JP6646505B2 - Shaft assembly, motor shaft, motor, motor pump, and method of manufacturing shaft assembly - Google Patents

Description

  The present invention relates to a shaft assembly, a motor shaft, a motor, a motor pump, and a method for manufacturing a shaft assembly.

  In a motor pump, rotational driving force is transmitted by a main shaft in which a motor shaft and a pump shaft are joined. Here, the pump shaft is generally formed of a corrosion-resistant material such as a stainless steel material in order to prevent corrosion due to a handling fluid (liquid or gas). In addition, the motor shaft is generally formed of a material that is inexpensive or has excellent workability such as cutting. For example, in the case of an induction motor, in addition to the above conditions, it is preferable to use a magnetic material for the motor shaft from the viewpoint of performance. Therefore, a carbon steel material for machinery is used. Therefore, the main shaft of the motor pump is configured by joining the motor shaft and the pump shaft formed of different materials. In this case, for example, pressure welding is used as a general method for joining. In pressure welding, two shafts are joined by rotational friction and pressing pressure on the end face. An example of the main shaft of the motor pump configured as described above is described in, for example, Patent Document 1.

  On the other hand, a power transmission mechanism to the impeller is provided on the pump shaft. A common power transmission mechanism is, for example, fastening using a key. However, forming a keyway in a pump shaft is not easy, and may be a cost issue. Also, for example, in a multi-stage pump, a thin press impeller may be used in order to suppress the cost of the impeller alone, but in the case of fastening using a key, a fastening portion is provided with a boss to prevent deformation of the impeller. Had to be reinforced. In order to solve the problem of fastening using such a key, it has been proposed to make a pump shaft portion of a main shaft into a spline shape having a plurality of grooves formed in a longitudinal direction. In the spline shape, since the torque transmitted to the impeller is dispersed, even a press-made impeller can be fastened without reinforcement with a boss.

  The spline shape can be formed, for example, by rolling the pump shaft. In this case, as described above, the main shaft is formed by joining the pump shaft and the motor shaft by, for example, pressure welding, and after adjusting the outer peripheral surface of the joined shaft to be concentric by machining by cutting or the like. The rolling process is performed on the pump shaft portion. Such a rolling process has been useful because an even groove can be efficiently formed and the cost is low.

JP-B-62-53729

  However, since the rolling process belongs to a special type of processing, there may be situations where the rolling process is not available. Then, the present inventors examined forming the spline shape of the pump shaft by a more general drawing process. Here, both the rolling process and the drawing process belong to plastic working. In the rolling process, while the shaft is rotated, the drawing process is performed while the shaft is drawn in the longitudinal direction. Therefore, in the drawing process, a portion that constitutes the outermost diameter is processed throughout the longitudinal direction of the shaft. In the case of employing the drawing process, it is necessary to change the process in consideration of this point.

  For example, a shaft sealing device such as a mechanical seal for preventing the fluid handled inside the pump from flowing out is attached to the main shaft. Since the mounting portion of the shaft sealing device may corrode under the influence of the handling fluid, it is preferable that the mounting portion is formed of a corrosion-resistant material like the pump shaft. On the other hand, it is preferable that the mounting portion of the shaft sealing device has a cylindrical surface on which no groove or the like is formed in terms of the function of the seal, and has a larger diameter than the pump shaft. When the spline shape is formed by rolling as described above, the pump shaft and the mounting portion of the shaft sealing device as described above are integrally formed of a corrosion-resistant material, and then only the pump shaft portion is formed. It is also possible to form a spline shape. However, for the reasons described above, such a process cannot be adopted when forming a spline shape by drawing.

  In consideration of the above points, when forming a spline shape using drawing, for example, a main shaft is formed by joining the following three parts. The first portion is a pump shaft formed of a corrosion-resistant material and having a spline shape formed on an outer peripheral surface by a drawing process. The second portion is a mounting portion of the shaft sealing device which is also formed of a corrosion-resistant material, has a larger diameter than the first portion, and has no spline shape formed on the outer peripheral surface. The third part is a motor shaft formed of, for example, carbon steel for machinery.

