Canned motor to reduce cogging torque

Abstract

Canned motor for reducing a cogging torque, the canned motor comprising: a can (10) which is inserted into a housing (1) for sealing a coil mounted within the housing (1); and a stator (20) mounted on an outer peripheral surface of the can (10) and inserted along an inner peripheral surface of the housing (1); wherein a plurality of fixing guides (11) protrude from an outer peripheral surface of the split tube (10), and metal pins (12) are inserted into the fixing guides (11) to be integral with the fixing guide (11); wherein the metal pins (12) are inserted into slot openings (22) of the stator (20) when inserting them into the stator (20) and are attached to the same.

Description

BACKGROUND(a) Technical field

[0001] The present invention relates to a canned motor for reducing cogging torque. More specifically, it relates to a canned motor for suppressing the generation of cogging torque by inserting magnetic metal pins into slotted openings of a stator, thereby reducing noise and vibration during operation of the canned motor. (b) Background of the invention

[0002] A canned pump is generally used to increase hydraulic pressure, e.g., a pump motor. The canned pump is provided such that a coil of a motor, i.e., a power source of the pump, is sealed by a canned casing, and water compressed by the pump reciprocates between a rotating shaft and a rotor housed within the can. The water, which appropriately cools the frictional heat generated by a rotating body, can act as a lubricant around the rotating friction part. A canned pump is generally manufactured by integrating an impeller and a motor. That is, a canned motor, i.e., a power source of a canned pump, is generally integrally coupled with the canned motor to prevent fluid leakage.

[0003] In relation to Fig. 1, a conventional canned motor includes a housing 1 having a certain volume, a stator 2 mounted on an inner peripheral surface of the housing 1, a coil (not shown) mounted on a periphery of the stator 2 to generate electromagnetic interaction between the stator 2 and a rotor 3, a can 4 inserted into the housing 1 to seal the coil and the stator 2, a rotor 3 received and rotatably mounted within the can by electromagnetic interaction, and a rotating shaft 5 press-fitted with the rotor 3 to be rotated in conjunction with the rotor 3.

[0004] An impeller 6 of a pump is coupled to one end of the rotating shaft 5, and as the rotor 3 rotates, the impeller 6 rotates in conjunction with the rotating shaft 5 to suck in and discharge water. The can 4 serves to prevent water from leaking to the outside of the can 4, within which a coil is mounted, and is generally made of polyphenylene sulfide (PPS).

[0005] As in Fig. As illustrated in Fig. 2, the stator 2 is mounted on an outer peripheral surface of the can 4. When electric power is applied to the coil, the stator 2 rotates and drives the rotor 3 due to electromagnetic interaction with the rotor 3. A plurality of slots 7 are peripherally formed in the stator 2, and slot openings 8 with a size of approximately 0.8 mm are formed between the slots 7 and the can 4. Although the conventional canned motor has a simple structure and excellent waterproofing performance, a high cogging torque is generated due to the slot openings of the stator, which greatly causes noise and vibration.

[0006] From DE 10 2009 047 454 A1, as the closest prior art, a canned motor is known, comprising: a can, which is - usually - inserted into a housing for sealing a coil mounted within the housing; and a stator, which is mounted on an outer peripheral surface of the can and - usually - inserted along an inner peripheral surface of the housing; wherein a plurality of fastening guides protrude from an outer peripheral surface of the can. OVERVIEW OF REVELATION

[0007] It is therefore the object of the present invention to provide a canned motor for reducing a cogging torque, by which a cogging torque due to slot openings of a stator is reduced by integrally forming magnetic metal pins on an outer peripheral surface of a can by insert injection-molding and inserting the metal pins into the slot openings of the stator when assembling the can and stator.

[0008] The object is achieved by a canned motor having the features of claim 1. Advantageous further developments can be found in the subclaims.

[0009] In one aspect, the present invention provides a canned motor for reducing cogging torque, the canned motor including: a can inserted into a housing for sealing a coil mounted inside the housing; and a stator mounted on an outer peripheral surface of the can and inserted along an inner peripheral surface of the housing, wherein a plurality of fixing guides protrude from an outer peripheral surface of the can, and metal pins are inserted into the fixing guides to be integral with the fixing guide. More specifically, the metal pins are inserted into and attached to the slotted holes of the stator upon insertion of the stator into the stator.

