JP5410385B2 - Thrust force measuring instrument and method of measuring thrust force using the same - Google Patents

Description

  The present invention relates to a thrust force measuring device that measures a thrust force applied in the axial direction of a main shaft, and a thrust force measuring method using the thrust force measuring device.

  For example, various pumps are manufactured, and the discharge performance of the pumps is also various. As a high-lift pump, a multistage centrifugal pump is known in which impellers in which a plurality of vanes (blades) are arranged in a spiral shape are incorporated in multiple stages (see, for example, Patent Document 1).

As shown in FIG. 4, when a fluid is supplied from the suction casing 1b, the multistage centrifugal pump 110 (hereinafter referred to as a pump) circulates through the impellers 19 incorporated in multiple stages in order, and the flow velocity and hydraulic pressure. This is a pump that discharges fluid from the discharge casing 1c.
As shown by the arrow, the fluid S flows from the suction casing 1b, is accelerated by the rotation of the impeller 19 in which spiral vanes (blades) are formed, and is temporarily discharged in the outer circumferential direction. Thereafter, the fluid makes a U-turn in the vicinity of the outer peripheral portion, returns to the vicinity of the main shaft 3, flows into the next impeller 19, and is discharged at a further accelerated flow rate by the rotation of the impeller 19. This is repeated by the number of multi-stage impellers 19 and finally discharged from the discharge casing 1c while increasing the pressure of the fluid.

In such a single suction impeller 19, a thrust force (load) is generated from the right direction to the left direction with respect to the main shaft 3. Since the thrust force is generated for each impeller 19, in the case of a multistage system, the thrust force increases by the number of stages.
In the case of the newly designed pump 110, even if the thrust force is estimated by calculation, there is a case where they do not coincide with each other. Therefore, the completed pump 110 is actually operated in a factory and the thrust force is measured. Further, the target value of the life of the thrust bearing is adjusted based on this measured value so as to be cleared.

  Generally, the thrust bearing includes a rolling bearing and a sliding bearing. When a sliding bearing such as a tilting pad type bearing is used as the thrust bearing of the pump 110, the thrust force can be measured using a sliding bearing having a built-in sensor such as a load cell. On the other hand, when a rolling bearing is used as the thrust bearing of the pump 110, it is necessary to attach a sensor separately. However, it is required to measure the thrust force without affecting the pump 110 as much as possible, such as additional processing.

FIG. 6A shows a predetermined arrangement of the pump 110 and the electric motor 30, and FIG.
FIG. 6 is a layout view in which a conventional thrust force measuring device is arranged between a pump 110 and an electric motor 30.
As shown in FIG. 6B, the conventional thrust force measuring method is performed by mounting a conventional thrust force measuring device 20 between the pump 110 and the electric motor 30 shown in FIG. The main shaft 3 of the pump 110 and the main shaft 23 of the thrust force measuring device 20 are connected by a coupling 21, and the motor shaft of the electric motor 30 and the main shaft 23 of the thrust force measuring device 20 are connected by a coupling 40. Then, after the operation becomes possible, the thrust force measuring device 20 is driven to rotate.
Since the conventional thrust force measuring device 20 includes sensors 24 and 24 for measuring the thrust force, the thrust force applied to the main shaft 3 of the pump 110 can be measured.

Japanese Patent Laid-Open No. 11-82364 (paragraph 0002, FIG. 3, FIG. 5)

However, since the conventional thrust force measuring device 20 is fixed to the floor (floor), the electric motor 30 has to be moved once from the fixed position, and it takes time to measure the thrust force including the centering operation. there were.
In addition, the conventional method for measuring the thrust force by the thrust force measuring device 20 requires that the connected state in which the pump 110 and the electric motor 30 are centered and connected be broken once, and it takes time to restore and wasteful work. There was a problem that there were many. This work took 1-2 days.

  In addition, this thrust force measurement may be performed at the factory of the customer after a certain number of years. The measurement work at the factory of the customer has a problem that the conventional thrust force measuring instrument 20 cannot measure due to problems such as installation space.