  The present inventors have tried to join the three parts as described above by pressure welding. However, in the process, we faced major challenges. At the stage when the three parts including the pump shaft part are joined, a spline shape is already formed on the outer peripheral surface of the pump shaft. Therefore, the outer peripheral surface of the pump shaft cannot be machined by cutting or the like. In order to adjust the three parts to be concentric, only the outer peripheral surface of the mounting part of the shaft sealing device and the outer peripheral surface of the motor shaft part are cut. It will be processed by. However, the pump shaft is often less than half the length of the entire main shaft, for example, about 1/3. Therefore, when trying to align the center of the pump shaft portion with the center of another portion, for example, in the motor shaft portion located on the opposite side to the pump shaft portion, it is necessary to considerably increase the allowance of the base material for adjustment. . This is not practical because the necessary material increases and the processing time for adjustment also increases.

  The present invention has been made in view of the above circumstances. An object of the present invention is to provide a new and improved shaft assembly, a motor shaft, a motor, a motor pump, and a shaft assembly capable of increasing a degree of freedom of a process for forming a main shaft of a motor pump. It is to provide a manufacturing method of.

According to one aspect of the present invention, a pump shaft, an impeller mounting portion to which an impeller is mounted, a first reduced diameter portion formed at one end of the pump shaft, and a first reduced diameter portion A pump shaft having a first screw portion provided at the tip of the pump, a pump-side fitting hole into which the first reduced-diameter portion is fitted, and a second screw portion screwed to the first screw portion are provided at the tip. A motor-side fitting hole configured to fit the second reduced diameter portion of the motor shaft, and a coupling member having an outer peripheral surface configured to mount the shaft sealing device, wherein A shaft assembly including a joint member in which the fitting hole and the motor-side fitting hole are concentric with each other is provided.
The shaft assembly includes a pump shaft, a motor shaft, and a coupling member, and the coupling member is also a mounting portion of the shaft sealing device. Since the pump shaft and the motor shaft are directly joined by screwing, and the two fitting holes of the joint member are concentric with each other, the concentric accuracy of the shaft assembly including the pump shaft and the motor shaft is ensured. Is easy. Therefore, for example, a step of joining three parts including the pump shaft after the formation of the pump shaft can be easily adopted. Further, since the fitting between the pump shaft and the motor shaft and the joint member does not need to be press-fitted, for example, a step of joining the motor shaft and the joint member after the motor shaft is assembled into the motor becomes possible. .

In the above shaft assembly, the pump shaft and the coupling member may be formed of a corrosion-resistant material, and the coupling member may have a portion having a larger diameter than the impeller mounting portion.
Since the joint member is also a mounting portion of the shaft sealing device, it can be formed of a corrosion-resistant material like the pump shaft.

In the shaft assembly described above, the impeller mounting portion may be a spline portion having a spline formed on an outer peripheral surface.
The spline structure has the advantage that the torque transmitted to the impeller is dispersed. For example, if a step of joining the three parts including the pump shaft after the formation of the pump shaft as described above is employed, it is easy to use the drawing process for forming the spline.

In the above shaft assembly, the pump shaft has a first tapered surface formed at a boundary between the impeller mounting portion and the first reduced diameter portion, and the joint member corresponds to the first tapered surface. And a second tapered surface formed at the inlet of the pump-side fitting hole.
By forming the tapered surface, concentric accuracy can be more easily ensured.

In the above shaft assembly, the fitting between the first reduced diameter portion and the pump side fitting hole may be press-fitting.
For example, by press-fitting one of the two fittings, the concentric accuracy can be improved. Pressing both of the two fittings is not excluded. Further, as described above, both of the two fittings need not be press-fitted.

The shaft assembly described above may further include a motor shaft.
That is, the shaft assembly is provided in a state where the joint member is joined to the pump shaft, and the motor shaft may be joined to this later, or the state where the pump shaft, the joint member, and the motor shaft are joined. A shaft assembly may be provided.

The shaft assembly may further include a seal member that seals a gap between the end surface of the second reduced diameter portion and the inner peripheral surface of the motor-side fitting hole.
Since the joint member is also a mounting portion of the shaft sealing device, a seal member that prevents the fluid handled by the pump from flowing out through the gap inside the joint member may be effective.

