JPH0113836Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention is for supporting a driven rotating body that is rotationally driven following a motor-driven driving rotating body on a shaft that supports an impeller in a magnetic pump. Regarding the support structure of

[Technical background of the invention and its problems]

In this type of magnetic pump, the driven rotating body has a driven side magnet corresponding to the driving side magnet of the driving rotating body, but this driven magnet is located on the so-called liquid contact side where it is likely to come into contact with the pumping liquid together with the shaft. Therefore, if the supplied liquid is a chemical or the like, it is likely to corrode, so the driven magnet is generally coated with a corrosion-resistant synthetic resin layer. Furthermore, for shafts, brittle materials such as corrosion-resistant ceramics are increasingly being used instead of metals.

As shown in FIG. 5, for example, in the conventional structure, a shaft 1 supporting an impeller (not shown)
On the other hand, a square key 3 having a rectangular cross section is used to support the driven rotating body 2 so as to rotate together with the shaft 1. Then, this is fitted into a corresponding key groove 4 bored in the outer peripheral part of the shaft 1 along the axial direction, and a support hole 5 corresponding to the outer peripheral contour of the shaft 1 and the key 3 is inserted into the driven rotary body 2.
The shaft 1 and the key 3 are fitted into the support hole 5 to support the shaft 1 and the key 3. Here, the synthetic resin layer 6 covers the entire inner and outer peripheral portions of the driven magnet 7 in contact with the shaft 1. Also, the fifth
In the figure, hatching of the cross section of each member is omitted for explanation.

Such a square key 3 is generally used when a rotating body such as a gear is supported on a shaft. However, when applied to a support portion for a shaft and a driven rotating body supported by the shaft in a magnetic pump, the following problems occur.

That is, due to the nature of pump operation, an overload acts on the shaft 1 through the impeller when starting or stopping, and this is transmitted as an impact load, so the synthetic resin layer 6 of the driven rotor 2 has no support. A crack 9 can easily enter through the edge portion 8 of the hole 5. Further, when the shaft 1 is made of a brittle material such as ceramic, the crack 11 is likely to enter the shaft from the edge portion 10 of the keyway 4. That is, the impact load acts as concentrated stress on these edge portions 8 and 10, and since the material of the member corresponding to the key 3 is a synthetic resin or brittle material, it is weak against impact and is prone to cracking. Therefore, the occurrence of this crack causes the pump to malfunction, and is also a cause of deteriorating the life of the pump.

[Purpose of invention]

Therefore, the present invention was developed based on the above-mentioned circumstances, and its purpose is to minimize the occurrence of cracks in the support part between the shaft and the driven rotating body, and to provide a simple and durable structure. The purpose of the present invention is to provide a support structure for a certain magnetic pump.

[Summary of the idea]

In order to achieve the above object, the present invention basically consists of forming a flat notched surface on the outer peripheral surface of the shaft in place of the conventional configuration of a square key and a corresponding rectangular keyway. , a key member having a notched circular cross section is arranged with respect to the cutout surface, and a key member is arranged along the central axis of the synthetic resin layer of the driven rotor in accordance with the outer peripheral contour formed by the shaft and the key member. The present invention proposes a support structure in which a support hole is formed and a shaft and a key member are fitted into the support hole to support a driven rotating body on the shaft so as to be able to rotate together with the shaft.

By adopting the above structure, the edge portion that causes stress concentration in the support hole is eliminated, so the stress is effectively distributed and the occurrence of cracks is suppressed as much as possible.Moreover, the key member is formed on the shaft. Because it is in close contact with the flat notch surface and does not shift,
Reliable rotation transmission is achieved, and the formation of the flat notch surface and the manufacture of the key member are easy, and the above-mentioned objects of the present invention are fully achieved.

[Example of idea]

Embodiments of the present invention will be described below with reference to FIGS. 1 to 4.

In FIG. 1, 20 is a pump head which has a suction port 21 and a discharge port 22 for the liquid to be pumped, and has an impeller 23 arranged therein, and 24 is a pump head which has an impeller 23 inside.
A shaft is fixedly supported at one end by a cap 25 and rotatably supported along the center axis of the pump by a pair of left and right bearings 26 and 27.
29 is a driven rotary body supported on the shaft 24 on the liquid wetted side side while being surrounded by the casing 28; 30 is a back casing that surrounds the casing 28 and the driven rotary body 29; A driving rotary body 31 placed on the liquid contact side is a motor that is supported by the pump frame 32 and rotationally drives the driving rotary body 30 via a motor shaft 31a.

When the motor 31 is energized during pump operation, the drive rotor 30 is rotated in one direction, and the drive side magnet 33 provided inside it acts on the driven side magnet 34 of the corresponding driven rotor 29. The rotating body 29 is rotated following the driving rotating body 30.

The rotation of this driven rotary body 29 is caused by the rotation of the support portion 3.
5 to the shaft 24, thereby rotationally driving the impeller 23 to perform pump feeding.

As shown in FIGS. 2 to 4, the support portion 35
, a flat cutout surface 3 is provided on the outer peripheral surface of the shaft 24.
6 and a flat surface 37a corresponding to this notch surface.
A key member 37 having a notched circular cross section is provided, and this key member 37 is disposed on the flat notched surface 36, so that the outer peripheral contour formed by the combination of the shaft 24 and the key member 37 is A support hole 38 having a curved surface configuration that exactly corresponds to the support hole 38 is formed in the driven rotary body 29 along the central axis line.
8 is fitted with the shaft 24 and the key member 37 disposed thereon.

