing a process of joining the pump-side coupling and the spacer.

Fig. 16(a) is a schematic plan view of a C-shaped buckle, and Fig. 16(b) and (c) are schematic cross-sectional views showing a working process of removing a C-shaped buckle from a pump shaft.

Figure 17 (a) is a schematic cross-sectional view showing an example of a structure in which a ring for dividing the pump-side coupling to the pump shaft in the axial direction is provided in the pump-side coupling, Fig. 17 (b) shows a diagram of a ring that is divided into two and a ring that is divided into two.

Fig. 18 (a) and (b) show the state of the positioning structure of the pump-side coupling using the two-part ring as shown in Fig. 17 (a) during operation and at the time of disassembly. In the sectional view, the eighteenth (a) shows the operation, and the eighteenth (b) shows the decomposition.

Figure 19 (a) is a schematic cross-sectional view showing the normal assembled state of the pump shaft and the pump side coupling, and the nineteenth (b) shows that the fixing bolt does not enter the groove of the pump shaft, the pump shaft A schematic cross-sectional view of the pump-side coupling in a poorly assembled state.

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 (b).

Fig. 21 (a) and (b) are views showing an example of a groove of a pump shaft used in the embodiment shown in Figs. 19(a) and (b), and Fig. 21 (a) A schematic cross-sectional view of the pump shaft and the pump side coupling is shown, and a twenty-first diagram (b) is a side view of the pump shaft with the groove.

Hereinafter, embodiments of the turbo pump of the present invention will be described with reference to the first to eleventh drawings. In the first to the eleventh, the same or equivalent components are denoted by the same reference numerals and the description thereof will be omitted.

The first figure shows a cross-sectional view of a turbo pump according to an embodiment of the present invention. As shown in the first figure, the turbo pump includes a casing 1 having a suction port 1a and a discharge port 1b, and a casing cover 2 fixed to the casing 1. An impeller 3 is disposed in a pump casing formed by the casing 1 and the casing cover 2.

As shown in the first figure, the impeller 3 is supported by a pump shaft (spindle) 4. A mechanical seal 5 is provided as a shaft sealing device in a portion of the pump shaft 4 that penetrates the casing cover 2 constituting the pump casing. A motor mount 6 for supporting a motor (not shown) is provided above the cabinet cover 2. In the first figure, the illustration of the motor is omitted and the motor shaft 7 of the motor is shown. A liner ring 8, 8 is provided in the gap between the lower end portion of the impeller 3 and the pump casing.

As shown in the first figure, the pump side coupling 10 is fixed to the pump shaft 4 supporting the impeller 3, and the motor side coupling 11 is fixed to the motor shaft 7 of the motor, and the pump side coupling 10 is coupled to the motor side. A spacer 12 is interposed between the shaft segments 11. That is, the coupling structure of the pump shaft 4 of the pump and the motor shaft 7 of the motor is constituted by the pump side coupling 10, the motor side coupling 11, and the spacer 12. The pump side coupling 10 and the spacer 12 are coupled by fasteners such as bolts and nuts, and the motor side coupling 11 and the spacer 12 are coupled by fasteners such as bolts and nuts. When the coupling structure is used, it is not necessary to move the weight, that is, the motor, and the mechanical seal 5 can be repaired and replaced only by the operation of disassembling the pump side coupling 10 and the spacer 12. Further, a work window (not shown) when the mechanical seal 5 is inspected and replaced is formed in the motor mount 6.

The second drawing shows a schematic cross-sectional view showing an example of the structure of the fixed motor shaft 7 and the motor side coupling 11 in the turbo pump shown in the first figure. As shown in the second figure, a key 13 is inserted between the motor shaft 7 and the motor side coupling 11, and the motor side coupling 11 and the motor shaft 7 are integrally rotated. Further, a plurality of (two in the figure) female threads are formed in the motor side coupling 11, and the bolts 14 are screwed on the female threads of the motor side couplings 11. By strongly abutting the key 13 at the front end of the bolt 14 The screw 14 is screwed in, and the motor side coupling 11 is fixed to the motor shaft 7 without axial movement. Further, since the front end of the bolt 14 is configured to abut against the key 13, the outer diameter surface of the motor shaft 7 can be prevented from being damaged during fixing.

Thus, by axially fixing the motor shaft 7 and the motor side coupling 11 by using the bolts 14, the motor side coupling 11 can be prevented from coming off the motor shaft 7, even if the pump is subjected to high axial thrust conditions, The present coupling structure consists of the pump side coupling 10, the motor side coupling 11 and the spacer 12. Further, the motor side coupling 11 and the motor shaft 7 are fixed by a heat jacket (or press fitting), and the motor side coupling 11 can be prevented from coming off.

