JP2007092978A - Water lubrication bearing device and pump device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water lubrication bearing device capable of obtaining sufficient wear resistance and corrosion resistance even when using a material being comparatively inexpensive and easily worked and to provide a pump device using it. <P>SOLUTION: In this water lubrication bearing device 5 used in the pump device 1, a bearing 52 among a shaft body 51 and the bearing 52 is constituted by a sintered body having the following composition: nickel:16 to 18 wt.%, zinc: 18 to 20 wt.%, graphite: 1 to 5 wt.%, and copper: remaining part. Preferably, it is sintered by adding tungsten particles having average particle diameter of 8 to 16 μm of 1 to 10 wt.%. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a water-lubricated bearing device using water interposed between a shaft body and a bearing that receives the shaft body as a lubricant, and a pump device including the water-lubricated bearing device.

In a pump device that handles water, a water-lubricated bearing device that uses water interposed between a shaft body and a bearing that receives the shaft body as a lubricant is used as a bearing device for rotating an impeller. Such a water-lubricated bearing device is required to have corrosion resistance that does not cause corrosion due to water or a salt contained therein, in addition to wear resistance. For this reason, the bearings are conventionally constituted by ceramics such as alumina, zirconia, and silicon nitride, while the shaft body is constituted by ceramics or a stainless material coated with ceramics such as titanium nitride, titanium carbide, and chromium nitride. Yes. Various types of materials have been studied for bearing devices using liquid as a lubricant, but these do not use water as a lubricant (see, for example, Patent Documents 1 to 5).
JP 2001-192754 A JP 2002-180162 A JP 2002-180163 A JP 2002-180164 A JP 2002-285265 A

  However, ceramics such as alumina, zirconia, and silicon nitride are all expensive and have problems of poor workability and difficulty in obtaining dimensional accuracy.

  In view of the above problems, to provide a water-lubricated bearing device capable of obtaining sufficient wear resistance and corrosion resistance even when using a material that is relatively inexpensive and easy to process, and a pump device using the same. is there.

  In order to solve the above-described problem, in the present invention, in a water-lubricated bearing device using water interposed between a shaft body and a bearing that receives the shaft body as a lubricant, at least one of the shaft body and the bearing. One is characterized by comprising a sintered body containing copper, nickel, zinc, and graphite.

  In the water-lubricated bearing device according to the present invention, at least one of the shaft body and the bearing is made of a sintered body containing copper, nickel, zinc, and graphite. In the sintered body, the graphite is used as a solid lubricant. Demonstrate the function. Moreover, graphite has a characteristic that lubricity is further improved in the presence of moisture, and is suitable for use in a water-lubricated bearing device. Copper, nickel, and zinc alloys have high corrosion resistance. For this reason, according to the present invention, it is not necessary to use ceramics such as alumina, zirconia, and silicon nitride, so that the cost of the water-lubricated bearing device can be reduced and the workability is good. Cheap.

  In the present invention, among the shaft body and the bearing, for example, the bearing is made of the sintered body.

In the present invention, the sintered body has, for example, the following composition: nickel: 16 to 18% by weight
Zinc: 18-20% by weight
Graphite: 1-5% by weight
Copper: Has a balance.

  In the present invention, it is preferable that the sintered body is further sintered by including at least one of tungsten, molybdenum, and tricopper phosphide. Tungsten, molybdenum, etc. are hard and wear-resistant as blended in high-speed steel (high speed), but they are easy to combine with carbon to form carbides, such carbides are hard, High wear resistance. For this reason, when tungsten, molybdenum, or tricopper phosphide is added, overall wear resistance is improved.

  In the present invention, it is preferable that the sintered body is further sintered by containing tungsten particles having an average particle diameter of 8 to 16 μm. In this case, it is preferable that the compounding quantity of tungsten in the said sintered compact is 1 to 10 weight%. In the present invention, a white phase is sintered at a temperature of 900 to 1050 ° C., for example, 950 ° C., because a liquid phase appears at a sintering temperature exceeding 1110 ° C. However, in such a temperature range, tungsten and molybdenum do not bind strongly to the white material. Therefore, if the particle size is too fine, it is easy to fall off by sliding, and the added effect is lost. On the other hand, if the particle size is too large, the surface area ratio becomes small and the effect of addition decreases. Therefore, it is preferable that the average particle diameter of the tungsten particles to be added is 8 to 16 μm.

  In the present invention, the density of the sintered body is preferably 85 to 90% of the true density. Generally, the higher the density, the higher the wear resistance, but in the case of a sintered material, it cannot be increased to the true density. Conversely, lowering the density has the advantage of making it easier to achieve dimensional accuracy. Further, if there is a hole, it becomes a escape place for abrasion powder and the seizure resistance is improved. Therefore, it is preferable that the true density of the sintered body is 85 to 90%.

