Motor shaft grounding device

Abstract

The present invention relates to a motor shaft grounding device capable of preventing damage to a bearing by reducing the shaft voltage generated by a motor shaft by grounding the motor shaft. The motor shaft grounding device comprises: a ring plate having a hole that passes through the middle and fastened to a motor main body; a pair of fastening plates installed on both sides of the inner circumferential surface of the ring plate; and a filament unit fastened to the fastening plates and having an end portion electrically connected to the outer circumferential surface of the motor shaft. With this configuration, the motor shaft grounding device can be fastened to the motor main body to ground the motor shaft by a simple method and thereby effectively reduce the shaft voltage and prevent damage to the bearing.

Description

Motor shaft grounding device

[0001] The present invention relates to a motor shaft grounding device, and more particularly, to a motor shaft grounding device capable of preventing damage to a bearing due to a shaft voltage of a motor.

[0002] Recently, purely electric, eco-friendly vehicles, such as electric vehicles and fuel cell vehicles, have been attracting attention. These electric, eco-friendly vehicles are equipped with electric motors, which generate rotational power from electric energy, instead of internal combustion engines like conventional engines.

[0003] A motor used as a power source for an eco-friendly vehicle includes a housing, a stator fixedly installed inside the housing, and a rotor positioned with a certain gap from the stator and rotating around a motor shaft, which is a drive shaft.

[0004] Motors used in eco-friendly vehicles receive three-phase AC power through an inverter. The inverter converts the battery's DC power into three-phase AC through power module switching. The three-phase voltage is not a perfect sine wave, but rather a square wave, so the sum of the three-phase voltages is not zero. This is called the common-mode voltage. The common-mode voltage applied to the motor coils causes an axial voltage to be generated on the motor shaft due to the parasitic capacitance within the motor.

[0005] The shaft voltage generated in this way causes a potential difference between the inner and outer rings of the bearing supporting the motor shaft, which induces erosion of the bearing through a discharge mechanism inside the bearing, and this erosion has a serious impact on the durability of the motor, such as by damaging the bearing.

[0006] The present invention was created to solve the above problems, and its purpose is to provide a motor shaft grounding device that can prevent damage to a bearing by grounding the motor shaft and reducing the axial voltage generated from the motor shaft.

[0007] In order to achieve the above-described purpose, a motor shaft grounding device according to a preferred embodiment of the present invention comprises: a ring plate having a center formed through and fastened to a motor body; a pair of fastening plates installed on both sides of an inner circumference of the ring plate; and a filament portion fastened to the fastening plates and having an end electrically contacting an outer circumference of a motor shaft.

[0008] More specifically, the fastening plate may include: a fastening plate body having a center formed through and installed on an inner surface of the ring plate; a plurality of radially formed through holes formed through the fastening plate body; a fastening portion formed across the center of the through holes in a radial direction in the fastening plate body and fastening while surrounding the filament portion; and a guide portion provided on at least one side of the fastening portion to support a side surface of the filament portion.

[0009] Here, the fastening portion may include a base portion provided across the center of the through hole and on which the filament portion is mounted; a first bend portion provided on one side of the base portion in the circumferential direction and configured to wrap the filament portion mounted on the base portion while being bent and deformed; and a second bend portion provided on the other side of the base portion in the circumferential direction and configured to wrap the filament portion mounted on the base portion while being bent and deformed.

[0010] At this time, the guide portion may be provided on both sides of the base portion in the circumferential direction, and may be provided on the outer side of the first bend portion and the second bend portion in the longitudinal direction of the filament portion to support both sides of the filament portion.

[0011] As another example, the fastening member may be formed such that the first bending member is positioned at the center and the second bending members are positioned on both sides of the first bending member in the radial direction.

[0012] In addition, the motor shaft grounding device of the present invention may be formed such that the ring plate includes a fastening groove formed inwardly on the inner surface, and the fastening plate body includes a positional groove formed inwardly on the inner surface and having the same shape as the fastening groove of the ring plate.

[0013] At this time, the fastening plate may be formed so that the fastening portion is symmetrical left and right with respect to a reference line passing through the center point and the center of the positioning groove.

[0014] In this case, a pair of the fastening plates may be installed on both sides of the ring plate so that the positioning groove is positioned at the same position as the fastening groove, and the filament portion may be positioned at the same position centered on the ring plate.

