Sensing device

Abstract

The embodiment discloses a sensing device including a stator connected to a first shaft, a first gear rotating in conjunction with the stator, a second gear rotating in conjunction with the first gear, a magnet coupled to the second gear, and a magnetic element disposed to correspond to the magnet, wherein one surface of the magnet disposed to face the magnetic element has an elliptical shape. Accordingly, even if the center of the magnet disposed on the second gear does not coincide with the center of the magnetic element in the axial direction, forming an offset, the sensing device can improve the accuracy of measuring the steering angle through the shape of the magnet.

Description

Technical Field

[0001] The embodiments relate to a sensing device.

Background Art

[0002] In order to ensure the steering stability of a vehicle, a steering assist device that uses separate power to assist steering can be used in the vehicle. In particular, an electric power steering device (EPS, Electronic Power Steering System) with less power loss and excellent accuracy is used.

[0003] The electric power steering device drives a motor with an electronic control unit (Electronic Control Unit) according to operating conditions and driver operation information sensed by a vehicle speed sensor, a torque sensor, an angle sensor, etc., to ensure turning stability and provide a rapid restoring force, thereby enabling the driver to drive safely.

[0004] The angle sensor measures the steering angle of the steering wheel by using a main gear that rotates in conjunction with the rotation of the rotor, a sub-gear that meshes with the main gear and rotates, a magnet coupled to the sub-gear, and a Hall IC (Hall IC) that senses a change in the magnetic force of the magnet.

[0005] However, when the center of the magnet fixed to the sub-gear and the center of the Hall IC arranged corresponding to the magnet are not accurately aligned (aligned), it is difficult to measure the accurate steering angle.

[0006] That is, due to the offset generated in the arrangement of the center of the magnet and the center of the Hall IC, there is a problem that the measurement accuracy of the angle sensor decreases. For example, an assembly error occurs when installing a substrate on which the Hall IC is arranged in a casing, and an assembly error occurs when arranging the sub-gear in the casing, etc., resulting in a problem that the offset is formed in the arrangement of the magnet and the Hall IC.

[0007] Furthermore, when the angle sensor uses two sub-gears, two magnets, and two Hall ICs, there is a problem that the assembly tolerance further increases, and thus the reliability of the measurement accuracy further decreases.

[0008] Therefore, in fact, there is a demand for the development of a sensing device that can improve the measurement accuracy of the steering angle even when the assembly tolerance of the angle sensor is formed.

Summary of the Invention

Problems to be Solved by the Invention

[0009] The embodiment provides a sensing device that can improve the measurement accuracy of the steering angle even when an offset in arrangement is formed between a magnet fixed to a sub-gear and a magnetic element that senses a change in the magnetic field of the magnet.

[0010] The problems to be solved by the embodiment are not limited to the problems mentioned above, and other problems not mentioned here will be clearly understood by those skilled in the art from the following description.

Means for Solving the Problems

[0011] The above problems are achieved by a sensing device including a stator connected to a first axis, a first gear that rotates in conjunction with the stator, a second gear that rotates in conjunction with the first gear, a magnet coupled to the second gear, and a magnetic element arranged to correspond to the magnet, wherein one surface of the magnet arranged to face the magnetic element has an elliptical shape.

[0012] The above problems are achieved by a sensing device including a stator connected to a first axis, a first gear that rotates in conjunction with the stator, a second gear that rotates in conjunction with the first gear, a magnet coupled to the second gear, and a magnetic element arranged to correspond to the magnet, wherein one surface of the magnet arranged to face the magnetic element includes a plane and an inclined surface formed by inclining with respect to the plane.

[0013] The above problem is achieved by a sensing device including a stator connected to a first axis, a first gear that rotates in conjunction with the stator, a second gear that rotates in conjunction with the first gear, a magnet coupled to the second gear, and a magnetic element arranged to correspond to the magnet, wherein the magnet has a shape such that the difference between the maximum value of the X flux in the X direction and the maximum value of the Y flux in the Y direction is within 15% based on an offset of 1 mm.

