JPH07217593A - Submerged bearing for self-contained water lubrication - Google Patents

Abstract

PURPOSE:To increase a quantity of lubricating-water and to improve a cooling effect by a method wherein the piping on the feed water side of a bearing is coupled to the delivery side of an impeller, the drainage side is coupled to the suction side of the impeller, and a differential pressure equivalent to the head of a pump is exerted between the feed and discharge of lubricating-water. CONSTITUTION:In a horizontal mixed flow pump, an impeller 1 is attached on a rotary shaft 2 and rotatably supported by internal and external bearings 3 and 4 and driven by a prime mover through a shaft coupling 5. The internal bearing 3 is attached to a bearing housing 7 incorporated in a casing 6. In this case, one end of a lubricating water pipe 8 is attached on the end face on the opposite drive side of the internal bearing 3 and the other end thereof is connected to the flow passage side of the casing 6 situated upper stream from the impeller 1. Lubrication water is introduced in a bearing gap through a gap 10 between the impeller 1 and a bearing outer cylinder and guided to a lubrication water piping 8. This constitution exerts a differential pressure on a gap between the water feed side and the drainage side of the internal bearing 3, increases a quantity of lubricating-water, and improves the cooling effect of the internal bearing 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a submerged bearing for an axial flow / oblique flow type pump, and more particularly, to a horizontal shaft type axial flow type where the bearing load is severe.
The present invention relates to a submersible bearing of a mixed flow pump.

[0002]

2. Description of the Related Art Conventionally, in relation to this type of technology, Japanese Patent Laid-Open No.
There is a canned pump described in −93998 publication. This is common in the sense that the water discharged from the impeller is guided to the bearings for lubrication and cooling, but structurally, the lubricating water is introduced from the back surface of the core plate of the centrifugal impeller, and the impeller is Lubrication water is drained from a hole that penetrates the core of the rotating shaft.

When this method is applied to a large-sized pump, it is necessary to make holes in the impeller and the rotating shaft, which is not practical in terms of strength and workability.

[0004]

In the conventional submersible bearing of self-contained water type, since there is no differential pressure between the water supply side and the drainage side of the bearing, the amount of lubricating water entering the bearing gap is insufficient. When the shaft and bearing locally contact and generate heat, the cooling capacity becomes insufficient, causing heat cracks.
As the damage progressed, it sometimes led to breakage.

As a method of preventing this, there has been adopted a method of supporting the bearing with a cushioning material or a split type to prevent one-sided contact.

An object of the present invention is to enhance the cooling effect by increasing the amount of lubricating water, lower the temperature of the sleeve and bush of the bearing, and improve the bearing load capacity.

[0007]

[Means for Solving the Problems] The above object is to introduce water on the discharge side of the pump to the water supply side of the bearing and to guide drainage of the bearing on the suction side of the pump, thereby providing a differential pressure between the supply and drainage of the bearing. It becomes possible by generating.

Further, when the bearing is on the downstream side of the impeller, the water pressure around the housing of the bearing is almost equal to the discharge pressure, so this is guided to the water supply side of the bearing and the drain side of the bearing. It is possible to achieve this by providing a pipe at the end and leading it to the upstream side of the impeller.

[0009]

In the self-contained water type submersible bearing, it is usual to supply the lubricating water from one end surface and discharge the lubricating water from the other end surface. Now, the pressure on the supply side is the discharge pressure Pd of the pump,
If the pressure on the discharge side is the suction pressure Ps of the pump, the difference ΔP between the two is

[0010]

## EQU00001 ## .DELTA.P = Pd-Ps (1)

The flow rate Q of lubricating water flowing through the bearing gap is

[0012]

## EQU2 ## Q = {πdc ³ p ₀ (1 + 1.5ε ² )} / 3ηl (2)

Where d is the shaft diameter, c is the bearing clearance, p ₀ is the feed / drain pressure difference ΔP, ε is the eccentricity, η is the viscosity of the lubricating water, and l
Is the width of the bearing.

From this, it can be seen that the flow rate Q of the lubricating water flowing through the bearing gap increases in proportion to the differential pressure ΔP.

[0015]

EXAMPLE FIG. 1 shows an example of the present invention.

FIG. 1 shows an example of a horizontal mixed flow pump, in which an impeller 1 is mounted on a rotary shaft 2, supported by an inner bearing 3 and an outer bearing 4, and driven by a prime mover via a shaft coupling 5. It is like this.

The inner bearing 3 is attached to a bearing housing 7 contained in a casing 6. A lubricating water pipe is attached to the end face of the bearing opposite to the drive side, and this pipe is connected to the flow path side of the casing 6 on the upstream side of the impeller.

FIG. 2 is a sectional view of a bearing when the bearing of the present invention is adopted as an internal bearing. The bearing outer cylinder 11 has a bush 12 serving as a sliding member fixed therein. Further, it is sealed by an end cover 13 on the opposite side.
A hole is formed in the center of the end cover 13 so as to communicate with the lubricating water pipe.

A sleeve 14 as a sliding member is fitted on the rotary shaft 2 so as to slide between it and the bush 12.

Lubricating water is introduced into the bearing gap 15 through the gap 10 between the impeller 1 and the bearing outer cylinder 11, and is further guided to the lubricating water pipe through the pocket 16.

Next, the effect of this embodiment will be described.

In FIG. 2, since the lubricating water pipe 8 communicates with the suction side of the pump, the pressure in the pocket portion of the internal bearing can be reduced to near the suction pressure of the pump.

The pressure of the lubricating water supplied to the internal bearing is close to the discharge pressure of the impeller.

Therefore, a differential pressure of ΔP = Pd-Ps can be applied between the water supply side and the drainage side of the internal bearing, the amount of lubricating water can be increased, and the effect of cooling the sleeve and bush of the bearing can be improved. And the load capacity of the bearing can be improved.

[0025]

According to the present invention, the amount of bearing lubrication water is increased by self-supplied water by a simple structural change in which the lubrication water pipe is attached to the end face on the opposite drive side of the bearing without adding special equipment such as a water supply pump. It is possible to improve the load capacity and the life of the bearing.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view of an embodiment of the present invention implemented as an internal bearing.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Impeller, 2 ... Rotating shaft, 3 ... Internal bearing, 4 ... External bearing, 5 ... Shaft coupling, 6 ... Casing, 7 ... Bearing housing, 8 ... Lubricating water piping, 9 ... Casing, 10 ... Gap.

Claims (1)

[Claims] 1. A pump comprising an impeller, a power transmission shaft, a bearing, a bearing housing and a casing, wherein the water of its own is used as lubricating water for the bearing, and a pipe on the water supply side of the bearing is connected to the impeller. A self-supplying submersible bearing characterized in that a differential pressure corresponding to the head of the pump is applied between the supply and discharge of lubricating water by connecting the discharge side and the drain side to the suction side of the impeller. .