  Accordingly, the present invention provides a thrust force measuring device that can be easily installed and easily assembled regardless of the installation location of the pump or the floor space, and a method for measuring the thrust force using the thrust force measuring device. It is an issue to provide.

  A thrust force measuring device (10) according to claim 1 is a thrust force measuring device (10) for measuring a load in a thrust direction applied to a main shaft (3) of a pump (100), the pump body (1). Adapter (5) attached to an oil jacket bracket (2) fixed to one end of the head (1a) of the head, and an extension shaft (6) attached to one end of the main shaft (3) and extending the main shaft (3). ), A ring-shaped thrust collar (7g) inserted into the extension shaft (6), and a sliding bearing with a built-in sensor that measures the thrust force by sliding while contacting the thrust collar (7g). And a housing (8) that supports the sliding bearing with built-in sensor (7) and is connected to the adapter (5).

  The invention described in claim 2 is the thrust force measuring instrument (10) according to claim 1, wherein the mounting hole of the adapter (5) is an oil jacket formed in the oil jacket bracket (2). (11) It is characterized by matching with the fixing hole.

  The invention described in claim 3 is the thrust force measuring device (10) according to claim 1, wherein the housing (8) is divided into an upper housing (8b) and a lower housing (8a). It is characterized by being.

  The invention described in claim 4 is a method for measuring the thrust force using the thrust force measuring device (10) according to claim 1, wherein the thrust jacket (2) of the pump (100) is used. A first step of removing the oil jacket (11), a second step of assembling the thrust force measuring device (10) to the oil jacket bracket (2) of the pump (100), and driving the pump (100). And a third step of measuring a thrust force applied to the main shaft (3).

According to the first aspect of the present invention, the thrust force measuring device is attached to the oil jacket bracket fixed to one end of the head of the pump body, so that the connected state between the centrifugal pump and the electric motor can be maintained as it is. It is possible to move the motor, and the two couplings do not need to be aligned, can be installed easily, and is not installed on the floor. Can be provided.
Moreover, it is not necessary to fix to a floor and to prevent rotation by attaching to an oil jacket bracket via an adapter without installing between a centrifugal pump and an electric motor. Further, the housing can be easily prevented from being rotated by being mounted on the oil jacket bracket.
Furthermore, by installing a thrust force measuring instrument via an adapter in the space from which the oil jacket has been removed, installation space can be secured, so installation is possible in a small space, regardless of the installation location of the pump or the floor space. it can.

  According to the invention of claim 2, by making the mounting hole of the adapter coincide with the fixing hole of the oil jacket, the oil jacket is removed from the oil jacket bracket, the adapter is fixed instead of the oil jacket, and the thrust force is measured. Since the device can be attached, it is possible to reduce the man-hours for attaching the thrust force measuring device.

  According to the invention of claim 3, since the housing is divided into the upper housing and the lower housing, the assembly of the load cell can be facilitated, the positioning of the load cell, the routing of the electric wire, etc. can be facilitated. Work time for work and disassembly work can be shortened.

According to the invention according to claim 4, since the installation space can be secured by installing the thrust force measuring instrument through the adapter in the space of the oil jacket in the first step, the installation location of the pump, the width of the floor space, etc. Despite this, it can be installed in a small space.
In addition, since the thrust force measuring instrument is assembled to the oil jacket bracket in the second step, it is not necessary to fix it to the floor and prevent it from rotating, so that it is possible to easily prevent the housing from rotating by attaching it to the oil jacket bracket.
Furthermore, since the connected state of the centrifugal pump and the electric motor can be maintained as it is, it is not necessary to move the electric motor, the centering of the two couplings is not required, it can be easily installed, and it is not installed on the floor. Thus, it is possible to provide a method for measuring the thrust force using a thrust force measuring instrument that is easy to align and easy to assemble.

It is an expanded sectional view of the thrust force measuring device of this invention shown in the axial end of FIG. It is a disassembled explanatory drawing explaining the assembly procedure of the thrust force measuring device of this invention. (A) is sectional drawing which shows the state which attached the thrust force measuring device of this invention to the centrifugal pump, (b) is a front view which shows a mode that the centrifugal pump and the electric motor were connected. It is sectional drawing which shows the present multistage centrifugal pump and shows an oil jacket at one end. It is sectional drawing which shows the state which removed the oil jacket arrange | positioned at the end of the present multistage centrifugal pump, and is sectional drawing which shows the state before mounting | wearing with the thrust force measuring device of this invention. (A) is the layout which connected the electric motor to the multistage centrifugal pump, (b) is the layout which mounted the conventional thrust force measuring device between the pump and the electric motor.

