KR20130079252A - Coolant pump assembly - Google Patents

Abstract

PURPOSE: A coolant pump assembly is provided to connect the shaft of motor and the shaft of coolant pump with a flexible coupling unit, which has a gear, in order to attenuate the axial vibration. CONSTITUTION: A second tooth-shape member (102) of an upper shaft (301) assembly is lead-in to a second engaging unit (203) of the coupling unit housing. A first tooth-shape member (302) of the upper shaft assembly is lead-in to a first engaging unit (201) of the coupling unit housing. The rotary shaft is arranged by engaging the second tooth-shape member and the second engaging unit, and by engaging the first tooth-shape member and the first engaging unit. The shaft arrangement is adjusted by rotating a vibration shaft (101) and the upper shaft even if the arrangement of one shaft is bad.

Description

[0001] COOLANT PUMP ASSEMBLY [0002]

The present invention relates to a coolant pump assembly in which a reactor coolant pump and an electric motor are connected.

As is well known, the reactor coolant pump is provided between the steam generator and the reactor of the primary system of the nuclear power plant. The reactor coolant pump is a core device of a nuclear steam supply system (NSSS) that sucks coolant or coolant (hereinafter referred to as 'coolant') heat-exchanged in the steam generator and discharges it to a reactor.

Reactor coolant pumps are a key component of the reactor cooling system and require vibration reduction to improve the performance of the unit. A pump unit for pumping the coolant is provided below the reactor coolant pump, and a driving unit for providing a driving force to the pumping unit is provided on the pumping unit.

Generally, the vibration of the rotating body is generally caused by poor connection alignment or insufficient rotating stiffness. Therefore, the center of the drive shaft and the driven shaft must be precisely aligned in order to increase the life of the machine and to minimize the noise.

In a conventional reactor coolant pump assembly, a shaft of a coolant pump and a shaft of a motor are connected by fasteners such as bolts. However, since it is impossible to use the fastener to perfectly match the shaft center of the motor and the coolant pump, researches on the structure of the coolant pump assembly that can reduce the vibration when supplying the coolant are being conducted.

It is an object of the present invention to provide a coolant pump assembly capable of attenuating shaft vibration by connecting a shaft of a motor and a shaft of a coolant pump to a flexible coupling unit provided with a gear.

Another object of the present invention is to provide a coolant pump assembly including a Curved Tooth Gear coupling unit, which provides a method of driving a coolant pump assembly in which shaft vibration is attenuated during shaft rotation.

In order to solve the above problems, a bearing assembly for a coolant pump according to an embodiment of the present invention includes a coolant pump having a shaft on which a first toothed member is formed, and a second toothed member A second coupling portion to which the second toothed member is inserted, and a coupling member having both sides of the first coupling portion into which the first toothed member is inserted, wherein the first coupling portion, the second coupling portion, And between the first toothed members and between the second engaging portion and the second toothed member are formed to be engaged with gears.

As an example related to the present invention, the gear is machined such that the tip of the gear is curved so as to attenuate the shaft vibration due to the axial alignment error.

In order to solve the above problems, a reactor coolant pump including a pumping unit for pumping a coolant, a drive unit for supplying a driving force to the pumping unit, and a power transmission unit for transmitting the power of the drive unit to the pumping unit, The bearing has a bearing assembly for the coolant pump as described above.

According to an embodiment of the present invention, the bearing assembly for a coolant pump includes a bearing housing having a bearing cover coupled to an upper opening, and the upper shaft penetrates through the center.

According to another aspect of the present invention, the power transmission unit includes a frame for supporting the driving unit, an upper shaft disposed in the frame in the axial direction, and a driving unit coupled to the driving unit and the upper shaft, And an oil reservoir cover formed around the bearing assembly for the coolant pump and having an opening having a diameter larger than that of the bearing cover at an upper end thereof, .

A coolant pump assembly including a connecting member having a curved toothed gear according to at least one embodiment of the present invention configured as described above facilitates axial alignment of the motor shaft and the upper shaft of the motor And performs a function of correcting a certain range of axial alignment errors.