The third diagram is a schematic cross-sectional view showing an example of the structure of the fixed pump shaft 4 and the pump side coupling 10 in the turbo pump shown in the first figure. As shown in the third figure, a circumferential groove 4g is formed at a predetermined position of the pump shaft 4, and a C-shaped buckle 16 is mounted in the circumferential groove 4g. The C-shaped retaining ring 16 is used to axially position the pump-side coupling 10 to the pump shaft 4. Alternatively, a screw, a bolt or a bolt may be used instead of the C-shaped buckle 16 .

The fourth drawing shows a schematic cross-sectional view of another example of the configuration of the fixed pump shaft 4 and the pump side coupling 10 in the turbo pump shown in the first figure. As shown in the fourth figure, a female screw 4s is formed at a predetermined position of the pump shaft 4, and a through hole 10h is formed in a cylindrical portion of the pump-side coupling 10. The bolt 18 is inserted into the through hole 10h, and the pump side coupling 10 and the pump shaft 4 can be fixed by screwing the bolt 18 to the female screw 4s.

Thus, by using the bolt 18 to axially fix the pump side coupling 10 and the pump shaft 4, the pump shaft 4 can be prevented from falling off, and even the pump under high axial thrust conditions can be used by the pump side coupling 10 The motor side coupling 11 and the spacer 12 constitute the present coupling structure.

The fifth figure shows the fixed pump shaft 4 and pump side in the turbo pump shown in the first figure. A schematic cross-sectional view of still another example of the construction of the coupling 10. As shown in the fifth figure, a through hole 4h is formed at a predetermined position of the pump shaft 4, and a through hole 10h is formed in the cylindrical portion of the pump side coupling 10. Then, the pump side coupling 10 and the pump shaft 4 can be fixed by inserting the plug 19 into the through hole 10h of the pump side coupling 10 and the through hole 4h of the pump shaft 4.

Thus, by using the bolt 19 to axially fix the pump side coupling 10 and the pump shaft 4, the pump shaft 4 can be prevented from falling off, and even the pump under high axial thrust conditions can be used by the pump side coupling 10 The motor side coupling 11 and the spacer 12 constitute the present coupling structure.

Fig. 6 is a schematic cross-sectional view showing still another example of the configuration of the fixed pump shaft 4 and the pump side coupling 10 in the turbo pump shown in Fig. 1. As shown in the sixth figure, a key 13 is interposed between the pump shaft 4 and the pump-side coupling 10, and the pump shaft 4 and the pump-side coupling 10 are integrally rotated. A groove 4G is formed at a predetermined position of the pump shaft 4, and a female thread 10s is formed in a cylindrical portion of the pump-side coupling 10. Then, the bolt 20 is screwed with the female thread 10s of the pump side coupling 10, and the front end of the bolt 20 is fitted into the aforementioned groove 4G. The pump side coupling 10 and the pump shaft 4 can be fixed by screwing the bolt 20 so that the front end of the bolt 20 strongly abuts against the bottom of the groove 4G of the pump shaft 4.

Thus, by using the bolt 20 and the groove 4G to axially fix the pump side coupling 10 and the pump shaft 4, the pump shaft 4 can be prevented from falling off, and even if the pump is subjected to high axial thrust, the pump side can be used. The coupling 10, the motor side coupling 11 and the spacer 12 constitute the present coupling structure.

Further, at the time of fixing, since the front end of the bolt 20 abuts against the bottom of the groove 4G, damage to the outer diameter surface of the pump shaft 4 can be prevented. Therefore, it is possible to prevent the pump-side coupling 10 from being detached when the pump-side coupling 10 is attached and detached, and the pump-side coupling 10 is easily reversibly attached.

When the combination of the bolt 20 and the groove 4G shown in Fig. 6 is used, the upper end portion of the groove 4G of the pump shaft 4 is caught (engaged) by the bolt 20, and the pump shaft 4 can be prevented from falling off due to the axial thrust. The number of bolts can also Increase depending on the axial thrust, or increase the bolt size.

7(a), (b), (c), and (d) are detailed views of the groove 4G of the pump shaft 4 shown in the sixth drawing, and the seventh drawing (a) shows the groove 4G. In the front view of an example, the seventh diagram (b) shows a cross-sectional view of another example of the groove 4G, and the seventh diagrams (c) and (d) show the arrow diagram of the seventh diagram (b).

The groove 4G shown in the seventh diagram (a) is constituted by a circumferential groove formed by 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.

The grooves 4G shown in the seventh (b) and (c) are formed by circular grooves which are provided at intervals in the circumferential direction of the pump shaft 4. The circular groove system includes a circular section or an elliptical profile. The inner diameter of the circular groove is set to be slightly larger than the outer diameter of the bolt 20. Further, the groove 4G shown in the seventh diagram (d) is constituted by a polygonal groove which is provided at intervals in the circumferential direction of the pump shaft 4. The polygonal groove includes a polygonal section such as a square section or a hexagonal section. The interval between the opposite sides of the polygonal groove is set to be slightly larger than the outer diameter of the bolt 20.

