electric machine

Abstract

A motor includes a housing including a partition wall partitioning a first space and a second space, a stator disposed in the first space, a rotor disposed in the stator, a shaft rotating together with the rotor and having a sensor magnet disposed at one end thereof, and a printed circuit board disposed in the second space and having a position detection sensor disposed on one surface thereof, the position detection sensor facing the sensor magnet in a vertical direction, wherein the partition wall has a shaft hole penetrating from one surface to the other surface.

Description

TECHNICAL FIELD

[0001] The present embodiment relates to an electric motor. BACKGROUND

[0002] The following description provides background information on the present embodiment and does not describe the prior art.

[0003] A pump is used to discharge a flow at a constant pressure. Oil circulated by the pump can be used to operate a hydraulic system using hydraulic pressure, or for cooling or lubricating action.

[0004] A mechanical oil pump (MOP) is an oil pump that operates using the power of a machine, such as an engine.

[0005] Recently, research into hybrid vehicles and electric vehicles has been actively conducted in order to improve fuel efficiency and reduce carbon emissions.

[0006] Accordingly, there is an increasing demand for an electric oil pump (EOP) operated by an electric motor instead of a mechanical oil pump (MOP) operated by the power of a machine, such as an engine.

[0007] The EOP can include a normal motor region and a pump region. The motor region includes a stator, a rotor, and a rotating shaft. The pump region includes an inner rotor coupled to one end of the rotating shaft to receive a rotational force from the rotating shaft, and an outer rotor accommodating the inner rotor.

[0008] In order to detect the position of the rotor or the rotating shaft, a magnet can be installed on an end portion of the rotating shaft. In addition, a printed circuit board on which a position detection sensor is mounted can be provided in a region separated from the motor region. Accordingly, the position detection sensor detects a magnetic force generated from the magnet according to the rotation of the rotating shaft, and can detect the position of the rotating shaft.

[0009] Considering the structural characteristics inside the pump, the printed circuit board should be provided in a region separated from the arrangement region of the rotating shaft. However, as the distance between the magnet and the position detection sensor becomes greater, the strength variation of the magnetic force becomes weaker, and thus there is a problem in that the rotational position of the rotor and the rotating shaft cannot be accurately detected. SUMMARY

[0010] TECHNICAL PROBLEM

[0011] The present embodiment aims to provide an electric motor capable of accurately detecting the position of a rotating shaft by improving the structure and reducing the size of the product.

[0012] TECHNICAL SOLUTION

[0013] In one embodiment, the electric motor includes a housing including a partition wall that separates a first space and a second space, a stator disposed in the first space, a rotor disposed in the stator, a shaft that rotates together with the rotor and is provided with a sensor magnet at one end of the shaft, and a printed circuit board disposed in the second space and having a position detection sensor disposed on one surface to face the sensor magnet in a vertical direction, wherein a shaft hole is provided in the partition wall to penetrate from one surface to the other surface.

[0014] In addition, the electric motor can include a sealing member that contacts the partition wall with a lower surface, and the accommodation groove is formed such that the position detection sensor is disposed on an upper surface of the accommodation groove.

[0015] In addition, the partition wall can include a first guide protruding upward from the upper surface and a second guide protruding upward from an upper surface of the first guide.

[0016] In addition, an upper surface of the sensor magnet can be disposed lower than an upper surface of the second guide, and can be disposed higher than the upper surface of the partition wall.

[0017] In addition, the sealing member includes a first body disposed on a lower surface of the printed circuit board and a second body protruding downward from a lower surface of the first body, and the second body can be disposed inside the second guide.

[0018] In addition, a lower surface of the second body can contact an upper surface of the first guide.

[0019] In addition, a side surface of the second body can contact an inner surface of the second guide.

[0020] In addition, a lower surface of the first body can contact an upper surface of the second guide.

[0021] In addition, an inner peripheral surface of the shaft hole can be formed with an inclined surface such that a cross-sectional area becomes larger as it travels downward.

