JP2956881B2 - Pump bearing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing device for a pump having a pump casing, an impeller and a rotating shaft of the impeller in a casing.

[0002]

2. Description of the Related Art Generally, a bearing device for a high-pressure pump which is lubricated with a process fluid handled by the pump is widely known. However, when the process liquid is a low-viscosity liquid such as water, LPG, or liquid hydrogen, a dynamic pressure bearing that performs a bearing action by sliding does not have a sufficient load capability. Furthermore, when the discharge pressure from the impeller is not sufficiently high, such as at the time of startup or low-speed operation, the hydrostatic bearing cannot perform its function. A pump using a hydrostatic bearing is disclosed in, for example, Japanese Patent Publication No. 61-5558 and Japanese Patent Application Laid-Open No. 58-13195.

[0003]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a rolling bearing that supports the thrust force and the radial load of the rotating shaft at the time of start-up or low-speed operation, and is in non-contact with the rotating shaft near the rated rotation. An object of the present invention is to provide a pump bearing device in which a thrust force is not generated by a thrust balance mechanism, and a radial force is supported by a hydrostatic journal bearing.

[0004]

According to the present invention, in a bearing device for a pump having a pump casing, an impeller, and a rotating shaft of the impeller in the casing, the rotating shaft has a tapered portion having a narrower impeller side. The bearing provided on the pump casing supports the rotating shaft via a sleeve having a tapered surface that engages with the tapered portion, and the wear ring provided on the suction side and the back side of the impeller has a large diameter on the back side. Yes,
A thrust balance mechanism is provided on the back side of the impeller.

Further, according to the present invention, the thrust balance mechanism varies in accordance with the axial position of the impeller in the radial direction of the balance chamber provided radially inward of the wear ring on the back surface of the impeller. And a gap.

Further, according to the present invention, the gap is constituted by a balance sheet provided on the pump casing and a throttle ring provided on the impeller.

In the present invention, the pump casing is provided with a bearing passage for guiding the discharge liquid of the impeller, and a hydrostatic journal bearing using the discharge liquid is provided.

In the present invention, the hydrostatic journal bearing has a pocket communicating with the bearing passage through a throttle communicating with the bearing passage.

In the present invention, the pump is applied to a vertical shaft pump having an impeller provided below.

[0010]

Therefore, the tapered surface of the sleeve is engaged with the tapered surface of the rotating shaft at the time of start-up or low-speed rotation, and the rotating shaft is supported by the rolling bearing. At the time of start-up or low-speed rotation, even if lubrication is insufficient, there is no inconvenience in bearing by the rolling bearing.

When the rotation speed approaches the rated rotation speed, a thrust force in a direction in which the tapered surface of the sleeve separates from the rotation shaft is generated due to a difference in diameter between the first and second wear rings as the discharge pressure increases. That is, the suction side (front) of the impeller
The diameter of the wear ring provided on the rear side is smaller than the diameter of the wear ring provided on the back, and the discharge pressure of the impeller is applied to the wear ring, so the thrust force on the front side increases and the axial thrust force increases. Occurs. As a result, the rolling bearing is in a non-contact state, and the problem of lubrication does not occur.

Further, the thrust force is balanced by the thrust balance mechanism, and a stable rotation is obtained by receiving a radial load by the hydrostatic journal bearing.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a pump using the bearing device according to the present invention, and in the illustrated example, a vertical shaft pump in which an impeller is located on a lower side.

An impeller 1 is fixed to a lower end of a rotating shaft 2 which is rotated by a motor (not shown). The impeller 1 has a second wear ring 7 provided at a suction port I of a casing C.
It is located at.

A ring-shaped projection 1a is provided on the upper surface, that is, the rear surface (motor-side surface) of the impeller 1, and is located radially inward of the first wear ring 6 provided on the pump casing 4. ing. The diameter of the first wear ring 6 is larger than the diameter of the second wear ring 7.

A throttle ring 8 is formed radially inward of the protrusion 1a provided on the back surface of the impeller 1, and a balance sheet 9 is attached to the pump casing 4 corresponding to the throttle ring 8, and a throttle sheet 9 is provided. The gap S between the ring 8 and the balance sheet 9 forms a stop. The protrusion 1a forms a balance chamber 10. The throttle ring 8, the balance sheet 9, the gap S, and the balance chamber 10 constitute a thrust balance mechanism.

In the example shown in the drawing, a front combination angular contact bearing is used as the rolling bearing 3 which rotatably supports the rotating shaft 2. The outer ring 3a of the rolling bearing 3 is fixed to the pump casing 4, and the inner ring 3b is provided with a sleeve 5 having a tapered surface 5a such that the inner circumference becomes narrower on the impeller 1 side. The tapered surface 5a is engaged with the tapered portion 2a of the rotating shaft 2 at the time of startup or low-speed rotation as described later.

