JPH0712084A - Rear thrust bearing structure in magnet pump - Google Patents

Abstract

PURPOSE:To improve durability of a magnet pump, and reduce cost by radiating effectively sliding motional frictional heat generated in a rear thrust bearing part at abnormal operation time such as idle running of a pump, and preventing adverse influence upon surrounding members while restraining a temperature rise in a slidingly movable part. CONSTITUTION:A rear thrust bearing 41 is arranged opposite movably slidingly on a shaft end surface 42 of a spindle 34 being in a cantilever condition on the rear side in the vicinity of an impeller 26. Sliding motional frictional heat generated here is radiated excellently by being influenced by cooling operation of agitation in a casing of the impeller 26 and by a heat radiating effect by a circulating flow, and a temperature rise in a slidingly movable part is restrained, and adverse influence upon surrounding members by the heat can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnet pump for rotationally driving an impeller in a pump chamber by a magnetic coupling of a driving magnet and a driven magnet which face each other, and a driven rotating body including the impeller. The present invention relates to an improvement in a front thrust bearing and a rear thrust bearing, which support a thrust related to a part, particularly, a rear thrust bearing.

[0002]

2. Description of the Related Art A magnet pump of this type is known, for example, having a structure shown in FIG. That is, the known magnet pump 1 shown in FIG. 3 defines a pump chamber 2 inside and includes a front casing 5 having a suction port 3 along the axial direction indicated by the axis XX and a discharge port 4 along the circumferential direction. And an impeller 6 that is rotatably arranged in the pump chamber 2 and has a front side (right side in the drawing) facing the suction port 3.
And a bottomed cylindrical rear casing that cooperates with the front casing 5 to fluid-tightly surround the pump chamber 2, and a drive magnet 8 that is arranged outside the rear casing 7 and has a ring shape. A drive rotor 10 that receives a rotational drive force from a drive motor (not shown) disposed therein, and a drive coupling that is disposed in the rear casing 7 and forms a magnetic coupling with the drive magnet 8 via the rear casing. A driven rotary body 12 which is provided with a driven magnet 11 opposed to each other like a ring and is rotatable integrally with the impeller.
A base end portion of the rear casing 7 is fixed to the bottom portion 7a of the rear casing 7 via a boss 13 that is integrally projected from the bottom portion, and the base portion is axially protruded in a cantilevered manner and the driven rotor is provided on the protrusion 14a. And a spindle 14 that rotatably supports 12 via a sleeve bearing 15.

In the above-mentioned known magnet pump 1,
The driven rotary body 12 is driven to rotate following the rotation of the drive rotary body 10, whereby the impeller 6 rotates and the pump feed fluid flows from the suction port 3 into the pump chamber 2 as shown by the arrow, and is discharged. It is sent out from the outlet 4 as shown by the arrow.
During this pump operation, a part of the fluid in the pump chamber 2 also circulates as a circulating flow into the inner rear part of the rear casing 7, and the sleeve-shaped bearing 15 and the spindle 14 which are integrally provided with the driven rotating body 12 As shown by the broken line arrow in the sliding portion 15a between them, the bearing 15 flows in from the rear end side, escapes to the front end side and circulates through the communication hole 16 provided in the central portion of the impeller 6, and the sliding portion 15a has a cooling effect and a lubricating effect that suppress heat generation due to friction. The sliding portion 15
A spiral or splined flow groove is formed in a.

Since the front side of the impeller 6 facing the suction port 3 has a negative pressure during operation of the pump, the driven rotating portion of the driven rotor 12 together with the impeller 6 normally thrusts in the direction of the suction port 3, that is, in the front direction. To receive
A ring-shaped front thrust bearing 17 that supports this is provided in the front casing 5, and a mouth ring 18 provided on the impeller 6 side is in sliding contact with the front thrust bearing 17. Further, thrust may act on the driven rotating portion in the direction opposite to the suction port 3, that is, in the rear direction. This is because the driven rotating portion rotates while vibrating in the thrust direction when an abnormal operation such as a pump idle operation or air entrainment occurs. Therefore, a rear thrust bearing 19 that supports the thrust in the rear direction is provided on the boss 13 around the spindle 14, and the rear end edge of the sleeve-shaped bearing 15 is slidably contacted with the rear thrust bearing 18 when the thrust in the rear direction occurs. It is configured to let.