In the above-mentioned shaft assembly, the motor shaft has an extended portion having a diameter larger than the second reduced diameter portion, and a third tapered surface formed at a boundary between the extended portion and the second reduced diameter portion. The joint member may have a fourth tapered surface formed at the entrance of the motor-side fitting hole corresponding to the third tapered surface.
As in the case of the pump shaft side, by forming a tapered surface on the motor shaft side, it is possible to further easily ensure concentric accuracy. The tapered surface may be formed only on one of the pump shaft side and the motor shaft side, may be formed on both sides, or may not be formed.

  According to another aspect of the present invention, a motor shaft provided on a joint member having an outer peripheral surface formed at one end of the motor shaft and configured to mount a shaft sealing device is provided. A first reduced-diameter portion configured to fit into the fitting hole, and a pump-side fitting hole of a joint member provided at the tip of the first reduced-diameter portion and concentric with the motor-side fitting hole. A motor shaft is provided that includes a first screw portion configured to screw with a second screw portion provided at a distal end of a second reduced diameter portion of the fitted pump shaft.

  A motor including the motor shaft described above, a rotor attached to the motor shaft, and a stator corresponding to the rotor may be provided.

  According to still another aspect of the present invention, there is provided a pump including an impeller, a casing accommodating the impeller, and a pump shaft, wherein the pump shaft has one of an impeller mounting portion to which the impeller is mounted, and a pump shaft. A pump further including a first reduced diameter portion formed at an end portion, and a first screw portion provided at a tip of the first reduced diameter portion, a rotor, a stator corresponding to the rotor, and a motor to which the rotor is attached A motor including a shaft, wherein the motor shaft is provided at a second reduced-diameter portion formed at one end of the motor shaft, and at a tip of the second reduced-diameter portion. A motor further having a second screw portion to be fitted, a pump side fitting hole into which the first reduced diameter portion fits, a motor side fitting hole into which the second reduced diameter portion fits, and a shaft sealing device. Includes an outer peripheral surface configured to be mounted A joint member, a motor pump and a joint member are concentric with each other and the pump-side fitting hole and the motor-side fitting hole is provided.

  According to still another aspect of the present invention, a first step of forming a pump shaft, and a step of mounting the pump shaft in a pump-side fitting hole of a joint member having an outer peripheral surface configured to mount a shaft sealing device. A second step of fitting a first reduced-diameter portion formed at one end to a motor-side fitting hole of a joint member concentric with the pump-side fitting hole; While fitting the formed second reduced diameter portion, a first screw portion provided at the distal end of the first reduced diameter portion and a second screw portion provided at the distal end of the second reduced diameter portion And a third step of screwing together.

  In the above method of manufacturing a shaft assembly, the second step may include a step of press-fitting the first reduced diameter portion into the pump-side fitting hole.

  In the method of manufacturing the shaft assembly, the third step may be performed after the motor shaft is assembled in the motor.

  In the method of manufacturing the shaft assembly, the first step may include a step of forming a spline on the outer peripheral surface of the pump shaft by drawing.

It is a schematic longitudinal section showing a motor pump concerning one embodiment of the present invention. FIG. 2 is a view showing a shaft assembly constituting a main shaft of the motor pump shown in FIG. 1. FIG. 3 is an exploded view showing the shaft assembly shown in FIG. 2. FIG. 4 is an enlarged sectional view showing a joint portion of the shaft assembly shown in FIGS. 2 and 3. It is an expanded sectional view showing a joined part of a shaft assembly concerning a modification of one embodiment of the present invention. It is a flowchart which shows the example of the manufacturing method of the shaft assembly which concerns on one Embodiment of this invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic longitudinal sectional view showing a motor pump according to one embodiment of the present invention. Referring to FIG. 1, the motor pump includes a pump 100 and a motor 200 that drives the pump 100. In the illustrated example, the pump 100 is a multi-stage pump and includes a plurality of impellers 120 mounted on a pump shaft 110. The impeller 120 is housed in a casing 130, and fluid is pumped by rotation of the impeller 120 in the casing 130. Guide vanes 140 for guiding the fluid between the impellers 120 are also provided in the casing 130. Further, in the illustrated example, the pump 100 is a vertical shaft pump, and fluid is sucked from a suction port 150 located on the opposite side to the motor 200 and is discharged from a discharge port 160 on the side closer to the motor 200.

