WO2016151556A2

WO2016151556A2 - An improved bldc water pump minimizing attrition on shaft

Info

Publication number: WO2016151556A2
Application number: PCT/IB2016/051738
Authority: WO
Inventors: Kabir BHANDARI; Amardip KUMAR; Kumar Abhishek; Navdeep DAHIYA
Original assignee: Padmini Vna Mechatronics Pvt. Ltd.
Priority date: 2015-03-24
Filing date: 2016-03-27
Publication date: 2016-09-29
Also published as: WO2016151556A3

Abstract

An improved BLDC water pump rotor comprising of Housing having magnets attached at one end of the housing surface and the extension of the Guiding pin and integrally formed with the housing surface of the extension portion a Rotor Assembly with Top Bush; and Bottom Bush; wherein, the Bottom Bush and Top Bush are lined with friction reducing material, that forms the area around the Guiding Pin with ultra high wearing resistant materials to minimize attrition on shaft; and enhancing the space between the Guiding Pin and Rotor Assembly to avoid contact. The improved BLDC water pump has up to 60% less wear and tear rate, increases 66% reliability and is up to 30 % cheaper in terms of cost as opposed to the conventional BLDC water pump.

Description

"AN IMPROVED BLDC WATER PUMP MINIMIZING ATTRITION ON

SHAFT"

FIELD OF THE INVENTION

The present invention provides an improved BLDC water pump minimizing attrition on shaft. More specifically, the improvement provides lining of bushes made with ultra high wear resistant material between guiding pin and rotator, thus avoiding friction caused by rusting thereby decreasing the wear and tear, and increasing reliability in a cost effective manner.

BACKGROUND OF THE INVENTION

The introduction of the electronic control systems led to the replacement of the Brushed Pumps by the Brushless Direct Current (BLDC) motor technology. The major advantage of these pumps is long life, efficiency, and reliability due to exclusion of the brushes that used to wear out with use.

BLDC PUMPs are widely used in Aquarium, Small fountains, Landscaping features, Cooling system, Circulating system, Bathroom products, Medical devices, Solar water system, Air conditioning pumping, Foot tub, Plumbing mattress, Chemical industry, Scientific research, Small irrigation system, Water treatment equipment, etc.

The main components of the BLDC motor are stator and rotor. The BLDC motor stator is made preferably out of laminated steel stacked up to carry the windings. Windings in a stator can be arranged in two patterns; i.e. a star pattern (Y) or delta pattern^). The major difference between the two patterns is that the Y pattern gives high torque at low RPM and the Δ pattern giv e low torque at low RPM. This is because in thte configuration, half of the voltage is applied across the winding that is not driven, thus increasing losses and in turn, efficiency and torque. The rotor of a typical BLDC motor is made out of permanent magnets. Depending upon the application requirements, the number of poles in the rotor may vary.

Another rotor parameter that impacts the maximum torque is the material used for the construction of permanent magnet; the higher the flux density of the material, the higher the torque.

The underlying principles for the working of a BLDC motor are the same as for a brushed DC motor; i.e., internal shaft position feedback. In case of a brushed DC motor, feedback is implemented using a mechanical commutator and brushes. With a BLDC motor, it is achieved using multiple feedback sensors. The most commonly used sensors are hall sensors and optical encoders.

With the introduction of electronic control systems for electric motors, the industry objectives of long life, efficiency, reliability and low EM interference have become achievable. This is in part due to the advent of brushless direct current (BLDC) motor technology. Thus, not only the problems associated with the prior art permanent magnet direct current motors are overcome, but advances in MOS-FET devices have led to further performance advantages. While prior art BLDC motor designs have achieved their intended purpose, problems still exist. For example, the addition of control circuitry within the motor has increased design and manufacturing complexity of the motor. More specifically, the control circuitry must be appropriately packaged to protect it from the fluid in which the motor is submerged. If the fluid contacts the control circuitry corrosion and malfunctioning of the circuit will occur. The control circuitry includes temperature sensitive components that may be damaged by excessive heat applied during either the manufacturing of the motor or operation of same. Furthermore, the control circuitry is susceptible to radiated emissions from surrounding electrical devices.

The major problem associated with a BLDC water pump is quite obvious. As these pumps are submerged during operation the problem of corrosion and wear is quite common. Further, there is continuous friction between the guiding pin and the rotor that may decrease the products longevity and performance. Although there are pumps that come with expensive rust resistant coatings on the internal assembly such as the bush and the guiding pin, it has not been cost effective and full proof.