[0022] As another embodiment, the electric motor includes a housing including a partition wall that separates a first space and a second space, a stator disposed in the first space, a rotor disposed in the stator, a shaft that rotates together with the rotor and is provided with a sensor magnet at one end of the shaft, and a printed circuit board disposed in the second space and having a position detection sensor disposed on one surface to face the sensor magnet in a vertical direction, wherein a shaft hole is provided in the partition wall to penetrate from one surface to the other surface, and wherein a sealing member is disposed between an inner peripheral surface of the shaft hole and the sensor magnet.

[0023] Advantageous effects

[0024] According to the present application, since the distance between the sensor magnet and the position detection sensor is formed closer than in the prior art, there is the advantage that the positions of the rotor and the shaft can be detected more accurately.

[0025] In addition, since a portion of the shaft arrangement region is compensated for by the shaft hole, there is the advantage that the product can be miniaturized. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a perspective view of a motor according to a first embodiment of the present application.

[0027] Figure 2 is a perspective view of a motor according to a first embodiment of the present application, shown at a different angle.

[0028] Figure 3 is a plan view showing the upper surface of a motor according to a first embodiment of the present application.

[0029] Figure 4 is a sectional view of a shaft hole according to a first embodiment of the present application.

[0030] Figure 5 is a perspective view showing the upper surface of a second space according to a first embodiment of the present application.

[0031] Figure 6 is a perspective view showing the combined state of a sealing member in Figure 5

[0032] Figure 7 is a sectional view of a rotation sensing structure according to a first embodiment of the present application.

[0033] Figure 8 is a perspective view of a motor according to a second embodiment of the present application.

[0034] Figure 9 is a perspective view of a motor according to a second embodiment of the present application, shown from another angle.

[0035] Figure 10 is a plan view showing the upper surface of a motor according to a second embodiment of the present application.

[0036] Figure 11 is a perspective view showing the bottom surface of a second space according to a second embodiment of the present application.

[0037] Figure 12 is a perspective view of a rotation sensing structure according to a second embodiment of the present application.

[0038] Figure 13 is a sectional view of a rotation sensing structure according to a second embodiment of the present application. DETAILED DESCRIPTION​

[0039] Hereinafter, preferred embodiments of the present application will be described in detail with reference to the accompanying drawings.

[0040] However, the technical idea of the present application is not limited to some embodiments to be described, but can be implemented in various forms, and one or more constituent elements can be selectively combined or replaced between embodiments within the scope of the technical idea of the present application.

[0041] In addition, unless explicitly defined and described otherwise, the terms used in the embodiments of the present application, including technical and scientific terms, can be interpreted as meanings that can be commonly understood by one of ordinary skill in the art, and the commonly used terms (for example, terms defined in a dictionary) can be interpreted in the meaning that considers the context of the prior art.

[0042] In addition, the terms used in the present specification are used to describe the embodiments, and are not intended to limit the present application.

[0043] In the present specification, the singular form can include the plural form unless specifically stated and described otherwise, and when described as "at least one of (or more than one of) A, B, and C", it can include one or more of all combinations of A, B, and C that can be combined.

[0044] In addition, in describing the components of the embodiments of the present application, terms such as first, second, A, B, (a), and (b) can be used. These terms are used only to distinguish the components from other components, and the terms are not limited to the essence, order, or sequence of the components.

[0045] Also, when a component is described as being "connected", "coupled", or "linked" to another component, the component can not only be directly connected, coupled, or linked to the other component, but can also include a case where another component is "connected", "coupled", or "linked" between the component and the other component.

[0046] In addition, when described as being "on" or "under" each component, "on" or "under" can not only include a case where the two components are in direct contact with each other, but also include a case where one or more other components are formed or disposed between the two components. In addition, when expressed as "on" or "under", based on one component, not only the upward direction can be included, but also the downward direction can be included.

[0047] Figure 1 is a perspective view of a motor according to a first embodiment of the present application; Figure 2 is a perspective view of a motor according to a first embodiment of the present application, shown at different angles; Figure 3is a plan view showing an upper surface of a motor according to a first embodiment of the present application; Figure 4 is a sectional view of a shaft hole according to the first embodiment of the present application; Figure 5 is a perspective view showing an upper surface of a second space according to the first embodiment of the present application;

[0048] Figure 6 is a perspective view showing a combined state of a sealing member in Figure 5 ; Figure 7 is a sectional view of a rotation sensing structure according to the first embodiment of the present application.