An embodiment of a thrust force measuring instrument 10 according to the present invention will be described in detail with reference to the drawings.
As shown in FIG. 3B, for example, the main shaft 3 of a multistage centrifugal pump (hereinafter referred to as pump) 100 and the motor shaft of the electric motor 30 are connected by a coupling 40. A thrust force measuring device 10 is recombined and attached to one end of the pump 100. By doing so, since the connection between the centrifugal pump 100 and the electric motor 30 can be maintained as it is, the centering operation which has been time-consuming so far becomes easy, and a great saving of work time is achieved. Can do.

FIG. 1 is an enlarged cross-sectional view of the thrust force measuring instrument 10 shown in FIG.
As shown in FIG. 1, the thrust force measuring instrument 10 is fixed to the head 1a with an oil jacket bracket 2 interposed therebetween, and an adapter 5 having connecting portions 5a and 5b on both end faces, and an extension screwed to the main shaft 3. A shaft 6, a sensor built-in slide bearing 7 for measuring a thrust force is incorporated in the extension shaft 6, and includes a housing 8 fixed to the adapter 5 and a sealing member 9 that closes one end of the housing 8 that opens. .

<Adapter configuration>
The adapter 5 is a connecting member in which flange-shaped connecting portions 5a and 5b are formed on both left and right end surfaces. Further, it is a spacer for securing a space and is an oil jacket for lubricating the bearing 4. The adapter 5 has a substantially cylindrical shape having a through-hole 5 c in the center, and the connecting portion 5 a of the flange on the left end surface is fixed to the oil jacket bracket 2. Further, the outer rings of the existing bearings 4 and 4 are fitted into the through holes 5 c of the adapter 5.
The adapter 5 is fixed to the oil jacket bracket 2 by a plurality of stud bolts 2a and nuts 2c.

<Configuration of extension shaft>
The extension shaft 6 is connected to the shaft end of the main shaft 3 and extended.
As shown in FIG. 2, a female screw 3 a and a centering hole 3 b are formed at the right end of the main shaft 3. The extension shaft 6 is formed with a male screw 6a and a centering shaft 6b corresponding to the female screw 3a and the centering hole 3b. The extension shaft 6 is fitted to the main shaft 3 by fitting the centering shaft 6b and the centering hole 3b. The core of the extension shaft 6 is made to coincide with each other, and is fixed to the main shaft 3 integrally by fastening the female screw 3a and the male screw 6a. Further, a thrust collar 7g sandwiched between a first sensor built-in slide bearing 7a and a second sensor built-in slide bearing 7b, which will be described later, is fixed to the extension shaft 6. .

<Composition of thrust color>
The thrust collar 7g has a ring shape in which a through hole into which the extension shaft 6 is fitted is formed at the center, is formed in a flat disk shape, and is integrally fixed to the extension shaft 6 by a key 6k. . Further, it is fixed in the axial direction by a nut 6d arranged at the shaft end of the extension shaft 6 via a collar 6c.
Both sides of the thrust collar 7g that receives the thrust load are finished with high precision.

<Housing configuration>
The housing 8 is a support member that supports the extension shaft 6 and the sliding bearing 7 with a built-in sensor for measuring the thrust force. The housing 8 slides with a ring-shaped thrust collar 7g, which will be described later, being sandwiched between the first thrust shoe 7d and the second thrust shoe 7f. It also has a jacket function.
In the housing 8, a flange-like connecting portion 8 c is connected to the connecting portion 5 b of the adapter 5 by a plurality of bolts 8 d.
The housing 8 is divided into two pieces, a lower housing 8a and an upper housing 8b. By this division, the electric wires of the first load cell-attached 7c and the second load cell 7e, which will be described later, can be easily passed out from the electric wire through holes 8e, 8f provided in the upper housing 8b.
Further, the rotation preventing pins 7p and 7p of the first load cell 7c and the second load cell 7e can be easily mounted.

