JP2001263290A - Pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pump capable of ensuring sufficient load resistance property with respect to a bearing, prevent both failures of a main shaft and the bearing even if uneven contact is generated, utilizing pumping liquid as lubricating water, and carrying out a stable operation for a long period, in the pump wherein the bearing is disposed in a pumping water passage and the pumping water is used as bearing lubricant. SOLUTION: In the pump wherein pumping water is used for bearing lubricant, the synthetic resin made bearing is housed in the bearing part, a foreign matter separating means opened to the pumping water passage is disposed in the vicinity of one end of the bearing part, and a cylindrical negative pressure generating mechanism having a prescribed length is disposed around the bearing casing for leading pumping water having passed the foreign matter separating means to a sliding surface of the bearing part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a vertical and horizontal axis type pump used as a pump for draining rainwater, for example, which deals with pumping containing foreign matters and lubricates bearings. The present invention relates to the improvement of this kind of pump used as an agent.

[0002]

2. Description of the Related Art Pumps of this type are available in both a vertical axis and a horizontal axis, and ceramic bearings having excellent wear resistance and capable of using pumped liquid as lubricating water have been widely used as bearings. An elastic support structure is often used for ceramic bearings from the viewpoint of avoiding damage caused by contact. For example, Japanese Patent Application Laid-Open No. 8-338425 discloses that the outer periphery of a sleeve is coated with cemented carbide or ceramics, the sliding portion of the bearing is also coated with cemented carbide or ceramics, and both ends of a bearing are provided in the bearing housing at both ends in the axial direction of the bearing. There is disclosed a configuration in which a lubricating water supply space and a lubricating water discharge space are provided, and a stirring member is provided in the lubricating water supply space so as to rotate integrally with a rotating shaft and supply lubricating water to a sliding portion and a slit. The stirring member includes an annular flow path that is introduced along the axial direction by rotation, and a plurality of radial flow paths that communicate with the annular flow path and discharge circulating water to the outer peripheral side by centrifugal force.

[0003]

In the above-mentioned prior art,
Although it is described that a ceramic bearing is used, during operation, when the sleeve is eccentrically inclined in the direction of action of the fluid force, the bearing portion tries to follow the sleeve, but does not immediately tilt due to the inertia force of the bearing portion, First, if the lower end surface (or upper end surface) of the bearing portion comes into contact with the sleeve, and the one-sided contact state is strong, both the sleeve and the bearing may be damaged, resulting in breakage. Further, since the elastic support structure is employed, the number of parts is large and the cost is high as compared with the rigid support structure.

[0004] In addition, the structure is such that water is supplied to the bearing surface by centrifugal force to lubricate the drainage water. In this configuration, however, a water supply port must always be provided on the upstream side of the flow. The degree of freedom is reduced, and when mounted in the opposite direction, the lubrication effect may be significantly reduced.

As described above, in the above bearing structure,
Sufficient consideration was not given to high reliability for long-term use.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to ensure a sufficient load-bearing capacity for a bearing. An object of the present invention is to provide a pump of this type which can prevent both of them from being damaged and can operate stably for a long period of time by using pumped water as a lubricant.

[0007]

In order to achieve the above object, in a pump using pumping water as a lubricant for a bearing, the bearing portion is formed of a resin bearing, and is provided near one end of the bearing portion. It has a foreign matter separating means opening to the pumping passage, and a negative pressure generating mechanism for feeding or introducing the pumped water passing through the foreign matter separating means to the sliding surface of the bearing portion.

In a drain pump having such a bearing device, since a thermoplastic resin is contained in a bearing portion, a stable low friction coefficient can be obtained up to a high load region under water lubrication. This is because in the high load area, even if water film breakage occurs locally, the sliding surface of the bearing softens and flows easily,
This is because when the flow becomes smooth, the flow ends, and the flow is stabilized in a familiar state.

