JPH08296580A - Bearing for rotary pump - Google Patents

Abstract

PURPOSE: To provide a bearing for a rotary pump in which a friction coefficient is small and stable. CONSTITUTION: A bearing 17 for rotatably supporting the rotary shaft 14 of a rotary pump is formed of a ceramic member with independent pores formed by mixing ceramic powder with hollow carbon beads of 5-150μm in diameter and molding and baking this. In this bearing 17, liquid enters into the pores existing on the inner peripheral surface 17c, and a relatively large quantity of liquid is held between the bearing 17 and the rotary shaft 14. At the rotating time of the rotary shaft 14, this liquid acts as a lubricant, so that a friction coefficient is small and stable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary pump bearing such as a canned pump, and more particularly to a rotary pump bearing having a small friction coefficient and a stable coefficient.

[0002]

2. Description of the Related Art FIG. 8 is a sectional view showing a canned pump. The canned pump has a structure in which the electric motor unit 10 and the pump unit 20 are integrated, and the electric motor unit 10 includes an electric motor unit housing 11 and a stator 12 arranged inside the housing 11 in a tubular shape.
And a rotor 15 arranged along the central axis of the stator 12. The rotor 15 is the rotating shaft 1
4 and an iron core 13 in which a conductor is wound. Further, the rotary shaft 14 is provided with flange portions 16a and 16b at positions sandwiching the iron core 13, and outer portions of the flange portions 16a and 16b are fitted into bearings 47 made of ceramics or the like. Are rotatably supported by two bearings 47.

On the other hand, the pump portion 20 is composed of a pump portion housing 21 and a rotating spring 22 attached to the tip portion of the rotary shaft 14 protruding from the electric motor portion 10. In addition, the pipe 23 allows the liquid in the pump to flow through the electric motor unit 1.
0 for supplying to the bearing 47 arranged on the rear side.

In the thus constructed canned pump, the liquid in the pump infiltrates between the rotary shaft 14 and the bearing 47, and the liquid acts as a lubricant when the rotary shaft 14 rotates. Therefore, the coefficient of friction between the rotary shaft 14 and the bearing 47 is relatively small.

A bearing for a rotary pump is required to have high strength, excellent corrosion resistance and wear resistance, and a small coefficient of friction against a rotating shaft and be stable. For this reason, conventionally, the bearing of this type of rotary pump is formed of ceramics or the like as described above.

However, in the bearing of the conventional rotary pump, since the amount of liquid retained between the bearing and the rotary shaft is small, the reduction of the friction coefficient with respect to the rotary shaft is not sufficient and the friction coefficient is stable. There is a problem that it does not exist. Therefore, there is a demand for a bearing that has a smaller friction coefficient and is stable.

By the way, conventionally, a so-called porous ceramic member having pores in the tissue is known as a ceramic member which is lightweight, has excellent wear resistance, and can reduce the friction coefficient. Such a porous ceramics member is manufactured by the method described below.

(1) First Method First, a small amount of a binder is added to a ceramic powder, and the ceramic powder is compacted at a low pressure so as to have sufficient pores inside. Then
This molded body is heated to a predetermined temperature in a predetermined atmosphere and fired. This makes it possible to obtain a low-density ceramic (porous ceramics) member.

(2) Second Method First, a small amount of binder and a large amount of resin are mixed with ceramic powder, and the mixture is molded under high pressure and then fired. During the firing process, the resin becomes gas and scatters from the molded body, resulting in the formation of pores. In this way, a low density ceramic member can be obtained.

(3) Third Method First, a bead-shaped polystyrene resin is mixed with ceramic powder, which is molded under high pressure and then fired. During the firing process, the resin becomes gas and scatters from the molded body, resulting in the formation of pores. In this way, a low density ceramic member can be obtained.

However, if the above-mentioned conventional method for manufacturing a porous ceramic member is applied to a bearing of a rotary pump, there are the following problems.

