JP2003343480A - Pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pump with improved corrosion resistance, wear resistance or the like of the bearing supporting the rotary body, thereby extending a service life. <P>SOLUTION: A dynamic bearing 8 is made up of a sintered material containing nickel, boron nitride and graphite, and a porosity of 10% or less. The rotary body 3 forcibly sending the liquid containing water is rotatably supported by the dynamic bearing 8. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pump for pumping a liquid such as cooling water under pressure.

[0002]

2. Description of the Related Art In a pump for circulating a liquid, a rotary shaft and an impeller (rotary vane) attached to the rotary shaft are provided in a housing arranged on a circulating flow path of the circulating liquid. There is a type in which a rotator provided with is disposed and the circulated liquid is caused to flow from the inside of the housing into the circulation flow path by rotating the rotator by an electric motor or the like. By the way, in the pump as described above, it is necessary to use the bearing that supports the rotating shaft of the rotating body in a state of being immersed in the liquid in the housing. Conventionally, rolling bearings and slide bearings have been used for such bearings, but when the circulating fluid contains water, corrosion of the bearing fluid may occur if the circulating fluid contains water. As a result, the pump life could be shortened. It has also been proposed to use a bearing in which a bearing component is formed of a ceramic material, but the corrosion resistance to the circulating liquid containing water, the wear resistance in liquid use, and the sliding property are not sufficient. It was difficult to improve the pump life.

In view of the above-mentioned conventional problems, the present invention provides a pump which can improve the corrosion resistance and wear resistance of a bearing that supports a rotating body and thus can prolong the service life. The purpose is to do.

[0004]

A pump of the present invention is provided with a rotary body for pumping a liquid containing water, and a dynamic pressure bearing for rotatably supporting the rotary body using the liquid as a lubricating fluid. At least the bearing surface of the dynamic pressure bearing, while containing nickel, boron nitride, and graphite,
It is characterized by being made of a sintered material having a porosity of 10% or less (claim 1).

In the pump constructed as described above, as the sintered material constituting at least the bearing surface of the dynamic pressure bearing,
By including nickel, boron nitride, and graphite, the inventors of the present invention have found that the corrosion resistance of the bearing, and the wear resistance and sliding characteristics of the rotating body at the start of rotation can be improved. It was Further, the inventors of the present invention reliably prevent the pressure loss from occurring in the dynamic pressure generated between the dynamic pressure bearing and the rotating body by setting the porosity of the sintered material to 10% or less. I found that I can do it.

Further, in the above pump (claim 1),
It is preferable that the sintered material contains 40 to 60% by weight of the nickel and the remaining composition contains the boron nitride and the graphite (claim 2). In this case, by setting the content ratio of nickel to a value within the above range, it is possible to effectively improve the corrosion resistance of the dynamic pressure bearing, and by including boron nitride and graphite in the remaining content ratio, The strength (wear resistance) and lubricity (sliding characteristics) of the bearing can be reliably improved.

Further, the pump (claim 1 or 2) may be provided with a touch-down bearing which rotatably supports the rotating body coaxially with the dynamic pressure bearing (claim 3). In this case, when the pump is started or stopped, the touchdown bearing supports the rotating body, so that the contact of the dynamic pressure bearing with the rotating body can be prevented.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the pump of the present invention will be described below with reference to the drawings. still,
In the following description, a case where an axial flow type pump that circulates cooling water (antifreeze liquid) composed of a mixed liquid of water and ethylene glycol as a liquid containing water in a flow path is exemplified. FIG. 1 is a sectional view showing the structure of a pump according to an embodiment of the present invention. In the figure, a pump 1 of the present embodiment includes a cylindrical housing 2 and a rotating body 3 that pumps the cooling water from the suction port 2a side of the housing 2 to the discharge port 2b side. The housing 2 is arranged in the middle of the flow path, and its suction port 2a and discharge port 2b are connected to a pipe (not shown) forming the flow path.