[0014] Preferably, with reference to the minor axis of the one surface, an S pole may be arranged in one region of the one surface and an N pole may be arranged in the other region.

[0015] Here, one surface of the magnet includes a flat surface and an inclined surface inclined with respect to the flat surface, and the angle at which the flat surface and the inclined surface meet may be arranged parallel to the minor axis.

[0016] Also, with reference to the axial direction of the second gear, the boundary line between the one region and the other region may be arranged to overlap with the magnetic element.

[0017] Also, the inclined surface may be inclined in the central direction of the magnet.

[0018] Also, the thickness of the peripheral region may become smaller as it goes towards the central region.

[0019] Also, one surface of the central region may have a flat surface, and one surface of the peripheral region may include an inclined surface. Here, the other surface of the magnet may be a plane parallel to the plane of the central region.

[0020] Also, the sensing point of the magnetic element may be arranged to overlap with the plane of the central region with reference to the axial direction of the first gear.

[0021] Also, one surface of the magnet may include one surface of the central region and one surface of the peripheral region, and may be a surface facing the magnetic element.

[0022] Further, the length of the plane of the central region may be within 0.2 to 0.8 of the length of the major axis with reference to the major axis direction of the magnet.

[0023] On the other hand, the magnet includes a body portion including the plane and a protruding portion including the inclined surface, the plane is disposed between the two inclined surfaces, and the magnetic element may be disposed so as to overlap with an end portion of the protruding portion with reference to the radial direction of the second gear.

[0024] Here, a part of the magnetic element may be disposed so as to overlap with the inclined surface with reference to the axial direction.

[0025] Further, the width of the magnetic element in the minor axis direction may be larger than the length of the minor axis A2 of the magnet, and the width in the major axis direction may be smaller than the length of the major axis A1 of the magnet.

[0026] On the other hand, the problem can be achieved by a sensing device including a stator connected to a first axis, a first gear that rotates in conjunction with the stator, a second gear that rotates in conjunction with the first gear, a magnet coupled to the second gear, and a magnetic element disposed so as to correspond to the magnet, and one surface of the magnet disposed so as to face the magnetic element is formed in a shape having a major axis and a minor axis.

Advantages of the Invention

[0027] In the sensing device according to the embodiment, even if an offset is formed in the arrangement because the centers of the magnet disposed on the second gear and the magnetic element do not coincide in the axial direction, the measurement accuracy of the steering angle can be improved through the shape of the magnet.

[0028] The embodiment can improve the measurement accuracy of the steering angle by forming the shape of one surface of the magnet arranged to face the magnetic element to include a minor axis and a major axis with different lengths. Here, the minor axis can be defined as a virtual axis that is the shortest distance among the virtual lines passing through the rotation center formed on one surface of the magnet, and the major axis can be defined as a virtual axis that is the longest distance among the virtual lines.

[0029] The embodiment can improve the measurement accuracy by forming an inclined surface on one surface of the magnet arranged to face the magnetic element.

[0030] The various and beneficial advantages and effects of the embodiment are not limited to the above-described content and will be more easily understood in the process of explaining the specific embodiments of the embodiment.

Brief Description of the Drawings

[0031]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Figure 19

Figure 20

Figure 21

Figure 22

Embodiments for Carrying Out the Invention

[0032] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0033] However, the technical idea of the present invention is not limited to some of the described embodiments, but can be embodied in various different forms, and within the scope of the technical idea of the present invention, one or more of its components can be selectively combined or replaced between the embodiments for use.

[0034] Also, the terms (including technical and scientific terms) used in the embodiments of the present invention can be interpreted in a meaning generally understood by those with ordinary knowledge in the technical field to which the present invention pertains, unless specifically defined and described clearly, and terms generally used like those defined in a dictionary can be interpreted considering their meaning in the context of the related technology.