[0005]

As described above, the rear end edge of the sleeve-shaped bearing is in sliding contact with the rear thrust bearing when an abnormal operation such as an idle operation or air entrainment of the pump occurs. The frictional heat generated in the contact area was a problem. That is, unlike the front thrust bearing, the rear thrust bearing is provided in the inner rear part of the rear casing, so that the heat dissipation of frictional heat is bad and seizure of the bearing part occurs when the temperature rises, especially around the rear casing. In the case of using a synthetic resin molded product as a member, there is a problem of adverse effects due to heat such as damage to the member due to melting. Further, when the rear end edge of the sleeve-shaped bearing is in sliding contact with the rear thrust bearing, there is a problem that heat generation and poor circulation of the circulating flow entering the sliding portion between the spindle-shaped bearing and the spindle further aggravate the situation. It was

In order to solve the above problems, a structure has been proposed in which a heat-resistant material is used around the sliding portion such as a rear thrust bearing to provide heat insulation. However, in this case, the cost increase due to the heat insulating structure is unavoidable, and since the heat is not dispersed to the surroundings by the heat insulating material, the temperature of the sliding part rapidly rises even in a short idle operation. However, there is a problem that so-called heat shock is likely to occur due to the immediate priming.

Therefore, the present invention has been made in view of the above-mentioned problems of the prior art, and an object thereof is to suppress the generation of frictional heat of a sliding portion as much as possible even when an abnormal operation such as an idle operation of a pump occurs. , It is not necessary to have a heat insulating structure around the sliding portion, and resin molded products can be used for the surrounding members such as the rear casing without worrying about the durability of the pump and the rear thrust bearing in the magnet pump. To provide the structure.

[0008]

In order to achieve the above-mentioned object of the present invention, in the present invention, a pump chamber is defined inside, and a front is provided with a suction port along the axial direction and a discharge port along the circumferential direction. A casing, an impeller rotatably disposed in the pump chamber and having a front side facing the suction port, a bottomed cylindrical rear casing that cooperates with the front casing to fluid-tightly surround the pump chamber, and the rear casing. The impeller having a drive rotor disposed outside and having a drive magnet, and a driven magnet disposed inside the rear casing and facing the drive magnet via the rear casing so as to form a magnetic coupling. And a driven rotary body that is rotatable integrally with the rear casing, and is fixed to the bottom portion of the rear casing and projects in the axial direction in a cantilever manner. On the premise of a magnet pump having a spindle for rotatably supporting the driven rotating body on the protruding portion, a rear thrust bearing member is provided axially opposite the shaft end surface of the spindle along the axial direction. A structure of a rear thrust bearing is provided, which is arranged so as to be slidably contactable with an end face and has a support portion for supporting the rear thrust bearing member provided on the rear side of the impeller or the front side of the driven rotating body.

Further, according to the present invention, the structure of the rear thrust bearing having a configuration in which one of the shaft end surface of the spindle and the rear thrust bearing member, which are capable of sliding contact with each other, is formed into a spherical shape. Is also proposed.

[0010]

According to the rear thrust bearing of the present invention,
A rear thrust bearing member is arranged so as to be slidably contactable with the shaft end surface of the spindle, and a support portion for supporting the rear thrust bearing member is provided on the back side of the impeller, that is, on the rear side or the front side of the driven rotary body. Therefore, when the driven rotor and the driven rotating portion of the impeller oscillate in the thrust direction due to abnormal operation of the pump or the like and move in the rear direction, the rear thrust bearing member comes into contact with the shaft end surface of the spindle in the fixed state. It will be in sliding contact. The rear thrust bearing member is arranged on the rear side behind the impeller in the vicinity of the inner part of the rear casing unlike the rear inner part of the rear casing, so that heat is easily dissipated and the rear thrust bearing member receives a cooling effect by stirring in the casing of the impeller. Since it is easy, the heat generated during sliding between the rear thrust bearing member and the shaft end surface of the spindle is radiated well,
The temperature rise of the sliding portion including the thrust bearing member can be suppressed. Further, since the flow path of the circulation flow passing between the spindle and the sleeve-shaped bearing is not blocked, good cooling action and lubrication action around the spindle are maintained, and the circulation flow becomes the rear thrust bearing portion. Is also affected,
Better heat dissipation is achieved.

Further, in the structure in which one of the shaft end surface of the spindle and the sliding contact portion of the rear thrust bearing member is spherical, the sliding contact area becomes small, and the heat generation can be suppressed to a very small level.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a magnet pump embodying the structure of a rear thrust bearing according to the present invention will be described below with reference to FIGS. 1 and 2. In the magnet pump 20 shown in FIG. 1, 21 is a pump main body having a drive motor (not shown) built therein, 22 is attached to the pump main body, defines a pump chamber 23 inside, and is an axis indicated by an axis XX. A front casing having a suction port 24 along the direction and a discharge port 25 along the circumferential direction, an impeller 26 rotatably arranged in the pump chamber 23, and the front side (right side in the drawing) faces the suction port 24, Reference numeral 27 denotes a ring-shaped front thrust bearing provided on the front casing 22 for slidingly contacting a mouth ring 28 provided on the impeller 26. Reference numeral 29 is attached to the pump body 21 and cooperates with the front casing 22 to move the pump chamber 23. A bottomed cylindrical rear casing 30 that is fluid-tightly enclosed is disposed outside the rear casing 29, and a drive magnet 31 is also provided. Drive rotor to obtain a rotational driving force from the driving motor in the pump body 21 with the annular, 32 drive magnet 31 via the rear casing while being located within the rear casing 29
And a driven rotor 33 having a ring-shaped driven magnet 33 facing each other so as to form a magnetic coupling with the impeller 26 assembled and fixed in an integrally rotating state. 34 is integrally provided on a bottom portion 29a of the rear casing 29 so as to project from the bottom portion. Boss 35
Is a spindle that is fixed by and axially protrudes in the form of a cantilever.