When the circular groove or the polygonal groove shown in the seventh (b), (c), and (d) is used, since the contact area between the groove and the fixing screw and the bolt is increased, the contact surface pressure can be reduced, so that Can withstand the characteristics of greater axial thrust. In the illustrated example, two circular grooves or polygonal grooves are formed in the circumferential direction of the pump shaft 4, but the number of circular grooves or polygonal grooves can be appropriately changed depending on the axial thrust applied to the pump shaft 4.

The eighth and ninth drawings show detailed schematic cross-sectional views of the fitting portions of the motor-side coupling 11 and the spacer 12 in the turbo pump shown in the first figure.

In the example shown in the eighth figure, the outer diameter of the flange portion of the motor side coupling 11 is slightly larger than the outer diameter of the flange portion of the spacer 12, and is at the flange portion of the motor side coupling 11 A concave portion 11a is formed in the outer peripheral portion, and an outer diameter portion of the spacer 12 is fitted into the concave portion 11a. That is, the motor side coupling is combined by fitting 11 and spacer 12. Further, a recess portion may be provided in the flange portion of the spacer 12, and the outer diameter portion of the flange portion of the motor side joint 11 may be fitted into the recess portion.

In the example shown in the ninth embodiment, the concave portion 12a is formed in the flange portion of the spacer 12, and the convex portion 11b is formed in the flange portion of the motor side coupling 11, and the concave portion 12a and the convex portion 11b are fitted. Further, a convex portion may be formed in the flange portion of the spacer 12, and a concave portion may be formed in the flange portion of the motor side coupling portion 11. In the example shown in the ninth diagram, the fitting portion of the motor-side coupling 11 and the spacer 12 is formed radially inward of the outermost diameter portion of the motor-side coupling 11 and the spacer 12. In the example shown in the ninth embodiment, the fitting portion of the component is not the outermost diameter portion, and when the component is separately stored, it is difficult to inadvertently damage or scratch the fitting portion.

As shown in the eighth and ninth drawings, the motor side joint 11 and the spacer 12 are combined by fitting to form a high concentricity and a straight angle. The fitting of the pump side coupling 10 and the spacer 12 is also the same as the example shown in the eighth and ninth drawings.

In the above embodiment, regarding the fastening method of the pump shaft 4 and the pump-side coupling 10, the motor shaft 7 and the motor-side coupling 11, in order to prevent the bolt shear damage caused by the impact load, it is preferable to use a ream bolt. ), or the fitting of the bolt and the bolt hole by a clearance fit or a transition fit to reduce the gap between the bolt and the bolt hole.

Next, the replacement process of the mechanical seal 5 in the turbo pump shown in the first figure will be described with reference to the tenth to fifteenth drawings. In the tenth to fifteenth drawings, only the main parts related to the replacement of the mechanical seal 5 are illustrated. That is, the casing 1 is only shown as a portion holding the backing ring 8, and the casing cover 2 and the motor base 6 are not shown.

Fig. 10(a) is a schematic cross-sectional view showing an initial state (normal state) before the mechanical seal 5 is attached to the pump shaft 4 and the mechanical seal 5 is replaced. As shown in the tenth figure (a), the pump shaft 4 is coupled to the pump side. Section 10 is such that the bolt 20 is inserted into the groove 4G of the pump shaft 4 by screwing in. Further, the pump-side coupling 10 and the spacer 12 are fixed by the fastening bolt 21 and the nut 22, and the motor-side coupling 11 and the spacer 12 are fixed by the fastening bolt 21 and the nut 22. Further, instead of using the nut 22, a female screw may be formed on the flange portion of the pump-side coupling 10, and a female screw may be formed on the upper flange portion of the spacer 12.

Fig. 10(b) is a view showing a first step of the replacement process of the mechanical seal 5, and is a schematic cross-sectional view showing a process of releasing the fixing of the pump side coupling 10 and the spacer 12. As shown by the arrow in the figure (b), the fixing of the pump side coupling 10 and the spacer 12 is released by detaching the bolt 21 and the nut 22 of the pump side coupling 10 and the spacer 12. The rotor (the impeller 3, the pump shaft 4, the mechanical seal 5, and the pump side coupling 10) is dropped onto the backing ring 8 held by the casing 1. Therefore, the impeller 3 is in contact with the collar 8.

Fig. 11(a) is a view showing a second step of the replacement process of the mechanical seal 5, and is a schematic sectional view showing a process of removing the spacer 12. As shown by the upper right arrow of the eleventh figure (a), the bolt 21 and the nut 22 of the motor side coupling 11 and the spacer 12 are detached, and the bolt 20 is detached as shown by the lower right arrow, and the pump is flanked. The shaft joint 10 is moved to the lower side so that the lower end of the pump side coupling 10 contacts the mechanical seal 5, ensuring sufficient space below the spacer 12. Next, the spacer 12 is removed as indicated by the central arrow of Fig. 11(a). At this time, since there is sufficient space between the lower end of the spacer 12 and the upper end of the pump shaft 4, the spacer 12 can be sufficiently left to exit in the lateral direction.