[0049] Referring to Figures 1 to 7 , an appearance of the motor 100 according to the first embodiment of the present application can be formed by combining the case 110 with the cover 200. The cover 200 can be combined to the upper surface of the case 110.

[0050] A first space 111 can be formed inside the case 110, thereby disposing the stator 120, a rotor (not shown), and the shaft 180. A separate cover (not shown) can be combined to the lower surface of the case 110 to cover the lower surface of the case 110. Separate spaces inside the case can be partitioned by the first space 111.

[0051] In the first space 111, the stator 120, the rotor (not shown), and the shaft 180 can be disposed. The stator 120 can include a stator core 122 and a coil 124 wound around the stator core 122. An insulator (not shown) can be disposed on the outer surface of the stator core 122, thereby winding the coil 124.

[0052] A rotor combined with a shaft can be disposed at the center inside the stator 120. The rotor can include a rotor core and a magnet. Accordingly, when a current is applied to the coil, the shaft can rotate together with the rotor through electromagnetic interaction between the coil and the magnet. A bearing 186 for supporting rotation of the shaft 180 can be disposed in the first space 111.

[0053] A second space 118 can be formed on the upper surface of the case 110, thereby disposing a printed circuit board 190. The second space 118 can be formed to be more concave downward than other regions of the upper surface of the case 110. The second space 118 can be partitioned from the other regions by an edge portion 119. When the cover 200 is combined to the upper surface of the case 110, the second space 118 can be covered from the outer regions.

[0054] The printed circuit board 190 can be disposed in the second space 118. A plurality of electronic elements for driving the motor 100 can be disposed in the printed circuit board 190. A position detection sensor 192, which will be described later, can be disposed in the printed circuit board 190.

[0055] The first space 111 and the second space 118 can be partitioned by the partition wall 140. A lower surface of the partition wall 140 can form an upper surface of the first space 111. An upper surface of the partition wall 140 can form a bottom surface of the second space 118.

[0056] The terminal 130 can be disposed on the bottom surface of the second space 118 by the partition wall 140. The terminal 130 can electrically couple the printed circuit board 190 and the coil 124 to each other.

[0057] Meanwhile, the sensor magnet 182 can be disposed at one end of the shaft 180 to detect the position of the rotor and the shaft 180. The sensor magnet 182 can be coupled to the upper end of the shaft 180. The sensor magnet 182 can be coupled to the upper outer circumferential surface of the shaft 180.

[0058] The position detection sensor 192 can be disposed on the lower surface of the printed circuit board 190 facing the sensor magnet 182. The position detection sensor 192 and the sensor magnet 182 can be disposed to face each other in the up-and-down direction. The position detection sensor 192 can detect a magnetic force generated by the sensor magnet 182 to detect the position of the shaft 180. The position detection sensor 192 is a 3-axis linear sensor capable of detecting the position in the X-axis, Y-axis, and Z-axis directions, and can detect the position of the shaft 180 by converting two sensing values among the measured values into linear values. The position detection sensor 192 can include a Hall sensor. The separation distance between the sensor magnet 182 and the position detection sensor 192 can be 1.0 mm or less.

[0059] An upper surface of the sensor magnet 182 can be disposed higher than the upper surface of the partition wall 140. The upper surface of the sensor magnet 182 can be disposed higher than the bottom surface of the second space 118.

[0060] The shaft hole 150 can be formed in the partition wall 140 so that at least a portion of the shaft 180 penetrates from the upper surface to the lower surface. A portion of the upper end of the shaft 180 can be disposed inside the shaft hole 150 through the shaft hole 150. Since the sensor magnet 182 is disposed at the upper end of the shaft 180, the sensor magnet 182 and the position detection sensor 192 can be disposed close to each other through the shaft hole 150.

[0061] In detail, on the upper surface of the partition wall 140, a first guide 152 protruding upward and having an inner side provided with a shaft hole 150, and a second guide 154 protruding upward from the upper surface of the first guide 152 can be included. The first guide 152 and the second guide 154 can be formed to have steps. The first guide 152 can be disposed inside the second guide 154. The upper surface of the second guide 154 can be formed to be higher than the upper surface of the first guide 152. The upper end of the shaft 180 and the upper surface of the sensor magnet 182 can be disposed to be lower than the upper surface of the first guide 152.