1 is a cross-sectional view of a bearing assembly region of a reactor coolant pump according to one embodiment of the present invention.
Figure 2 shows a coolant pump assembly.
3 is a cross-sectional view of a coolant pump assembly coupling unit in accordance with one embodiment of the present invention.
Figure 4 is an enlarged view of the coolant pump assembly coupling unit of Figure 3;
Figure 5 is a conceptual view of the coolant pump assembly coupling unit of Figure 3;

Hereinafter, a coolant pump assembly according to an embodiment of the present invention will be described in detail with reference to the drawings. In the present specification, different embodiments are given the same or similar reference numerals, and the description thereof is replaced with the first explanation. As used herein, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a bearing assembly area of a nuclear coolant pump.

As shown in FIG. 1, a frame 20 for supporting the motor of the driving unit 10 is provided below the driving unit 10 of the reactor coolant pump.

A flange (22) for supporting the motor in contact with the frame (20) is formed at an upper end of the frame (20).

A receiving space is formed in the frame 20.

Inside the frame 20, there is provided a bearing assembly 30 for axially supporting the rotation axis of the pumping part.

The bearing assembly 30 includes a bearing housing 31 having a receiving space upwardly opened therein, a bearing cover 33 for blocking an opening of the upper portion of the bearing housing 31, And a collar member (37) provided inside the bearing housing (31).

The bearing housing 31 is formed to open upward.

A bearing cover 33 is provided at an upper end of the bearing housing 31 to open and close the opening.

The bearing housing 31 is rotatably received with a rotation shaft, more specifically, an upper shaft 35.

A gear type coupling unit (45) is provided at the upper end of the upper shaft (35) so that the driving force of the electric motor can be transmitted.

The gear type coupling unit 45 includes an external gear 36 integrally formed with the upper shaft 35 and an external gear 36 formed to be engaged with the external gear 36 on the inner surface of the coupling unit housing 46 And an internal gear 47.

On the other hand, the upper shaft 35 is provided with a disc-shaped collar member 37.

The collar member 37 is configured to be in axial contact with the bearing cover 33 and the bearing housing 31, respectively. Thereby, the upper shaft 35 is supported in the axial direction.

Between the collar member 37 and the bearing cover 33, pads 41 are provided which are in sliding contact with each other in the axial direction.

An oil reservoir (51) is provided on the outer side of the bearing housing (31).

An oil reservoir cover 55 is provided above the oil reservoir 51.

The oil storage tank cover 55 is provided with an oil cooler 57 for cooling the oil in the oil storage tank 51.

2 is a cross-sectional view of a coolant pump assembly in accordance with one embodiment of the present invention.

2, the reactor coolant pump according to an embodiment of the present invention includes a pumping unit 110 for pumping a coolant and a drive unit 160 for providing a driving force to the pumping unit 110 .

The reactor coolant pump includes, for example, a so-called "vertical pump" in which the pumping portion 110 and the driving portion 160 are arranged along the vertical direction. More specifically, the driving unit 160 is provided on the pumping unit 110.

The pumping unit 110 includes a casing 120 having a receiving space therein, a lower shaft 135, and a rotatable shaft 135 rotatable about the lower shaft 135 in the casing 120. [ And an impeller 130 disposed to be disposed.

A diffuser or guide vane 150 for guiding the coolant sucked by the impeller 130 is provided at one side of the impeller 130.

The pumping unit 110 is provided with a sealing unit 137 to prevent the coolant from leaking along the rotating shaft (lower shaft 135). The sealing unit 137 is implemented, for example, by so-called three-stage mechanical seals disposed axially and spaced apart.

And a power transmission unit 170 for transmitting the power of the driving unit 160 to the pumping unit 110 on the upper side of the pumping unit 110.

An intermediate shaft 155 is provided between the pumping part 110 and the power transmitting part 170. The intermediate shaft 155 is detachably provided between the lower shaft 135 and the upper shaft 175 described later.