Further, since the thermoplastic resin flows easily at the local contact portion, the main shaft side is not damaged. Further, foreign matter separating means opening into the pumping passage near one end of the bearing portion,
And by providing a negative pressure generating mechanism for introducing the pumped water that has passed through the foreign matter separating means to the sliding surface of the bearing portion, the bearing sliding surface is lubricated with the pumping liquid containing almost no foreign matter and is not damaged, Long-term stable sliding characteristics can be obtained. As a result, it is possible to provide a pump of this type which can operate stably for a long period of time by using the pumped liquid as lubricating water.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. Here, the case of a pump using a thermoplastic resin for the bearing will be described, but the material of the resin is not particularly limited.

Here, a description will be given of a negative pressure generating mechanism introduced into the bearing sliding surface of the pumped water that has passed through the foreign matter separating means. The position where the negative pressure generating mechanism is provided is not particularly limited. Furthermore, here, the case where the bearing is in the pumping channel will be described. However, the case where the bearing is provided other than the pumping channel may be used, and the mounting position of the bearing is not particularly limited.

FIG. 1 shows a first embodiment of the present invention.
This drawing particularly shows the periphery of a bearing device of a pump provided with a negative pressure generating mechanism. The pump has a pump casing 2 and
It comprises a resin bearing device 3 attached to the pump casing 2 and blades (not shown) fixed to the lower end of the main shaft 1. The arrows in the figure indicate the flow direction of the pumped liquid. At one end (downstream side) of the resin bearing device 3 is provided a foreign matter separating means 4 constituted by an annular member 4 a provided so as to surround the outer periphery of the main shaft 1. A plurality of radial communication holes 5 are provided on the bearing side of the annular member 4a. At the other end (upstream side) of the resin bearing device 3, there is provided a negative pressure generating mechanism 7 fixed to the main shaft 1 and configured by a cylindrical member 7 a provided so as to surround the bearing casing 6.

Next, the operation of this embodiment in the above configuration will be described. Although the result of the material sliding test will be described later, since the thermoplastic resin is contained in the bearing portion, a stable low friction coefficient can be obtained up to a high load region under water lubrication. This is because, in a high load region, even when a water film break occurs locally, the sliding surface of the bearing softens and easily flows, and when the surface becomes smooth, the flow ends, and the bearing is stabilized in a conformed state. Further, since the thermoplastic resin easily flows at the local contact portion, the main shaft side is not damaged. On the other hand, the gap 8 between the annular member 4a and the spindle 1
The pumped liquid supplied from the container contains foreign matter, and is supplied to the separation unit 8a while being stirred with the rotation of the main shaft 1. In the separation section 8a, the pumped liquid rotates with the rotation of the main shaft 1 because the pumped liquid has viscosity. At this time, the centrifugal force F = mr
ω ² (where m is mass, r is radius, and ω is angular velocity) acts. Therefore, the foreign matter flows on the inner peripheral side wall surface of the annular member 4a by the effect of the centrifugal force. The foreign matter is discharged to the outer peripheral side from the communication hole 5 provided in the annular member 4a. In this way, the pumped liquid near the end face of the resin bearing 3 on the outer periphery of the main shaft 1 becomes a fluid containing almost no foreign matter.

The other end (upstream side) of the resin bearing device 3 is fixed to the main shaft 1, surrounds the bearing casing 6, is open on the opposite side of the fixed end, and has a cylindrical member 7a having a predetermined length in the axial direction. Is provided. The bearing casing 6 is stationary even when the main shaft 1 rotates. By the rotation of the main shaft 1, a swirling flow is given to the fluid stored inside the tubular member 7a. A part of the fluid is discharged from the opening into the pump casing 2 by the action of the swirling flow. At this time, 7c near the lower end of the bearing
Thus, the static pressure in the vicinity of the outer periphery of the main shaft 1 is reduced as compared with a case where the spindle 1 does not rotate. Therefore, a part of the pumped water that has passed through the foreign matter separating means 4 is guided to the gap between the main shaft 1 and the resin bearing 3 to lubricate the bearing. When the rotational force is constant, the diameter of the bearing casing,
A gap between the inner diameter of the upper cylinder member 7a and the outer periphery of the bearing casing,
By appropriately selecting the length and the length, the generated static pressure can be arbitrarily determined.