The rotating body 3 has a rotating shaft 4 having an axial length and an impeller 5 integrally rotatably mounted on an outer peripheral surface 4a of the rotating shaft 4 on one end side thereof. When rotated by the electric motor 7 in the R direction in the drawing, the rotating body 3 introduces the cooling water into the housing 2 through the suction port 2a, and the cooling water is supplied to the housing 2 as shown by an arrow F in the drawing. After flowing through the inside, the cooling water is sent out from the discharge port 2b. The rotating shaft 4 and the impeller 5 are made of a metal having excellent corrosion resistance against cooling water, for example, stainless steel, and have the strength required for the rotating body 3. In addition, a spherical portion 4b is formed at the tip end on the one end side of the rotary shaft 4, and the spherical portion 4b is formed in the housing 2
The rotating body 3 is adapted to rotate in a state of being in contact with the spherical seat 6a of the disk-shaped pivot plate 6 fixed inside. The pivot plate 6 is made of, for example, the above-mentioned stainless steel, and restricts the rotary body 3 from moving to the left side in the drawing when the rotary body 3 pumps cooling water.
Further, the pivot plate 6 is appropriately provided with a plurality of openings 6b for flowing the cooling water along the circumferential direction so as to suppress the decrease in pump efficiency as much as possible.

The electric motor 7 is, for example, a housing 2.
The stator winding 7a arranged outside the housing and the housing 2
And a cylindrical motor rotor 7b fixed inside the rotary shaft 4. More specifically, the motor rotor 7b includes a cylindrical portion 7c into which the rotating shaft 4 is press-fitted, and a plurality of ribs 7d that are equidistantly arranged at predetermined intervals in the circumferential direction between the cylindrical portion 7c. Is attached to the central portion in the axial direction of the rotor 7b so that the cooling water flowing from the one end opening 7b1 of the rotor 7b can have a plurality of ribs 7d.
It is configured to flow out from the other end opening portion 7b2 through each of the above. Also, these motor rotor 7b and cylindrical portion 7
The c and the rib 7d are made of a magnetic material such as iron that has been subjected to anticorrosion treatment with an anticorrosive paint or the like, and ensure the required strength, waterproofness against the cooling water, and corrosion resistance. Then, the electric motor 7 generates a rotating magnetic field by energizing the stator winding 7a,
The rotating body 3 is rotated at a desired rotation speed by the magnetic field action between the rotating magnetic field and the motor rotor 7b made of a magnetic body. In addition to the above description, a resin-molded permanent magnet is provided on the outer peripheral side of the motor rotor 7b, and the rotor 3 is rotated by the interaction between the magnetic field of the permanent magnet and the rotating magnetic field from the stator winding 7a. It may be configured.

The rotating body 3 is composed of a motor rotor 7b.
Is rotatably supported in the housing 2 by a pair of dynamic pressure bearings 8 which are provided so as to sandwich in the left-right direction. The dynamic pressure bearing 8 is made of a sintered material containing nickel, boron nitride, and graphite, has corrosion resistance to cooling water, and the rotating body 3 when the rotating body 3 starts or stops rotating. It is configured to improve wear resistance and sliding characteristics against contact with the rotating shaft 4. In addition, the above-mentioned sintered material has a porosity of 10 after the sintering treatment, which is obtained by the actual density relative to the theoretical density of the sintered material.
% Or less, and is configured to reliably prevent pressure loss from occurring in the dynamic pressure generated in the dynamic pressure generating groove described later.

Concretely speaking, the dynamic pressure bearing 8 comprises 40
-60% by weight of nickel and 60-40% by weight of a mixture of boron nitride and graphite are sintered at a predetermined temperature, and a sizing treatment is performed after this sintering treatment to obtain about 20% of pores. The rate is limited to 10% or less, and the annular fixing portion 8a fixed to the housing 2 is provided concentrically with the fixing portion 8a, and the inner peripheral surface 8b1 has a spiral pattern or a herring. And a ring-shaped dynamic pressure generating portion 8b in which the above-mentioned band-shaped dynamic pressure generating groove (not shown) such as a bone pattern is formed. Further, the dynamic pressure bearing 8 uses the cooling water flowing in the housing 2 as a lubricating fluid, as shown by an arrow F1 in the figure, and the dynamic pressure generating portion 8b.
The rotating body 3 is supported in the radial direction by generating a dynamic pressure according to the rotation of the rotating body 3 between the dynamic pressure generating groove and the rotating shaft outer peripheral surface 4a facing the groove. Although the gap between the dynamic pressure generating portion 8b and the rotary shaft 4 is exaggerated in FIG. 1, the actual size of the gap is set to about several tens of μm, and the dynamic pressure generating portion 8b is shown. Is the outer peripheral surface 4 of the rotating shaft 4.
The above-mentioned dynamic pressure is appropriately generated and the rotating body 3 is stably supported without causing cavitation and abnormal sound and vibration due to the cavitation.
Further, in this dynamic pressure bearing 8, a plurality of openings 8c are equally spaced along the circumferential direction between the fixed portion 8a and the dynamic pressure generating portion 8b.
Are provided, and cooling water is passed through these openings 8c so as to suppress the decrease in pump efficiency as much as possible.