The power transmission unit 170 includes a frame for supporting the driving unit 160, an upper shaft 175 disposed along the vertical direction inside the frame and connected to the pumping unit 110 at a lower end thereof, A collar member 220 coupled to the upper shaft 175, a bearing housing 210 for receiving the collar member 220 therein, and a bearing cover disposed at an upper opening of the bearing housing 210 A first tooth member 242 detachably coupled to the upper shaft 175 and a second tooth member 242 coupled to the first tooth member 242 and the teeth 262. The bearing assembly 180 includes a bearing assembly 180 axially supporting the upper shaft 175, A coupling unit (240) having a first coupling unit housing (245) coupled to the first coupling unit housing (245) and a second coupling unit housing (247) detachably coupled to the first coupling unit housing (245) An oil reservoir 185 formed around the housing 210, and an oil reservoir And an oil reservoir cover (190) provided at the upper end of the oil reservoir (185).

The pumping part 110 is provided at its upper side with a frame forming an accommodation space therein.

The frame is composed of a plurality of frames along the vertical direction.

The driving unit 160 is disposed at an upper end of the frame.

The frame supports the driving unit 160.

And a flange 173 extended outwardly to support the lower end of the driving unit 160 is provided at an upper end of the frame.

The frame is, for example, of a cylindrical shape.

And the intermediate shaft 155 is provided in an inner lower region of the frame.

The upper shaft 175 is connected to the upper end of the intermediate shaft 155.

The bearing assembly 180 is provided on the upper side of the intermediate shaft 155 inside the frame.

The bearing assembly 180 includes a bearing housing 210 having an upwardly open receiving space therein and a collar member 220 coupled to the upper shaft 175. The bearing assembly 210 includes an upper opening of the bearing housing 210, And a bearing cover (235) for cutting off.

The collar member 220 is integrally rotatably coupled to the upper shaft 175.

Pads are provided on the bottom surface and the top surface of the collar member 220, respectively.

Inside the bearing housing 210, a supporting portion for rotatably supporting the collar member 220 is provided.

The support portion is configured to protrude inward along the radial direction from the inner surface of the bearing housing 210.

A sheet is provided between the support and the pads of the collar member 220. The sheet is configured to be in sliding contact with the pad.

A bearing cover 235 is provided on the upper opening of the bearing housing 210 to open and close the opening.

The bearing cover is detachably coupled to the bearing housing 210 by a plurality of fastening members (e.g., bolts).

The bearing cover 235 includes a pad or sheet that is slidably in contact with the pad of the collar member 220, for example.

An oil reservoir (185) for storing oil is provided outside the bearing housing (210). More specifically, for example, the oil reservoir 185 is formed in a space between the frame and the bearing housing 210.

On the other hand, an oil reservoir cover 190 is provided above the oil reservoir 185.

The oil reservoir cover 190 is coupled to be supported by the frame.

The oil reservoir cover 190 is disposed at the upper end of the oil reservoir 185, for example, with an opening at the center.

The oil reservoir cover 190 is configured to have an outer diameter corresponding to the inner diameter of the frame.

The opening of the oil reservoir cover 190 is formed, for example, larger than the bearing cover 235. Thus, the bearing cover 235 is drawn out through the opening of the oil reservoir cover 190.

The oil reservoir cover 190 is provided with an opening cover 194 for opening and closing the opening.

The opening cover 194 is divided into a plurality of portions along the circumferential direction and is constituted by a plurality of partial covers. 4, the number and the size of the partial covers 194 are not limited to the number of the open covers 194, Is appropriately adjusted.

The oil reservoir cover 190 is provided with a seat for seating the opening cover 194.

The opening cover 194 is detachably coupled to the oil reservoir cover 190. For example, each of the opening covers 194 is coupled to the oil reservoir cover 190 with a plurality of fixing bolts.

Each of the opening covers 194 is fixed to the seat portion using the fixing bolts after being seated on the seat portion.

A penetrating portion is formed at the center of the opening cover 194.

The power transmission unit 170 includes a coupling unit 240 that transmits the driving force of the driving unit 160 to the upper shaft 175.

