JP3983749B2 - Magnet coupling pump - Google Patents

Description

  The present invention relates to a magnetic coupling type pump that transmits a rotational force of an electric motor to a rotating body such as a rotor or an impeller via a magnetic coupling. More specifically, the present invention relates to an improvement in a bearing structure for rotatably supporting a driven shaft (rotating shaft) of a driven inner magnet portion to which a motor side output (rotational force) is transmitted from a driving outer magnet portion via a magnetic force. .

  For example, among the uniaxial eccentric screw pumps, the magnetic coupling type uniaxial eccentric screw pump does not have a shaft sealing portion between the motor side output shaft and the rotor side driven shaft, and is constituted by the partition member 9 (see FIGS. 4 and 5). Since it is completely blocked, there is no fear of liquid leakage, so it is mainly used for transferring chemicals.

  Conventionally, for example, as shown in FIG. 4, a double-end support structure is adopted in which bearings 20 and 23 for supporting the driven shaft 14 are arranged on the front and rear sides of the inner ring side magnet 13a. In the case of this structure, since the front and rear bearings 20 and 23 are in contact with the transfer liquid, sleeve bearings are generally used for the bearings 20 and 23. Since this structure is supported at both ends, the allowable radial load on the driven shaft 14 is increased.

  Further, as shown in FIG. 5, a cantilever support structure is employed in which the bearing 20 that supports the driven shaft 14 is disposed only in front of the inner ring side magnet 13a. Also in this structure, a sleeve bearing is used because the bearing 20 is in contact with the transfer liquid. In addition, this structure is simplified and can be reduced in size, but the allowable radial load is significantly reduced at the same size compared to the both-end support structure. For this reason, in order to cope with the load at the same level as the both-end support structure, the size must be increased. 4 and 5, reference numeral 9 is a partition member, 11 is a drive shaft, and 12a is an outer ring side magnet.

According to the prior art, a rear thrust bearing member is disposed so as to be slidable in contact with the shaft end surface of the spindle along the axial direction facing the shaft end surface of the spindle, and a support portion for supporting the rear thrust bearing member is disposed on the rear side of the impeller. Or the structure of the rear thrust bearing in the magnet pump provided in the front side of the driven rotary body is proposed. On the projecting portion of the spindle of this pump, a magnet driven rotating body is cantilevered rotatably via a sleeve bearing (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 7-12084 (paragraph numbers 0008, 0010, 0013 and FIGS. 1 and 2)

  The above-described conventional magnet coupling type uniaxial eccentric screw pump has the following structural and material problems.

1. Structural issues When the radial load is large, the sleeve bearing part, which is the bearing part of the magnetic coupling, becomes larger, which causes an increase in the size of the magnetic coupling itself, which is a major factor that hinders downsizing and space saving of the pump as a whole. It has become.

    a) As described above, when the double-end support structure is adopted when the radial load is large, a sleeve bearing is usually installed on the partition member at the rear of the pump, which is structurally large and heavy. In addition, in order to ensure the concentricity of the partition wall member and its related parts, extremely high processing accuracy is required, requiring skill in processing, taking time and labor, and increasing the cost of parts.

    b) On the other hand, when a cantilever support structure is adopted, the structure is simplified. However, if the size is the same as that of both ends, the allowable load of the sleeve bearing is reduced. This leads to an increase in the size of parts and increases the part cost.