[0010] In some exemplary embodiments, the can can be formed together with the metal pins by overmolding such that the metal pins are firmly seated within the mounting guides. Furthermore, the left and right sides of the mounting guides, which contact the slot openings of the stator, can be opened such that the inserted metal pins directly contact the stator. Furthermore, the metal pin can be formed from a magnetic material.

[0011] Since the canned motor of the present invention has a structure in which magnetic metal pins are inserted into slot openings of a stator, cogging torque due to the slot openings is reduced, which enables the reduction of torque ripple, noise, and vibration, and the improvement of motor efficiency. The canned motor of the present invention also enhances the strength and reliability of the canned motor by forming fastening guides on an outer peripheral surface of the can, thereby improving reliability. Furthermore, the fastening guides of the can are matched to the slot openings of the stator, which enables the prevention of stator slippage. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The above-mentioned and other features of the present invention will now be described in detail with reference to certain exemplary embodiments thereof, which are illustrated in the accompanying drawings, which are given below for illustrative purposes only and thus do not limit the present invention, and in which: Fig. 1 is a sectional view illustrating a conventional canned motor; Fig. 2 is a sectional view illustrating a composite structure of a can and a stator of the conventional canned motor; Fig. 3 is a perspective view illustrating a can of a canned motor according to an embodiment of the present invention; and Fig. 4 is a sectional view illustrating a composite structure of the can and a stator of the canned motor according to the embodiment of the present invention. DETAILED DESCRIPTION

[0013] Reference will now be made in detail to various embodiments of the present invention, examples of which are illustrated in the accompanying drawings and described below. While the invention will be described in connection with exemplary embodiments, it should be understood that the present description is not intended to limit the invention to these exemplary embodiments. On the contrary, the invention is intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents, and other embodiments which may be included within the spirit and scope of the invention as defined by the appended claims.

[0014] It should be understood that the term "vehicle" or "vehicular" or other similar term used herein includes motor vehicles in general, such as passenger cars, which include sport utility vehicles (SUVs), buses, trucks, various business cars, watercraft, which include a variety of boats and vessels, aircraft, and the like, and includes hybrid vehicles, electric vehicles, plug-in electric hybrid vehicles, hydrogen-powered vehicles, and other alternative fuel vehicles (e.g., fuels derived from raw materials other than petroleum). As referred to herein, a hybrid vehicle is a vehicle that has two or more power sources, such as both gasoline-powered and electric-powered vehicles.

[0015] As is well known in the art, a canned motor generally includes a housing having a certain volume, a stator mounted on an inner peripheral surface of the housing, a coil mounted on a periphery of the stator for generating electromagnetic interaction between the stator and a rotor, a can inserted into the housing to seal the coil and the stator, a rotor received and rotatably mounted within the can by electromagnetic interaction, and a rotating shaft press-fitted with the rotor to be rotated in conjunction with the rotor.

[0016] An impeller, such as a pump, is coupled to one end of a rotating shaft. As the rotor rotates, the impeller rotates in conjunction with the rotating shaft to draw in and discharge water. The can serves to guide and contain the water flow, preventing it from escaping to the outside of the can, where a coil is wired.

[0017] The stator is mounted on an outer peripheral surface of the can and fixed to an inner wall surface of the housing, so that when electric power is applied to the coil, the rotor rotates and drives due to electromagnetic interaction with the stator. A plurality of slots are peripherally formed in the stator, and slot openings of a predetermined size are formed between the slots and an inner wall surface (an inner peripheral surface of the stator that contacts the can).

[0018] According to the present invention, in a canned motor having a can 10 and a stator 20, the stator 20 has closed slots 21 without any opened portion by inserting magnetic metal pins 12 into the slot openings 22 and suppresses a cogging torque generated due to the slot openings 22 of the stator 20.

[0019] For this purpose, the canned motor for reducing a cogging torque according to the present invention, as shown in Fig. 3 illustrates a can 10 having a plurality of fastening guides 11 peripherally formed on an outer peripheral surface thereof, and metal pins 12 inserted into the fastening guide 11. The fastening guides 11 integrally protrude from an outer peripheral surface of the can 10 when the can 10 is injection-molded, for example, and the metal pins 12 are mounted in the can 10 by insert molding, for example, while being inserted into the fastening guides 11.