The coupling unit 240 may include, for example, a first toothed member 242 releasably coupled to the top shaft 175, a first coupling member 242 to be engaged in teeth with the first toothed member 242, And a second coupling unit housing (247) detachably coupled to the housing (245) and the first coupling unit housing (245).

The coupling unit 240 includes a second toothed member 248 having one side connected to the driving unit 160 and the other side coupled to the second coupling unit housing 247.

The first toothed member 242 is coupled to the upper end of the upper shaft 175.

A lower support member coupled to the upper shaft 175 and restraining downward movement of the first toothed member 242 is provided below the first toothed member 242.

The upper end of the first toothed member 242 is coupled to the upper end of the upper shaft 175 to prevent the upward movement of the first toothed member 242.

The upper support member is detachably coupled to the upper shaft 175 by a plurality of fastening members (e.g., bolts).

The first toothed member 242 is provided with an external gear.

The first coupling unit housing 245 is provided with an internal gear which is coupled with the external gear to be rotated.

The second coupling unit housing 247 is disposed above the first coupling unit housing 245.

The first coupling unit housing 245 and the second coupling unit housing 247 are detachably coupled. For example, the first coupling unit housing 245 and the second coupling unit housing 247 are releasably coupled by a plurality of fastening members (e.g., bolts and nuts) (not shown).

The second toothed member 248 is coupled to the upper side of the second coupling unit housing 247. Although not specifically shown in the figure, the second coupling unit housing 247 is provided with an internal gear, and the second toothed member 248 is constituted to include an external gear to be engaged with the internal gear.

A rotation shaft insertion hole is formed at the center of the second toothed member 248 so that the rotation shaft 167 of the motor 165 of the driving unit 160 can be inserted. The second coupling unit housing 247, the first coupling unit housing 245, and the second coupling unit housing 247, which are rotatably engaged with each other when the rotation shaft of the electric motor 165 is rotated, The rotational force of the electric motor 165 is transmitted to the upper shaft 175 through the first toothed member 242.

Meanwhile, a coupling unit housing 239 accommodating the coupling unit 240 is provided outside the coupling unit 240.

The coupling unit housing 239 defines an enclosed receiving space therein.

The coupling unit housing 239 has a plurality of partial housings coupled along the vertical direction.

The lower end of the coupling unit housing 239 is detachably coupled to the opening cover 194.

For example, the coupling unit housing 239 is provided with a flange extending radially outwardly.

The flange is formed with a bolt hole through which a plurality of bolts fastened to the opening cover 194 can be inserted.

3 is a cross-sectional view of a coolant pump assembly coupling unit in accordance with an embodiment of the present invention.

Referring to Figure 3, the coolant pump assembly includes a coolant pump, an electric motor, and a coupling unit housing.

The coolant pump includes a pump housing forming a pump chamber.

A first toothed member 302 is formed at one end of the upper shaft 301.

The first toothed member 302 is fixed to the upper shaft 301. The fixing method may be any method as well as fixing by pressing and fastening.

Gears are formed on the outer peripheral surface of the second toothed member 102.

The gear may be a normal spur gear. The gear may be a curved tooth gear with a high tolerance of misalignment. By using the Curved Tooth Gear Coupling unit, various advantages such as an increase in the allowable limit of the misalignment of the shaft alignment, improvement of the attenuation of the transmitted shaft vibration, and dispersion of the concentrated load at the gear teeth can be obtained . The curved tooth gear may be a crowned gear. The crowning process means that the end face of the gear is rounded appropriately in the direction of the butterfly to smoothly engage the gear during loading.

The electric motor is connected to the upper shaft (301) to rotate the upper shaft (301). A second toothed member 302 is formed on the outer peripheral surface of the electric motor shaft 101 of the electric motor.

The second toothed member 102 is fixed to the electric motor shaft 101 of the electric motor. The fixing method may be any method as well as fixing by pressing and fastening.

A gear 302a is formed on the outer circumferential surface of the first toothed member 302. The gear may be a general spur type gear. The gear may also be a curved tooth gear.

The coupling unit housing includes a first coupling portion 203 into which the first toothed member 302 is inserted and a second coupling portion 201 into which the second toothed member 102 is inserted.