[0035] Also, the terms used in the embodiments of the present invention are for explaining the embodiments and are not intended to limit the present invention.

[0036] In this specification, the singular form can also include the plural form unless specifically mentioned in the text, and when described as "at least one (or one or more) of A and (or) B, C", it can include one or more of all combinations that can be combined with A, B, and C.

[0037] Also, when explaining the components of the embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. can be used.

[0038] Such terms are merely for distinguishing the components from other components and are not limited to the essence, order, or sequence of the corresponding components by such terms.

[0039] When a component is described as being "coupled", "connected", or "joined" to another component, this includes not only cases where the component is directly coupled, connected, or joined to the other component, but also cases where the component is "coupled", "connected", or "joined" by one or more additional components between the component and the other component.

[0040] Also, when something is described as being formed or disposed "above or below" each component, above or below includes not only cases where two components are in direct contact with each other, but also cases where one or more additional components are formed or disposed between the two components. Also, when expressed as "above or below", it can include the meaning not only in the upward direction but also in the downward direction with respect to one component.

[0041] The sensing device according to the embodiment can be disposed between an output shaft (not shown) and an input shaft (not shown) of a steering shaft. Here, the output shaft may be called the first shaft, and the input shaft may be called the second shaft.

[0042] FIG. 1 is a perspective view showing a sensing device according to an embodiment, FIG. 2 is a bottom perspective view showing the sensing device according to the embodiment, and FIG. 3 is an exploded perspective view showing the sensing device according to the embodiment. Here, the Z direction illustrated in FIGS. 1 to 3 may mean the axial direction, and the R direction may mean the radial direction. And the axial direction and the radial direction may be perpendicular to each other. Also, the reference numeral "C" illustrated in FIGS. 1 to 3 may mean the rotation center of the rotor 100, the stator 200, and the first gear 300. And the reference numeral "C1" illustrated in FIGS. 2 and 3 may be the rotation center of the second gear 400 and the magnet 500. And the "C" and the "C1" may be arranged in parallel with respect to the axial direction.

[0043] Referring to FIGS. 1 to 3, the sensing device 1 according to the embodiment may include a rotor 100 connected to the second shaft which is the input shaft, a stator 200 connected to the first shaft which is the output shaft, a first gear 300 that rotates in conjunction with the rotation of the stator 200, a second gear 400 that rotates in conjunction with the rotation of the first gear 300, a magnet 500 coupled to the second gear 400, and a magnetic element 600 arranged to correspond to the magnet 500. Here, the magnetic element 600 may be arranged on a circuit board 700 and may be called a magnetic sensing element. And the first gear 300 may be called a main gear, and the second gear 400 may be called a sub-gear.

[0044] At this time, in the sensing device 1, due to assembly tolerances and the like, the centers of the magnet 500 arranged on the second gear 400 and the magnetic element 600 do not coincide axially, so an offset may be formed in the arrangement. Here, the assembly tolerances may be formed by the coupling of the stator 200 and the first gear 300, the gear backlash formed when the first gear 300 and the second gear 400 mesh, and the coupling of the circuit board 700 and a housing (not shown). Accordingly, the offset may be formed due to the assembly tolerances and the like.

[0045] Therefore, even if the offset is formed in the sensing device 1, it is possible to prevent the measurement accuracy of the steering angle from decreasing through the shape of the magnet 500. For example, as shown in FIG. 3, the sensing device 1 may form the shape of one surface of the magnet 500 arranged to face the magnetic element 600 in an elliptical shape, or form an inclined surface on the one surface to minimize the influence of the offset. That is, the sensing device 1 can improve the measurement accuracy of the steering angle by minimizing the influence of the offset on the change in the magnetic field sensed by the magnetic element 600 through the shape of the magnet 500.

[0046] On the other hand, the sensing device 1 according to the embodiment can also measure the torque of the steering shaft. Accordingly, the sensing device 1 can include a torque sensor 900 disposed on the circuit board 700 so as to face the collector 800 and one side of the collector 800.