2. Material issues Select materials that satisfy corrosion resistance (chemical properties), sliding properties (mechanical properties), and strength (mechanical properties) for the rotating and stationary components of the sliding part of the sleeve bearing. There is a need to. As described above, when the sleeve bearing is used particularly in contact with a chemical solution, it is common to use a corrosion-resistant metal material such as stainless steel, titanium alloy, or Hastelloy as the material.

    a) When using a corrosion-resistant metal material in contact with the chemical solution, it will not corrode at room temperature unless the selection is correct, but the chemical solution may be affected by physical or chemical action such as local heat generation at the sliding part of the sleeve bearing. There is a risk that the local corrosiveness (chemical aggressiveness) increases, and the sliding portion is subject to corrosion deterioration or wear deterioration.

    b) Even when the surface of a corrosion-resistant metal material is subjected to thermal spraying, plating, diffusion hardening, etc., the local corrosion resistance of the chemical solution is still increased, and the problem of sleeve bearing wear and surface peeling cannot be avoided. .

    c) Magnet coupling type single-shaft eccentric screw pumps are often used as chemical injection pumps for disinfection and pH adjustment in water treatment processes at water purification plants, etc. ). For this reason, there is a demand for absolute life and reliability of this type of pump.

  The present invention has been made in view of the above-mentioned points, and can solve the above-mentioned structural problems and material problems, and provides a magnet coupling type pump that is simplified in structure as compared with a double-end support structure. Another object of the present invention is to provide a magnet coupling pump that can extend the life and improve the reliability, particularly when used as a chemical injection pump.

In order to solve the above-described object, the magnet coupling pump according to the present invention is configured such that a driven outer magnet portion rotating integrally with a motor output shaft is moved to a driven inner magnet portion in a pump housing partitioned by a partition member via a magnetic force. In a magnet coupling pump that transmits a rotational force and generates a conveying force by rotating a rotor, an impeller, an impeller, and the like connected to a shaft that rotates integrally with the driven inner magnet portion, the rear end is A bearing housing having a cylindrical portion extending to the driven inner magnet portion and the space portion of the shaft is integrally fixed to the pump housing so as to surround the periphery of the shaft, and an outward flange portion is provided at the tip. A front sleeve bearing provided between the inner peripheral surface of the bearing housing and the outer peripheral surface of the shaft; The rear sleeve bearing having an outward flange portion between front inner peripheral surface of the driven inner magnet portion and the rear portion outer peripheral surface of the bearing housing to the tip, as well as interposed respectively, said rear sleeve bearing and the front sleeve bearing It is arranged that at least a part of is overlapped in the front-rear direction of the pump .

According to the magnet coupling pump of the present invention having the above-described configuration, sleeve bearings are respectively disposed between the shaft and the driven inner magnet portion that rotates integrally with the shaft, and the relative rotational sliding contact portion with the bearing housing. The shaft is provided by a double sleeve bearing which is disposed so as to overlap at least partially in the front inner side and the rear outer side , that is, in the front-rear direction (axial direction) of the pump, with the bearing housing interposed therebetween. And the driven inner magnet part are rotatably supported. Basically, the sleeve bearing of the conventional partition wall member (bottomed cylindrical rear housing) is omitted to form a cantilever support structure, so that an allowable radial load can be obtained. Compared to the conventional double-sided support structure, the durability is improved compared to the conventional cantilevered support structure. Structure can be simplified to a simplified, size and weight reduction can be achieved.

  Also, depending on the design philosophy, the front inner sliding part can withstand the load, and the rear outer sliding part is an emergency (emergency) sliding part when trouble occurs in the front inner sliding part. Can play a role. And providing an emergency sliding part will improve reliability.