<Configuration of sensor built-in plain bearing>
The sensor built-in slide bearing 7 is formed in a ring shape and includes a first sensor built-in slide bearing 7a and a second sensor built-in slide bearing 7b, and slides in contact with the thrust collar 7g.
Further, each of the inner circumferences is loosely fitted to the extension shaft 6. Further, the first sensor built-in slide bearing 7a and the second sensor built-in slide bearing 7b are arranged to face each other symmetrically about the thrust collar 7g, and are supported on the inner peripheral surface of the housing 8 described above.
The first sensor built-in slide bearing 7a is formed in a ring shape, a first load cell 7c that converts axial thrust force into an electrical signal, and a first thrust shoe 7d that has a sliding surface that enables smooth sliding. Are integrally formed. The first load cell 7c is embedded with three load cells arranged in three equal positions. Thereby, the accuracy of measurement can be improved.
The second sensor built-in slide bearing 7b is also formed in a ring shape and has a second load cell 7e that converts axial thrust force into an electrical signal and a second thrust shoe that has a sliding surface that enables smooth sliding. 7f is integrally formed. The second load cell 7e is also embedded with three load cells arranged in three equal positions. Thereby, like the above, the measurement accuracy can be improved.
A disc-shaped thrust collar 7g supported by the extension shaft 6 is sandwiched between the first thrust shoe 7d and the second thrust shoe 7f.
The first sensor built-in sliding bearing 7a and the second sensor built-in sliding bearing 7b are supported by the housing 8, and are provided with a gap from the outer periphery of the extension shaft 6. The first sensor built-in sliding bearing 7a and second The sensor built-in slide bearing 7b is not rotated because it is locked to the upper housing 8b by the rotation preventing pins 7p and 7p.

<Configuration of sealing member>
The sealing member 9 is a sealing cover for closing one end of the housing 8 to prevent leakage of lubricating oil.

Here, the assembly procedure of the thrust force measuring instrument 10 of the present invention will be described.
As shown in FIG. 4, the procedure for removing the oil jacket 11 disposed at one end of the conventional pump 110 is as follows.
B) Remove the lubricating oil from the housing 18 and remove the end cover 13 from the housing 18.
B) Remove the disk-shaped oil finger 14 from the main shaft 3 and remove the bolt 15 from the thrust inner cover 16.
C) Remove the bolt 17 from the housing 18 of the oil jacket 11 and remove the housing 18 from the oil jacket bracket 2.

FIG. 5 shows the result of removing the oil jacket 11 according to the procedures of A to C.
As shown in FIG. 5, after the current oil jacket 11 is removed, the oil jacket bracket 2 fixed to one end of the head 1a of the pump 110, the main shaft 3 protruding from the right end of the oil jacket bracket 2, and the main shaft The bearings 4 and 4 that are rotatably supported at one end of 3 are left.
The thrust force measuring device 10 is assembled to a member based on these.

The assembly procedure of the thrust force measuring instrument 10 is as shown in FIG.
1) The bearings 4 and 4 are fitted into the through holes 5 c of the adapter 5, and the stud bolt 2 a screwed into the mounting hole of the oil jacket bracket 2 using this as a guide is passed through the hole of the connecting portion 5 a of the adapter 5. Further, the boss 5d is inserted into the reference hole 2b of the oil jacket bracket 2, the center is aligned, the adapter 5 is fixed by the nut 2c, and the thrust inner cover 16 is attached to the adapter 5.
2) The lower housing 8a is fixed to the adapter 5, the extension shaft 6 is fixed to the main shaft 3, and a circular spacer 7h for adjusting the gap and a shim 7i (not shown) are attached through the extension shaft 6.
Note that the shaft 6b of the extension shaft 6 is fitted into the reference hole 3b of the main shaft 3 to perform centering, and the cores of the main shaft 3 and the extension shaft 6 are easily aligned.
3) The first sensor built-in slide bearing 7a, the disc-shaped thrust collar 7g, and the second sensor built-in slide bearing 7b are passed through the extension shaft 6, and this thrust collar 7g is fixed to the extension shaft 6 via the collar 6c by the nut 6d. .
4) Wires are passed through the wire through holes 8e and 8f of the upper housing 8b, and the upper housing 8b is fixed to the adapter 5 and sealed by the sealing member 9 through the shim 9a that fills the gap in the thickness direction of the sensor-equipped sliding bearing 7. To do.
5) Thrust inner cover 16 is adjusted with a gasket, and it is confirmed that the bearing 4 is not restrained in the thrust direction, and lubricating oil is supplied from the adapter 5 and the oil supply port of the lower housing 8a.
6) Slide bearing with built-in sensor Each wire connected to 7 is connected to an amplifier that amplifies the electrical resistance provided outside.
This completes the assembly of the thrust force measuring instrument 10 of the present invention.