[0047] In addition, the sensing device 1 can further include a housing (not shown) that forms an outer shape and supports and protects each component.

[0048] The rotor 100 can be rotatably disposed inside the stator 200. And the rotor 100 can be connected to a second shaft that is an input shaft among the steering shafts. And the input shaft can be a steering shaft connected to the vehicle's steering wheel. Here, the inner side can mean a direction toward the center C with reference to the radial direction, and the outer side can mean a direction opposite to the inner side.

[0049] The rotor 100 can include a cylindrical yoke 110 and a magnet 120 disposed on the yoke 110.

[0050] The yoke 110 can be coupled to the second shaft. Accordingly, the yoke 110 can rotate in conjunction with the rotation of the second shaft.

[0051] The magnet 120 can be disposed outside the yoke 110. Here, the magnet 120 can be adhesively fixed or press-fitted to the outer peripheral surface of the yoke 110. And the magnet 120 can be called a rotor magnet or a main magnet.

[0052] The stator 200 can be rotatably disposed outside the rotor 100. And the stator 200 can be connected to a first shaft that is an output shaft.

[0053] Referring to FIG. 3, the stator 200 may include a holder 210 connected to the output shaft, a body 220 disposed on one side of the outer peripheral surface of the holder 210, and a pair of stator teeth 230 disposed on the body 220.

[0054] The holder 210 may be connected to the first axis, which is the output axis among the steering axes. Accordingly, the holder 210 can rotate in conjunction with the rotation of the first axis. Here, the holder 210 may be formed of a metal material, but is not necessarily limited thereto. For example, different materials having a certain strength or more may be used so that the first axis can be inserted and fixed.

[0055] The body 220 may be disposed at one end of the holder 210. For example, the body 220 may be disposed at one end of the holder 210 by an insert injection method using a synthetic resin such as resin. And the magnet 120 of the rotor 100 may be rotatably disposed inside the body 220.

[0056] And the body 220 may include holes formed for coupling with the stator teeth 230.

[0057] The stator teeth 230 may be coupled and fixed to the body 220. At this time, the stator teeth 230 may be configured in a pair so as to be disposed on the upper and lower portions of the body 220, respectively. Here, the stator teeth 230 may be called a stator ring.

[0058] Also, the stator teeth 230 may include a plurality of teeth 231 spaced apart from each other along the inner peripheral surface of the body 220, and the teeth 231 may be disposed to correspond to the magnet 120. For example, the teeth 231 may be disposed outside the magnet 120 with respect to the radial direction.

[0059] The first gear 300 can be arranged to be interlocked with the rotation of the stator 200. For example, the first gear 300 can be coupled to the body 220 of the stator 200 and rotate in conjunction with the rotation of the stator 200.

[0060] The first gear 300 can be formed in a ring shape, and a plurality of gear teeth can be formed on the outer peripheral surface. And the gear teeth of the first gear 300 can mesh with the gear teeth of the second gear 400.

[0061] The second gear 400 can rotate in conjunction with the rotation of the first gear 300. For example, the second gear 400 can mesh with the first gear 300. At this time, the second gear 400 can be arranged to have a different rotation center C1 from the first gear 300.

[0062] Referring to FIG. 3, the second gear 400 can include a second gear body 410 formed in a disc shape and a boss 420 protruding axially from the second gear body 410. Here, the boss 420 can be called a first protrusion or a second gear protrusion.

[0063] The second gear body 410 can include gear teeth formed on the outer peripheral surface so as to mesh with the gear teeth of the first gear 300.

[0064] The boss 420 can be formed in a cylindrical shape. And a magnet 500 can be arranged inside the boss 420. Accordingly, the magnet 500 can also rotate in conjunction with the rotation of the second gear 400. Here, the boss 420 is exemplified as being formed in a cylindrical shape in which the magnet 500 is fixed inside, but is not necessarily limited thereto. For example, the boss 420 may be formed in various forms that can be coupled to the magnet 500 while preventing the flow of the magnet 500.