The magnet coupling pump according to claim 2 includes a driven inner magnet portion that transmits a rotational force via a magnetic force from a driving outer magnet portion that rotates integrally with the motor output shaft, and includes a discharge port or a suction port. A pump housing comprising a housing and a bottomed cylindrical rear housing for partitioning the inner and outer magnet parts; a stator having a male screw rotor connected to a front end opening of the front housing and rotatably inserted; and a front end of the stator An endstat connected to the opening and forming a suction port or a discharge port, a shaft connected to the driven inner magnet portion so as to be integrally rotatable, and having an outward flange at a tip, and the shaft and the rotor are connected to the rotor. A mug having a coupling rod coupled so as to be integrally rotatable through a joint that allows eccentric rotation A coupling type uniaxial eccentric screw pump, wherein the pump housing is configured so that a bearing housing having a rear end extending from the driven inner magnet portion and the cylindrical portion of the shaft is surrounded by the shaft housing. A front sleeve bearing having an outward flange portion at the tip thereof is provided between the inner peripheral surface of the bearing housing and the outer peripheral surface of the shaft, and a rear sleeve bearing having an outward flange portion at the tip is provided. Between the rear outer peripheral surface of the bearing housing and the front inner peripheral surface of the driven inner magnet portion, at least a part of the front sleeve bearing and the rear sleeve bearing is disposed in the front-rear direction (axial direction) of the pump. It is characterized by being arranged so as to overlap with each other.

  According to the magnet coupling pump of claim 2, since the uniaxial eccentric screw pump is a positive displacement pump, the transfer amount is controlled based on the number of rotations of the pump. It is extremely effective for injecting chemicals in water treatment processes such as water purification plants.

  4. The front sleeve bearing according to claim 3, wherein the front sleeve bearing is formed of PTFE (polytetrafluoroethylene) with filler or PEEK (polyether ether ketone) with filler, and the front portion is formed on the outer peripheral surface of the shaft. A cylindrical sleeve formed of silicon carbide (SiC) is preferably attached to the sliding contact portion with the sleeve bearing so as to be integrally rotatable. The filler refers to a polymer organic material such as carbon fiber, glass fiber, graphite, metal powder, and plastic.

  According to the magnet coupling pump of claim 3, since the silicon carbide sleeve has a thermal conductivity that is four times or more that of a corrosion-resistant metal material constituting the shaft, for example, austenitic stainless steel, the load is the same and the same level. When there is a calorific value, the temperature rise of the sliding part is greatly reduced. As a result, the corrosiveness of the chemical solution is prevented from increasing. In addition, a silicon carbide sleeve that slides directly as compared to a corrosion-resistant metal material is less likely to deteriorate in terms of physical properties, and thus extends its life. Furthermore, since PTFE containing filler or PEEK containing filler is used for the sleeve bearing, which is the sliding material on the other side, local corrosion deterioration and wear deterioration compared to when sliding with a shaft made of a corrosion-resistant metal material. Is significantly reduced. Specifically, in the wear test in sodium hypochlorite, the life was increased by 15 times or more compared with the case where titanium alloy JIS 60 type was used for the shaft.

As described above, the magnet coupling pump according to the present invention can rotate the shaft and the driven inner magnet coupling with a double sleeve bearing at two locations, the front inner side and the rear outer side, with the bearing housing interposed therebetween. Since the conventional sleeve bearing on the bulkhead member side is omitted and the cantilever support structure is adopted, the allowable radial load can be increased compared to the conventional cantilever support structure, and at the same time, the structure compared to the conventional double-end support structure. Can be simplified and simplified, and the size and weight can be reduced.

  Embodiments of a magnet coupling pump according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a cross-sectional view showing an embodiment in which the present invention is applied to a magnet coupling type single-shaft eccentric screw pump, and a part thereof is omitted. FIG. 2 is an enlarged cross-sectional view of the magnet coupling portion of FIG.

  As shown in FIG. 1, a pump body portion 2 of a uniaxial eccentric screw pump 1 includes a male screw rotor 3 having a true circular section and a female screw hole 4 having an oval cross section having an opening cross section having a pitch twice that of the rotor 3. The rotor 3 rotates eccentrically around the central axis N within the female screw hole 4. The rotor 3 revolves in the female screw hole 4 in the direction opposite to the rotation around the central axis N while rotating in one direction, and the rotor 3 rotates in the cross section at an arbitrary position of the female screw hole 4 and has an oval opening. Reciprocates in the long axis direction.