That is, in the first and second methods,
In both cases, the pores are likely to be continuous, and the pore distribution is not uniform. When a ceramic member having continuous pores is used for the bearing, liquid permeates the bearing and liquid leakage occurs. Therefore, a ceramic member having continuous pores is not suitable as a bearing for a rotary pump. Also, if the pores are continuous,
There is also a problem that the mechanical strength of the ceramic member is significantly reduced and the strength required for the bearing cannot be maintained. It is also possible to reduce the amount of pores to form so-called independent pores in which the pores are not continuous. However, in the first and second methods, since the pores formed at the grain boundaries have a polygonal shape, there is a problem that the strength of the ceramic member is significantly reduced. That is, when a ceramic member having polygonal pores receives an external force or thermal stress, the stress concentrates at the corners of the pores, which becomes the starting point of the destruction, and the ceramic member is destroyed. Further, if the distribution of pores is non-uniform, it will be one of the causes of the large variation in the mechanical properties of the ceramic member, and the reliability will be impaired.

Further, in the third method, a large amount of gas generated by the decomposition of the resin causes cracks inside the material, and the gas reacts with oxygen in the atmosphere to generate carbon monoxide. It may be generated and may hinder the sintering of ceramics.

A first object of the present invention is to provide a rotary pump bearing which has a small friction coefficient and is stable.

A second object of the present invention is to provide a lightweight and high-strength rotary pump bearing.

Further, a third object of the present invention is to provide a bearing for a rotary pump, in which the amount of gas generated during firing is small and the occurrence of cracks can be avoided.

[0017]

A bearing for a rotary pump according to a first aspect of the present invention is a rotary pump in which at least an inner peripheral surface is made of a ceramic member having independent pores, and a rotary shaft rotatably slides on the inner peripheral surface. A bearing of a pump, characterized in that the ceramic member is formed by mixing ceramic powder and hollow beads, and molding and firing the mixture.

A bearing for a rotary pump according to a second aspect of the present invention is a bearing for a rotary pump in which at least an inner peripheral surface is made of a ceramic member having independent pores, and a rotary shaft rotatably slides on the inner peripheral surface. , The ceramic member,
It is characterized in that it is formed by mixing ceramic powder, hollow beads and resin, and molding and firing the mixture.

A bearing of a rotary pump according to a third aspect of the present invention includes a first bearing member that is loosely fitted to a rotary shaft, and a rotary member that is fitted to the rotary shaft and rotates together with the rotary shaft. In the bearing of the rotary pump configured by the second bearing member that slides with the first bearing member, at least one of the sliding surfaces of the first and second bearings is made of ceramic powder. It is characterized in that it is composed of a ceramic member having independent pores formed by mixing hollow beads and molding and firing the mixture.

A bearing of a rotary pump according to a fourth aspect of the present invention includes a first bearing member which is loosely fitted to a rotary shaft, and a rotary shaft which is fitted to the rotary shaft and rotates together with the rotary shaft. In the bearing of the rotary pump configured by the second bearing member that slides with the first bearing member, at least one of the sliding surfaces of the first and second bearing members is a ceramic powder. It is characterized in that it is composed of a ceramic member having independent pores formed by mixing hollow beads and a resin, molding and firing the mixture.

The material of the hollow beads is at least one selected from the group consisting of oxides, carbides, nitrides, borides, composite compounds, carbon and organic substances.
One kind or two or more kinds can be used. The diameter of the independent pores is preferably 5 to 150 μm, and the surface porosity of the ceramic member is preferably 3 to 28%.

[0022]

In the bearings of the rotary pump according to the first and second aspects of the present invention, the inner peripheral surface portion on which the rotary shaft slides is formed by molding and firing a mixture of ceramic powder and hollow beads. It is composed of a ceramic member. Such a ceramic member generates extremely less decomposed gas during the firing process as compared with the case where the conventional solid resin beads are used. Therefore, it is possible to avoid the occurrence of cracks that reduce the strength of the bearing. Further, by uniformly mixing the hollow beads in the ceramic powder beforehand, the independent pores can be uniformly distributed in the member. The material of the hollow beads may be appropriately selected according to the components of the ceramic powder to be the matrix. For example, the hollow beads can be used alone or as a mixture of two or more of those formed of oxides, carbides, nitrides, borides, composite compounds, carbon and organic substances. According to the present invention, a bearing composed of an impermeable ceramic member having various pores as a main component and various ceramics such as oxides, carbides, or nitrides can be obtained.