The support hole 38 is formed in the synthetic resin layer 3 of the driven rotating body 29.
9 is formed on the inner circumferential portion. The synthetic resin layer 39 covers the entire magnet 33 over the inner and outer peripheries and both ends of the driven magnet 33. Since the thickness of the inner circumferential portion of the synthetic resin layer 39 is uniform around the support hole 38 as seen in FIG. 2, the stress on the inner circumferential portion is also uniformly distributed. In the axial direction, the support hole 38 closely corresponds to the outer peripheral contours of the shaft 24 and the key member 37.
It is formed in the length range of the key member 37. One end of the support hole 38, that is, the hole 38 in FIG.
The right end of the shaft 2 formed on the driven rotating body 29
4, and the left end of the hole 38 communicates with a large diameter hole 40 (FIG. 4).

Therefore, after inserting the driven rotating body 29 onto the shaft 24 from the end of the shaft before the large diameter round hole 40 side, the large diameter round hole 40 is inserted into the annular member 41 (FIG. 1).
It is fixed in the axial direction by closing with.
For example, the member 41 may have a structure in which the large-diameter round hole 40 is a screw hole and is screwed into the large-diameter round hole 40 as shown in the embodiment, or a structure in which it is driven into the large-diameter round hole 40.

As can be seen in FIG. 3, the flat cutout surface 36 is parallel to the central axis and has a length along the axis of the key member 3.
7 are set to the same dimensions that can be fitted. Therefore, in the fitted state, the key member 37 is fixed to the shaft 24 in the axial direction.

The key member 37 has a notched circular column shape, in other words,
The width of the flat bottom surface 37a of the semicylindrical shape matches the width of the flat cutout surface 36 of the shaft 24. Further, the radius of curvature of the curved peripheral surface of the key member 37 is smaller than the radius of curvature of the peripheral surface of the shaft 24.

Therefore, the outer peripheral contour of the combination of the shaft 24 and the key member 37 has a daruma shape, and the support hole 38 is tightly fitted into this, so that the shaft 24 is integrated with the rotation of the driven rotary body 29. Rotate to. Unlike the case where a conventional rectangular key is used, the support hole 38 does not have a noticeable edge portion, and because the entire support hole 38 has a curved surface structure, concentration of stress can be avoided.

Note that when fitting the key member 37 to the flat cutout surface 36 of the shaft 24, if the adhesive is interposed between the key member 37 and the floor surface 37a and the key member 37 is brought into close contact with the floor surface 37a, it will be easier to insert the rotary body 29 onto the shaft 24. Since the key member 37 does not shift in position, assembly work can be performed efficiently. However, since the shaft 24 and the key member 37 are tightly fitted into the support hole 38 after insertion, the force transmission remains the same even when no adhesive is used.

Further, the key member 37 can be made of the same metal material as the shaft 24 or a brittle material such as ceramic.

Furthermore, by using a key member having a curved outer circumferential surface in this manner, the contact area with the support hole is expanded due to the combination with the outer circumferential surface of the shaft.
Therefore, since the force transmission area becomes larger, the force per unit area of the transmission surface can be reduced. That is, since the structure reduces the force acting on each part and eliminates the effect of concentrated stress, more effective force transmission can be achieved.

[Effect of idea]

As described above, in the present invention, instead of the conventional structure of a square key and a keyway in the supporting part of the shaft and the driven rotating body, a key member having a curved surface structure is arranged on a flat notch formed on the shaft. As a result, the stress applied to the synthetic resin layer of the driven rotor was dispersed and concentration of stress was eliminated, making it possible to minimize the occurrence of cracks and improve durability. Therefore, even if a brittle material such as ceramic is used as the shaft material, the problem of cracks can be largely solved, and a magnetic pump with a simple structure and long life can be provided.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view of a magnetic pump according to an embodiment of the present invention, Fig. 2 is an enlarged sectional view taken along the - line in Fig. 1, Fig. 3 is an exploded perspective view of the support section, and Fig. 4 is an exploded perspective view of the support section. FIG. 5 is an enlarged sectional view of the main part taken along the line - in FIG. 1, and FIG. 24...shaft, 29...driven rotating body, 30
... Drive rotating body, 33 ... Drive side magnet, 3
4... Drive side magnet, 35... Support part, 36
... Flat notch surface, 37 ... Key member, 38 ... Support hole, 39 ... Synthetic resin layer.

Claims (1)

[Claims for Utility Model Registration] (1) A motor-driven drive rotating body having a drive side magnet, a driven side magnet, and a synthetic resin layer covering the driven side magnet, and rotationally driven to follow the drive side magnet. A key member comprising: a driven rotary body, and a shaft that supports an impeller; a flat notched surface is formed on the outer peripheral surface of the shaft; the key member has a flat notched surface corresponding to the notched surface and has a notched circular shape in cross section; is placed on the flat notch surface, a support hole corresponding to the outer peripheral contour formed by the shaft and the key member is formed in the synthetic resin layer along the central axis of the driven rotating body, and a A support structure for a magnetic pump in which a driven rotating body is integrally and rotatably supported on a shaft by fitting the shaft and a key member. (2) The support structure in a magnetic pump according to claim 1, wherein the shaft is made of a brittle material. (3) The support structure in a magnetic pump according to claim 2, wherein the key member is made of a brittle material. (4) The support structure for a magnetic pump according to claim 3, wherein the shaft and the key member are made of ceramic.