Further, by setting the nickel content in the above sintered material to a value within the above range, the corrosion resistance of the dynamic pressure bearing 8 to cooling water can be effectively improved. Further, by including boron nitride and graphite in the remaining content ratio, the strength (wear resistance) and lubricity (sliding characteristics) of the bearing 8 can be surely improved. still,
If the content of nickel is less than 40% by weight or more than 60% by weight, the corrosion resistance of the dynamic pressure bearing 8 to cooling water decreases. On the other hand, when boron nitride is not added to the rest of the composition, boron nitride is not formed in the sintered material and strength is reduced, so that the wear resistance of the dynamic pressure bearing 8 is reduced. If graphite is not added to the remaining composition, the self-lubricating property cannot be effectively imparted to the sintered material, and the sliding characteristics of the dynamic pressure bearing 8 are deteriorated. Further, when the porosity exceeds 10%, the dynamic pressure bearing 8 has a sparse density structure, and it is not possible to generate and maintain a desired dynamic pressure, and the supporting accuracy of the rotating body 3 is low. descend.

As described above, in the pump 1 of this embodiment, the dynamic pressure bearing 8 is made of a sintered material containing nickel, boron nitride and graphite and having a porosity of 10% or less. It is possible to configure a bearing having excellent corrosion resistance, wear resistance at the start of rotation, and sliding characteristics.
Further, since the porosity is 10% or less, it is possible to reliably prevent pressure loss from occurring in the dynamic pressure generated by the rotation of the rotating body 3, and to support the rotating body 3 in a stable state. it can. As a result, the life of the dynamic pressure bearing 8 and thus the life of the pump 1 can be extended. Further, since the rotating body 3 is supported by the dynamic pressure bearing 8 using the cooling water which is the circulating water of the pump 1 as the lubricating fluid, unlike the case where the rolling bearing in which the grease is filled is used, Grease does not flow out due to infiltration of circulating water, its viscosity does not decrease, and deterioration does not occur, and it prevents contamination of circulating water and deterioration of bearing performance, and is highly environmentally friendly and long-lasting. It is possible to easily configure a pump for cooling the engine or the like that can maintain the rotation accuracy of the rotating body 3 throughout.

According to a verification test conducted by the inventors of the present invention, the rotating body 3 was rotated at 10,000 rpm to obtain 60
Even if a pump that circulates water at a temperature of 0 ° C. is continuously operated for 6 months or longer, no signs of failure have appeared in the dynamic pressure bearing 8 and the pump 1, and it has been proved that the pump life can be significantly extended.

Further, in the above description, the motor rotor 7b
Although the configuration in which the pair of dynamic pressure bearings 8 are provided so as to sandwich in the left and right direction has been described, the present invention uses the dynamic pressure bearings 8 made of the above-mentioned sintered material to pressure-feed a liquid containing water. The configuration of the rotating body 3 such as the shape of the dynamic pressure bearing 8, the number and location of installation, or the shape and number of the impeller 5 is not limited to the above, as long as it rotatably supports 3.

Specifically, instead of the pair of dynamic pressure bearings 8, as shown in FIG. 2, a cylindrical sleeve fixed to the inner peripheral surface of the housing 2 so as to face the outer peripheral surface of the motor rotor 7b. The dynamic pressure bearing 18 may be configured by the member 18a to rotatably support the rotating body 3. Similar to the dynamic pressure bearing 8, the sleeve member 18a is made of the above sintered material containing nickel, boron nitride, and graphite and having a porosity of 10% or less. Has a dynamic pressure generating groove (not shown) for generating a desired dynamic pressure according to the rotation of the rotating body 3 between the opposing outer peripheral surface 7b3 of the motor rotor 7b.
8a1. Note that, in FIG. 2, the gap between the sleeve member 18a and the outer peripheral surface 7b3 is exaggerated and shown, and this gap is about several tens of μm, and the sleeve member 18a is similar to the case shown in FIG. The rotator 3 is stably supported by appropriately generating the dynamic pressure without causing cavitation and abnormal noise and vibration due to the cavitation with the outer peripheral surface 7b3. Further, since the sleeve member 18a is made of the above-mentioned sintered material, the dynamic pressure bearing 18 can obtain the same effect as that of the dynamic pressure bearing 8 shown in FIG.