Here, the operation of the thrust force measuring device 10 will be described with reference to the drawings.
As shown in FIGS. 3A and 3B, when the fluid is supplied from the suction casing 1b to the multistage centrifugal pump 100 and the motor (motor) 30 is started, the main shaft 3 to which the multistage impeller 19 is fixed. The extension shaft 6 rotates, and the pressure of the fluid is gradually increased by the action of the impeller 19 to discharge the fluid from the discharge casing 1c.
At this time, as shown in FIG. 1, a minute strain is generated in a strain gauge (not shown) built in the first load cell 7c and the second load cell 7e according to the thrust force (load). This minute distortion is converted into an electrical signal, transmitted, amplified by an amplifier (amplifier), and further processed to calculate a thrust force to Newton (N) and displayed on a display. In this way, the measurement of the thrust force is repeated several times, and the data collection is finished.

  The procedure for disassembling the thrust force measuring instrument 10 is the reverse of the above assembling procedure as shown in FIG. Since this is an overlapping description, it is omitted here.

  Further, as shown in FIG. 4, the procedure for assembling the oil jacket 11 of the centrifugal pump 110 is the reverse of the procedure for removing the centrifugal pump 110 described above. Since this is an overlapping description, it is omitted here.

As a result, the time required for the operation of the thrust force measuring instrument 10 of the present invention is shown.
1. Removal of the oil jacket 11 of the centrifugal pump 110 ... 10 minutes Assembling of the thrust force measuring instrument 10 ... 60 minutes Thrust force measurement: 10 minutes 4. Disassembly of thrust force measuring instrument 10: 20 minutes Assembly of the oil jacket 11 of the centrifugal pump 110 ... 20 minutes Thereby, the total of each work can be shortened to just 2 hours.
One of the reasons that the assembling work of the thrust force measuring instrument 10 can be shortened to 60 minutes by facilitating the centering work, as shown in FIG. 2, is the centering hole 3b and the extension shaft 6 at the right end of the main shaft 3. The centering shaft 6b is fitted, the reference hole 2b of the oil jacket bracket 2 and the boss 5d of the adapter 5 are fitted, and the boss 8g of the housing 8 is fitted to the reference hole boss 5e of the adapter 5.

In the modification of the method for assembling the thrust force measuring instrument 10 shown in FIG. 2, after the housing 8 is assembled once, the upper housing 8b and the lower housing 8a are fixed together, and the housing 8 is handled as one unit without being disassembled. As a result, the time can be further reduced by 30 minutes from the second time. For example, according to the following procedure.
1) The bearings 4 and 4 are inserted into the through holes 5c of the adapter 5, the holes of the connecting portion 5a of the adapter 5 are passed through the stud bolts 2a of the oil jacket bracket 2, the adapter 5 is fixed by the nut 2c, and the thrust inner cover 16 Is attached to the adapter 5 (same as above).
2) With the housing 8 suspended by an overhead crane or the like, the male screw 6 a of the extension shaft 6 is screwed into the female screw formed at one end of the main shaft 3 to extend to the main shaft 3.
3) As shown in FIG. 2, in the case where it is excessive or insufficient as compared with the protruding length L of the main shaft 1, several gaskets or the like are sandwiched between the connecting portion 5b of the adapter 5 and the housing 8 and adjusted.
4) (Not required)
5) Thrust inner cover 16 is adjusted with a gasket, and it is confirmed that the bearing 4 is not restrained in the thrust direction, and lubricating oil is supplied from the adapter 5 and the oil supply port of the lower housing 8a.
6) Slide bearing with built-in sensor Each electric wire connected to 7 is connected to an amplifier that amplifies an electric signal provided outside. (same)
The assembly procedure of the thrust force measuring instrument 10 as described above may be used.