  On the other hand, in the illustrated example, the motor 200 is a permanent magnet type electric motor, and includes a rotor 220 attached to a motor shaft 210 and a stator 230 corresponding to the rotor 220. The motor shaft 210 rotatably supported by the load-side bearing 241 and the non-load-side bearing 242 rotates together with the rotor 220, and transmits a rotational driving force to the pump shaft 110. The rotor 220 and the stator 230 are housed in a space surrounded by the frame 250, the load-side bracket 261, and the non-load-side bracket 262. Further, a fan 270 for cooling the inside of the motor 200 using the rotational driving force is attached to the motor shaft 210.

  The configuration of the pump 100 and the motor 200 as described above is an example, and is not limited to the illustrated example, and various configurations are possible. For example, in the illustrated example, the pump 100 is a multi-stage vertical pump, but in other examples, it may be any type of pump, such as, for example, a centrifugal pump, a gear pump, or a cascade pump. Similarly, the motor 200 is a permanent magnet type electric motor in the illustrated example, but may be any type of motor such as an induction motor or a synchronous motor other than the permanent magnet type in other examples. Good.

  A shaft sealing portion 300 is provided between the pump 100 and the motor 200. The joint member 310 is disposed on the shaft sealing portion 300. In the present embodiment, the joint member 310 is a joint between the pump shaft 110 and the motor shaft 210, and is also a mounting portion of the shaft sealing device. A mechanical seal 320, which is a shaft sealing device, is arranged to face the outer peripheral surface of the joint member 310. The seal between the outer peripheral surface of the joint member 310 and the mechanical seal 320 prevents the fluid handled inside the pump 100 from flowing out.

  Hereinafter, the structure of the shaft assembly including the pump shaft 110, the motor shaft 210, and the joint member 310, which constitutes the main shaft of the motor pump as described above, will be further described.

  FIG. 2 is a view showing a shaft assembly constituting a main shaft of the motor pump shown in FIG. FIG. 3 is an exploded view of the shaft assembly shown in FIG. Referring to FIGS. 2 and 3, the shaft assembly includes a pump shaft 110, a motor shaft 210, and a coupling member 310.

  The pump shaft 110 is formed of a corrosion-resistant material, for example, a stainless steel material. Pump shaft 110 includes a spline portion 111, a reduced diameter portion 112, and a screw portion 113. Here, the spline portion 111 is a portion in which a plurality of grooves in the longitudinal direction, that is, splines are formed on the outer peripheral surface, and corresponds to an impeller mounting portion to which the impeller 120 is mounted. The reduced diameter portion 112 is formed at one end of the pump shaft 110 and fits into a pump-side fitting hole 312 of a joint member 310 described later. The screw portion 113 is provided at the tip of the reduced diameter portion 112 and is screwed to a screw portion 211 of the motor shaft 210 described later.

  The motor shaft 210 is formed of, for example, a carbon steel material for machinery. The motor shaft 210 includes, in order from the side joined to the pump shaft 110, a screw portion 211, a reduced diameter portion 212, an extension portion 213, a load-side bearing mounting portion 214, a large-diameter portion 215, a rotor mounting portion 216, and A bearing mounting portion 217 is included. Here, the screw portion 211 is provided at the tip of the reduced diameter portion 212 and is screwed with the screw portion 113 of the pump shaft 110 described above. The reduced diameter portion 212 is formed at one end of the motor shaft 210 and fits into the motor-side fitting hole 313 of the joint member 310. The extension portion 213 forms an outer peripheral surface that is continuous with the outer peripheral surface 311 of the joint member 310 when the motor shaft 210 is fitted to the joint member 310, and has the same outer diameter as the joint member 310.