[0062] An inclined surface 156 can be formed on the inner circumferential surface of the shaft hole 150 such that the cross-sectional area widens as it travels downward. Unlike this, the inner circumferential surface of the shaft hole 150 can be a curved surface having a shape in which the cross-sectional area widens as it travels downward. Accordingly, when the shaft 180 is fitted inside the housing 110, the shaft 180 can be easily guided to the shaft hole 150.

[0063] A sealing member 220 can be disposed on the lower surface of the printed circuit board 190. The upper surface of the sealing member 220 is coupled to the lower surface of the printed circuit board 190, and the lower surface can be coupled to the upper surface of the partition wall 140. The sealing member 220 can be disposed to surround the position detection sensor 192.

[0064] In more detail, the sealing member 220 can include a first body 224 coupled to the lower surface of the printed circuit board 190, and a second body 226 protruding downward from the lower surface of the first body 224 and disposed inside the second guide 154. The cross-sectional area of the second body 226 can be formed to be smaller than that of the first body 224.

[0065] The lower surface of the second body 226 can be in contact with the upper surface of the first guide 152. The side surface of the second body 226 can be in contact with the inner surface of the second guide 154. The lower surface of the first body 224 can be in contact with the upper surface of the second guide 154. According to the structure as described above, the first space 111 and the second space 118 can be sealed from each other by the sealing member 220.

[0066] Meanwhile, inside the first body 224 and the second body 226, a receiving groove 222 in which the position detection sensor 192 is received can be formed. That is, the receiving groove 222 can be formed to be more recessed downward than other areas from the center of the upper surface of the sealing member 220.

[0067] The sealing member 220 can be formed of a rubber or a resin material.

[0068] According to the above-described structure, since the distance between the sensor magnet and the position detection sensor is formed closer than in the prior art, there is an advantage that the positions of the rotor and the shaft can be more accurately detected.

[0069] In addition, since a portion of the shaft arrangement region is compensated for by the shaft hole, there is an advantage that the product can be miniaturized.

[0070] Hereinafter, an electric motor according to a second embodiment will be described.

[0071] Figure 8 is a perspective view of an electric motor according to the second embodiment of the present application; Figure 9 is a perspective view of an electric motor according to the second embodiment of the present application, shown from another angle; Figure 10 is a plan view showing an upper surface of an electric motor according to the second embodiment of the present application; Figure 11 is a perspective view showing a bottom surface of a second space according to the second embodiment of the present application; Figure 12 is a perspective view of a rotation sensing structure according to the second embodiment of the present application; Figure 13 is a sectional view of a rotation sensing structure according to the second embodiment of the present application.

[0072] Referring to Figures 8 to 13 The appearance of the electric motor 300 according to the second embodiment of the present application can be formed by combining the case 310 and the cover 500. The cover 500 can be combined to the upper surface of the case 310.

[0073] A first space 311 can be formed inside the case 310, so that the stator 320, the rotor (not shown), and the shaft 380 are disposed. A separate cover (not shown) can be combined to the lower surface of the case 310 to cover the lower surface of the case 310. Separate spaces inside the case can be partitioned by the first space 311.

[0074] In the first space 311, the stator 320, the rotor (not shown), and the shaft 380 can be disposed. The stator 320 can include a stator core 322 and a coil 324 wound around the stator core 322. An insulator (not shown) can be disposed on the outer surface of the stator core 322, so that the coil 324 is wound.

[0075] On the inside of the stator 320, a rotor combined with the shaft 380 can be disposed at the center. The rotor can include a rotor core and a magnet. Accordingly, when a current is applied to the coil, the shaft can rotate together with the rotor through electromagnetic interaction between the coil and the magnet. A bearing 386 for supporting the rotation of the shaft 380 can be disposed in the first space 311.

[0076] A second space 318 can be formed on the upper surface of the housing 310 so as to provide the printed circuit board 390. The second space 318 can be formed to be more recessed downward than other areas of the upper surface of the housing 310. The second space 318 can be separated from the other areas by the edge portion 317. The second space 318 can be covered from the outside area when the cover 500 is coupled to the upper surface of the housing 310.