  The water-lubricated bearing device according to the present invention is used, for example, as a bearing device that rotatably supports an impeller in a pump device. When the bearing device is made of a copper-based material as in the present invention, the vibration absorption capability is high, and thus the water-lubricated bearing device according to the present invention is suitable for use in a pump device.

  In the water-lubricated bearing device according to the present invention, one of the shaft body and the bearing is composed of a sintered body containing copper, nickel, zinc, and graphite, so that it is less expensive than ceramics such as alumina, zirconia, and silicon nitride. In addition, since the workability is good, there is an advantage that dimensional accuracy is easily obtained.

  A water-lubricated bearing device and a pump device to which the present invention is applied will be described below with reference to the drawings.

(overall structure)
FIG. 1 is a half sectional view schematically showing the configuration of a water-lubricated bearing device and a pump device to which the present invention is applied. A pump device 1 shown in FIG. 1 is a water pump that sends water W by the rotation of an impeller 61. A motor chamber is formed on the lower side of the partition wall 3, an upper side is a pump chamber, and an inflow pipe (not shown). ) Is sucked out from an outflow pipe (not shown).

  A stator 4 including a core 41 and a winding 42 is fixed on a substrate 43 in the motor chamber. On the other hand, in the pump chamber, a support shaft 51 (shaft body) whose lower end is fixed to the partition wall 3 is erected, and the rotor 6 is rotatably supported by the support shaft 51.

  The rotor 6 includes a cylindrical bearing 52 supported by a support shaft 51, and the support shaft 51 and the bearing 52 constitute a water-lubricated bearing device 5 that uses water interposed therebetween as a lubricant. Yes.

  An impeller 61 is configured on the rotor 6, and a rotor magnet 62 that is circumferentially opposed to the stator 4 is fixed to the inner peripheral surface of the cylindrical portion of the rotor 6 via the partition wall 3. Therefore, when the winding 42 is energized, the rotor 6 rotates around the support shaft 51 and the impeller 61 pumps the water W.

(Configuration of water-lubricated bearing device)
In the pump device 1 configured as described above, the support shaft 51 and the bearing 52 used in the water-lubricated bearing device 5 are each configured as follows.

First, the bearing 52 has the following composition: nickel: 16 to 18% by weight
Zinc: 18-20% by weight
Graphite: 1-5% by weight
Copper: It consists of a sintered body having a balance. That is, it consists of a sintered body obtained by adding graphite to the same composition (nickel + zinc + copper) as that of Western white. Here, tungsten, molybdenum, or tricopper phosphide may be further added to the sintered body. Of these additives, it is effective to add 1 to 10% by weight of tungsten particles having an average particle diameter of 8 to 16 μm.

  In order to manufacture such a bearing 52, first, the above raw materials are mixed and then formed into a predetermined shape. Next, sintering is performed at a temperature of 900 to 1000 ° C. in an ammonia decomposition gas atmosphere. Then, the sizing process is performed to re-compress to a predetermined shape to adjust the dimensions and the inner surface porous. Next, washing and oil impregnation are performed. The density of the bearing 52 (sintered body) thus formed is 85 to 90% of the true density.

(Main effects of this form)
Thus, in the water-lubricated bearing device 5 used in the pump device 1 of the present embodiment, the bearing 52 is composed of the above-described sintered body, so that sufficient corrosion resistance to water is provided as described in detail in Examples. In addition to providing sufficient wear resistance. In addition, the sintered body is advantageous in that it is easy to achieve dimensional accuracy because it is cheaper than ceramics such as alumina, zirconia, and silicon nitride and has good workability.

  In this embodiment, the pump device 1 having the circumferentially opposed structure has been described. However, the pump device having a surface-facing structure in which the stator and the rotor magnet face each other in the axial direction, or the rotor magnet and the drive magnet are opposed to each other. The present invention may be applied to a magnetic coupling type pump device in which a driven magnet faces through a partition wall.

  The result of evaluating the corrosion resistance and wear resistance of the water-lubricated bearing device under the following conditions will be described. The composition of the white is 63% by weight of copper, 18% by weight of nickel and 19% by weight of zinc.

(Corrosion resistance / salt water immersion test results)
The bearing was immersed in salt water (sodium chloride concentration 5%) for 72 hours with the following materials, and the presence or absence of rust was investigated. As a result, the following results were obtained.

Material Evaluation result Western white A
Western white + graphite 5 wt% A
Western white + graphite 5 wt% + tungsten 5 wt% A
Bronze B
Phosphor bronze C
SUS316 C
SUS410 D
In the evaluation results, “A” is the best, and “B”, “C”, and “D” indicate that the corrosion resistance is lowered.

  As described above, it was confirmed that excellent corrosion resistance was exhibited when using white and white as a base.