[0020] Since an injection-molding resin may be injected into a mold to form an injection-molded part while another part is inserted within a specific portion of the mold during an insert-molding process, the inserted part is integrally formed as a portion of the injection-molded part in this embodiment of the present invention. Consequently, since the split tube 10 and the metal pins 12 are insert-molded in this embodiment of the present invention, the metal pins 12 are integrally formed on an outer peripheral surface of the split tube while being inserted into the fixing guides 11. The fixing guide 11 extends perpendicular to a circumferential direction of the split tube 10, and the metal pins 12 are inserted into and connected to the fixing guide 11.

[0021] The split tube 10 and the metal pins 12 are formed integrally, for example, by overmolding, such that the metal pins 12 are firmly seated within the fastening guides 11 of the split tube 10. Consequently, the metal pins 12 are prevented from being separated from the fastening guides 11 of the split tube 10.

[0022] As in the Fig. 3 and Fig. 4, the left and right ends of the inserted metal pins 12 are exposed through the opening on the left and right sides of the fixing guides 11, which contact the slotted openings 22 of the stator 20. That is, since the metal pins 12 are tightly fitted to the inner wall surfaces of the fixing guides 11, they are prevented from being separated from the fixing guides 11 even if portions of the fixing guides 11 are opened during the formation of the fixing openings 11. As shown in Fig. 3, by exposing the left and right ends of the metal pins 12, which are formed such that the left and right ends of the mounting holes 11 are opened lengthwise and which are inserted into the mounting holes 11, the metal pins 12 are allowed to directly contact the stator 20.

[0023] That is, since the fixing guides 11 are inserted into the slotted holes 22 of the stator 20, when the gap tube 10 is inserted into the stator 20, the metal pins 12, the opposite ends of which are shown in Fig.4 are exposed, inserted into the slot openings 22 to fit the slot openings 22, and the metal pins 12 are attached to the slot openings 22 to directly contact the stator 20. Thus, the stator 20 is mounted on an outer peripheral surface of the can 10 to have the slots 21 with the closed slot openings 22. Furthermore, the metal pins 12, which are inserted into and fitted to the slot openings 22, are formed of a magnetic material.

[0024] Meanwhile, the fixing guides 11 protrude from an outer peripheral surface of the can 10 to reinforce the can 10 and also serve to guide a mounting location when the stator 20 is assembled with the can 10. Furthermore, the canned motor of the present invention can prevent slippage of the stator 20 by inserting the metal pins 12 of the can 10 into the slotted holes 22 of the stator 20 and fitting the metal pins 12 to the slotted holes 22.

[0025] As described above, the canned motor of the present invention includes a can 10 which is inserted into a housing to seal a coil mounted inside the housing, and a stator 20 which is mounted on an outer peripheral surface of the can 10 and inserted along an inner peripheral surface of the housing, wherein metal pins 12 are mounted on an outer peripheral surface of the can 10 to be inserted into the fixing guides 11 to be integral with the fixing guides 11.

Claims

[1] Canned motor for reducing a cogging torque, the canned motor comprising: a can (10) which is inserted into a housing (1) for sealing a coil mounted within the housing (1); and a stator (20) mounted on an outer peripheral surface of the can (10) and inserted along an inner peripheral surface of the housing (1); wherein a plurality of fixing guides (11) protrude from an outer peripheral surface of the split tube (10), and metal pins (12) are inserted into the fixing guides (11) to be integral with the fixing guide (11); wherein the metal pins (12) are inserted into slot openings (22) of the stator (20) when inserting them into the stator (20) and are attached to the same. [2] Canned motor according to claim 1, wherein the can (10) is formed together with the metal pins (12) by overmolding in order to fix the metal pins (12) in the fixing guides (11). [3] A canned motor according to claim 1, wherein left and right sides of the fixing guides (11) contacting the slotted holes (22) of the stator (20) are opened to allow the inserted metal pins (12) to directly contact the stator (20). [4] Canned motor according to claim 1, wherein the metal pin (12) is formed of a magnetic material. [5] Canned motor according to claim 1, wherein the metal pins (12) reduce a cogging torque. [6] A canned motor according to claim 1, wherein the metal pins (12) reduce noise and vibration during operation of the canned motor.

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