[0015] According to the motor shaft grounding device of the present invention, the motor shaft can be grounded in a simple manner by being fastened to the motor body, thereby effectively reducing shaft voltage and preventing damage to the bearing.

[0016] And, according to the present invention, the effect of improving resistance performance can be obtained by providing filament portions on both sides of the ring plate.

[0017] In addition, according to the present invention, guide parts for supporting both sides of the filament part are further provided on both sides of the fastening part that fastens the filament part, so that the filament part can be supported more stably.

[0018] FIG. 1 is a schematic drawing showing a motor having a motor shaft grounding device installed according to an embodiment of the present invention;

[0019] Figure 2 is a perspective view schematically illustrating a motor shaft grounding device according to an embodiment of the present invention;

[0020] Figure 3 is an exploded perspective view schematically illustrating a motor shaft grounding device according to an embodiment of the present invention;

[0021] Figure 4 is a plan view schematically illustrating a motor shaft grounding device according to an embodiment of the present invention;

[0022] Fig. 5 is a cross-sectional view schematically illustrating the AA area of ​​Fig. 4;

[0023] Figure 6 is a perspective view schematically illustrating a fastening plate extracted from a motor shaft grounding device according to an embodiment of the present invention.

[0024] FIG. 7 is a perspective view schematically illustrating another embodiment of a fastening plate in a motor shaft grounding device according to an embodiment of the present invention.

[0025] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0026] The present invention is susceptible to various modifications and embodiments. Specific embodiments are illustrated in the drawings and described in detail in the detailed description. This is not intended to limit the invention to specific embodiments, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention.

[0027] The terminology used in this application is solely for the purpose of describing specific embodiments and is not intended to limit the present invention. Singular expressions may include plural expressions, unless the context clearly dictates otherwise.

[0028] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries, such as those defined in the present application, may be interpreted to have a meaning consistent with their meaning in the context of the relevant technology, and, unless explicitly defined herein, may not be interpreted in an idealized or overly formal sense.

[0029]

[0030] Hereinafter, specific embodiments of the present invention will be described with reference to the attached drawings.

[0031] FIG. 1 is a schematic drawing of a motor having a motor shaft grounding device installed according to an embodiment of the present invention, FIGS. 2 to 4 are a perspective view, an exploded perspective view, and a plan view schematically illustrating the motor shaft grounding device, and FIG. 5 is a cross-sectional view schematically illustrated by cutting along the AA section of FIG. 4. In addition, FIG. 6 is a schematic perspective view of a fastening plate extracted from the motor shaft grounding device, and FIG. 7 is a schematic perspective view of another embodiment of the fastening plate.

[0032] Referring to FIGS. 1 to 7, a motor shaft grounding device (100) according to an embodiment of the present invention is a device that is provided in a motor body (10), electrically connected to a motor shaft (20), and then grounded to reduce shaft voltage generated in the motor shaft (20).

[0033] To this end, a motor shaft grounding device (100) according to an embodiment of the present invention comprises a ring plate (200) having a center formed through and fastened to a motor body (10), a pair of fastening plates (300) installed on both sides of the inner surface of the ring plate (200), and a filament portion (400) fastened to the fastening plate (300) and having an end electrically contacting the outer surface of the motor shaft (20).

[0034] Here, the ring plate (200), the fastening plate (300), and the filament portion (400) are made of a conductive material that conducts electricity for grounding. For example, the ring plate (200) and the fastening plate (300) may be made of aluminum.

[0035] In addition, the filament portion (400) can be formed by bundling strands made of at least one of carbon fiber, stainless steel, and conductive plastic.

[0036] For example, the filament portion (400) may be formed into a brush shape by bundling carbon fiber strands having a diameter of about 5 to 100 μm.

[0037] The above fastening plate (300) is configured such that a plurality of the above filament parts (400) are fastened radially, and the above filament parts (400) are installed on the inner surface of the above ring plate (200) in a fastened state.

[0038]

[0039] *38 More specifically, the fastening plate (300) may include a fastening plate body (310) having a center formed through and installed on the inner surface of the ring plate (200), a plurality of radially formed through holes (320) formed through the fastening plate body (310), a fastening portion (330) formed across the center of the through holes (320) in a radial direction in the fastening plate body (310) and fastening while surrounding the filament portion (400), and a guide portion (334) provided on at least one side of the fastening portion (330) and supporting a side surface of the filament portion (400).