  When the thrust force is measured for a long time and the lubricating oil of the thrust force measuring device 10 needs to be removed, the lubricating oil of the thrust force measuring device 10 is circulated by an external forced oil pump and removed by a heat exchanger or the like. It doesn't matter. The forced oil pump may be a shaft end oil pump attached to the shaft end of the extension shaft 6.

In the present invention, the measurement of the thrust force applied to the main shaft 3 of the pump 100 has been described as an embodiment. However, a main shaft other than the pump 100 may be used. Or other types of rotation axis.
There are various specifications of the pump 100, and the thrust force changes when the flow rate of the pump changes. It changes even if the specific gravity of the fluid is different.
One method of reducing this thrust force is the balance drum specification. In the case of this balance drum specification pump, the direction of thrust force may act in the opposite direction, so two sensors are arranged so as to be able to cope with such specifications, but only one sensor is used. You may prepare two sets for right hand and left hand.

1 Pump body
1a Head (Discharge head)
1b Suction casing 1c Discharge casing 2 Oil jacket bracket 2a Stud bolt 2b Reference hole 2c Nut 3 Main shaft 4 Bearing (bearing)
5 Adapter (spacer)
5a, 5b Connecting part (flange)
5c Through hole 5d Boss 5e Reference hole 6 Extension shaft 6a Male thread 6b Centering shaft 6c Collar 6d Nut 7 Slide bearing with built-in sensor
7a Sliding bearing with built-in first sensor
7b Sliding bearing with built-in second sensor
7c 1st load cell 7d 1st thrust shoe 7e 2nd load cell 7f 2nd thrust shoe 7g Thrust collar 7h Circular spacer 7i Shim 7p Pin 8 Housing 8a Lower housing 8b Upper housing 8c Connecting part (flange)
8d Bolt 8e, 8f Wire through hole 8g Boss 9 Sealing member 9a Shim 9b Bolt 10 Thrust force measuring instrument 11 Oil jacket 12 Plug (plug for cooling water)
13 End cover 14 Oil finger 15 Bolt 16 Thrust side inner cover
17 bolt 18 housing
19 impeller 19a vane (blade)
20 Thrust force measuring device (conventional type)
21, 40 Coupling 30 Electric motor (motor)
100,110 Multistage centrifugal pump (pump)
S Fluid flow

Claims (4)

A thrust force measuring device (10) for measuring a load in a thrust direction applied to the main shaft (3) of the pump (100),
An adapter (5) attached to an oil jacket bracket (2) fixed to one end of the head (1a) of the pump body (1);
An extension shaft (6) attached to one end of the main shaft (3) and extending the main shaft (3);
A ring-shaped thrust collar (7g) inserted into the extension shaft (6);
A sliding bearing with built-in sensor (7) that slides in contact with the thrust collar (7g) and measures the thrust force;
A housing (8) for supporting the sensor built-in sliding bearing (7) and connected to the adapter (5);
A thrust force measuring device (10) comprising:   The thrust force measuring device according to claim 1, wherein the mounting hole of the adapter (5) coincides with a fixing hole of an oil jacket (11) formed in the oil jacket bracket (2). 10).   The thrust force measuring device (10) according to claim 1, wherein the housing (8) is divided into an upper housing (8b) and a lower housing (8a). A first step of removing the oil jacket (11) from the oil jacket bracket (2) of the pump (100);
A second step of assembling the thrust force measuring device (10) to the oil jacket bracket (2) of the pump (100);
A third step of driving the pump (100) and measuring a thrust force applied to the main shaft (3);
A method for measuring thrust force using a thrust force measuring device (10) according to claim 1, characterized in that

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