WO2021199011A1

WO2021199011A1 - An improved electric water pump with split housing assembly

Info

Publication number: WO2021199011A1
Application number: PCT/IB2021/052820
Authority: WO
Inventors: Kabir BHANDARI; Amardip KUMAR; Praveen Gupta; Ashok Kumar
Original assignee: Padmini Vna Mechatronics Pvt. Ltd.
Priority date: 2020-04-03
Filing date: 2021-04-05
Publication date: 2021-10-07

Abstract

The present invention provides an improved electric water pump with a split housing assembly to be used for cooling of components in an electric/hybrid vehicles which is a cost effective and allows ease of manufacture and assembling without any compromise in performance, comprising of a water chamber (12), a motor chamber (13), a rotor casing assembly, a bush (14) wherein, the rotor casing assembly comprises of a rotor casing with an over molded shaft, the water chamber (12) includes a volute casing (1) for reducing complexity, the motor chamber (13) comprises of a stator assembly (3), housing sub-assembly that has a mounting assembly (9) for mounting the improved electric water pump (100) and the rotor casing (8) assembly separates the water chamber (12) and the motor chamber (13) to form split housing assembly so that the improved electric water pump (100) allows a volume flow rate at varying pressure.

Description

“AN IMPROVED ELECTRIC WATER PUMP WITH SPLIT

HOUSING ASSEMBLY”

FIELD OF THE INVENTION

The present invention relates to an improved electric water pump that allows a volume flow rate at a pressure on demand. More particularly, the present invention relates to an electric water pump having a split housing assembly used in cabin heating, exhaust gas recirculation (EGR) cooling, battery cooling and inverter cooling applications.

BACKGROUND OF THE INVENTION

An electric water pump is an electrically controlled BLDC i.e. brushless DC motor based electric pump widely used for cooling of engine, low pressure EGR cooling, power electronics, inverter cooling and battery cooling in electric /hybrid vehicles. A brushless DC motor is an electronically commuted DC motor which does not have brushes. These types of motors are highly efficient in producing a large amount of torque over a vast speed range. In brushless motors, permanent magnets rotate around a fixed armature and overcome the problem of connecting current to the armature.

Brushless DC motors (BLDC) are used for a wide variety of application requirements such as varying loads, constant loads and positioning applications in the fields of industrial control, automotive, aviation, automation systems, health care equipment etc. Conventionally, the water pump installed in vehicles for the purpose of cooling of components of the vehicle is driven through a belt connected to the crankshaft of the engine. However, the electric/hybrid vehicles require an electrically driven water pump for the cooling of components.

In state of the art, an electrical water pump comprises a plurality of components such as a volute casing, a housing sub-assembly, a cover, a rotor, a shaft, a stator, a water chamber and sealing rings used while assembling of the components. The plurality of components are generally made as separate parts and then assembled that makes the process of assembly time consuming. Further, due to assembling of separate parts, the chances of failure related to misalignment increase as well as the cost due to manufacture of separated parts increase.

KR20160118612A discloses a pump cover comprising a pump cover including an inlet through which cooling water flows and an outlet through which pressurized cooling water exits, a stator chamber in which a stator for generating a magnetic field is generated by a control signal applied from the outside, a shaft rotatable with the rotor and fixed to the front end of the shaft so as to be rotatable relative to the shaft and an impeller which rotates together with the inlet and pressurizes the cooling water introduced into the inlet, wherein a part of the shaft is provided with a wing portion for promoting the flow of the cooling water. The main drawback of the invention is that the efficiency of these types of pumps are low in the range of 60-70%.

Therefore, there is a need to develop a cost effective electric water pump that allows ease of manufacture and assembling without any compromise in performance.

OBJECT OF THE INVENTION

The main object of the present invention is to provide an improved electric water pump that allows a volume flow rate at pressure as per demand on supply of DC as input.

Another main object of the present invention is to provide an electric water pump having a split housing assembly to be used in cabin heating, EGR cooling, battery cooling and inverter cooling applications.

Yet another object of the present invention is to provide a split housing assembly having a water chamber separated from the motor chamber using a rotor casing containing an over molded shaft assembled together by the process including but not limited to welding.

Still another object of the present invention is to provide a cost effective, simple and effective split housing assembly of an electric water pump.

SUMMARY OF THE INVENTION The present invention provides an improved electric water pump with a split housing assembly to be used for cooling of components in an electric /hybrid vehicle which is a cost effective and allows ease of manufacture and assembling without any compromise in performance.

In a main embodiment, the present invention provides an improved electric water pump comprising of a water chamber, a motor chamber, a rotor casing assembly. The rotor casing assembly comprises of a rotor casing with an over molded shaft assembled together using process such as but not limited to welding. The water chamber comprises of a plurality of components such as but not limited to volute casing, a rotor assembly, a washer and the motor chamber comprises a plurality of components such as but not limited to a stator assembly, housing sub assembly, a printed circuit board (PCB) assembly, a cover and a tapping screw. The rotor casing assembly separates the water chamber and the motor chamber to form split housing assembly. Said improved electric water pump allows a volume flow rate at varying pressure.