Fig. 11(b) is a view showing a third step of the replacement process of the mechanical seal 5, and is a schematic sectional view showing a process of detaching the pump side coupling 10 from the pump shaft 4. The pump side coupling 10 is detached from the pump shaft 4 as indicated by the upper right arrow of Fig. 11(b). Further, even if the bolt 20 is not detached from the pump-side coupling 10, the pump-side coupling 10 can be detached from the pump shaft 4 if it is retracted to a state where the front end of the bolt 20 does not enter the groove 4G.

The twelfth figure is a view showing a fourth step of the replacement process of the mechanical seal 5, and is a schematic sectional view showing a process of detaching the mechanical seal 5 from the pump shaft 4. The mechanical seal 5 is detached from the pump shaft 4 as indicated by the arrow in the twelfth figure. Thus, the decomposition process shown in the tenth (b)th to twelfthth drawings is completed.

Fig. 13(a) is a view showing a fifth step of the replacement process of the mechanical seal 5, and is a schematic sectional view showing a process of mounting the mechanical seal 5 to the pump shaft 4. As shown by the arrow in Fig. 13(a), the mechanical seal 5 to be replaced is attached to the pump shaft 4.

Fig. 13(b) is a view showing a sixth step of the replacement process of the mechanical seal 5, and is a schematic sectional view showing a process of attaching the pump side coupling 10 to the pump shaft 4. The pump side coupling 10 is attached to the pump shaft 4 as indicated by the arrow in Fig. 13(b).

Fig. 14(a) is a view showing a seventh step of the replacement process of the mechanical seal 5, and is a schematic sectional view showing a process of fixing the pump side coupling 10 and the pump shaft 4. As shown in Fig. 14(a), the pump side coupling 10 is mounted to the pump shaft 4, and the pump side coupling 10 is moved to the lower side so that the lower end of the pump side coupling 10 is in contact with the mechanical seal. The piece 5 ensures a sufficient space above the pump shaft 4.

Fig. 14(b) is a view showing an eighth step of the replacement process of the mechanical seal 5, and shows a process of inserting the spacer 12 between the pump side coupling 10 and the motor side coupling 11. Sectional view. As shown in Fig. 14(b), the spacer 12 is inserted between the motor side coupling 11 and the pump shaft 4. At this time, since there is sufficient space between the motor side coupling 11 and the pump shaft 4, the spacer 12 can be sufficiently filled.

Fig. 15(a) is a view showing a ninth step of the replacement process of the mechanical seal 5, and is a schematic sectional view showing a process of fixing the motor side coupling 11 and the spacer 12. As shown by the upper right arrow of Figure 15 (a), the motor is fixed by tightening (fastening 1) the bolt 21 and the nut 22. The side joint 11 and the spacer 12 are connected. At this time, as shown in the eighth and ninth drawings, the motor side coupling 11 and the spacer 12 are combined by fitting, and high concentricity and straight angle can be formed.

Next, after the pump side coupling 10 is moved upward, as shown by the lower right arrow of FIG. 15(a), the bolt 20 is screwed with the female thread 10s of the pump side coupling 10 by the bolt 20 The front end abuts against the bottom of the groove 4G of the pump shaft 4 to fasten (fasten 2) the bolt 20 to fix the pump side coupling 10 and the pump shaft 4.

Fig. 15(b) is a view showing a tenth step of the replacement process of the mechanical seal 5, and is a schematic sectional view showing a process of joining the pump side coupling 10 and the spacer 12. The pump side coupling 10 and the spacer 12 are fixed by tightening (fastening 3) the bolt 21 and the nut 22 as indicated by the arrow of the fifteenth figure (b). At this time, the entire rotor (the impeller 3, the pump shaft 4, the mechanical seal 5, and the pump side coupling 10) and the spacer 12 which are fixed to the backing ring 8 of the casing 1 are fixed by using the bolt 21 and the nut 22. . The entire rotor is gradually raised by tightening the bolt 21 and the nut 22. Then, when the bolt 21 and the nut 22 are completely tightened, the pump side coupling 10 and the spacer 12 are joined by fitting, and a high concentricity and a straight angle can be formed. At this time, the entire rotor is returned to the initial state (normal state), and the impeller 3 and the backing ring 8 are not in contact with each other, and the state shown in the tenth diagram (a) in which a clearance is formed therebetween is obtained. Thus, the mechanical seal replacement and reassembly process shown in the thirteenth (a) to fifteenth (b) ends.