Further, in the bearing according to the present invention, since the liquid enters the pores existing on the inner peripheral surface, a larger amount of liquid is interposed between the rotary shaft and the bearing than in the conventional case. That is, in the present invention, since a large amount of liquid acting as a lubricant can be interposed between the bearing and the rotary shaft, the coefficient of friction is small and stable. Moreover, the gas in the pores existing in the ceramic member acts as a thermal or mechanical buffer material. Therefore, the bearing according to the present invention,
Excellent thermal shock resistance and shock resistance.

Further, in the third and fourth inventions of the present application, the first bearing member arranged in a state of being loosely fitted to the rotating shaft, and the first bearing member rotating together with the rotating shaft and sliding on the first bearing member. Since at least one sliding surface portion of the second bearing member is formed by a ceramic member having independent pores formed by molding and firing a mixture of ceramic powder and hollow beads, The liquid penetrates into the pores of the sliding surfaces of the first and second bearing members,
And a relatively large amount of liquid is retained between the second bearing member. When the rotary shaft rotates, the liquid existing between the first and second bearing members acts as a lubricant, so that the friction coefficient between the first and second bearing members is small and stable. .

The hollow beads can be formed by utilizing the surface tension of the material such as soap bubbles. When hollow beads are formed by such a method, the beads have a substantially spherical shape. When such hollow beads are used, the pores formed in the ceramic member also become substantially spherical. Therefore, when stress is applied, it is possible to avoid the stress from concentrating at one point, and to avoid a sudden decrease in the strength of the ceramic member. Further, the mixing of the hollow beads has an effect as if the dispersant was added, and the strength of the ceramic member is improved as compared with the case where the hollow beads are not mixed.

By the way, the hollow beads, depending on the material thereof, are weak in strength and cannot withstand the compression molding of commonly used ceramics. In this case, it is preferable to add an appropriate amount of resin, mold at a low pressure not higher than the strength of the hollow beads, and then calcine.

A substance called a sintering aid is usually added to the normal pressure sintering of ceramics. When hollow beads are used as in the present invention, the hollow beads act as a sintering aid. You can also do it.

However, when the diameter of the independent pores is less than 5 μm, the effect of reducing the friction coefficient cannot be sufficiently obtained even if the surface porosity is increased. On the other hand, the diameter of the independent pore is 1
If it exceeds 50 μm, the strength is lowered. For this reason,
The diameter of the independent pores is preferably 5 to 150 μm. If the surface porosity of the ceramic member is less than 3%, the effect of reducing the friction coefficient is not sufficient. on the other hand,
When the surface porosity exceeds 28%, it becomes difficult to secure the sealing property required for the bearing of the rotary pump. Therefore, the surface porosity is preferably 3 to 28%.

[0029]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 is a sectional view showing a bearing of a rotary pump according to a first embodiment of the present invention. Bearing 17
Is formed in a cylindrical shape, and the inner peripheral surface 17c is
Is designed to slide and rotate. The bearing 17 is composed of a ceramic member formed by molding and firing a mixture of hollow beads in ceramic powder, and has spherical independent pores (hereinafter referred to as independent spherical pores) in the tissue. ing. That is, the inner peripheral surface 17 of the bearing 17
Pores are also opened in c and the outer peripheral surface. Hereinafter, an example of manufacturing the bearing of this example will be described.

Production Example 1 First, 15 parts by weight of a phenol resin and 1 part by weight of a release agent (stearic acid) were added to 100 parts by weight of SiC powder having an average particle size of 3.0 μm, and hollow carbon beads ( 2 parts by weight (particle size 50 μm or less) was added and mixed in a small kneader for 2 to 3 hours to obtain a molding material.