Further, in this embodiment, as shown in FIG. 2, a pair of impellers 5 are provided inside the motor rotor 7b, and the motor rotor 7b and the rotary shaft 4 are integrally rotatably connected to each other via the impellers 5. In addition, a pair of touchdown bearings 11 that rotatably support the rotating body 3 coaxially with the dynamic pressure bearing 18 are provided in the housing 2. Specifically, one end (outer periphery) side of the impeller 5 is the motor rotor 7b.
Is fixed to the inner peripheral surface side and the other end (inner circumference) is integrally rotatably attached to the outer peripheral surface side of the rotating shaft 4. As a result, the cylindrical portion 7c and the rib 7d shown in FIG. 1 can be omitted, and the impeller 5 can be attached to the motor rotor 7b.
Since it is provided inside the rotor, the rotating body 3, and thus the pump 1
The axial length of can be easily shortened.

The touchdown bearing 11 is made of a cylindrical member made of the sintered material, and the donut-shaped mounting member 1 is made of the sintered material.
It is arranged in the housing 2 via 0. The mounting member 10 includes an annular fixing portion 10a fixed to the housing 2, a ring-shaped portion 10b into which the touchdown bearing 11 is press-fitted and fixed, and the fixing portion 10a and the ring-shaped portion 10.
It is provided with a plurality of openings 10c formed at equal intervals along the circumferential direction with b, and cooling water is passed through the openings 10c to suppress deterioration of pump efficiency as much as possible. Further, the distance between the inner peripheral surface 11a of the touchdown bearing 11 and the outer peripheral surface 4a of the rotary shaft 4 is determined from the distance between the inner peripheral surface 18a1 of the dynamic pressure bearing 18 and the outer peripheral surface 7b3 of the motor rotor 7b. It is set to a small value of about several μm to several tens of μm, and the touchdown bearing 11 regulates the movable range of the rotating body 3 in the radial direction, and at the same time, when the pump 1 is started and stopped, the outer peripheral surface of the rotating shaft 4 is stopped. The contact with the motor bearing 7b of the dynamic pressure bearing 18 is prevented by abutting against the motor rotor 7b.

As described above, in this embodiment, the touchdown bearing 11 is provided and the motor rotor 7 of the dynamic pressure bearing 18 is provided.
Since contact with b is prevented, it is possible to reliably prevent wear and damage due to this contact from occurring in the dynamic pressure bearing 18 and the motor rotor 7b. Also, touchdown bearing 1
1 prevents the contact between the dynamic pressure bearing 18 and the motor rotor 7b. Therefore, even when the dynamic pressure bearing 18 cannot generate a dynamic pressure due to a coolant leak or the like, the bearing 18 and the rotor 7b are stopped. It is possible to prevent the collision with the above, and it is possible to prevent the dynamic pressure generating groove or the like from being deformed or damaged. Further, since the mounting member 10 and the touchdown bearing 11 are made of a sintered material like the dynamic pressure bearings 8 and 18, the corrosion resistance to cooling water can be improved and the rotary shaft 4 of the touchdown bearing 11 can be improved. Wear resistance and sliding characteristics can be improved, and the life of the touchdown bearing 11 and thus the pump life can be extended. Further, even when the touchdown bearing 11 is damaged for the purpose of frequently starting and stopping the pump 1, the pump 1 can be continuously used if only the touchdown bearing 11 is replaced. Further, since the rotary body 3 is rotatably supported by the dynamic pressure bearing 18 that faces the outer peripheral surface 7b3 of the motor rotor 7b, the axial length of the pump 1 can be made smaller than that using the pair of dynamic pressure bearings 8. The touchdown bearing 11 can be easily provided in the housing 2 without lengthening.

In the above description, the case where the present invention is applied to the axial flow type pump for circulating the cooling water has been described. However, the present invention is pure water such as distilled water or liquid such as aqueous solution containing chemical substances. It can be suitably used for various pumps such as an electric water pump having a rotating body that pumps the liquid and a dynamic pressure bearing that rotatably supports the rotating body by using this liquid as a lubricating fluid. Further, the dynamic pressure bearing in the present invention includes a bearing having no dynamic pressure groove, a slide bearing and a step bearing.