[0065] As shown in FIGS. 1 to 3, two second gears 400 may be arranged to improve the measurement accuracy of the steering angle. Accordingly, the second gear 400 may include a second-1 gear 400a and a second-2 gear 400b. Here, the second-1 gear 400a and the second-2 gear 400b are arranged so as to be able to mesh with the first gear 300, but are not necessarily limited thereto. For example, the second-1 gear 400a may be arranged to mesh with the first gear 300, and the second-2 gear 400b may be arranged to mesh with the second-1 gear 400a.

[0066] The magnet 500 may be coupled to the second gear 400. Accordingly, the magnet 500 shares the rotation center C1 with the second gear 400 and can rotate in conjunction with the rotation of the second gear 400. For example, the magnet 500 may be coupled to the boss 420 of the second gear 400 and rotate together with the second gear 400. Here, the magnet 500 may be called an angle magnet or a sub-magnet.

[0067] FIG. 4 is a drawing showing the arrangement relationship between the magnet and the magnetic element arranged in the sensing device according to the embodiment.

[0068] Referring to FIG. 4, when the magnet 500 and the magnetic element 600 are arranged such that the rotation center of the magnet 500 and the center of the magnetic element 600 coincide in the axial direction, an accurate measurement of the steering angle is possible. For example, when the center of the magnetic element 600 is located and aligned on the rotation center C1 of the magnet 500, an accurate measurement of the steering angle is possible.

[0069] FIG. 5 is a drawing showing an offset formed by the arrangement relationship between the magnet and the magnetic element arranged in the sensing device according to the embodiment. In FIG. 5, the reference numeral "C2" may be the center of the magnetic element 600.

[0070] Referring to FIG. 5, the magnet 500 and the magnetic element 600 may be arranged such that the centers of the magnet 500 and the magnetic element 600 disposed on the second gear 400 do not coincide axially due to assembly tolerances or the like.

[0071] For example, when C1 representing the center of rotation of the magnet 500 and C2 representing the center of the magnetic element 600 are arranged parallel to each other in the axial direction, the offset may be formed between C1 and C2. That is, an offset may be formed between the center of rotation C1 of the magnet 500 and the center C2 of the magnetic element 600 with reference to the radial direction with respect to the center of rotation C1 of the magnet 500.

[0072] Therefore, even if an offset is formed in the arrangement because the centers of the magnet 500 and the magnetic element 600 disposed on the second gear 400 do not coincide axially, the sensing device 1 can minimize the influence of the offset through the shape of the magnet 500.

[0073] Therefore, in order to confirm the effective difference due to the shape of the magnet 500 of the sensing device 1 according to the embodiment, a magnet having a shape different from that of the magnet 500 may be presented as a comparative example. And the influence of the offset on the measurement accuracy of the steering angle can also be confirmed through the flux sensed by the magnetic element of the comparative example.

[0074] FIG. 6 is a drawing showing the relationship between the X flux in the X direction and the Y flux in the Y direction with respect to the magnet flux sensed with respect to the magnetic element, FIG. 7 is a drawing showing the magnet and the magnetic element presented as a comparative example, FIG. 8 is a drawing showing the X flux and the Y flux due to the rotation of the magnet of the comparative example, and FIG. 9 is a drawing showing the non-linearity of the flux due to the offset of the comparative example. In FIG. 6, the X direction and the Y direction may be perpendicular to each other on the plane. And the drawing number "P" shown in FIG. 6 may be arranged on the C2 line passing through the center of the magnetic element.

[0075] Referring to FIG. 6, the magnet flux sensed by the magnetic element can be divided into an X flux in the X direction and a Y flux in the Y direction. At this time, Atan (arctangent) is calculated for angle calculation, and due to the difference in the maximum values of the X flux and the Y flux caused by the offset, an error in angle calculation may occur. Accordingly, non-linearity presented in relation to the measurement accuracy of the steering angle will occur. Here, the center of the magnetic element may be the center of sensing and may be called the sensing point P. At this time, the magnetic element may be a Hall IC.