Further, the foreign matter flowing into the gap is extremely smaller than the thickness of the water film and does not break the water film, so that it does not affect the fluid lubrication. here,
Although the case where the lubrication groove 9 is provided on the bearing sliding surface has been described, the presence or absence of the lubrication groove is not particularly limited.

As described above, since the bearing sliding surface is lubricated with the pumping liquid containing almost no foreign matter, sufficient load resistance for long-term use is ensured and stable sliding characteristics are obtained.
As a result, it is possible to provide a drain pump of this type that can operate stably for a long period of time by using the pumped liquid as lubricating water.

In order to confirm the effect of using the thermoplastic resin material for the bearing portion of the present invention, a ring (rotating material) and a plate shape (fixed material, radiation grooves 6 for water lubrication) were used for various materials.
A sliding element test was conducted using the combination of the present invention and the limit surface pressure and the damage of the sliding surface were examined. From the viewpoint of load resistance, the target value of the critical surface pressure is 5 MPa or more. Table 1 shows the results.

<Operating conditions> Circumferential speed: 5 m / s constant, Surface pressure: Until the load at which the friction coefficient starts to rise sharply, Sliding time: About 15 to 30 minutes at each load

[0019]

[Table 1]

The cemented carbide film and cemented carbide solid are nickel binder cemented carbides having corrosion resistance. PEEK resin was used as the thermoplastic resin.

As shown in Table 1 above, the test pieces No. 1
The combination of the present invention has the highest critical surface pressure. In addition, almost no damage was observed on the sliding surface after the test on both the rotating side and the fixed side. Test piece No. The critical surface pressure in the combination of the test pieces No. However, the sliding surface after the test showed almost no damage on both the rotating side and the fixed side.

On the other hand, for comparison, cemented carbide solid and S
Table 1 shows the characteristics of the combination with iC (conventional example). Test piece No. The critical surface pressure in the combination of No. 3 is N
o. Although the values are the same as those of the combination No. 2, slight damage was recognized on both the rotating side and the fixed side when the sliding surface after the test was observed.

As described above, when a PEEK-based resin is used for the bearing, in combination with a cemented carbide having corrosion resistance or double-layer stainless steel (Vickers hardness: 600 or more), both the rotating side and the fixed side are used. It was found that damage could be prevented.

The material for forming the thermoplastic resin layer is P
An EEK (polyetheretherketone) resin is preferably mixed with carbon fibers. When carbon fibers are mixed, the mechanical strength is improved. Since the thermoplastic resin does not change its shape due to swelling, the initial bearing sliding surface shape can be maintained for a long period of time, so that the reliability for long-term operation is significantly improved.

FIG. 2 shows a second embodiment of the present invention. The difference between the present embodiment and FIG.
0 is provided. A SUS304 sleeve 10 is mounted on the main shaft 1, and the sleeve 10 is fixed to the main shaft 1 by a detent (not shown), and the surface of the sleeve 10 is coated with a corrosion-resistant cemented carbide film 10a. . It goes without saying that even with such a configuration, the same operation and effect can be obtained. The present embodiment has the following effects. Should the surface 10a of the sleeve be damaged, only the sleeve 10 needs to be replaced, and the replacement cost can be reduced as compared with the case where the spindle itself is replaced. Also, as can be seen from Table 1, the corrosion-resistant cemented carbide coating 10
Since a is constructed, it is hardly damaged and the surface is hardly deformed, so that the load resistance is also improved. In addition, because the combination of cemented carbide and thermoplastic resin has good conformability,
The roughness of the sliding surfaces of the sleeve and the bearing becomes small and smooth. Therefore, the formation of the water film becomes good immediately after the start, and the load resistance is improved.

FIG. 3 shows a third embodiment of the present invention. The difference between this embodiment and FIG. 2 lies in that the foreign matter separating means 4 provided at one end of the thermoplastic resin bearing portion is provided on the upstream side, and the negative pressure generating mechanism 7 provided on the other end is provided on the downstream side. . The negative pressure generating mechanism 7 is fixed to the main shaft 1 and rotates with the main shaft 1.
b. In the case of such a configuration, since the generated negative pressure is smaller than that of the previous embodiment, it is better to install the negative pressure downstream of the flow. This embodiment has the following effects. By providing the annular member 4a on the upstream side, in the vicinity of the entrance 11 of the annular member 4a, a large foreign matter having a high flow velocity along the shape of the side surface of the pumping channel of the annular member 4a flows in this direction,
Large foreign matter hardly flows into the inside of the annular member 4a.