[0040] Here, the filament portion (400) fastened to the fastening portion (330) is arranged so that its end is exposed to the penetrating center of the fastening plate body (310) and is provided to contact the outer circumferential surface of the motor shaft (20).

[0041] In addition, the above fastening portion (330) may be provided in multiple numbers and arranged radially on the fastening plate body (310).

[0042] For example, as illustrated in FIG. 4, the fastening portions (330) may be formed in eight pieces at a 45-degree angle along the circumferential direction of the fastening plate body (310). Of course, the number of the fastening portions (330) is not limited thereto, and two or more may be provided and formed radially on the fastening plate body (310) at equal intervals.

[0043] As illustrated in FIG. 6, the fastening portion (230) may include a base portion (331) that is provided across the center of the through hole (320) and on which the filament portion (400) is mounted, a first bend portion (332) that is provided on one side of the base portion (331) in the circumferential direction and that wraps around the filament portion (400) mounted on the base portion (331) while being bent, and a second bend portion (333) that is provided on the other side of the base portion (331) in the circumferential direction and that wraps around the filament portion (400) mounted on the base portion (331) while being bent.

[0044] And, as shown in FIG. 6, the guide portion (334) is provided on both sides of the base portion (331) in the circumferential direction, and is provided on the outer side of the first bend portion (332) and the second bend portion (333) in the longitudinal direction of the filament portion (400) to support both sides of the filament portion (400).

[0045] With this configuration, four guide parts (334) are formed on both sides of both ends of the base part (331) to support the filament part (400) that is seated on the base part (331), and the first bending part (332) and the second bending part (333) can be bent and deformed into the filament part (400) to fasten and fix the filament part to the base part (331).

[0046] In this way, by providing the guide portion (334) on both sides of both ends of the base portion (331), the filament portion (400) can be stably fastened and fixed toward the central axis without shaking left and right.

[0047] And, as shown in FIG. 6, the fastening portion (330) may be formed by each of the first bending portion (332) and the second bending portion (333) being provided as one, and being bent and deformed on both sides of the base portion (331) to fasten and fix the filament portion (400) to the base portion (331).

[0048] Of course, the number of bending parts for fastening and fixing the above filament part (400) is not limited to two, and two or more may be provided.

[0049] As another example, as illustrated in FIG. 7, the fastening portion (330a) may be formed such that the first bend portion (332a) is positioned at the center, and second bend portions (333a) are arranged on both sides of the first bend portion (332a) based on the radial direction. That is, the second bend portions (333a) may be provided as a pair spaced apart from each other by a predetermined distance in the radial direction, and the first bend portion (332a) may be arranged between the pair of second bend portions (333a).

[0050] In this form, when the first bend portion (332a) and the second bend portion (333a) are bent to wrap the filament portion (400), the second bend portion (333a) and the first bend portion (332a) are sequentially arranged in the radial direction.

[0051] At this time, the guide portion (334a) may be provided on the outer side of the second bending portion (333a) provided on both sides of the first bending portion (332a).

[0052] The fastening portion (330) can be formed simultaneously in the press punching process to form the through hole (320) in the fastening plate body (310). That is, the fastening portion (330) is formed integrally with the fastening plate body (310).

[0053] In addition, the fastening portion (330) can be fastened and fixed to the filament portion (400) by applying a conductive adhesive or conductive grease to the inner surface that comes into contact with the filament portion (400). Through this, the filament portion (400) can be better fastened to the fastening portion (330) while improving electrical conductivity.

[0054] The above-described fastening plate (300) may be integrally fastened to the ring plate (200) by laser welding or spot welding after fastening the filament portion (400). Of course, the present invention is not limited thereto, and the fastening plate (300) may be fastened to the ring plate (200) using bolts.

[0055] The above ring plate (200) is formed in a ring shape with the center penetrating, and is fastened to the motor body (10) so that the motor shaft (20) is positioned penetrating the center. At this time, the filament portion (400) comes into contact with the outer peripheral surface of the motor shaft (20).

[0056] And, as shown in Fig. 5, the ring plate (200) is formed with both front and rear surfaces sunken inward, and a pair of the fastening plates (300) are fastened to each of the sunken inner surfaces. That is, the fastening plates (300) are fastened to each of the two sides of the ring plate (200), so that a greater number of filament portions (400) can come into contact with the motor shaft (20), thereby improving resistance performance.

