Patent Grant
8535001
This application is a section 371 of PCT/EP09/00297, filed 19 Jan. 2009, published 23 Jul. 2009 as WO 2009-090 099-A, and claims priority from DE 10 2008 005 245.0, filed 19 Jan. 2008, the entire content of which is hereby incorporated by reference.
The invention relates to a sheet-metal rotor wheel of a centrifugal pump with means for fastening onto the drive shaft of an electric motor.
A variety of different ways of fastening rotor wheels onto pumps are known. They require, typically, multiple parts, a difficult assembly process, and a substantial consumption of materials.
It is an object of the invention to provide a rotor wheel of the aforementioned type with fastening to the motor shaft which, despite simple construction and assembly, achieves an optimal transfer of power and an exact positioning of the rotor wheel.
In accordance with the invention, this object is achieved in that the rotor wheel has a central coaxial opening, into which a sleeve is coaxially secured, that the sleeve projects, at least on an impeller side, from the rotor wheel, and that the sleeve has, on its inner surface, axially parallel beads or ridges which engage into axially parallel slots or grooves of the motor drive shaft.
In such a structure, the sleeve serves both the function of power transfer and the setting of the exact position of the rotor wheel, and/or of the spacing distances of rotor wheels with respect to each other.
In this manner, high torques are transmissible to the rotor wheel, yet small consumption of material is achieved. Optimally, this structure is employed in making rotor wheels from sheet metal, which achieves a desirably low mass.
Further, one achieves an optimal oscillation behavior and a high compensation for tolerances. There is a structurally simple and secure fastening, requiring few parts, and one achieves simplicity in assembly, even when assembling two or more rotor wheels in a multi-stage pump.
A particularly simple structure, offering high torque transfer, is achieved when the ridges are formed by notching outward places in the sleeve wall. Further, it is advantageous when the axially parallel ridges are formed axially before a region of the sleeve which extends outward from the rotor wheel. It is suggested that the length of the ridges be 10% to 60% of the length of the sleeve.
In order to achieve simple and secure fastening of the sleeve into the rotor opening, it is suggested that an annular bulge or torus be provided on the sleeve outer wall. The annular bulge can be arranged in a central portion of the sleeve. Preferably, the sleeve is welded into place, in the central opening of the rotor wheel, by laser welding.
It is particularly advantageous to use a rotor wheel with such a sleeve in a multi-stage pump with multiple rotor wheels. The sleeves of the rotor wheels are arranged with their faces contacting each other, and the sleeve lengths determine the spacings of the rotor wheels from each other.
Advantageous embodiments of the invention are shown in the drawings and described in greater detail below. Shown are:
A centrifugal pump rotor wheel made of sheet metal features a central coaxial opening, using which the rotor wheel is fastened onto the shaft 1 of an electric motor (not shown). For this purpose, a sleeve 2, formed from a pipe section, is provided. The sleeve is inserted into the opening 3 of rotor wheel 4. During this, the sleeve 2 is shoved so far into the rotor opening 3 that an annular coaxial bulge 5, extending outwardly from sleeve 2, rests against a rim of opening 3. This assures an exact positioning of sleeve 2 with respect to rotor wheel 4.
After reaching this secure position, the sleeve 2 is fastened to the rotor opening rim by laser welding using laser beam LB as shown in
In a region 2a of sleeve 2, which starts at an end of the sleeve and stops before the annular bulge 5, a plurality of axially parallel beads or ridges 7 are formed in the inner wall of sleeve 2. In the embodiment shown in the drawings, four axially parallel beads project on the inner surface of sleeve 2 at respective identical intervals of 90 degrees, the shaft 1 having, at the same four places, a respective notch or groove 8, into which the bead 7 form-lockingly engages, so that a secure form-lock between shaft 1 and sleeve 2 is created with the rotor 4.
When using this manner of fastening in a two- or more-stage pump, two or more sleeves 2 are mounted on the shaft with their faces contacting each other, so that the lengths L of the sleeves, especially the lengths of regions 2a, which at least partially project out of the rotor wheel, define the exact positions of the rotor wheels on the shaft, and with respect to each other.
Depending upon the structure and function of the pumps and of the rotor wheels, sleeves 2 can be configured with differing lengths, as shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2008 005 245 | Jan 2008 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2009/000297 | 1/19/2009 | WO | 00 | 7/17/2010 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2009/090099 | 7/23/2009 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 3025800 | Hix et al. | Mar 1962 | A |
| 3116696 | Deters | Jan 1964 | A |
| 3265001 | Deters | Aug 1966 | A |
| 3288074 | Hall | Nov 1966 | A |
| 3477384 | Hlinka | Nov 1969 | A |
| 3612716 | Deters | Oct 1971 | A |
| 3837612 | Deters | Sep 1974 | A |
| 5176021 | Jensen et al. | Jan 1993 | A |
| 6168376 | Wagner | Jan 2001 | B1 |
| 7520454 | Zelder et al. | Apr 2009 | B2 |
| Number | Date | Country |
|---|---|---|
| 3939156 | May 1991 | DE |
| 199 53 911 | Nov 2000 | DE |
| 0 911 528 | Apr 1999 | EP |
| 0 911 528 | Feb 2003 | EP |
| Number | Date | Country | |
|---|---|---|---|
| 20110052402 A1 | Mar 2011 | US |