A driven rotating body 32 is rotatably supported on the protruding portion 34a of the spindle 34 via a sleeve-shaped bearing 36. The bearing 36 is fixed to the driven rotating body 32, and a spiral or splined flow groove is formed in the sliding portion 36a with the spindle 34.
During the operation of the pump, a part of the pump feed fluid flowing into the pump chamber 23 circulates as a circulating flow into the inner portion of the rear casing 29, and as shown by a broken arrow, from the rear end edge of the bearing 36 to the sliding portion. It enters into 36a and performs a cooling action and a lubricating action.

At the start of pump operation, the drive rotor 30 is first rotated by energization of the drive motor, and the driven rotor 32 is rotated integrally with the impeller 26 on the spindle 34 following this. As a result, the pump feed fluid flows from the suction port 24 into the pump chamber 23 as shown by the arrow, and is also delivered to the supply site (not shown) via the discharge port 25.

The components of the magnet pump described above are the same as those of the conventional structure described in FIG. As a material used for each member, the impeller 26, the rear casing 29, and the driven rotary body 32 are manufactured by molding synthetic resin. The sleeve bearing 36, the front thrust bearing 27, the mouth ring 28, and the spindle 35 are preferably made of a ceramic material having excellent corrosion resistance and hardness.

With respect to the embodiment of the magnet pump shown in FIG. 1, the structural portion of the rear thrust bearing which is a feature of the present invention will be described below. That is, the impeller 26 has the suction port 2
4, a boss-shaped support portion 40 is integrally provided at the center of the back surface of the impeller 26 on the front surface side or the back surface side or the rear side opposite to the front side, and the rear thrust bearing member 41 is attached thereto to attach the axis line X. The rear contact portion 41a of the rear thrust bearing member 41 exposed from the supporting portion 40 is made to have a tapered shape as shown in the drawing, and its tip is formed into a spherical shape. Is opposed to the flat shaft end surface 42 of the spindle 34.
Further, the communication hole 43 for circulating the pumping fluid is formed so as to penetrate through the both sides outside the central portion because the rear thrust bearing member 41 is arranged in the central portion of the impeller 26.

In the above structure, the driven rotor 32 receives the thrust in the front direction together with the impeller 26 during the steady operation of the pump.
The mouth ring 28 comes into contact with and slides and rotates. During this time, the rear thrust bearing member 41 is fixed to the shaft end surface 4 of the spindle.
Although not in contact with 2, the sliding portion of the rear thrust bearing member 41 when the driven rotating portion vibrates in the axial direction and receives rearward thrust due to idle operation of the pump, air entrainment, or the like. 41a is the shaft end surface 4 of the spindle
2, and the thrust in the rear direction is received. Friction heat is generated in the sliding portion 41a by continuing rotation of the driven rotating portion in this contact state. However, the friction heat is generated in the vicinity of the impeller 26, not in the inner portion of the rear casing as in the conventional structure. Since it is located on the rear side immediately after that, the cooling effect due to stirring in the casing of the impeller 26 is easily received, the frictional heat is radiated well, and the temperature rise around the sliding portion is suppressed.

Further, the sliding portion 4 of the rear thrust bearing member 41
By making 1a spherical, the shaft end surface 4 of the spindle
The sliding contact area with 2 becomes small, and heat generation at that portion can be further suppressed.

Further, a rear thrust bearing as in the conventional structure is not provided between the rear end edge of the sleeve-like bearing 36 and the boss 35, and the rear thrust bearing member 41 is in contact with the shaft end surface 42 of the spindle. Since this gap is always maintained even if there is, the fluid that has flowed into the inner rear portion of the rear casing 29 is circulated as a circulating flow from the rear end edge of the bearing 36 into the sliding portion 36a. Circulates through the communication hole 43 formed in the impeller 26 from the front edge of the flow.
Therefore, the cooling action and the lubricating action between the sleeve-shaped bearing 36 and the spindle 34 are always kept in a good state,
It also eliminates the risk of seizure or damage to parts. Further, since the circulating flow always extends around the rear thrust bearing member 41, heat dissipation is further promoted.