Next, using a mold heated to 180 ° C.,
These molding materials were molded under a molding pressure of 500 kg / cm ² and heated at a temperature of 1600 ° C. for 2 hours to carry out reaction sintering in which metallic silicon (Si) and carbon were reacted. Thus, the bearing of the example was manufactured.

FIG. 2 is a diagram showing the structure of the bearing manufactured according to Manufacturing Example 1, and FIG. 3 is a diagram showing the structure of the bearing manufactured according to Manufacturing Example 1 except that hollow beads are not used. As is clear from FIG. 2, in the bearing manufactured according to Manufacturing Example 1, the substantially spherical pores 2 and the metallic Si5 are substantially uniformly dispersed in the SiC4 as the matrix. That is, the carbon beads are converted into SiC and form independent spherical pores 2 in the tissue. On the other hand, as is clear from FIG. 3, in the bearing manufactured without using the hollow beads, although the metal Si5 and the carbon 6 are dispersed in the SiC4 as the matrix, the pores do not exist.

Production Example 2 First, easily sinterable alumina powder 1 having an average particle size of 0.5 μm
To 100 parts by weight, 10 parts by weight of a phenol resin, 1 part by weight of a release agent (stearic acid), 2 parts by weight of hollow glass beads (average particle diameter 15 μm) are added, and a small kneader is used for 2-3 times. A molding material was obtained by mixing for a time.

Next, using a mold heated to 180 ° C.,
This molding material was molded to obtain a cylindrical molded body. The molding pressure at this time is 500 kg / cm ² . Next, these molded bodies were heated in an air atmosphere at a temperature of 1600 ° C. for 2 hours to be sintered. As a result, the bearing of the example was completed.

FIG. 4 is a diagram showing the structure of the bearing manufactured by this manufacturing example 2, and FIG. 5 is a diagram showing the structure of the bearing manufactured in the same manner as manufacturing example 2 except that hollow beads are not used. As is clear from FIG. 4, the bearing manufactured according to Manufacturing Example 2 has substantially spherical independent pores (pores) having a diameter of about 10 to 15 μm in the alumina 1 matrix.
2 had a structure in which it was dispersed almost uniformly, and the surface porosity was about 8%. Further, the bearing of this example showed impermeability to fluid. On the other hand, as is clear from FIG.
In the bearing manufactured without using the hollow beads, remarkable cracks 3 were generated inside.

Production Example 3 First, 0.5 part by weight of B ₄ C powder, 3.0 parts by weight of carbon black powder and 3 parts by weight of polyvinyl alcohol per 100 parts by weight of SiC powder having an average particle size of 0.5 μm. .0
After addition by weight, water was further added and ball mill mixing (2 hours) was performed. Then, 2 parts by weight of hollow polystyrene beads having an average particle diameter of 100 μm were added, and spray drying granulation was performed to obtain a molding material. Then, this molding material was molded and fired to obtain a cylindrical bearing of the example. The bearing manufactured according to Manufacturing Example 3 also had independent spherical pores in the structure.

Production Example 4 First, 5.0 parts by weight of Y ₂ O ₃ powder and Al ₂ O were added to 100 parts by weight of Si ₃ N ₄ powder having an average particle size of 2.0 μm.
5.0 parts by weight of ₃ powders and 20 parts by weight of polystyrene were mixed, and further 3 parts by weight of hollow glass beads (Shirasu balloon) having a diameter of 50 to 150 μm were added and mixed with a small kneader to obtain a molding material. . Then, this molding material was heated to 150 ° C. and injection-molded to obtain a cylindrical molded body.

Next, this molded body was subjected to 1 in a nitrogen gas atmosphere.
Primary sintering was performed by heating at a temperature of 700 ° C. for 4 hours. Then, the primary sintered body was heated to 1850 ° C. and subjected to HIP (hot isostatic pressure) treatment for applying a pressure of 1000 kg / cm ² for 2 hours. Next, this sintered body was subjected to grinding finish processing to obtain a bearing of the example. Also in the bearing manufactured according to Manufacturing Example 4, independent spherical pores were present in the structure.