The joint member 310 is formed of a corrosion-resistant material, for example, a stainless steel material, similarly to the pump shaft 110. However, the pump shaft 110 and the joint member 310 do not necessarily need to be formed of the same material. The joint member 310 has the outer peripheral surface 311 configured to attach the mechanical seal 320 as described above. By having such an outer peripheral surface 311, the joint member 310 also functions as a mounting part of the mechanical seal 320. Further, a pump-side fitting hole 312 and a motor-side fitting hole 313 are formed inside the joint member 310. The pump side fitting hole 312 and the motor side fitting hole communicate with each other and are concentric with each other.

  In the shaft assembly as described above, for example, first, the reduced diameter portion 112 of the pump shaft 110 is fitted into the pump side fitting hole 312 of the joint member 310, and then the reduced diameter portion 212 of the motor shaft 210 is fitted to the joint member 310. The screw portion 113 is screwed into the screw portion 211 while being fitted in the motor side fitting hole 313. In the illustrated example, the screw portion 113 of the pump shaft 110 is shown as a male screw and the screw portion 211 of the motor shaft 210 is shown as a female screw. However, the relationship may be reversed. That is, a female screw may be formed on the pump shaft 110 and a male screw may be formed on the motor shaft 210.

  Here, the above two fittings, that is, fitting between the reduced diameter portion 112 of the pump shaft 110 and the pump side fitting hole 312 of the joint member 310, and fitting between the reduced diameter portion 212 of the motor shaft 210 and the joint member The fitting between the motor 310 and the motor-side fitting hole 313 is not transmission of the rotational driving force, but the concentric accuracy between the pump shaft 110 and the joint member 310 and between the motor shaft 210 and the joint member 310. The purpose is to secure. In the present embodiment, the rotational driving force of the motor shaft 210 is transmitted to the pump shaft 110 via a screw portion of the screw portion 211 and the screw portion 113. Therefore, as in the example described later, one or both of the above two fittings may be press-fitted, but the press-fitting in that case is weaker than a general press-fitting for the purpose of transmitting force. In other words, the press-fitting cost can be small.

  In addition to the above-described fitting, concentric accuracy can be ensured by abutment of end faces formed perpendicular to the axial direction. For example, the end face 111a formed at the boundary between the spline portion 111 and the reduced diameter portion 112 of the pump shaft 110 and the pump-side end face 312a of the joint member 310 can be abutted. Further, an end surface 213a formed between the extended portion 213 of the motor shaft 210 and the reduced-diameter portion 212 and an end surface 313a on the motor side of the joint member 310 can be abutted.

  FIG. 4 is an enlarged sectional view showing a joint portion of the shaft assembly shown in FIGS. 2 and 3. 4, the reduced diameter portion 112 of the pump shaft 110 fits into the pump side fitting hole 312 of the joint member 310, and the reduced diameter portion 212 of the motor shaft 210 fits into the motor side fitting hole 313 of the joint member 310. 2 shows a state in which the screw portion 113 of the pump shaft 110 is screwed with the screw portion 211 of the motor shaft 210.

In the illustrated example, an O ring 314 and a spacer ring 315 are provided in a gap between the end surface 212a of the reduced diameter portion 212 of the motor shaft 210 and the inner peripheral surface 313s of the motor side fitting hole 313 of the joint member 310. Inserted. The O-ring 314 is a seal ring that seals between the motor-side fitting hole 313 and the reduced diameter portion 112 of the pump shaft 110 (in another example, the screw portion 113). As described above, the mechanical seal 320 as the shaft sealing device is attached to the outer peripheral surface 311 of the joint member 310. Therefore, for example, from the gap between the end face 111a of the pump shaft 110 and the end face 312a of the joint member 310, the gap between the reduced diameter portion 112 and the pump side fitting hole 312, the reduced diameter portion 212 of the motor shaft and the motor The fluid handled inside the pump 100 may flow out through the gap between the side fitting hole 313 and the gap between the end face 213a of the motor shaft 210 and the end face 313a of the joint member 310. O-ring 314 reduces the likelihood of such spills. In addition, the arrangement of the O-ring 314 as shown in the illustrated example prevents the handled fluid from contacting the portion of the motor shaft 210, and the motor shaft 210 having lower corrosion resistance than the pump shaft 110 is affected by the handled fluid. Corrosion can also be prevented. For example, by appropriately setting the length of the spacer ring 315, the O-ring 314 can be pressed so that the above-described gap can be properly sealed.