(Abrasion resistance)
The following conditions Ring: SUS420J2
Plate: See Table 1 Material White graphite: 2% by weight, 4% by weight
Tungsten particles having an average particle diameter of 2 to 4 μm: 0% by weight, 3% by weight, 5% by weight
Tungsten particles with an average particle size of 8-16 μm: 0% by weight, 3% by weight, 5% by weight
Tricopper phosphide :: 0 wt%, 3 wt%, 5 wt%
In addition to forming a ring and a plate, a Ring-On-Plate test was performed in which a load of 4 kgf / cm ² was applied and rotating at 0.82 m / s, and the change in friction coefficient with time was investigated. The results are shown in FIGS.

  In Table 1, “Gr” represents graphite, “W (1)” represents tungsten particles having an average particle diameter of 2 to 4 μm, and “W (2)” represents tungsten particles having an average particle diameter of 8 to 16 μm. "Cu3P" indicates tricopper phosphide.

As shown in FIGS. 2 to 5, the wear resistance of the materials shown in Table 1 is as follows.
“Western + Gr” B
“Western + Gr + W (1)” B
“Western + Gr + W (2)” A
"Western white + Gr + Cu3P" A
Met. In this evaluation result, “A” is the best, and hereinafter, “B” and “C” indicate that the wear resistance is lowered.

  That is, when graphite is added to the base of white, the wear resistance is improved, and when tungsten particles having an average particle size of 8 to 16 μm are added, the wear resistance is further improved. In addition, wear resistance is greatly improved when graphite is added to the base of white and tricopper phosphide is added.

(Actual machine test with pump device)
The water-lubricated bearing device was configured under the following conditions, and was installed in the pump device shown in FIG.

Bearing dimensions: inner diameter 3.0φ, outer diameter 6.0φ, length 10mm
Inner Diameter Shape: True Flat Metal Shape Inner Porous Property: Area Ratio 20% or Less, Porosity 15 Volume% or Less Clearance with Spindle: 2-5μm
Material: Western white only, Level 1 and Level 9 in Table 1
Level 1: 2% by weight of graphite, the remaining white
Level 9: 2% by weight of graphite, 5% by weight of tungsten (W (2)), the rest of the ocean
White Sintering conditions: Ammonia gas decomposition gas atmosphere, peak temperature 950 ° C, 30 minutes Support shaft SUS420J2 + coating with titanium nitride Lubricant Water

  As a result, in the case of using a bearing composed of only white and white, the friction increased in 100 hours, and the pump device stopped. On the other hand, when a bearing having a composition of level 1 was used, no trouble occurred up to 2000 hours, and the friction increased in 3000 hours. Further, when a bearing having a composition of level 9 was used, no malfunction occurred even after 3000 hours.

(Other examples)
In addition to the above examples, various experiments were conducted by changing the composition. The bearing 52 had the following composition: nickel: 16 to 18% by weight
Zinc: 18-20% by weight
Graphite: 1-5% by weight
Copper: The balance is preferable, and when adding tungsten particles, it was confirmed that the average particle size was 8 to 16 μm and the blending amount was 1 to 10% by weight. In addition to tungsten and tricopper phosphide described in the above examples, it has been confirmed that molybdenum is effective for improving the wear resistance.

It is a half cross-sectional view of a water-lubricated bearing device and a pump device to which the present invention is applied. It is a graph which shows the abrasion-proof test result of the sintered compact of the composition shown to the levels 1 and 2 of Table 1. FIG. It is a graph which shows the abrasion-proof test result of the sintered compact of the composition shown to the levels 3-6 of Table 1. FIG. It is a graph which shows the abrasion-proof test result of the sintered compact of the composition shown to the level 7-10 of Table 1. FIG. It is a graph which shows the abrasion-proof test result of the sintered compact of the composition shown to the levels 11-14 of Table 1. FIG.

Explanation of symbols

1 Pump device 4 Stator 5 Water-lubricated bearing device 6 Rotor 51 Support shaft (shaft body)
52 Bearing 61 Impeller

Claims (8)

In a water-lubricated bearing device using water interposed between a shaft body and a bearing that receives the shaft body as a lubricant,
At least one of the shaft body and the bearing is made of a sintered body containing copper, nickel, zinc, and graphite.   The water-lubricated bearing device according to claim 1, wherein, of the shaft body and the bearing, the bearing is made of the sintered body. 3. The sintered body according to claim 1, wherein the sintered body has the following composition: nickel: 16 to 18% by weight
Zinc: 18-20% by weight
Graphite: 1-5% by weight
Copper: Water-lubricated bearing device characterized by being the balance.   4. The water-lubricated bearing device according to claim 1, wherein the sintered body is further sintered by including at least one of tungsten, molybdenum, and tricopper phosphide.   4. The water-lubricated bearing device according to claim 1, wherein the sintered body is further sintered by adding tungsten particles having an average particle diameter of 8 to 16 μm.   6. The water-lubricated bearing device according to claim 5, wherein the compounding amount of tungsten in the sintered body is 1 to 10% by weight.   7. The water-lubricated bearing device according to claim 1, wherein the sintered body has a density of 85 to 90% of a true density.   A pump device comprising a water-lubricated bearing device as defined in any one of claims 1 to 7.

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