FIG. 4 shows a fourth embodiment of the present invention. In this drawing, a negative pressure generating mechanism is provided in a horizontal shaft type pump.
Pumps are pump casing 2a and pump casing 2
and a blade (not shown) fixed to the left end of the main shaft 1. The arrows in the figure indicate the flow direction of the pumped liquid. At one end (downstream side) of the resin bearing device 3 is provided a foreign matter separating means 4 constituted by an annular member 4 a provided so as to surround the outer periphery of the main shaft 1. A plurality of radial communication holes 5 are provided on the bearing side of the annular member 4a. The main shaft 1 is connected to the other end (upstream side) of the resin bearing device 3.
And a negative pressure generating mechanism 7 composed of a cylindrical member 7a provided so as to surround the bearing casing 6. A SUS304 sleeve 10 is mounted on the main shaft 1. The sleeve 10 is fixed to the main shaft 1 with a rotation stopper (not shown), and the surface thereof is coated with a corrosion-resistant cemented carbide film 10a. It goes without saying that even with such a configuration, the same operation and effect can be obtained.

The present embodiment has the following effects. In the horizontal shaft type pump, the pump casing is filled with the pumping liquid by the vacuum pump before starting, but if the structure is difficult to discharge, the pumping time will be prolonged, which is problematic. Since the part 3, the foreign matter separating means 4, and the negative pressure generating mechanism 7 are all open and have no air pockets and can be easily evacuated, the evacuation time can be reduced.

FIG. 5 shows a fifth embodiment of the present invention. The difference between this embodiment and FIG. 2 is that a rectifying cylinder 12 is provided downstream of the foreign matter separating means 4 and a plurality of holes 13 are provided for communicating the inside of the rectifying cylinder 12 with the foreign matter separating portion. On the point.
It goes without saying that even with such a configuration, the same operation and effect can be obtained. The present embodiment has the following effects. By providing the rectifying cylinder 12, in the foreign matter separating means 4 constituted by the annular member 4a, large foreign matter discharged into the water pumping passage from the radial communication hole 5 provided on the bearing side of the annular member 4a is reduced to the main flow of the pumped liquid. At the same time, it can be reliably prevented from drifting near the entrance of the annular member 4a and reentering the foreign matter separating portion 8a, so that high reliability can be achieved. The holes 13 are provided for discharging foreign matter deposited inside the flow straightening cylinder, and are reliably discharged into the water pumping channel via the foreign matter separating portion, so that stable separation performance can be maintained for a long time.

FIG. 6 shows a sixth embodiment of the present invention. The difference between this embodiment and FIG. 2 is that the present embodiment uses a rotary force of the pumped liquid to convert the liquid into a swirling flow in a foreign matter separating portion constituting the foreign matter separating means 4 provided on the downstream side of the thermoplastic resin bearing portion. That is, a plurality of swirling blades 14 are provided and a swirling flow holding unit 15 is provided. Due to the rotation of the main shaft 1, the viscous pumped liquid rotates, and the swirling blades 14 accelerate the radial velocity and convert it into a swirling flow. The generated swirl flow is maintained by the swirl flow holding unit 15. For this reason, the large foreign matter is pushed to the outer peripheral side 15a of the swirling flow holding part 15, and the inner peripheral side becomes the pumped liquid containing almost no foreign matter. It goes without saying that even with such a configuration, the same operation and effect can be obtained. The present embodiment has the following effects. Since it is converted into a swirling flow utilizing the rotational force of the pumped liquid, it is possible to separate even small foreign substances.