The first engaging portion 203 and the second engaging portion 201 are disposed on both sides of the coupling unit housing so that the motor shaft 101 of the electric motor and the upper shaft 301 are axially aligned.

The transmission shaft 101 and the upper shaft 301 are disposed on the same axis when they are connected to the coupling unit housing.

The first engaging part 203 may be a casing having a gear 203a on an inner peripheral surface thereof.

The second engaging portion 201 may have the shape of a casing having a gear 201a on the inner peripheral surface thereof.

The gears included in the first and second coupling parts 203 and 201 may be spur gears or curved tooth gears.

The coupling unit housing according to an embodiment of the present invention includes a first casing having a first coupling portion 203 on an inner peripheral surface thereof, a second casing having a second coupling portion 201 on an inner peripheral surface thereof, And a spacer (202) connecting the first casing and the second casing.

The spacer 202 and the first casing, the spacer 202 and the second casing are coupled by fasteners 204 and 205 such as a hex nut.

Since the first casing, the second casing, and the spacer 202 are connected to each other, when the torque is applied to the second casing, the torque is transmitted to the first casing connected to the second casing.

In the above, the coupling unit housing is a subdivided coupling unit for the sake of easier understanding, and refers to a casing which forms the appearance of the coupling unit. That is, the coupling unit housing corresponds to a part of the coupling unit.

The coupling unit may be a coupling means designed with fasteners 204, 205, such as T-head screws.

The coupling unit may be a flexible coupling unit. When the electric shafts 101 and the upper shafts 301 are connected to each other by the flexible coupling unit, the allowable limit of the misalignment of the shafts is increased, and the shaft vibration is reduced.

According to an embodiment of the present invention, the flexible coupling unit may be a gear coupling unit. The gear coupling unit may be a curved tooth gear coupling unit.

In general, when there is an error in the axis alignment, a lateral vibration or a torsional vibration occurs when the shaft rotates.

These vibrations worn components of the coolant pump and reduce the performance of the coolant pump. However, the top axis 301 assembly of the present invention has a large tolerance for axis alignment errors.

The function of the upper shaft 301 assembly according to one embodiment of the present invention is as follows.

The second toothed member 102 formed on the outer circumferential surface of the drive shaft of the electric motor is drawn into the second engagement portion 201 of the coupling unit housing. Gears 102a and 201a are present between the second toothed member 102 and the second engaging portion 201. [

The first toothed member 302 formed on the outer circumferential surface of the upper shaft 301 is inserted into the first engaging portion 201 of the coupling unit housing. Gears 302a and 203a are present between the first toothed member 302 and the first engaging portion 203.

The second toothed member 102 and the second engaging portion 203, and the first toothed member 302 and the first engaging portion 201 are engaged with each other so that the rotational axis is aligned. Since the driving shaft of the electric motor and the upper shaft shaft 301 are not connected directly but connected by a coupling unit, axis alignment is easy.

In the case where the gear is a curved toothed gear, even when the alignment of one shaft is poor, the shaft alignment is corrected by rotating the transmission shaft 101 and the top shaft 301. Since this portion of the gear is rounded, the gear is engaged during rotation.

Figure 4 is an enlarged view of the coolant pump assembly coupling unit of Figure 3;

Referring to Fig. 4, the coupling unit housing includes a first casing, a spacer 202, and a second casing. The first casing and the spacer 202 are coupled with fasteners 204 and 205 such as bolts. The second casing and the spacer 202 are also coupled with fasteners 204 and 205 such as bolts.

The spacer 202 may have a hollow cylindrical shape. The spacer 202 serves to transmit the rotation of the second casing to the first casing.

A buffer member is included in the spacer 202. The buffer member serves to reduce the axial vibration of the motor shaft 101 and the top shaft 301 of the motor.

The coupling unit housing may have a structure in which the first casing and the second casing are connected without the spacer 202. [ In this case, the first casing and the second casing may be connected by fasteners (204, 205) or may be coupled by welding or the like.