Although the bearing 17 of the embodiment can be manufactured as in these manufacturing examples 1 to 4, the kinds of the ceramic powder and the hollow beads are not limited to those described in the above manufacturing examples 1 to 4. , Various ones can be used. For example, as the ceramic powder, alumina powder, silicon carbide powder, silicon nitride powder or other ceramic powder is used, and as the hollow beads, oxide, carbide, nitride, boride, complex oxide, carbon and The thing which consists of organic substances etc. can be used.

In this embodiment, since independent spherical pores are present on the inner peripheral surface 17c of the bearing 17, the fluid enters the pores and acts as a lubricant. Therefore, the coefficient of friction with respect to the rotating shaft 14 is extremely small and stable. Further, in this embodiment, since the pores are not continuous, it is possible to avoid the fluid from penetrating into the bearing 17 and to prevent the liquid leakage. Further, in this example, since the hollow beads are used to form the independent spherical pores, the amount of gas generated during firing is small, cracks can be prevented from occurring, and the inhibition of firing by gas is avoided. it can. Furthermore, in this embodiment, since the entire bearing is made of a ceramic member having independent spherical pores, it is not only lightweight, but also stress is concentrated at one point when an external force or thermal stress is applied. Since it can be avoided, the mechanical strength is also high.

In this embodiment, the pore diameter is 5 μm.
When it is less than the above range, the fluid does not penetrate into the pores, so that the effect of lowering the coefficient of friction cannot be sufficiently obtained, and when the diameter of the pores exceeds 150 μm, the strength of the material starts to decrease, which is not preferable. Also, the surface porosity is 3%
If it is less than the above, the effect of lowering the friction coefficient is not sufficient, and if the surface porosity is more than 28%, the fluid is often outflowed and the sustainability of the effect is poor. Therefore, it is preferable that the diameter of the pores is 5 to 150 μm and the surface porosity is 3 to 28%.

In the case of pressureless sintering, the hollow beads can act as a sintering aid by adjusting the sintering conditions. Further, the hollow beads can be formed by utilizing the surface tension of the material such as soap bubbles, and the hollow beads thus formed have a substantially spherical shape. When the hollow beads are made of a material that volatilizes and scatters during firing, it is preferable that the thickness of the hollow beads be thin and the amount of gas generated during firing be small from the viewpoint of crack prevention and prevention of sintering inhibition. It is preferable to reduce the thickness of the beads to 10 μm or less. Further, when the strength of the hollow beads is low as compared with the compression molding of ceramics, a resin may be added together with a small amount of a lubricant, molding may be performed at a low pressure not higher than the strength of the hollow beads, and then firing may be performed.

FIG. 6 is a sectional view showing an example in which the bearing of the first embodiment described above is applied to a canned pump. The canned pump has a structure in which an electric motor unit 10 and a pump unit 20 are integrated, and the electric motor unit 10 includes an electric motor unit housing 11 and a stator 12 arranged inside the housing 11 in a tubular shape. And a rotor 15 arranged along the central axis of the stator 12. The rotor 15 is composed of a rotor core 13 on which a conductor is wound, and a rotary shaft 14 penetrating the rotor core 13, and flange portions 16 a and 16 b are provided on both sides of the core 13. Has been. The rotating shaft 14 has cylindrical bearings 17 on the outer sides of the flange portions 16a and 16b.
And is rotatably supported by these two bearings 17. These bearings 17 are manufactured by the above-mentioned manufacturing example 1.
It is manufactured as described in (4).

On the other hand, the pump portion 20 is composed of a pump portion housing 21 and a rotating spring 22 attached to the tip portion of the rotary shaft 14 protruding from the electric motor portion 10. The pipe 23 is for supplying the liquid flowing in the pump unit 20 to the bearing 17 arranged on the rear side of the electric motor unit 10.