[0077] The printed circuit board 390 can be provided in the second space 318. A plurality of electronic elements for driving the motor 300 can be provided in the printed circuit board 390. A position detection sensor 392, which will be described later, can be provided in the printed circuit board 390.

[0078] The first space 311 and the second space 318 can be separated by the partition wall 340. The lower surface of the partition wall 340 can form the upper surface of the first space 311. The upper surface of the partition wall 340 can form the bottom surface of the second space 318.

[0079] The terminal 330 can be provided on the bottom surface of the second space 318 by the partition wall 340. The terminal 330 can electrically couple the printed circuit board 390 and the coil 324 to each other.

[0080] Meanwhile, a sensor magnet 382 can be provided at one end of the shaft 380 to detect the position of the rotor and the shaft 380. The sensor magnet 382 can be coupled to the upper end of the shaft 380. The sensor magnet 382 can be coupled to the upper outer circumferential surface of the shaft 380.

[0081] At the upper end of the shaft 380, a magnet cover 386 can be provided to surround the sensor magnet 382. The magnet cover 386 can be coupled to the upper end of the shaft 380 to accommodate the sensor magnet 382 inside. A through-hole 387 is formed in the magnet cover 386 from the upper surface to the lower surface so that the sensor magnet 382 can be disposed to face the position detection sensor 392 in the up-and-down direction.

[0082] The position detection sensor 392 can be provided on the lower surface of the printed circuit board 390 facing the sensor magnet 382. The position detection sensor 392 and the sensor magnet 382 can be disposed to face each other in the up-and-down direction. The position detection sensor 392 can detect the magnetic force generated by the sensor magnet 382 to detect the position of the shaft 380. The position detection sensor 392 is a 3-axis linear sensor capable of detecting the position in the X-axis, Y-axis, and Z-axis directions, and can detect the position of the shaft 380 by converting two of the sensed values in the measurement value into linear values. The position detection sensor 392 can include a Hall sensor. The separation distance between the sensor magnet 382 and the position detection sensor 392 can be 1.0 mm or less.

[0083] An upper surface of the sensor magnet 382 can be disposed higher than a lower surface of the partition wall 340. The upper surface of the sensor magnet 382 forms the same height as a bottom surface of the second space 318, or can be disposed higher than the bottom surface of the second space 318.

[0084] A shaft hole 342 can be formed on the partition wall 340 such that at least a portion of the shaft 380 penetrates from the upper surface to the lower surface. A portion of an upper end of the shaft 180 can be disposed inside the shaft hole 342 through the shaft hole 342. Since the sensor magnet 382 is disposed at the upper end of the shaft 380, the sensor magnet 382 and the position detection sensor 392 can be disposed relatively close to each other through the shaft hole 342.

[0085] Inside the shaft hole 342, a sealing member 400 can be disposed. The sealing member 400 can be disposed in a manner that an inner circumferential surface thereof is in contact with an inner circumferential surface of the shaft hole 342 such that a portion of the inner circumferential surface presses a portion of an outer circumferential surface of the shaft 380. The sealing member 400 can be formed of a rubber material to seal the first space 311 and the second space 318 from each other.

[0086] In detail, the sealing member 400 can have a ring-shaped cross-section in which a hole 420 is formed at the center. A rib 412 protruding at least partially outward can be formed on an outer circumferential surface of the sealing member 400. The rib 412 can be disposed at a lower end of the outer circumferential surface of the sealing member 400.

[0087] A rib groove 346 recessed more outward than other regions can be disposed in a region of the inner circumferential surface of the shaft hole 342 facing the rib 412. Accordingly, the rib 412 can be coupled to the rib groove 346. Accordingly, the sealing member 400 can be firmly fixed inside the shaft hole 342.

[0088] On the inner circumferential surface of the sealing member 400, a pressing portion 414 protruding more inward than other regions can be formed. The pressing portion 414 can be in contact with the outer circumferential surface of the shaft 380. The pressing portion 414 can be formed to press an outer surface of the magnet cover 386. Accordingly, no gap is generated between the magnet cover 386 and the sealing member 400 such that the first space 311 and the second space 318 can be sealed from each other.