The coupling unit housing may be a coupling unit having the first coupling portion 203 and the second coupling portion 201 on both sides thereof. The motor shaft 101 of the motor coupled to the second coupling portion 201 and the upper shaft 301 coupled to the first coupling portion 203 are positioned on the same axis so that the first coupling portion 203 and the second engaging part 201 are formed.

Gears are formed on the inner circumferential surface of the first engaging portion 203 and the second engaging portion 201.

The gear 203a of the first engagement portion can engage with the gear 302a of the first toothed member. The gear 201a of the second engagement portion can be engaged with the gear 102a of the second toothed member.

The gears are crowned. The crowning process means that the end face of the gear is rounded in the direction of the butterfly to smooth the engagement of the gear at the time of loading.

If this part of the gear is rounded, even if the gears are not fully engaged, some misalignment of the shaft alignment is compensated for by rotation. The curved tooth gear can reduce the transmission of the lateral vibration or the torsional vibration within a certain limit even when the connecting shaft of the electric shaft 101 and the upper shaft 301 is shifted.

5 is a conceptual view of the coolant pump assembly coupling unit of FIG. 3;

According to FIG. 5, a sealing member 206 such as an o-ring is attached to the coupling portion of the coupling unit.

The coolant pump assembly according to an embodiment of the present invention includes the following driving method.

The electric motor shaft 101 of the electric motor rotates the gear coupling unit engaged with the electric motor shaft 101. [ The gear coupling unit then rotates the top shaft 301 engaged with the gear coupling unit. The gear coupling unit may be a curved tooth gear coupling unit. Curved Tooth Gear Coupling unit compensates for axis alignment errors. Accordingly, when the coupling unit rotates, the shaft 101 vibrates due to the alignment of the shaft 301 with the shaft.

The coolant pump assembly having the curved toothed gear according to at least one embodiment of the present invention configured as described above facilitates axial alignment between the motor shaft and the upper shaft of the motor, And performs a function of correcting the error.

It is to be understood that the above-described phase axes and their driving methods are not limited to the configurations and methods of the embodiments described above, but the embodiments may be modified such that all or some of the embodiments are selectively And may be configured in combination.

110: pumping section 120: casing
130: impeller 150: guide vane
170: Power transmission unit 175: Upper shaft
180: Axial thrust bearing assembly 185: Oil reservoir
190: oil storage tank cover 194: opening cover
210: bearing housing 220: collar member
240: coupling unit 242: first toothed member
245: first coupling housing 247: second coupling member
248: second toothed member 252: rail

Claims (6)

A coolant pump having a shaft;
An electric motor having an electric shaft axially aligned with the shaft; And
And a coupling unit coupled to surround the outer circumference of the shaft and the electric shaft so as to reduce the axial vibration of the shaft aligned with the connecting shaft. The method of claim 1,
A tooth member is formed on the outer periphery of the shaft and the electric shaft,
The coupling unit includes:
And a first and a second engagement portion having teeth engaged with each of the toothed members. The method of claim 2,
The gear is,
Wherein the end portion of the bearing assembly is curved so as to attenuate shaft vibration due to axial alignment errors. 1. A nuclear reactor coolant pump comprising a pumping unit for pumping a coolant, a drive unit for providing a driving force to the pumping unit, and a power transmission unit for transmitting power of the drive unit to the pumping unit,
The power transmission unit includes:
A reactor coolant pump comprising a bearing assembly for a coolant pump according to any one of claims 1 and 2. The method of claim 3,
And the bearing assembly for the coolant pump includes a bearing housing having a bearing cover coupled to an upper opening thereof, wherein the upper shaft penetrates to the center thereof. 5. The method of claim 4,
The power transmission unit includes:
A frame supporting the driving unit;
An upper shaft disposed axially inside the frame;
A coupling unit coupled to the driving unit and the upper shaft so as to be disassembled from each other to transmit the power of the driving unit to the upper shaft; And
And an oil reservoir formed on the periphery of the bearing assembly for the coolant pump and having an opening having a diameter larger than that of the bearing cover at an upper end thereof.

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