OBJECT OF THE INVENTION

The main object of the invention is to provide an improved BLDC water pump to minimize attrition on shaft due to rotor movement. Yet another object of the invention is to provide an improved BLDC water pump with more space between the guiding pin and rotor assembly to avoid any contact of the shaft on the outer bush surrounding the guiding pin.

Yet another object of the invention is to provide an improved BLDC water pump with bushes of ultrahigh wear resistant properties, lined either continuously or intermittently to minimize attrition on shaft due to rotor movement around the Guiding Pin, therefore permanently obviating the problem caused by the friction of the rusting bushes, hence enhancing performance and longevity. It is yet another object of the invention to improve the performance BLDC water pump by lining the bushes with materials having ultrahigh wear resistant material that subsequently increases the performance that is calculated by measuring flow resistance and maximum pressure. Still another object of the invention is to provide an improved BLDC water pump to minimize attrition on shaft due to rotor movement thus considerably extending the life of the product and field performance. SUMMARY OF THE INVENTION

The invention provides an improved BLDC water pump to minimize attrition on BLDC shaft due to rotor movement, thus considerably enhancing the life of the product.

In an embodiment of the present invention an improved BLDC water pump is provided that minimizes attrition on shaft caused due to rotor movement, by providing more space between the guiding pin and the rotor which obviates any contact between the guiding pin and the rotor.

In another embodiment of the present invention an improved BLDC water pump is designed to minimize attrition on shaft by incorporating ultra high wear resistant materials such as Polyether, Ether, Ketone, etc. on the outer bushes continuously or intermittently around the Guiding Pin to specifically eliminate any friction caused by the rusting of the contact surfaces such as outer bushes and subsequently enhance the performance and durability of the product.

BRIEF DESCRIPTION OF THE DRAWINGS

A complete understanding of the system and method of the present invention may be obtained by reference to the following drawings:

FIG. 1 illustrates a conventional BLDC water pump;

FIG. 2 illustrates the new improved BLDC water pump;

FIG. 3 is a table comparing the Air Gap between the conventional BLDC water pump and the new improved BLDC water pump's guiding pin and rotor assembly;

FIG. 4 is a bar chart comparing the wear rate between conventional BLDC water pump and the new improved BLDC water pump;

FIG. 5 is a bar chart comparing the reliability of the conventional BLDC water pump and the new improved BLDC water pump;

FIG. 6 is a bar chart the cost of the conventional BLDC water pump and the new improved BLDC water pump; FIG. 7 is a conventional design of BLDC water pump rotor; and

FIG. 8 is the novel design of BLDC water pump rotor in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention will now be described more fully hereinafter with reference to the accompanying drawings in which a preferred embodiment of the invention is shown. This invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiment set forth herein. Rather, the embodiment is provided so that this disclosure will be thorough, and will fully convey the scope of the invention to those skilled in the art.

FIG. 1 illustrates a conventional BLDC water pump 100 comprising of Housing 1, Rotor Casing 2, Guiding Pin 3, Lamina Assembly 4, Lamina 5, Copper Wire(DC) 6, PCB 7, Terminal 8, Terminal Seal 9, Inner Bush 10, Rotor Assembly 11, Rotor 12, Impeller 13, Washer(Big) 14, Locking Washer 15, O-Ring(Big) 16, Volute Casing 17, O- Ring(Medium) 18, O-Ring(Small) 19, Screw (Self Threaded) 20 and a Washer(Small) 21.

The conventional BLDC water pump 100 has no friction reducing material between the Guiding Pin 3 and the Outer Bush (Not Labeled). The pump with constant use under water develops a considerable amount of friction due to rust formation. This decreases the performance of conventional BLDC water pump 100 by increasing the wear rate and further decreasing reliability. The conventional BLDC water pump 100 provides less space between the Guiding Pin 3 and the Outer Bush (Not Labeled) that may lead to contact of the Guiding Pin 3 on the Outer Bush, hence, decreasing the performance and longevity. FIG. 2 illustrates the new improved BLDC water pump 101 comprising of Housing 1, Rotor Casing 2, Guiding Pin 3, Lamina Assembly 4, Lamina 5, Copper Wire(DC) 6, PCB 7, Terminal 8, Terminal Seal 9, Inner Bush 10, Rotor Assembly 11, Rotor 12, Impeller 13, Washer(Big) 14, Locking Washer 15, O-Ring(Big) 16, Volute Casing 17, O- Ring(Medium) 18, O-Ring(Small) 19, Screw (Self Threaded) 20, Washer(Small) 21, Bottom Bush 22 and Top Bush 23.