As shown in the tenth to fifteenth drawings, when the spacer 12 of the middle portion of the motor side coupling 11 and the pump side coupling 10 is removed during the replacement process of the mechanical seal 5 of the present embodiment, The pump shaft 4 can be lowered and the pump side coupling 10 can be moved downward, so as to ensure a portion corresponding to the fitting portion between the spacer and the coupling, and the spacer 12 is sufficiently spaced apart in the lateral direction. Therefore, even if the pump including the impeller 3, the pump shaft 4, and the pump-side coupling 10 has no space for the falling space, the pump-side coupling 10, the motor-side coupling 11, and the spacer can be used. 12 The structure of the coupling is constructed.

Next, as shown in the third figure, when the C-type buckle 16 for axially positioning the pump-side coupling 10 to the pump shaft 4 is provided, refer to the sixteenth (a), (b), and (c) Explain the operation process of disassembling the C-shaped buckle 16 .

Fig. 16(a) is a schematic plan view showing a C-shaped clasp, and Figs. 16(b) and (c) are schematic cross-sectional views showing a working process of detaching the C-shaped retaining ring 16 from the pump shaft 4.

As shown in Fig. 16 (a), the C-shaped retaining ring 16 is provided with tool insertion holes 16h and 16h at both ends of the C-shaped body portion.

As shown in Fig. 16(b), the lower end surface of the pump side coupling 10 abuts against the C-shaped buckle 16 attached to the pump shaft 4. The organic casing cover 2 is below the C-shaped buckle 16 (refer to the first figure). When the C-shaped buckle 16 is detached from the pump shaft 4, as shown in Fig. 16(b), the loading and unloading tool 30 is visually inserted into the gap between the C-shaped buckle 16 and the casing cover 2, as shown in Fig. 16. (c), the claw portion 30a at the tip end of the loading and unloading tool 30 is inserted into the tool insertion hole 16h of the C-shaped clasp 16. Thereafter, the C-shaped buckle 16 is distracted by the loading and unloading tool 30, and the C-shaped buckle 16 is detached from the pump shaft 4.

As shown in FIGS. 16(b) and (c), when the operation of removing the C-shaped buckle 16 from the pump shaft 4 by the loading and unloading tool 30 is actually attempted, the gap between the C-shaped buckle 16 and the casing cover 2 is caused. Since it is narrow and the tool insertion hole 16h cannot be visually viewed from above, it is found that it is very difficult to insert the claw portion 30a of the loading and unloading tool 30 into the tool insertion hole 16h of the C-shaped buckle 16. Further, it has been found that the claw portion 30a of the loading and unloading tool 30 is easily taken out from the tool insertion hole 16h of the C-shaped buckle 16 during work.

Therefore, the inventors have thought of replacing the C-shaped buckle 16 with a ring divided into two.

Figure 17 (a) shows the division of the pump-side coupling 10 to the axial direction of the pump shaft 4 in two A schematic cross-sectional view of one example of the structure of the pump-side coupling is provided, and FIG. 17(b) shows a view of the ring that is divided into two and the ring-shaped retaining ring that is divided into two.

As shown in Fig. 17 (a), a circumferential groove 4g is formed at a predetermined position of the pump shaft 4, and a ring 31 divided into two is provided in the circumferential groove 4g. As shown in the upper perspective view of Fig. 17(b), the two divided rings 31 divide the circular ring into two. As shown in Fig. 17 (a), when the two divided rings 31 are installed in the circumferential groove 4g, the outer diameter of the ring 31 divided into two is the outer portion of the cylindrical portion of the pump side coupling 10 Set in the same way. The buckle 32 is fitted to the outer circumference of the outer circumference of the ring 31 and the outer circumference of the cylindrical portion of the pump side coupling 10. As shown in the lower perspective view in Fig. 17(b), the buckle 32 is formed in a short cylindrical shape. As shown in Fig. 17 (a), a plurality of (for example, four) female threads 10s are formed at a predetermined interval in the circumferential direction at a slightly upper end of the lower end portion of the cylindrical portion of the pump side coupling 10, and the buckle is formed. A through hole 32h is formed in the position corresponding to the female thread 10s on the 32. Further, a female screw 10Bs (described later) for disassembly is formed above the female screw 10s. The bolt 33 is inserted into the through hole 32h, and the bolt 32 is screwed to the female thread 10s to fix the buckle 32 to the cylindrical portion of the pump side coupling 10. When the buckle 32 is fixed to the pump-side coupling 10, the outer circumferential surface of the two rings 31 is in close contact with the inner circumferential surface of the buckle 32. Thereby, the two-divided ring 31 is fixed by the buckle 32 in the state of being attached to the circumferential groove 4g.