[0089] An inclined surface 416 having a shape in which a cross-sectional area thereof becomes smaller as it travels downward can be formed on an inner surface of the pressing portion 414. Accordingly, a region other than a lower end of the pressing portion 414 can be spaced apart from the outer surface of the magnet cover 386. That is, by forming a relatively small contact region between the sealing member 400 and the shaft 380, rotational efficiency of the shaft 380 can be improved.

[0090] In a peripheral region of the arrangement region of the shaft hole 342 in the upper surface of the partition wall 340, a protrusion 344 that protrudes upward more than other regions can be formed. Accordingly, the shaft hole 342 can be disposed inside the protrusion 344. Accordingly, since the upper end of the shaft 380 can be disposed relatively higher than other regions of the upper surface of the partition wall 340, the distance between the sensor magnet 382 and the position detection sensor 392 can be formed closer.

[0091] The upper surface of the protrusion 344 can be formed to protrude upward as it travels closer to the shaft hole 342 in the radial direction. The upper surface of the protrusion 344 can be a curved surface.

[0092] According to the above-described structure, since the distance between the sensor magnet and the position detection sensor is formed closer than in the related art, there is an advantage that the position of the rotor and the shaft can be more accurately detected.

[0093] In addition, since a portion of the shaft arrangement region is compensated for by the shaft hole, there is an advantage that the product can be miniaturized.

[0094] In the above description, all components constituting the embodiments of the present application are described to be combined or operated as a whole, but the present application is not necessarily limited to these embodiments. In other words, within the scope of the present application, all components can be selectively combined with one or more to be operated. In addition, unless explicitly stated otherwise, the above-described terms "include", "comprise" or "have" mean that the corresponding components can be inherent, and thus it should be understood that other components are not excluded but further include other components. Unless otherwise defined, all terms, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms commonly used, such as terms defined in a dictionary, should be interpreted in accordance with the meaning in the context of the related art, and unless explicitly defined in the present application, should not be interpreted in an ideal or overly formalized sense.

[0095] The above-described is only a description of the technical idea of the present application, and those skilled in the art to which the present application pertains can make various modifications and changes without departing from the essential characteristics of the present application. Therefore, the disclosed embodiments of the present application are not intended to limit the technical idea of the present application, but to describe the present application, and the scope of the technical idea of the present application is not limited by these embodiments. The scope of protection of the present application should be interpreted by the appended claims, and technical ideas within the equivalent scope thereof should be understood to be included in the scope of protection of the present application.

Claims

1. An electric motor comprising: a housing including a partition wall that separates a first space and a second space; a stator disposed in the first space; a rotor disposed in the stator; a shaft that rotates together with the rotor and is provided with a sensor magnet at one end of the shaft; a sealing member whose lower surface is in contact with the partition wall; and a printed circuit board disposed in the second space and having a position detection sensor disposed on one surface to face the sensor magnet in the up-down direction, wherein a shaft hole is provided in the partition wall to pass through from one surface to the other surface, and wherein at least a portion of the shaft is disposed in the shaft hole, wherein the partition wall includes a first guide that protrudes upward from an upper surface and a second guide that protrudes upward from an upper surface of the first guide, wherein the sealing member includes a first body disposed on a lower surface of the printed circuit board and a second body that protrudes downward from a lower surface of the first body, wherein the second body is disposed inside the second guide, wherein a lower surface of the first body is in contact with an upper surface of the second guide, wherein a lower surface of the second body is in contact with an upper surface of the first guide, and wherein a receiving groove in which the position detection sensor is disposed is formed on an upper surface of the sealing member. An upper surface of the sensor magnet is disposed lower than an upper surface of the second guide and higher than an upper surface of the partition wall.

2. The electric machine of claim 1, wherein, A side surface of the second body is in contact with an inner surface of the second guide.

3. The electric machine of claim 1, wherein, An inner peripheral surface of the shaft hole is formed with an inclined surface such that a cross-sectional area becomes larger as it travels downward.

4. The electric machine of claim 1, wherein, ​

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