Further, in the above description, the spherical portion 4b is provided at the tip end on the one end side of the rotating shaft 4, and the rotating body 3 is rotated with the spherical portion 4b being in contact with the spherical seat 6a of the pivot plate 6. Although the configuration has been described, the present invention is not limited to this. For example, the tip portion of the rotating shaft 4 is formed into a circular cross section without providing the spherical portion 4b, and instead of the spherical seat 6a, a herringbone shape or the like is formed on the axial end surface of the pivot plate 6 facing the rotating shaft tip portion. When a groove for dynamic pressure generation is formed and the rotor 3 pumps cooling water by the dynamic pressure generated by the groove,
2, while restricting the movement to the left side of the rotary body 3 in the axial direction.
It may be configured to support. When the rotating body 3 is axially supported by the pivot plate 6 as described above, the pivot plate 6 or the spherical portion 4b is made of the above-mentioned sintered material like the dynamic pressure bearings 8 and 18, so that the pivot plate 3 is supported. 6, the pump life can be easily extended. In each of the above-mentioned embodiments, the case where the dynamic pressure bearings 8 and 18, the pivot plate 6 and the like are entirely formed of the sintered material has been described. However, at least the bearing surfaces of the dynamic pressure bearings 8 and 18 and the pivot plate are shown. If at least the end face in the axial direction such as 6 is made of the above-mentioned sintered material, a desired effect can be exhibited. That is, a configuration may be adopted in which the parts other than the bearing surface and the like are made of a member made of another material, and the bearing surface made of the sintered material is fixed and engaged with the member.

[0023]

The present invention constructed as described above has the following effects. According to the pump of claim 1, nickel,
Since the sintered material containing boron nitride and graphite constitutes at least the bearing surface of the dynamic pressure bearing that rotatably supports the rotating body, the corrosion resistance of the bearing and the rotating body at the start of rotation, etc. It is possible to improve wear resistance and sliding characteristics. Moreover, the porosity of the sintered material is 10%.
Since the following is set, it is possible to constantly generate and maintain a desired dynamic pressure between the dynamic pressure bearing and the rotating body, and to improve the corrosion resistance of the bearing, etc. The bearing can be supported with high precision, and the life of the bearing and eventually the life of the pump can be extended.

According to the pump of claim 2, since 40 to 60% by weight of nickel is contained in the sintered material, the corrosion resistance of the dynamic pressure bearing can be effectively improved and the remaining Since 60 to 40% by weight is composed of a mixture of boron nitride and graphite, the wear resistance and sliding characteristics of the bearing can be reliably improved.

According to the pump of claim 3, the touchdown bearing can support the rotating body at the time of starting or stopping the pump to prevent the contact of the dynamic pressure bearing with the rotating body. Can be reliably prevented from occurring in the dynamic pressure bearing and the like, and the life of the bearing and the pump can be extended.

[Brief description of drawings]

FIG. 1 is a sectional view showing a configuration of a pump according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a configuration of a pump according to another embodiment.

[Explanation of symbols]

1 pump 3 rotating bodies 8,18 Dynamic bearing 11 Touchdown bearing

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masayoshi Onishi             3-5-8 Minamisenba, Chuo-ku, Osaka Koyo             Within Seiko Co., Ltd. (72) Inventor Yuichi Takii             3-5-8 Minamisenba, Chuo-ku, Osaka Koyo             Within Seiko Co., Ltd. F term (reference) 3H022 AA01 BA06 CA11 CA51 DA13                 3J011 AA11 BA02 DA02 SB15 SE05

Claims (3)

[Claims] 1. A pump provided with a rotary body that pumps a liquid containing water under pressure, and a dynamic pressure bearing that rotatably supports the rotary body using the liquid as a lubricating fluid, at least the dynamic pressure bearing. A pump characterized in that the bearing surface is made of a sintered material containing nickel, boron nitride, and graphite and having a porosity of 10% or less. 2. The sintered material contains 40 to 60 of the nickel.
The pump according to claim 1, wherein the pump contains the weight% and the boron nitride and the graphite are included as the rest of the composition. 3. The pump according to claim 1, further comprising a touchdown bearing that rotatably supports the rotating body coaxially with the dynamic pressure bearing.