  In the above example, the spacer ring 315 is not necessarily an independent member, and may be integrated with the reduced diameter portion 212 of the motor shaft 210, for example. However, in this case, since the inner diameter processing of the motor shaft 210 becomes complicated, it may be advantageous to prepare the spacer ring 315 as a separate component from the motor shaft 210 as described above. Further, instead of the seal ring such as the O-ring 314, or in addition to the seal ring such as the O-ring 314, the above-mentioned gap may be sealed by filling an amorphous sealing material, for example. That is, the embodiment of the present invention is not limited to the seal ring such as the O-ring 314, and may include an example in which various shapes of seal members seal the above-mentioned gap.

  FIG. 5 is an enlarged cross-sectional view showing a joint portion of a shaft assembly according to a modified example of one embodiment of the present invention. In the example shown in FIG. 5, a tapered surface is formed instead of the end surface which is decided to abut in the above-described embodiment. More specifically, a tapered surface 111b is formed at the boundary between the spline portion 111 and the reduced diameter portion 112 of the pump shaft 110, and a tapered surface 312b is formed at the entrance of the pump-side fitting hole of the joint member 310 correspondingly. Is done. Further, a tapered surface 213b is formed between the extended portion 213 and the reduced diameter portion 212 of the motor shaft 210, and a tapered surface 313b is formed correspondingly to the entrance of the motor side fitting hole of the joint member 310.

  These tapered surfaces can be formed, for example, by coaxial processing using a lathe. Therefore, by fitting the tapered surfaces together, concentric accuracy between the pump shaft 110 and the joint member 310 or between the motor shaft 210 and the joint member 310 can be effectively improved. When sufficient concentricity can be ensured by fitting the tapered surfaces, fitting between the reduced diameter portions 112 and 212 of the pump shaft 110 and the motor shaft 210 and the fitting holes 312 and 313 of the joint member 310 is weaker. May be sufficient. In this case, in order to prevent the handled fluid inside the pump 100 from flowing out through the gap of the fitting portion, a sealing material or an adhesive is applied to the fitting surface, and then each member is fitted. Is also good.

  However, for example, when the tapered surfaces are to be fitted to each other, the taper angles need to be uniform, and therefore, this modification cannot be applied to all cases. In other words, for example, when the pump shaft 110 and the joint member 310 or the motor shaft 210 and the joint member 310 are processed at different places, it is not easy to form a tapered surface with an equal angle. It may be appropriate to ensure the concentric accuracy using the abutment of the end surfaces as in the above embodiment.

  FIG. 6 is a flowchart illustrating an example of the method of manufacturing the shaft assembly according to the embodiment of the present invention described above. FIG. 6 illustrates steps related to the present embodiment in the manufacturing method, and other steps included in, for example, a normal manufacturing method of the shaft assembly may be omitted.

  In the manufacturing method of the illustrated example, first, the pump shaft 110 is formed (Step S101). This step may include forming a spline on the outer peripheral surface of the pump shaft 110. At this point, the pump shaft 110 has not been joined to any other member, and the spline portion 111 is a portion constituting the outermost diameter of the shaft. Therefore, the spline portion 111 can be formed by, for example, a drawing process.

Next, the pump shaft 110 is pressed into the joint member 310 (Step S103). Specifically, the reduced diameter portion 112 is pressed into the pump side fitting hole 312. As already described, the reduced diameter portion 11
The fitting (press-fitting in this example) between the pump 2 and the pump-side fitting hole 312 does not aim at transmitting the rotational driving force. Therefore, the press-fitting here may be weaker than the general press-fitting, that is, the press-fitting margin may be small. In the case of weak press-fitting, the press-fitting load can be suppressed, so that press-fitting can be performed even with a thin pump shaft 110 without bending. The press fit here may be shrink fit or cold fit, but press fit that can be processed at room temperature has an advantage in terms of productivity.