  An endstat 6 is attached to the tip of the stator 5 and serves as a suction port (this example) or a discharge port. On the other hand, the base end of the stator 5 is connected to the front housing 8 of the pump housing 7. The stator 5 and the end stud 6 are integrally connected to the front housing 8 by tightening bolts 10. In the present example, a discharge port 8a is provided upward near the front end of the front housing 8.

  A cylindrical driving outer magnet portion 12 having an opening on the tip side is integrally formed at the tip of a drive shaft 11 connected to an electric motor (not shown), and a cylindrical shape is formed on the tip side of the inner peripheral surface of the outer magnet portion 12. A drive outer ring side magnet 12a is provided integrally. A cylindrical driven inner magnet portion 13 integrally provided with a cylindrical driven inner ring side magnet 13a is disposed inwardly facing the driving outer ring side magnet 12a, and is driven by the proximal end side axial center portion of the inner magnet portion 13. The base end side protruding portion 14a of the shaft 14 as a shaft is integrally coupled. The shaft 14 is integrally provided with an outward flange 14b on the outer periphery on the front end side. A coupling rod 15 is connected to the tip of the shaft 14 via a universal joint 16 such as a universal joint. The coupling rod 15 is connected to the rotor 3 via a universal joint 17 such as a universal joint.

  A bottomed cylindrical rear housing 9 as a partition member that partitions the outer magnet portion 12 and the inner magnet portion 13 is provided on the rear side of the pump housing 7, and constitutes the pump housing 7 together with the front housing 8. Outward flanges 8b and 9b are formed on the outer periphery of the base end of the front housing 8 and the distal end of the rear housing 9, respectively, and the outward flange 18b of the bearing housing 18 is sandwiched between both flanges 8b and 9b. They are assembled together via a pair of O-rings 19.

  The bearing housing 18 has a substantially cylindrical shape. A front outer side 18c of the main body 18a slightly protrudes forward in a cylindrical shape, and a rear inner side 18d of the main body 18a extends rearward slightly longer than the length of the main body 18a in a cylindrical sleeve shape. Has been.

By configuring as described above, the space portions S1 and S are provided between the shaft 14 and the bearing housing 18 and between the bearing housing 18 and the inner magnet portion 13, respectively.
2 is formed. In the space portion S1 on the front inner side of these space portions S1 and S2, the front sleeve bearing 20 integrally provided with the outward flange portion 20a at the tip is integrally mounted on the inner peripheral surface of the bearing housing 18. Yes. Further, in the rear outer space S <b> 2, a front sleeve bearing 21 integrally provided with an outward flange portion 21 a at the tip is integrally attached to the front inner peripheral surface of the inner magnet portion 13.

  Since the uniaxial eccentric screw pump 1 of this example is used for transferring a chemical solution such as sodium hypochlorite, the shaft 14 and the bearing housing 18 are each made of titanium alloy JIS 60 type. Each is formed by PEEK containing a filler (glass fiber).

  By the way, the front and rear space portions S1 and S2 are both narrow space portions, and particularly the rear outer space portion S2 is very narrow. Therefore, it is extremely expensive to manufacture the sleeve bearings 20 and 21 arranged in both the space portions S1 and S2 so as to slide in contact with both the shaft 14 and the bearing housing 18 which are counterpart members from the initial state. Accuracy is required. However, since it is not necessary that both the inner and outer sliding portions of the sleeve bearings 20 and 21 are in contact from the initial state, for example, only the sleeve bearing 20 is in contact with the shaft 14 in the initial state. It can be designed such that the sleeve bearing 21 begins to contact the bearing housing 18 with the sleeve bearing 20 slightly worn. By doing so, the processing accuracy at the time of production can be lowered, and the production becomes easier.