As shown in Fig. 17(a), the inner diameter of the upper side of the pump side coupling 10 is set larger than the inner diameter of the lower side of the pump side coupling 10, and a step is formed on the upper side of the pump side coupling 10. Part 10D. A disk-shaped plate 35 is placed on the step portion 10D of the pump-side 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 35h of the plate 35, and the bolt 36 is screwed to the female thread 4s of the upper end portion of the pump shaft 4. Therefore, since the axial force can be received by the bolt 36 and the plate 35, the pump shaft 4 can be prevented from falling off, and even the pump under high axial thrust can be used by the pump side coupling 10 and the motor side. The present coupling structure composed of the coupling 11 and the spacer 12.

Fig. 18 (a) and (b) show the state of the positioning structure of the pump-side coupling 10 using the two-part ring formed as shown in Fig. 17 (a) during operation and at the time of disassembly. In the cross-sectional view, the eighteenth (a) shows the operation, and the eighteenth (b) shows the decomposition.

During operation, as shown in Fig. 18(a), the buckle 32 is in the lowered position, and the buckle 32 is fixed to the pump side coupling 10 by the bolts 33. The outer peripheral surface of the ring 31 divided into two is in close contact with the inner peripheral surface of the buckle 32, and the two divided rings 31 are fixed by the buckle 32 in a state of being attached to the circumferential groove 4g.

At the time of disassembly, the bolt 33 is removed, and the buckle 32 is slid upward along the cylindrical portion of the pump-side coupling 10, and as shown in FIG. 18(b), the bolt 33 is inserted through the through hole 32h. The bolt 33 is screwed to the female thread 10Bs for disassembly of the pump side coupling 10, and the buckle 32 is fixed to the cylindrical portion of the pump side coupling 10. Thereby, the two-divided ring 31 is loosened, and since the two-divided ring 31 is divided into two, even if there is no space, as shown by the arrow, it can be easily disassembled in the radial direction. Thereafter, the pump side coupling 10 is slid down along the pump shaft 4, and the spacer 12 can be detached.

Thus, the use of the two-part ring 31 shown in Figs. 17 and 18 and the positioning structure of the pump-side coupling 10 using the plate 35 and the bolt 36 can withstand an excessive axial load. And can be easily broken down. More specifically, it has the features listed below.

(1) The pump side coupling 10 and the pump shaft (spindle) 4 are strongly coupled by the plate 35 and the bolt 36, and can also withstand an excessive axial load.

(2) When the lower end of the pump side coupling 10 is fixed by the ring 31 divided into two, the attachment and disassembly are simple. That is, when the pump side coupling 10 is slid downward, the spacer 12 can be detached, and the cylindrical mechanical seal can be detached without detaching the motor side coupling 11.

(3) The buckle 32 which can be slid up and down and fixed can be fixed to the two rings 31 when sliding downward during operation, and can be detached and divided into two rings 31 during maintenance.

Next, as shown in the sixth figure, a groove 4G is provided on the outer peripheral surface of the pump shaft 4, and a female thread 10s is provided on the pump-side coupling 10 to screw the bolt 20 and the female thread 10s by the bolt 20 In the embodiment in which the front end is fitted into the groove 4G and the pump side coupling 10 is fixed to the pump shaft 4, the assembly state of the pump shaft 4 and the pump side coupling 10 is referred to the nineteenth (a), ( b) for explanation.

Fig. 19(a) is a schematic cross-sectional view showing a normal assembled state of the pump shaft 4 and the pump side coupling 10. As shown in Fig. 19(a), a groove 4G is formed at a predetermined position of the pump shaft 4, and a female thread 10s is formed on the cylindrical portion of the pump-side coupling 10. Then, the fixing bolt 20 is screwed to the female screw 10s of the pump side coupling 10, and the front end of the fixing bolt 20 is fitted into the groove 4G. The pump-side coupling 10 can be fixed to the pump shaft 4 by screwing the bolt 20 so that the front end of the fixing bolt 20 strongly abuts against the bottom of the groove 4G of the pump shaft 4. The pump-side coupling 10 is provided with a counterbore 10c for receiving the head portion 20a of the fixing bolt 20.

As shown in Fig. 19(a), when the pump shaft 4 and the pump side coupling 10 are normally assembled, when the screw 20 is screwed to the front end of the fixing bolt 20 to abut against the bottom of the groove 4G of the pump shaft 4, the entire The bolt head 20a is housed in the counterbore 10c. At this time, the end surface 20e of the bolt head portion 20a is set to be substantially flush with the outer peripheral surface 10e of the pump-side coupling 10 surrounding the counterbore 10c. Here, the term "same plane" means that in the cross-sectional view of Fig. 19(a), there is no step difference between the end surface 20e of the bolt head portion 20a and the outer peripheral surface 10e of the pump-side coupling 10 to form a flat surface. When the end surface 20e of the bolt head portion 20a is protruded (projected) from the outer peripheral surface 10e of the pump-side coupling 10 to be + (positive), it is in a state of a slight step within ±2 mm. The fixing bolt 20 of the example is a hexagon socket bolt, but a hexagon socket set screw can also be used. In the case of using the hexagon socket set screw, when the front end of the set screw abuts against the bottom of the groove 4G of the pump shaft 4, the end face of the hexagonal hole side of the set screw and the pump side joint surrounding the countersunk hole 10c The outer peripheral surface 10e of 10 is roughly in the same plane.