  Next, the motor shaft 210 and the pump shaft 110 are screwed together while fitting the motor shaft 210 to the joint member 310 (Step S105). Specifically, the screw portion 113 of the pump shaft 110 is screwed to the screw portion 211 of the motor shaft 210 while the reduced diameter portion 212 is fitted in the motor side fitting hole 313. For example, if the fitting between the reduced diameter portion 212 and the motor-side fitting hole 313 is relatively loose fitting, it becomes easy to execute this step after the motor shaft 210 is assembled into the motor 200. . In this case, the concentric accuracy between the motor shaft 210 and the joint member 310 is ensured by the dimensional accuracy of the fitting portion and the perpendicularity of the end surfaces 213a, 313a. If the tapered surfaces 213b and 313b corresponding to the motor shaft 210 and the joint member 310 can be formed as in the above-described modification, the concentricity between the motor shaft 210 and the joint member 310 can be more effectively achieved. Accuracy can be ensured.

  According to the steps of the manufacturing method of the present invention as described above, for example, after forming a spline on the outer periphery of the pump shaft by drawing, the three parts further including the joint member and the motor shaft are joined to form the main shaft of the motor pump. Is easy to form. In one, instead of joining the three parts sequentially, the pump shaft and the motor shaft are directly screwed together, while the mounting part of the shaft sealing device is used as a joint member. This is because the shafts are fitted to the respective shafts, so that the concentric accuracy of the entire main shaft can be easily ensured.

  In addition to the advantages described above, there may be advantages due to an increase in the degree of freedom of the process. For example, the spline is not limited to the case where the spline is formed on the outer peripheral surface of the pump shaft by the drawing process as described above, the case where the spline is formed by the rolling process or the cutting process, or the spline is not formed on the outer peripheral surface of the pump shaft. Even in this case, it can be advantageous to be able to retrofit the pump shaft and the motor shaft.

  For example, since the output of a pump is proportional to the product of the head and the flow rate, if these values are different, a pump having the same structure may not always be combined with a motor having the same output. That is, a motor having the same output may be combined with a plurality of types of pumps having different pump shaft lengths. In such a case, if it is necessary to join the pump shaft and the motor shaft in advance by press-fitting (for example, before assembling the motor shaft into the motor), all the motors joined to the pump shafts of different lengths are different It will be treated as a kind of motor. On the other hand, as in the above-described embodiment of the present invention, if the pump shaft and the motor shaft can be joined afterwards (for example, after the motor shaft is assembled into the motor), a motor having the same output is one type. A pump shaft of an appropriate length may be joined to the motor shaft when treated as a motor and combined with a pump. This has a great advantage in, for example, motor inventory management.

Further, the fact that the pump shaft and the motor shaft can be joined afterwards can be advantageous in terms of workability. If the pump shaft and the motor shaft need to be joined in advance (for example, before assembling the motor shaft into the motor) by press-fitting, the motor is used to assemble the pump with the pump shaft joined to the motor shaft. Will be provided. This means that the motor may be stored or transported with the thin pump shaft protruding from the motor body. If the pump shaft and the motor shaft can be retrofitted (for example, after the motor shaft is assembled into the motor) as in the above embodiment of the present invention, the motor can be stored or transported without the pump shaft being joined. For example, it is possible to eliminate a risk that the main shaft is damaged or bent by an impact applied to the pump shaft.

  As described above, the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the technical scope of the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field of the present invention can conceive various changes or modifications within the scope of the technical idea described in the claims. It is understood that also belongs to the technical scope of the present invention.

REFERENCE SIGNS LIST 100 pump 110 pump shaft 111 spline portion 112 reduced diameter portion 113 screw portion 120 impeller 130 casing 200 motor 210 motor shaft 211 screw portion 212 reduced diameter portion 213 extended portion 216 rotor mounting portion 220 rotor 230 stator 300 shaft sealing portion 310 joint member 311 Outer peripheral surface 312 Pump side fitting hole 313 Motor side fitting hole 314 O-ring 320 Mechanical seal

Claims (15)