  FIG. 3 is a partially enlarged sectional view showing another embodiment of the uniaxial eccentric screw pump. This example is a uniaxial eccentric screw pump 1 ′ for transferring a highly corrosive chemical solution such as sulfuric acid, hydrochloric acid, strong acid such as sodium hypochlorite or sodium hydroxide, strong base, etc. The following points are different from the above example. To do. Before integrally connecting the protruding portion 14a of the shaft 14 to the inner magnet portion 13, as shown in FIG. 3, a cylindrical sleeve 31 formed of silicon carbide (SiC) on the outer peripheral surface of the main body portion of the shaft 14 is moved back and forth. The O-rings 32 and 32 are interposed and adhered with an adhesive to be covered. That is, the shaft 14 made of a corrosion-resistant metal material such as stainless steel, titanium alloy, or Hastelloy is used only as a strength member, and the cylindrical sleeve 31 attached to the surface thereof is used as a sliding member.

  In the case of this example, the sleeve bearing 20 which is a counterpart member of the cylindrical sleeve 31 is formed by PEEK containing a filler. Although not shown, a PEEK sleeve bearing 21 filled with filler is brought into direct contact with the outer peripheral surface of the rear inner side 18d of the bearing housing 18 made of titanium alloy JIS 60, for example, in the space S2 outside the rear part. be able to. However, although structurally complicated, a silicon carbide (SiC) cylindrical sleeve (not shown) is integrally bonded to the outer peripheral surface of the rear inner side 18d of the bearing housing 18 so as to contain the filler. You may make it slide-contact with the sleeve bearing 21 made from PEEK.

  Table 1 below shows that the inventors of the present application conducted a wear test in sodium hypochlorite as a chemical solution for Example 1 (Combination B), Example 2 (Combination A), and Comparative Example (Combination C). It shows the results. The sliding material 1 in Table 1 is the cylindrical sleeve 31 (FIG. 3) in the combination A, the material of the shaft 14 in the combination B and C, and the sliding material 2 is the sleeve in the combination A, B and C. The material of the bearing 20 is indicated.

  From the wear test results shown in Table 1 above, it was confirmed that the combination of the sliding materials 1 and 2 of Example 2 would have a life (service life) 15 times longer than that of Example 1. That is, since the life of the sleeve bearing in the pump 1 of the first embodiment is estimated to be about 2 years, the sleeve bearing of the pump 2 of the second embodiment can be expected to have a life of 30 years or more. In other words, it is not necessary to replace the shaft 14 and the sleeve bearings 20 and 21 until the lifetime of the pump is reached.

  Further, as shown in the first embodiment, it is basically a cantilever structure and is rotatably supported by the two front and rear sleeve bearings 20 and 21, and at the same time, combined in each sliding portion as in the second embodiment. By selecting the sliding material 1 or 2 by A, a small magnet coupling type uniaxial eccentric screw pump having an allowable load equal to or greater than that of the conventional both-end support structure (see FIG. 4) is obtained. As a specific effect of the magnetic coupling type single-shaft eccentric screw pump, a magnet coupling (including a sleeve bearing) having a transmittable torque of 4.0 Nm has a weight ratio of about 40 compared to the conventional structure shown in FIG. % (Reduced weight of about 60%) is achieved. This effect is due to the reduction in size and weight of the rear housing 9 as the partition member and the reduction in size and weight of the front and rear magnet portions 12 and 13.

  As mentioned above, although several examples were given about the uniaxial eccentric screw pump among the magnet coupling type pumps of the present invention, it can also be carried out as follows.

  a) In the uniaxial eccentric screw pump of the above embodiment, by rotating the rotor 3 in the reverse direction, the transfer liquid is sucked from the discharge port 8a side and discharged from the endstat 6.

  b) The overall shape of the pump housing 7 can be arbitrarily changed.

  c) Needless to say, the present invention can also be applied to magnet pumps other than uniaxial eccentric screw pumps, swash plate pumps, centrifugal pumps, and axial flow pumps.