[0057] In addition, the ring plate (200) may include a fastening groove (210) formed inwardly from the inner surface, and the fastening plate body (310) may include a positioning groove (340) formed inwardly from the inner surface and having the same shape as the fastening groove (210) of the ring plate (200).

[0058] With this configuration, a pair of the fastening plates (300) are installed on both sides of the ring plate (200) so that the positioning groove (340) is positioned at the same position as the fastening groove (210), as shown in FIGS. 2 and 3.

[0059] And, as shown in FIG. 4, the fastening plate (300) can be formed so that the fastening portion (330) is symmetrical left and right with respect to the reference line (L) passing through the center point (C) and the center of the positioning groove (340).

[0060] In this way, when the fastening portion (330) is formed, if a pair of fastening plates (300) are installed on both sides of the ring plate (200) so that the positioning groove (340) is positioned at the same position as the fastening groove (210), the filament portion (400) can be fastened so that it is positioned at the same position with respect to the ring plate (200), as shown in FIG. 2.

[0061] Furthermore, in the case where a fixing projection (not shown) protruding in the axial direction is formed on the motor body (10), the fixing projection may be inserted into the positioning groove (340) and the fastening groove (210) for fastening.

[0062] In this way, the motor shaft grounding device (100) of the present invention can improve resistance performance by providing a pair of fastening plates (300) equipped with a plurality of filament parts (400) and fastening them to both sides of the ring plate (200) so that more filament parts (400) can be brought into contact with the motor shaft (20). In addition, guide parts (334) that support both sides of the filament parts (400) are further provided on both sides of the fastening parts (330) that fasten the filament parts (400), so that the filament parts (400) can be supported more stably so as not to shake left and right.

[0063]

[0064] Although the present invention has been described in detail through specific examples, this is for the purpose of specifically explaining the present invention, and the present invention is not limited thereto, and it is clear that the present invention can be modified or improved by a person having ordinary knowledge in the relevant field within the technical spirit of the present invention.

[0065] All simple modifications or changes of the present invention fall within the scope of the present invention, and the specific scope of protection of the present invention will be made clear by the appended claims.

Claims

1. A ring plate formed through the center and fastened to the motor body; A pair of fastening plates installed on both sides of the inner surface of the above ring plate; and A filament portion that is fastened to the above fastening plate and has an end that electrically contacts the outer surface of the motor shaft; A motor shaft grounding device including:

2. In paragraph 1, The above fastening plate is, A fastening plate body having a center formed through and installed on the inner surface of the ring plate; A plurality of through holes formed radially and penetrating through the above-mentioned fastening plate body; A fastening portion formed across the center of the through hole in the radial direction in the above fastening plate body and fastened while wrapping around the filament portion; and A guide portion provided on at least one side of the above fastening portion to support the side surface of the filament portion; A motor shaft grounding device characterized by including:

3. In paragraph 2, The above fastening part is, A base portion provided across the center of the above through hole and on which the filament portion is mounted; A first bending portion provided on one side of the circumferential direction of the base portion and wrapping the filament portion settled on the base portion while being bent and deformed; and A second bending portion provided on the other side of the circumferential direction of the base portion and wrapping the filament portion that is fixed to the base portion while being bent and deformed; A motor shaft grounding device characterized by including:

4. In paragraph 3, The above guide part, A motor shaft grounding device characterized in that it is provided on both sides of the circumferential direction of the base portion and is provided on the outer side of the first bend portion and the second bend portion in the longitudinal direction of the filament portion to support both sides of the filament portion.

5. In paragraph 3, The above fastening part is, A motor shaft grounding device characterized in that the first bending portion is positioned at the center and the second bending portions are formed to be positioned on both sides of the first bending portion based on the radial direction.

6. In paragraph 2, The above ring plate includes a fastening groove formed inwardly on the inner surface; A motor shaft grounding device characterized in that the above-mentioned fastening plate body is formed to be sunken inward on the inner surface and includes a positioning groove having the same shape as the fastening groove of the ring plate.

7. In paragraph 6, The above fastening plate, A motor shaft grounding device characterized in that the fastening portion is formed so as to be symmetrical left and right about a reference line passing through the center point and the center of the positioning groove.

8. In paragraph 7, A pair of the above fastening plates, A motor shaft grounding device characterized in that the positioning groove is installed on both sides of the ring plate so that the positioning groove is positioned at the same position as the fastening groove, and the filament portion is positioned at the same position centered on the ring plate.

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