The nineteenth (b) is a schematic cross-sectional view showing that the pump shaft 4 and the pump side coupling 10 are in an assembled state because the fixing bolt 20 does not enter the groove 4G of the pump shaft 4. As shown in Fig. 19(b), when the front end of the fixing bolt 20 is not inserted into the groove 4G of the pump shaft 4, that is, the end face of the bolt head 20a is not properly inserted into the groove 4G. 20e protrudes (projects) from the outer peripheral surface 10e of the pump side coupling 10. Therefore, the operator can easily understand the assembly failure state of the pump shaft 4 and the pump side coupling 10. When there is a poor assembly, the axial position deviation of the pump shaft 4 (X in Fig. 19(b)) may occur, or the pump shaft 4 may fall off (extract) due to the axial thrust. However, when the assembly of the pump shaft 4 and the pump-side coupling 10 is poor, as shown in Fig. 19(b), the end surface 20e of the bolt head 20a protrudes from the outer peripheral surface 10e of the pump-side coupling 10 ( Since it is protruded, the assembly failure state of the pump shaft 4 and the pump side coupling 10 can be easily understood, and therefore assembly failure can be prevented. In addition, the shape of the fixing bolt 20 is a hexagon socket head bolt, a set screw, or the like, and the pump side coupling 10 can be fastened to the pump shaft 4, and the shape thereof is not limited.

Fig. 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 (b). In the example shown in Fig. 20, the front end portion 20t of the fixing bolt 20 is formed in a non-thread shape. That is, in the fixing bolt 20 shown in Fig. 20, the front end portion 20t of the portion of the groove 4G inserted into the pump shaft 4 is a non-thread-shaped cylinder having a smaller diameter than the thread portion of the bolt.

The axial thrust acts on the pump shaft 4, and when the axial thrust cannot be supported 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 front end portion 20t of the fixing bolt 20 contact. At this time, when the fixing bolt 20 is a full thread, the thread shape may be deformed by contact or the like. Further, when the fixing bolt 20 is to be removed in the contact state, the fixing bolt 20 and the female thread 10s of the pump side coupling 10 may bite. The structure shown in Figure 20, because it is fixed The smooth outer peripheral surface of the front end portion 20t of the bolt 20 is in contact with the upper end surface of the groove 4G, so that the above deformation or biting is prevented.

Fig. 21 (a) and (b) are views showing an example of a groove 4G of the pump shaft 4 used in the embodiment shown in Figs. 19(a) and (b), and a twenty-first figure ( a) is a schematic cross-sectional view showing an assembled state of the pump shaft 4 and the pump-side coupling 10, and FIG. 21(b) is a side view of the pump shaft 4 provided with the groove 4G. In the example shown in Figs. 11(a) and (b), the groove 4G formed in the pump shaft 4 is a circular groove, and the corner portion of the inlet side of the groove 4G forms a chamfering CH or a taper shape T. As described above, when the chamfered corner or the taper shape T is formed at the entrance side corner portion of the groove 4G, the fixing bolt 20 is easily inserted into the groove 4G. Further, the corner portion of the front end portion 20t of the fixing bolt 20 also forms a chamfering CH or a taper shape T. Thereby, the fixing bolt 20 is also easily inserted into the female thread 10s.

Next, a description will be given of a preferred material for the motor shaft, the coupling (motor side, pump side), and the pump shaft.

Although the material of the motor shaft, coupling (motor side, pump side), and pump shaft can be arbitrarily selected, the selection of Table 1 below is preferred.

Because the pump shaft and the coupling need to be disassembled when the mechanical seal is replaced, it is formed. Gap fitting. When the temperature rises with the pump operation, when the material is combined, since the linear expansion coefficient of the pump shaft is larger than the coupling, the gap of the fitting portion is reduced, and the gap disappears depending on the temperature rise value. This is very helpful in preventing axial stretching to the main shaft due to axial thrust.

The motor shaft and the connecting shaft are fixed by a heat jacket or press-in because they do not need to be disassembled. Therefore, the material of the two parts is as long as the material of the same linear expansion coefficient is selected. However, the same effect as the pump shaft side is used. In order to further improve the effect of preventing the spindle from falling off in the axial direction, the motor shaft can also be made of a material having a large coefficient of linear expansion (for example, austenitic stainless steel). However, in order to exhibit the characteristics of the motor, the iron-based special steel such as S35C which uses a magnetic material in the motor main body portion needs to be joined by special pressure steel or austenitic stainless steel by pressure bonding or hot stamping (pressing).

The invention is applicable to other types of turbo pumps including single-stage, multi-stage upright type line pumps.

The embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the spirit and scope of the invention.

4‧‧‧ pump shaft

4G‧‧‧ trench

10‧‧‧ pump side coupling

10s‧‧‧ female thread

12‧‧‧ spacers

13‧‧‧ keys

20‧‧‧ bolt

Claims (20)

A turbo pump is provided with a mechanical seal at a portion of a main shaft supporting the impeller penetrating the pump casing, and is coupled to the main shaft by a pump side coupling, a motor side coupling, and a spacer interposed between the coupling shafts And a motor shaft of the motor, wherein the turbo pump is characterized in that: a groove is arranged on the outer surface of the spindle, and a female thread is arranged on the pump side coupling, so that the bolt is screwed with the female thread to embed the front end of the bolt In the aforementioned groove. A turbo pump according to claim 1, wherein the groove is formed by a circumferential groove extending in a circumferential direction of the spindle. A turbo pump according to claim 1, wherein the groove is formed by a circular groove having a circular cross section or an elliptical cross section, or a polygonal groove having a polygonal cross section. A turbo pump according to any one of the preceding claims, wherein the front end of the bolt abuts against the bottom of the groove. The turbo pump according to any one of claims 1 to 4, wherein a portion of the pump-side coupling provided with a female thread forms a counterbore, and the head of the bolt can be accommodated in the counterbore. The turbo pump according to claim 5, wherein the front end of the bolt head abuts the outer peripheral surface of the pump side coupling surrounding the counterbore hole when the front end of the bolt abuts against the bottom of the groove Roughly on the same plane. A turbo pump according to any one of claims 1 to 6, wherein the front end of the bolt embedded in the groove forms a smooth cylindrical shape without a thread. A turbo pump according to any one of claims 1 to 7, wherein the inlet side corner of the aforementioned groove is chamfered or tapered. A turbo pump according to any one of claims 1 to 8, wherein the corner of the front end of the bolt is chamfered or tapered. A turbo pump is provided with a mechanical seal on a portion of a main shaft supporting the impeller penetrating the pump casing, and the main shaft is coupled by a pump side coupling, a motor side coupling, and a spacer between the coupling shafts. a motor shaft of the motor, wherein the turbo pump is provided with a female thread in a direction orthogonal to the axial direction of the main shaft, and a through hole is formed in the pump side coupling, and the bolt is inserted into the through hole The bolt is screwed to the aforementioned female thread. A turbo pump is provided with a mechanical seal on a portion of a main shaft supporting the impeller penetrating the pump casing, and the main shaft is coupled by a pump side coupling, a motor side coupling, and a spacer between the coupling shafts. a motor shaft of the motor, wherein the turbo pump is provided with a through hole in a direction orthogonal to the axial direction of the main shaft, and a through hole is formed in the pump side coupling, and the pin is inserted through the two through holes hole. A turbo pump according to any one of claims 1 to 11, wherein a key is inserted between the aforementioned pump side coupling and the aforementioned main shaft. A turbo pump according to any one of claims 1 to 12, wherein a key is inserted between the aforementioned motor side coupling and the aforementioned motor shaft. The turbo pump of claim 12 or 13, wherein at least one of the pump side coupling and the motor side coupling is provided with a female thread at a position corresponding to the key to cause a bolt and the foregoing The female thread is screwed so that the front end of the bolt abuts against the aforementioned key. The turbo pump according to any one of claims 1 to 14, wherein the aforementioned spindle is provided with the aforementioned buckle of the pump side coupling for positioning. The turbo pump according to any one of claims 1 to 14, wherein the aforementioned spindle is provided with the aforementioned pump-side coupling for positioning into two rings, and in the pump-side coupling The cylindrical portion and the aforementioned two-part ring are fitted with a buckle. The turbo pump of claim 16, wherein the cylindrical portion of the pump side coupling is provided with a female thread in a direction orthogonal to the axial direction of the main shaft, and a through hole is provided in the buckle. A bolt is inserted into the through hole, and the bolt is screwed to the female thread. The turbo pump according to any one of the items 1 to 17, wherein a step portion is formed on an inner circumferential side of the pump side coupling portion, and a plate is mounted on the step portion in the through hole of the plate A bolt extending in the axial direction of the main shaft is inserted to screw the bolt with a female thread formed at an upper end portion of the main shaft. The turbo pump according to any one of claims 1 to 18, wherein at least one of the pump side coupling and the motor side coupling is at least the outer diameter of the fitting portion of the spacer The portion is formed on the inner side in the radial direction. The turbo pump according to any one of claims 1 to 19, wherein, when the mechanical seal is replaced, the fastening of the fastener having the screw connecting the spacer and the pump-side coupling is released, The rotating body including the impeller, the main shaft, and the pump-side coupling is dropped; after the mechanical seal is replaced, the rotating body is raised by the fastening operation of the fastener to return to a normal position.