In an embodiment of the present invention, the improvement mainly provides Bottom Bush 22 and Top Bush 23 lined on the Outer bush (Not Labeled). The Outer Bush area is area surrounding the Guiding Pin 3. The Bottom Bush 22 and Top Bush 23 are preferably made of materials with ultra high wearing resistant materials such as PAEK to minimize. The new improved BLDC water pump 101 with Bottom Bush 22 and Top Bush 23 provides a contact surface that does not rust; therefore there is no added friction with use. Additionally, the new improved BLDC water pump 101 therefore increases the performance, product life and durability. The improved performance of the BLDC water pump 101 is calculated by measuring flow resistance and maximum pressure output.

Further the new improved BLDC water pump 101 provides enhanced space between the Guiding Pin 3 and Rotor Assembly 11 to avoid contact.

The effect of these modifications on the new improved BLDC water pump 101 are compared to the conventional BLDC water pump 100 in Figs 3, 4, 5 & 6. FIG. 3 is a table comparing the Air Gap between the conventional BLDC water pump and the new improved BLDC water pump's guiding pin and rotor assembly. The table highlights significant increase in the Air Gap which is provided by the new design incorporated in the new improved BLDC water pump as compared to the conventional BLDC water pump.

FIG. 4 is a bar chart comparing the wear rate between conventional BLDC water pump and the new improved BLDC water pump. The table highlights a Bar chart comparing the wear rate between the existing models and the new improved model, which is provided by the new design incorporated in the new improved BLDC water pump as compared to the conventional BLDC water pump. The improved BLDC water pump has up to 60% decreases the wearing rate. FIG. 5 is a bar chart comparing the reliability of the conventional BLDC water pump and the new improved BLDC water pump. The Bar chart compares the reliability between the existing models and the new improved model, which is provided by the new design incorporated in the new improved BLDC water pump as compared to the conventional BLDC water pump. The improved BLDC water pump has up to 66% increases in the reliability.

FIG. 6 provides a Bar chart comparing the cost of the conventional BLDC water pump and the new improved BLDC water pump. The improved BLDC water pump is up to 30% cheaper in terms of cost as opposed to the conventional BLDC water pump.

FIG. 7 elucidates the conventional design of BLDC water pump rotor. The rotor comprising of Impeller 13, Rotor Assembly 12, Top Bush 22, Bottom Bush 23 and Guiding pin 3. FIG. 8 elucidates the novel design of BLDC water pump rotor. The rotor comprising of Impeller, Rotor Assembly, Top Bush, Bottom Bush and Guiding pin, wherein lining the Bottom Bush 22 and Top Bush 23 with friction reducing material that forms the area around the Guiding Pin 3 with ultra high wearing resistant materials to minimize attrition at Bottom Bush 22 and Top Bush 23; and enhancing the space between the Guiding Pin and Rotor Assembly to avoid contact.

The invention has been described in an illustrative manner, and it is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation. Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. The invention is defined by the claims.

Claims

CLAIMS WE CLAIM:

1. An improved BLDC water pump rotor comprising of:

a housing having at least one magnets attached at least one end of the housing surface; a rotor assembly fitted in the housing having a top bush and a bottom bush; and a guiding pin mounted coaxially in said housing and said rotor assembly and adapted to be driven by said brushless motor; wherein, the bottom bush and the top bush are lined with friction reducing material, that forms the area around the guiding pin with ultra high wearing resistant materials to minimize attrition on a shaft; and the guiding pin and the rotor assembly have further enhanced space to avoid contact within the shaft.

2. The BLDC pump as claimed in claim 1, wherein friction reducing material is selected from polyaryletherketone (PAEK) family having excellent mechanical and chemical resistance properties that are retained to high temperatures.

3. The BLDC pump as claimed in claim 1, wherein the improved BLDC water pump is working at significant increase in the air gap of 0.75.

4. The BLDC pump as claimed in claim 1, wherein the bottom bush and the top bush are each formed on the bottom and top surface or the side of the rotor assembly.

5. The BLDC pump as claimed in claim 1, wherein the guiding pin with ultra high wearing resistant materials specifically eliminate any friction caused by the rusting of the contact surfaces and subsequently enhance the performance and durability of the pump.