In the thus constructed canned pump, the bearing 17 is made of a ceramic member having independent spherical pores, and the pores are present on the inner peripheral surface. 14 and bearing 17
A relatively large amount of liquid is retained between and. When the rotating shaft 14 rotates, this liquid acts as a lubricant, so that the lubricating action can be reliably obtained, and the friction coefficient is small and stable.

FIG. 7 is a sectional view showing a bearing of a rotary pump according to a second embodiment of the present invention. It should be noted that this embodiment is an example in which the present invention is applied to a thrust bearing.

The thrust bearing 31 (first bearing member) and the thrust bearing 32 (second bearing member) are manufactured as in the above-mentioned manufacturing examples 1 to 4, and are ceramics having independent spherical pores. The member is formed in a hollow disk shape. These thrust bearings 31 and 32 are provided between the fixed side retainer 33 and the rotating side retainer 34.
Both of them are arranged in a state of being fitted to the rotary shaft 38 so as to support the load applied in the axial direction.

The fixed side retainer 33 has a fixing pin 35.
Is fixed to the fixed portion 36 by fitting into holes provided in both the retainer 33 and the fixed portion 36.
The rotating side retainer 34 is fixed to the rotating shaft 38 by a fixing pin 37. Rotating side retainer 3
The hole 34a of No. 4 is set to have a diameter substantially equal to that of the rotating shaft 38. In addition, the rotary shaft insertion hole 33 of the fixed side retainer 33
a is set to be slightly larger than the diameter of the rotary shaft 38.
Then, when the rotary shaft 38 rotates, the sliding surface 32 a of the thrust bearing 32 rotates while sliding on the sliding surface 31 a of the thrust bearing 31.

In this embodiment, the thrust bearing 3
The liquid enters the pores present on the sliding surfaces 31a and 32a of the first and the second bearings 32, respectively, and a relatively large amount of the liquid is retained between the bearings 31 and 32. When the rotary shaft 38 rotates, this liquid acts as a lubricant, so that the thrust bearings 31, 3
The frictional resistance between the two is small and stable. Further, since the thrust bearings 31 and 32 are made of ceramic members, they have excellent corrosion resistance. Furthermore, since the pores are not continuous, it is possible to prevent the liquid from penetrating into the thrust bearings 31 and 32, and there is no risk of liquid leakage.

Manufacturing Example 1 for the bearing according to this embodiment
Was manufactured by and the performance was investigated. That is, the SiC powder, the phenol resin, the release agent (stearic acid) and the hollow carbon beads were mixed in the proportions shown in Production Example 1, molded and fired under the same conditions as in Production Example 1, and the thrust of the Example was obtained. Manufactured bearings. Then, the thrust bearing is used to measure the torque in water and the friction coefficient μ of the bearing is measured.
I asked. However, the rotation speed of the rotating shaft during torque measurement is 60
00r. p. m, load is 50 kg / cm ² , tap water is used as the liquid, and the liquid temperature is 90 ° C.

As a result, the friction coefficient μ of this bearing is 0.0
It was stable at a low value of 1. This is because there are pores on the sliding surfaces 31a and 32a of the two thrust bearings 31 and 32, so that a liquid film is easily formed between the sliding surfaces of the two thrust bearings 31 and 32. It is considered that the liquid film acts as a lubricant.

In this example, when the pore diameter was less than 5 μm, the liquid did not enter the pores, and the effect of lowering the friction coefficient was not sufficiently obtained. Also, the diameter of the pores is 1
When it exceeds 50 μm, the strength of the material starts to decrease, which is not preferable. Further, when the surface porosity is less than 3%, the effect of lowering the friction coefficient is small, and when it exceeds 28%, the sealing property is difficult. Therefore, the diameter of the pores of the ceramic member is 5 to 150 μm, and the surface porosity is 3
It is preferably set to 28%.

[0053]

As described above, according to the present invention, since the sliding surface portion is made of the ceramic member having the independent pores, the permeation of the liquid can be avoided and the liquid enters the pores of the surface. Since this acts as a lubricant, the coefficient of friction is small and stable.