A pump shaft, an impeller mounting portion to which an impeller is mounted, a first reduced diameter portion formed at one end of the pump shaft, and a first provided at a tip of the first reduced diameter portion. A pump shaft having a threaded portion of
A pump-side fitting hole in which the first reduced-diameter portion fits, and a second reduced-diameter portion of a motor shaft provided with a second screw portion screwed to the first screw portion at the tip end And a joint member having an outer peripheral surface configured to mount a shaft sealing device, wherein the pump-side fitting hole and the motor-side fitting hole are separated from each other. A shaft assembly comprising: a concentric coupling member. The pump shaft and the coupling member are formed of a corrosion-resistant material,
The shaft assembly according to claim 1, wherein the joint member has a portion having a larger diameter than the impeller mounting portion.   The shaft assembly according to claim 2, wherein the impeller mounting portion is a spline portion having a spline formed on an outer peripheral surface. The pump shaft has a first tapered surface formed at a boundary between the impeller mounting portion and the first reduced diameter portion,
The shaft assembly according to any one of claims 1 to 3, wherein the joint member has a second tapered surface formed at an inlet of the pump-side fitting hole corresponding to the first tapered surface. Three-dimensional.   The shaft assembly according to any one of claims 1 to 4, wherein the fitting between the first reduced-diameter portion and the pump-side fitting hole is press-fitting.   The shaft assembly according to claim 1, wherein the shaft assembly further includes the motor shaft.   The shaft assembly according to claim 6, further comprising a seal member that seals a gap between an end surface of the second reduced diameter portion and an inner peripheral surface of the motor-side fitting hole. The motor shaft has an extended portion having a diameter larger than the second reduced diameter portion, and a third tapered surface formed at a boundary between the extended portion and the second reduced diameter portion,
8. The shaft assembly according to claim 6, wherein the joint member has a fourth tapered surface formed at an entrance of the motor-side fitting hole corresponding to the third tapered surface. 9. A motor shaft,
A first shaft formed at one end of the motor shaft and configured to fit into a motor-side fitting hole provided in a joint member having an outer peripheral surface configured to mount a shaft sealing device. A reduced diameter portion,
The pump shaft is provided at the distal end of the first reduced diameter portion, and is provided at the distal end of the second reduced diameter portion of the pump shaft fitted to the pump side fitting hole of the joint member concentric with the motor side fitting hole. And a first screw portion configured to screw with the second screw portion. A motor shaft according to claim 9,
A rotor attached to the motor shaft,
And a stator corresponding to the rotor. A pump including an impeller, a casing accommodating the impeller, and a pump shaft, wherein the pump shaft includes an impeller mounting portion to which the impeller is mounted, and a pump shaft formed at one end of the pump shaft. A pump further comprising: a first reduced diameter portion; and a first screw portion provided at a distal end of the first reduced diameter portion;
A motor including a rotor, a stator corresponding to the rotor, and a motor shaft to which the rotor is attached, wherein the motor shaft has a second reduced-diameter portion formed at one end of the motor shaft; A motor provided at the tip of the second reduced diameter portion and further having a second screw portion screwed to the first screw portion;
A pump-side fitting hole in which the first reduced-diameter portion fits, a motor-side fitting hole in which the second reduced-diameter portion fits, and an outer peripheral surface configured to mount a shaft sealing device. A motor pump, comprising: a joint member, wherein the pump-side fitting hole and the motor-side fitting hole are concentric with each other. A first step of forming a pump shaft;
A second step of fitting a first reduced-diameter portion formed at one end of the pump shaft into a pump-side fitting hole of a joint member having an outer peripheral surface configured to be fitted with a shaft sealing device; When,
The first reduced diameter portion is fitted to a motor side fitting hole of the joint member concentric with the pump side fitting hole with a second reduced diameter portion formed at one end of the motor shaft. And a third step of screwing a first screw portion provided at a tip of the second screw portion and a second screw portion provided at a tip of the second reduced diameter portion.   The method of manufacturing a shaft assembly according to claim 12, wherein the second step includes a step of press-fitting the first reduced diameter portion into the pump-side fitting hole.   14. The method according to claim 12, wherein the third step is performed after the motor shaft is assembled into a motor.   The method of manufacturing a shaft assembly according to any one of claims 12 to 14, wherein the first step includes forming a spline on an outer peripheral surface of the pump shaft by drawing.

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