FIG. 2 shows a modified structure of the rear thrust bearing shown in the embodiment of FIG. This will be described by giving the same reference numerals to the parts corresponding to those in FIG. 1. In this modified structure, instead of the structure in which the support part for supporting the rear thrust bearing member 41 is provided on the impeller 26, the driven rotary body 32 is replaced.
Member 4 which forms a part of the and which constitutes the front side
It is configured to be provided on the No. 4. That is, the intermediate member 44 is formed in a cylindrical shape having a bottom and is fixed to the outer peripheral portion of the sleeve-shaped bearing 36, and the bottom portion 44a is located between the shaft end surface 42 of the spindle 35 and the rear side of the impeller 26. The rear thrust bearing member 41 is attached and fixed to the bottom portion 44a as a support portion.

In the above modified structure, the sliding portion 41a of the rear thrust bearing member 41 has a flat surface shape, while the axial end surface 42 of the spindle 34 has a spherical sliding portion 42.
Although a is formed, the above-described effects can be obtained by providing the spherical sliding portions on either one of the sliding portions. However, even if the mutual sliding portions are both flat surfaces, a substantial effect which has not been obtained can be obtained, and the sliding portion is not limited to the spherical shape.

A communication hole 45 is formed in the bottom portion 44a of the intermediate member 44, communicates with the communication hole 43 formed in the central portion of the impeller 26, and flows out through the sliding portion 36a of the sleeve bearing 36. Are circulated as shown by the broken line, and thereby the sliding friction heat generated at the rear thrust bearing member 41 is radiated more favorably.

Although the embodiment and the modified structure of the present invention have been described above, the present invention is not limited to this.

[0024]

As described above, according to the present invention, the rear thrust bearing is arranged on the rear side of the impeller or the front side of the driven rotating body, instead of the conventional structure in which the rear thrust bearing is provided inside the rear casing. However, since it is configured to slide on the shaft end surface of the spindle, the heat generated in the sliding portion is radiated well.
In particular, since the cooling action by stirring in the casing of the impeller is exerted, better heat dissipation is performed, and problems such as member damage due to temperature rise around the sliding part are eliminated, and there is also a gap between the sleeve-shaped bearing and the spindle. Since the flow path of the circulating flow is not blocked, a stable cooling action and a lubricating action are always obtained, and since the circulating flow is always exerted on the rear thrust bearing portion, a better heat dissipation is achieved and a heat insulating structure or the like is provided. It is possible to provide a magnet pump which has a high durability and is easy to reduce the cost because it is possible to use a molded product of synthetic resin for the peripheral member such as the rear casing without the need to take special measures.

[Brief description of drawings]

FIG. 1 is an overall broken view of essential parts of an embodiment of a magnet pump that embodies a structure of a rear thrust bearing according to the present invention.

FIG. 2 is an enlarged sectional view of a main part of a magnet pump showing a modified structure of a rear thrust bearing according to the present invention.

FIG. 3 is a cross-sectional view of essential parts of a magnet pump including a rear thrust bearing according to a conventional structure.

[Explanation of symbols]

 20 Magnet Pump 26 Impeller 29 Rear Casing 32 Driven Rotating Body 34 Spindle 40 Supporting Part 41 Rear Thrust Bearing Member 42 Spindle Shaft End Surface 44 Intermediate Member 44a Bottom Part (Supporting Part)

Claims (2)

[Claims] 1. A front casing (22) which defines a pump chamber (23) inside and has a suction port (24) along the axial direction and a discharge port (25) along the circumferential direction, and inside the pump chamber. An impeller (26) that is rotatably arranged and has a front side facing the suction port, a bottomed cylindrical rear casing (29) that cooperates with the front casing to fluid-tightly surround a pump chamber, and an outside of the rear casing. And a driven rotating body (30) having a driving magnet (31) and a driven magnet which is disposed in the rear casing and faces the driving magnet via the rear casing so as to form a magnetic coupling. A driven rotating body (32) having (33) and capable of rotating integrally with the impeller; and a bottom portion (29a) of the rear casing.
And a spindle (34) that is fixed to the shaft and axially projects in a cantilevered manner and that rotatably supports the driven rotating body on the projection (34a). The rear thrust bearing member (41) is arranged so as to be slidably contactable with the shaft end surface of the spindle along the axial direction facing the (42), and the support portion (40, 44a) for supporting the rear thrust bearing member is provided. A structure of a rear thrust bearing in a magnet pump, which is provided on a rear side of an impeller (26) or a front side of a driven rotary body (32). 2. The spindle (26) capable of sliding contact with each other.
The structure of the rear thrust bearing in the magnet pump according to claim 1, wherein the sliding contact portion (41a, 42a) of either one of the shaft end surface (42) and the rear thrust bearing member (41) is formed into a spherical shape.