A hydrostatic journal bearing 11 is provided above the rolling bearing 3. The bearing 11 has an impeller 1
The high-pressure water is supplied from a bearing passage 13 communicating with the discharge water passage 12 of the first embodiment.

FIGS. 3 and 4 show the hydrostatic journal bearing 11.
And a throttle 11a communicating with the bearing passage 13
Are formed, and a groove 11c extending in the axial direction is formed.

In operation, the rotating shaft 2 receives a downward force in FIG. 1 by its own weight at the time of start-up and low-speed operation, so that the tapered portion 2a of the rotating shaft 2 and the tapered surface 5 of the sleeve 5
a and receives a thrust load and a radial load by the rolling bearing. When the rotation speed increases, the impeller 1
However, since the diameters of the first wear ring 6 and the second wear ring 7 provided on the impeller 1 are different, the impeller 1 has a larger diameter first wear ring 6. , That is, an upward thrust force.

Since this thrust force increases with an increase in the number of revolutions, it is inconvenient if there is no thrust bearing when overcoming its own weight. However, in the present invention, the balance room 1
0 allows this thrust force to be balanced.

That is, while the discharge pressure of the impeller 1 is low, the pressure in the balance chamber 10 is released because the gap S is large, and the pressure is low. However, as the discharge pressure of the impeller 1 increases, the impeller 1 moves upward as shown in FIG.
Becomes smaller as indicated by S ', the pressure in the balance chamber 10 increases, and the thrust force is balanced. As a result, the tapered surface 5a of the sleeve 5 has a gap δ with the tapered portion 2a of the rotating shaft 2 as shown in FIG. 2, and is in a non-contact state, and the rolling bearing 3 is stationary.

The static pressure journal bearing 11 has a load capacity when the discharge pressure of the pump increases. Therefore, at the time of startup and low speed, the load is received by the rolling bearing, and near the rated rotation, the load is supported by the thrust balance mechanism using the increased discharge pressure of the pump and the static pressure journal bearing.

In the above-described embodiment, the taper surface 5a of the sleeve 5 is described as being engaged by its own weight. However, if a thrust generating device that engages the taper surface 5a at the time of startup or low-speed operation is provided, a horizontal type is provided. Can be implemented.

[0026]

As described above, according to the present invention, the following excellent effects can be obtained. (1) Since the rolling bearing operates only at the time of startup or low-speed rotation, the operation time of the rolling bearing can be extremely reduced even if lubricated with a low-viscosity liquid. (2) In the vicinity of the rated rotation, the rolling bearing is in a non-contact state, and the thrust force is supported by the thrust balance mechanism and the radial force is supported by the hydrostatic journal bearing, so that stable rotation can be obtained. (3) Therefore, a long service life can be obtained even with self-lubrication with a pump that handles a low viscosity liquid.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a state at the time of starting a pump embodying the present invention.

FIG. 2 is a sectional view showing a state of a rated rotation of the pump of FIG. 1;

FIG. 3 is a view of a hydrostatic journal bearing according to the present invention as viewed from a lower half.

FIG. 4 is a side view of FIG. 3;

[Explanation of symbols]

 C: Casing I: Suction port S: Gap δ: Gap 1 ... Impeller 1a ... Protrusion 2 ... Rotary shaft 2a ... Tapered section 3 ... Rolling Bearing 4 Pump casing 5 Sleeve 5a Tapered surface 6 First wear ring 7 Second wear ring 8 Throttle ring 9 Balance sheet 10 ..Balance chamber 11 ・ ・ ・ Static journal bearing 11a ・ ・ ・ Restrictor 11b ・ ・ ・ Pocket 11c ・ ・ ・ Groove

Claims (6)

(57) [Claims] 1. A bearing device for a pump having a pump casing, an impeller, and a rotating shaft of the impeller in a casing, wherein the rotating shaft has a tapered portion on the impeller side narrowing, and a bearing provided on the pump casing. Supports the rotating shaft via a sleeve having a tapered surface that engages with the tapered portion, and the wear ring provided on the suction side and the back side of the impeller has a large diameter on the back side and a thrust balance on the back side of the impeller. A pump bearing device comprising a mechanism. 2. A thrust balance mechanism comprising a balance chamber provided radially inward of a wear ring on a back surface of an impeller and a gap which varies radially inward of the balance chamber depending on an axial position of the impeller. The bearing device for a pump according to claim 1. 3. The bearing device for a pump according to claim 2, wherein said gap is constituted by a balance sheet provided on a pump casing and a throttle ring provided on an impeller. 4. The pump bearing device according to claim 1, wherein a bearing passage for guiding the discharge liquid of the impeller is provided in the pump casing, and a hydrostatic journal bearing by the discharge liquid is provided. 5. The bearing device for a pump according to claim 4, wherein the hydrostatic journal bearing has a pocket that communicates through a throttle that communicates with the bearing passage. 6. The pump bearing device according to claim 1, wherein the pump is a vertical shaft pump provided with an impeller below.