Further, since the ceramic member has the independent pores formed by using the hollow beads, the amount of gas generated at the time of firing is small, cracks can be avoided, and firing is hindered. Can be prevented.

Further, since the bearing of the rotary pump according to the present invention has pores, it is lightweight, and since the pores are substantially spherical, it is possible to avoid concentration of stress at one point when stress is applied. Therefore, the bearing of the rotary pump according to the present invention has high mechanical strength.

That is, according to the present invention, it is possible to provide a bearing for a rotary pump, which can maintain the sealing property for a long time, has a small and stable coefficient of friction, is lightweight, has high strength, and is easy to manufacture.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a structure of a bearing manufactured according to Manufacturing Example 1.

FIG. 3 is a view showing the structure of a bearing manufactured in the same manner as in Manufacturing Example 1 except that hollow beads are not used.

FIG. 4 is a diagram showing a structure of a bearing manufactured according to Manufacturing Example 2.

FIG. 5 is a view showing the structure of a bearing manufactured in the same manner as in Manufacturing Example 2 except that hollow beads are not used.

FIG. 6 is a sectional view showing an example in which the present invention is applied to a canned pump.

FIG. 7 is a sectional view showing a bearing according to a second embodiment of the present invention.

FIG. 8 is a cross-sectional view showing a canned pump.

[Explanation of symbols]

 1 ... Alumina 2 ... Pore 3 ... Crack 4 ... SiC 5 ... Metal Si 6 ... Carbon 10 ... Motor part 11 ... Motor part housing 12 ... Stator 13 ... Iron core 14, 38 ... Rotating shaft 15 ...... Rotor 16a, 16b ...... Flange part 17, 47 ...... Bearing 20 ...... Pump part 21 ...... Pump part housing 22 ...... Rotating spring 31, 32 ...... Thrust bearing 33, 34 ...... Retainer 35, 37 ... Fixing pin

Claims (6)

[Claims] 1. A bearing (17) for a rotary pump, wherein at least an inner peripheral surface (17c) is made of a ceramic member having independent pores, and a rotary shaft (14) rotatably slides on the inner peripheral surface (17c). A bearing for a rotary pump, wherein the ceramic member is formed by mixing ceramic powder and hollow beads, and molding and firing the mixture. 2. A bearing (17) for a rotary pump, wherein at least an inner peripheral surface (17c) is made of a ceramic member having independent pores, and a rotary shaft (14) rotatably slides on the inner peripheral surface (17c). A bearing for a rotary pump, characterized in that the ceramic member is formed by mixing ceramic powder, hollow beads and resin, and molding and firing the mixture. 3. A first bearing member (31) arranged loosely fitted to the rotary shaft (38), and a first bearing member (31) arranged fitted to the rotary shaft (38) together with the rotary shaft (38). A bearing for a rotary pump comprising a second bearing member (32) that rotates and slides on the first bearing member (31), wherein the first bearing member (31) and the second bearing are provided. At least one of the sliding surfaces (31a, 32a) of the member (32) is composed of a ceramic member having independent pores formed by mixing ceramic powder and hollow beads, molding and firing the mixture. A bearing for a rotary pump, which is characterized in that 4. A first bearing member (31) arranged loosely fitted to the rotary shaft (38), and a first bearing member (31) arranged fitted to the rotary shaft (38) together with the rotary shaft (38). A bearing for a rotary pump comprising a second bearing member (32) that rotates and slides on the first bearing member (31), wherein the first bearing member (31) and the second bearing are provided. At least one of the sliding surfaces (31a, 32a) of the member (32) is composed of a ceramic member having independent pores formed by mixing ceramic powder, hollow beads and resin, and molding and firing the mixture. Bearings for rotary pumps. 5. The method according to claim 1, wherein the hollow beads are made of at least one selected from the group consisting of oxides, carbides, nitrides, borides, composite compounds, carbon and organic substances. Bearings for the described rotary pump. 6. The diameter of the independent pores is 5 to 150 μm,
The bearing for a rotary pump according to any one of claims 1 to 5, wherein the ceramic member has a surface porosity of 3 to 28%.