Structure improving device for permanent magnet canning pump

Abstract

The invention provides the structure improvement of a permanent magnet canned pump made of plastic or provided with a plastic liner. The rigidity improvement method comprises the following steps that a pumping rear cover axal hole base and a metal rear box axal supporting base axially enter into an internal diameter space of a motor rotor main yoke; the axal supporting base is closely combined with the axal hole base so as to increase the rigidity of a fixing shaft and shorten the length of a moment arm of loading force; the rear cover axal hole base is provided with a sensor according to requirements; the sensor is formed by a secondary magnet group and sensing components, and a close loop magnetic line is formed between the secondary magnet group and the sensing components; the secondary magnet group is arranged on the inner side of the main yoke of the motor rotor, is opposite to a main magnet group and is packaged with the motor rotor; the sensing components are formed by a secondary yoke and a sensing component; when the motor rotor rotates, the sensing component outputs a sensing voltage signal by cutting a magnetic line, and the sensing component is arranged in an annular groove of the rear cover axal hole base and is protected by the rear cover; and the sensing component can be a plurality of sensing coils, a plurality of Hall components and the like, and can be used for monitoring bearing abrasion or satisfying driving requirements.

Description

[0001] This application is a divisional application with application number 2011103300199 technical field [0002] The sealless canned pump is an integrated motor and pump, and its motor rotor and stator coil are sealed and protected by corrosion-resistant materials, and it is directly in contact with the conveying liquid. The drive motor of the sealless canned pump It can be divided into induction motors, hereinafter referred to as induction canned pumps, and permanent magnet motors, hereinafter referred to as permanent magnet canned pumps, which are gradually being valued by users in many industrial applications that require zero leakage, especially those containing toxic, flammable, and highly corrosive products. In addition, the rotor of the canned pump without shaft seal is in direct contact with the conveying liquid. Most of them use wear-resistant ceramic sliding bearings, such as graphite, alumina, silicon carbide, etc., but bearing wear will cause the rotor to run ecce...

AI Technical Summary

Problems solved by technology

[0007] In 2009, the Taiwan patent TWM369391 improved the structure of the permanent magnet canned pump, which is used in high temperature and corrosion resistant applications. The motor structure is a cantilever fixed shaft structure, but the motor is designed with a radial air gap inner rotor. The package thickness of this cited case includes corrosion Margin, the thickness of one side is 3mm and the total air gap width is 8mm. The non-sensing component method is used to calculate the magnetic pole position to drive the permanent magnet motor, and the rigid composite fixed shaft structure is used to meet the high temperature and high horsepower applications; but the cited case Structure without bearing wear monitoring function

[0009] In 2005, the Japanese patent JP2005344589A-CANNED MOTOR PUMP was applied to permanent magnet canned pumps for engine cooling. The cited case is that the small power pump has a simple fixed shaft structure. The ceramic shaft is supported and fixed by heat-resistant plastic structural parts, including a tripod and pump On the back cover, a secondary magnet and Hall assembly are installed in the inner diameter space of the main magnet yoke to detect the position of the magnetic pole to drive the permanent magnet motor. The Hall assembly axially protrudes from the bottom of the back cover, and the rotor The length of the magnet is also elongated relative to the axial direction to reduce the axial elongation of the independent Hall assembly; the cleaning liquid delivery does not need to consider the increased load caused by bearing wear, and a simple fixed shaft structure is used, but increasing the length of the magnet will increase the cost and can only be detected The diffuse magnetic field lines on the surface of the measuring magnet are not conducive to the precise position detection of the magnetic poles

[0011] In 2008, the Japanese patent JP2008220008A--BRUSHLESS MOTOR AND FLUID PUMP DEVICE was applied to the permanent magnet canned pump for engine cooling. The cited case is that the small power pump has a simple fixed shaft structure, and the ceramic shaft is supported and fixed by heat-resistant plastic structural parts. It includes a tripod and a pump back cover. A Hall component and its drive circuit board are installed outside the bottom of the motor back cover to detect the position of the magnetic poles to drive the permanent magnet motor. The length of the magnet is axially extended so that the tail end is close to the Hall Hall assembly, and the tail end of the magnet is processed into a bevel, so that the magnetic field line can be shot obliquely through the Hall assembly installed on the circuit board to improve the detection accuracy of the magnetic pole position; the cleaning liquid does not need to consider the increased load caused by bearing wear, use Simple fixed shaft structure, but increasing the length of the magnet will increase the cost, and it can only detect the magnetic field lines that diffuse obliquely on the surface of the magnet, which is not conducive to the accurate position detection of the magnetic poles

[0019] In 2000, the US patent US6114966A--Motor having a bearing wear monitoring device was applied to induction canned pumps. This cited case clearly pointed out that although installing multiple induction coils at the front and rear ends of the stator can indeed detect the axial wear of the bearing, but Motor maintenance may replace the stator, rotor, shaft and induction coil. At this time, the mechanical axial positioning of the stator and rotor may not be consistent with the electrical axial positioning, or the rewinding of the induction coil may be inconsistent, which will cause major abnormalities in the signal. That is, the detection device must be able to adjust the relative position and reset the axial wear signal to zero. The method is that the rotor has a slightly longer thickness than the stator. When assembling, the distance between the rotor end face and the stator end face must be confirmed on the shaft end side, and the rotor end faces are aligned. In the center of the coil, the slightly longer part of the rotor protrudes from the end face of the stator. The end of the rotor completely covers the coil and has an axial margin. When the front thrust bearing wears out, the rotor moves forward, and the signal of the front coil changes obviously, but the signal of the coil at the end changes. lower;

[0026] 2. Hall components are installed to drive the pump conveniently but the magnet must be lengthened;

[0028] The various problems and solutions proposed have their practicability, but these solutions cannot simultaneously meet the needs of improving the rigidity of the fixed shaft and installing sensors to improve reliability. The structure of the permanent magnet canned pump of this invention Improvements must overcome the following problems:

[0029] Problem 1: The strength weakness of the material itself

[0031] Question 2: Bearing wear monitoring needs

[0033] Problem 3: Low cost requirements for high air gap motor characteristics

[0037] Question 5: Signal Quality Requirements When Using Sensors

[0039] Problem 6: Ease of repair and replacement parts

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