The improved rotor casing assembly having an over molded shaft assembled in the rotor casing reduces the complexity as well as reduces the time in assembling thus proving a cost-effective electric water pump.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 shows of an exploded view an improved electric water pump in accordance with an embodiment of the present invention.

Fig. 2(a) shows across sectional view of an improved electric water pump in accordance with an embodiment of the present invention.

Fig. 2(b) shows a side view of an improved electric water pump in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Many aspects of the invention can be better understood with references made to the drawings below. The components in the drawings are not necessarily drawn to scale. Instead, emphasis is placed upon clearly illustrating the components of the present invention. Moreover, like reference numerals designate corresponding parts through the several views in the drawings. Before explaining at least one embodiment of the invention, it is to be understood that the embodiments of the invention are not limited in their application to the details of construction and to the arrangement of the components set forth in the following description or illustrated in the drawings. The embodiments of the invention are capable of being practiced and carried out in various ways. In addition, the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.

The present invention provides an improved electric water pump that allows a volume flow rate at pressure on demand when direct current is given as an input.

In a main embodiment, the present invention provides an improved electric water pump comprising of a water chamber, a motor chamber, a rotor casing assembly. The rotor casing assembly comprises of a rotor casing with an over molded shaft assembled together using process such as but not limited to welding. The water chamber comprises of a plurality of components including but not limited to volute casing, a rotor assembly, a washer and the motor chamber comprises a plurality of components such as but not limited to a stator assembly, housing sub-assembly, a printed circuit board (PCB) assembly, a cover and a tapping screw. The rotor casing assembly separates the water chamber and the motor chamber to form split housing assembly. Said improved electric water pump allows a volume flow rate at varying pressure. Table 1 shows an experimental data for volume flow rate varying at varying pressure for the improved electric water pump.

Table 1

Variation in volume flow rate with varying pressure

Now referring to Fig. 1, an exploded view of an electric water pump is shown. The improved electric water pump (100) comprises of a volute casing (1), a rotor assembly (2), a rotor casing (8), a stator assembly (3), a housing sub-assembly (4) with a mounting assembly (9), an over molded shaft (10), a printed circuit board (PCB) assembly (5) and a cover (6). A washer (7) is assembled between the rotor assembly (2) and said volute casing (1). A self-tapping screw (11) for fastening the printed circuit board (PCB) assembly (5) with the housing sub assembly (4).

Now referring to Fig. 2(a) and Fig. 2(b), a sectional view and a side view of an improved electric water pump (100). Said improved electric water pump (100) comprises of a water chamber (12), a motor chamber (13) and a rotor casing assembly. The volute casing (1) and rotor assembly (2) constitute the water chamber (12). Further, the stator assembly (3), printed circuit board (PCB) assembly (5) and the cover (6) constitute the motor chamber (13). The rotor casing (8) separates the water chamber (12) and the motor chamber (13). The rotor casing (8) is assembled with an over molded shaft (10) using a method including but limited to welding and forms a rotor casing assembly. A bush (14) is provided surrounding the shaft (10). The improved electric water pump (100) provides a volute casing (1) that reduces complexity and the rotor casing (8) holding the over molded shaft (10) and housing sub-assembly (4) that holds the stator assembly (3) and printed circuit board (PCB) assembly (5) attached to it. A cover (6) is attached to the housing sub-assembly (4) at the bottom of improved electric water pump (100). A mounting assembly (9) is provided at two sides of the housing sub assembly (4) for mounting the improved electric water pump (100).

Therefore, the present invention provides an improved electric water pump that allows a volume flow rate at pressure on demand. The electric water pump has a simple and effective split housing assembly that is low cost and at the same time reduces complexity.

The foregoing description of embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the invention. The embodiments were chosen and described in order to explain the principals of the invention and its practical application to enable one skilled in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated.

Claims

We claim:

1. An improved electric water pump (100), comprising: a water chamber (12); a motor chamber (13); a rotor casing assembly; and a bush (14); wherein; said rotor casing assembly comprises of a rotor casing (8) with an over molded shaft

(10); said water chamber (12) includes a volute casing (1) and a rotor assembly (2) and a washer (7); said motor chamber (13) comprises of a stator assembly (3), a housing sub-assembly (4), a PCB assembly (5), a cover (6) and a self-tapping screw (11); said housing sub-assembly (4) has a mounting assembly (9) for mounting the improved electric water pump (100); and said rotor casing (8) assembly separates said water chamber (12) and said motor chamber (13) to form split housing assembly so that said improved electric water pump (100) allows a volume flow rate at a varying pressure.

2. The improved electric water pump (100) as claimed in Claim 1, wherein said washer (7) is assembled between the rotor assembly (2) and said volute casing (1).

3. The improved electric water pump (100) as claimed in Claim 1, wherein said self tapping screw (11) is for fastening said PCB assembly (5) with said housing sub assembly (4).

4. The improved electric water pump (100) as claimed in Claim 1, wherein said cover (6) is attached to said housing sub assembly (4) at bottom of said improved electric water pump (100).

5. The improved electric water pump (100) as claimed in Claim 1, wherein said rotor casing (8) is assembled with an over molded shaft (10) using a method including but limited to welding and forms said rotor casing assembly.

6. The improved electric water pump (100) as claimed in Claim 1, wherein said bush (14) is surrounding said over molded shaft (10).