FIG. 7 shows a seventh embodiment of the present invention. The difference between this embodiment and FIG. 2 lies in that a flinger 16 is provided on the main shaft side downstream of the foreign matter separating means 4. It goes without saying that even with such a configuration, the same operation and effect can be obtained. The present embodiment has the following effects. Since large foreign matter can be scattered in the radial direction at the flinger 16, large foreign matter can be removed from near the upper part of the annular member constituting the foreign matter separating means. Further, although the pumped liquid in the pump casing falls immediately after the pump stops, the flinger prevents foreign matter from directly entering the inside of the annular member. Therefore, it is possible to prevent foreign matters from being deposited inside the annular member.

[0032]

As described above, in a pump having such a bearing device, since a thermoplastic resin is housed in the bearing portion, a stable low friction coefficient up to a high load region under water lubrication is obtained. Obtained and have sufficient load bearing capacity. In addition, even if one-side contact occurs, the thermoplastic resin easily flows at the local contact portion, so that the main shaft side is not damaged. Since the thermoplastic resin does not swell, the initial bearing clearance can be reduced.
High rigidity of the bearing can be achieved. Furthermore, by providing a foreign matter separating means opening into the pumping passage near one end of the bearing portion and a negative pressure generating mechanism near the other end to guide the pumped water after the foreign matter separation to the bearing sliding surface, the bearing sliding surface is provided. Is lubricated with a pumping liquid containing almost no foreign matter, so that sufficient load resistance can be secured for long-term use, and stable sliding characteristics can be obtained. As a result, it is possible to provide a pump of this type that can operate stably for a long period of time by using the pumped liquid as lubricating water.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of a vertical axis pump according to the present invention.

FIG. 2 is a sectional view showing a second embodiment of the vertical axis pump according to the present invention.

FIG. 3 is a sectional view showing a third embodiment of the vertical axis pump according to the present invention.

FIG. 4 is a sectional view showing a fourth embodiment of the horizontal shaft pump according to the present invention.

FIG. 5 is a sectional view showing a fifth embodiment of the vertical axis pump according to the present invention.

FIG. 6 is a sectional view showing a sixth embodiment of the vertical axis pump according to the present invention.

FIG. 7 is a sectional view showing a seventh embodiment of the vertical axis pump according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Main shaft, 2 ... Pump casing, 3 ... Resin bearing device,
4: foreign matter separating means, 5: communication hole, 6: bearing casing,
7: Pumping means, 7a: cylindrical member, 8a: foreign matter separating portion, 4a: annular member, 10: sleeve, 10a: cemented carbide, 12: rectifying cylinder, 14: turning blade.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hideki Akiba 603, Kandamachi, Tsuchiura-shi, Ibaraki Pref. Industrial Machinery Systems Division, Hitachi, Ltd. F-term in the Industrial Machinery Systems Division, Ritsusei Works 3H022 AA01 BA06 CA17 CA46 CA54 DA04 3H071 AA01 CC26 CC27 CC41 DD31 DD46 DD89 EE01 EE07 3J011 BA02 JA02 KA02 MA21 MA23 SC01

Claims (4)

[Claims] 1. A pump using pumping water as a lubricant for a bearing, wherein a resin bearing is housed in the bearing section, and foreign matter separating means is provided near one end of the bearing section, the foreign matter separating means being open to a water pumping passage. A pump provided with a negative pressure generating mechanism for introducing pumped water having passed through the means to a sliding surface of the bearing portion. 2. A pump in which a bearing is provided in a pumping passage and pumping water is used as a bearing lubricant, wherein a resin bearing is used for the bearing portion, and foreign matter separating means opening to the pumping passage is provided near one end of the bearing portion. A pump provided with a negative pressure generating mechanism for introducing pumped water passing through the foreign matter separating means to a sliding surface of the bearing portion. 3. The pump according to claim 1, wherein said negative pressure generating mechanism comprises a cylindrical member having one end fixed to a rotary shaft of the pump and the other end open, and surrounding the outer periphery of a casing of said bearing. A pump characterized by being made. 4. A pump having a bearing in a pumping passage and using pumped water as a bearing lubricant, wherein a resin bearing is used for the bearing portion, and foreign matter separating means opening into the pumping passage near one end of the bearing portion. A pump provided with a cylindrical member that rotates together with the pump main shaft so as to accommodate a bearing casing near the other end of the bearing portion.