It is sectional drawing which shows the Example which applied this invention to the magnet coupling type uniaxial eccentric screw pump, and one part was abbreviate | omitted and represented. It is an expanded sectional view of the magnet coupling part of FIG. It is sectional drawing which expanded a part which shows another Example of the uniaxial eccentric screw pump concerning this invention, and abbreviate | omitted and represented. It is an expanded sectional view corresponding to FIG. 2 which shows the both-ends support structure of the conventional common magnet coupling type uniaxial eccentric screw pump. It is an expanded sectional view corresponding to Drawing 2 showing the cantilever support structure of the conventional general magnet coupling type uniaxial eccentric screw pump.

Explanation of symbols

1-1 'single-shaft eccentric screw pump 2 Pump body 3 Male threaded rotor 4 Female threaded hole 5 Stator 6 Endstat 7 Pump housing 8 Front housing 8a Discharge port 9 Rear housing (partition wall member)
11 Drive shaft 12 Outer magnet portion 12a Driving outer ring side magnet 13 Inner magnet portion 13a Driven inner ring side magnet 14 Shaft (driven shaft)
15 Coupling rod 16/17 Universal joint 18 Bearing housing 19/32 O-ring 20/21 Sleeve bearing 31 Cylindrical sleeve

Claims (3)

Rotational force is transmitted from the driving outer magnet part rotating integrally with the motor output shaft to the driven inner magnet part in the pump housing partitioned by the partition member via magnetic force, and connected to the shaft rotating integrally with the driven inner magnet part. In a magnet coupling pump that generates a conveying force by rotating a rotating body such as a rotor, impeller, and impeller
A bearing housing having a cylindrical portion extended at a rear end of the driven inner magnet portion and a space portion of the shaft is integrally fixed to the pump housing so as to surround the periphery of the shaft,
A front sleeve bearing having an outward flange portion at the front end is disposed between the inner peripheral surface of the bearing housing and the outer peripheral surface of the shaft, and a rear sleeve bearing having an outer flange portion at the front end is disposed at the rear outer peripheral surface of the bearing housing. It is provided between the front inner peripheral surfaces of the driven inner magnet part, and is arranged so that at least a part of the front sleeve bearing and the rear sleeve bearing overlap in the front-rear direction of the pump. Magnet coupling type pump. A bottomed cylinder that has a driven inner magnet part that transmits rotational force via a magnetic force from a driving outer magnet part that rotates integrally with the motor output shaft, and partitions the front housing having a discharge port or a suction port from the inner and outer magnet parts A pump housing composed of a rear housing, a stator having a male screw rotor connected to the front end opening of the front housing and rotatably inserted, and an end connected to the stator front end opening and forming a suction port or a discharge port The shaft is connected to the stat and the driven inner magnet portion so as to be integrally rotatable, and has a shaft having an outward flange at the tip, and the shaft and the rotor can be integrally rotated via a joint that allows eccentric rotation of the rotor. A magnetic coupling type uniaxial eccentric screw pump having a coupling rod to be coupled ,
Trailing edge is bearing housing with a cylindrical portion extending in a space portion of the shaft and the driven inner magnet unit, fixedly integrally with the pump housing so as to surround the periphery of the shaft, outside the distal end A front sleeve bearing having a facing flange portion is provided between the inner peripheral surface of the bearing housing and the outer peripheral surface of the shaft, and a rear sleeve bearing having an outward flange portion at the tip is provided on the rear outer peripheral surface of the bearing housing and the driven inner side. A magnet coupling that is interposed between front inner peripheral surfaces of the magnet part, and is arranged so that at least a part of the front sleeve bearing and the rear sleeve bearing overlap in the front-rear direction of the pump. Type pump. The front sleeve bearing is formed of filled PTFE or filled PEEK, and a cylindrical sleeve formed of silicon carbide can be integrally rotated on the sliding contact portion with the front sleeve bearing on the outer peripheral surface of the shaft. The magnet coupling type pump according to claim 1 or 2, which is attached to the pump .

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