[0076] Referring to FIG. 7, the sensing device presented as a comparative example may include a magnetic element 10, a sub-gear 20, and a magnet 30 fixed to the sub-gear 20 and arranged to face the magnetic element 10. At this time, a predetermined offset may be formed between the magnetic element 10 and the magnet 30 due to assembly tolerances and the like.

[0077] Here, the magnet 30 of the sensing device presented as a comparative example may be formed in a cylindrical shape, and one surface 31 of the magnet 30 arranged to face the magnetic element 10 may be circular and formed to have a predetermined radius r. Accordingly, when the offset occurs, the sensing device presented as a comparative example has difficulty in coping with the offset.

[0078] Referring to FIG. 8, with reference to a virtual line passing through the center C1, an S pole may be arranged on one side of the magnet 30 and an N pole may be arranged on the other side. At this time, the sensing point P of the magnetic element 10 may be arranged on one surface 31 of the magnet 30 so as to be separated from the rotation center C1 of the magnet 30 by a predetermined distance due to the offset. As shown in FIG. 8, the measured values of the X flux and the Y flux may be represented by waveforms according to the rotation angle of the magnet 30.

[0079] When referring to FIG. 8 and comparing the measured values of the X Flux and Y Flux with the abnormal values, a difference may occur between the measured values and the abnormal values due to the offset. For example, looking at 45 degrees in FIG. 8, it can be confirmed that a difference occurs when comparing the measured values of the X Flux and Y Flux with the abnormal values. Here, the measured values may mean the values actually measured by the magnetic element with the offset reflected, and the abnormal values may be the theoretical values calculated when the centers of the magnet and the magnetic element coincide.

[0080] Thereby, when measuring the steering angle using the sensing device, the offset will affect the accuracy. Such an effect can be more clearly confirmed through FIG. 9.

[0081] FIG. 9 is a drawing comparing the measured values and abnormal values of the flux due to the offset of the comparative example to confirm the measurement accuracy of the steering angle, and the abnormal values can be expressed linearly. And the difference between the measured values and the abnormal values can be expressed non-linearly (in a waveform) and can be called non-linearity. At this time, the non-linearity can be expressed in units of angles.

[0082] Referring to FIG. 9, it can be confirmed that the non-linearity increases due to the difference between the measured values due to the offset and the abnormal values. Here, the non-linearity can be expressed by the maximum value of the difference between the abnormal values and the measured values. Accordingly, the value at the point farthest from the abnormal values can be provided as the non-linearity value, and the maximum value of the non-linearity value may appear at the rotation angles of 45 degrees, 135 degrees, 225 degrees, and 315 degrees of the magnet 30.

[0083] Therefore, it can be confirmed that the measurement accuracy of the steering angle due to the offset is related to the non-linearity. For example, it can be confirmed that the greater the non-linearity value, the lower the measurement accuracy of the steering angle.

[0084] On the one hand, the offset distance can be changed by various factors such as the accumulation of assembly tolerances. Therefore, it is intended to examine in detail how the increase in the offset affects the measurement accuracy with reference to the comparative examples illustrated in FIG. 7.

[0085] FIG. 10 is a drawing showing the X flux and Y flux due to the offset of the comparative example, FIG. 11 is a drawing showing the maximum values of the X flux and Y flux due to the offset of the comparative example, and FIG. 12 is a drawing showing the relationship between the offset of the comparative example and non-linearity.

[0086] Referring to FIG. 10, it can be confirmed that as the offset increases in the sensing device according to the comparative example, the maximum value of the Y flux also increases. Accordingly, by examining in detail around 45 degrees in FIG. 10, it can be confirmed that the difference between the X flux and the Y flux also increases.

[0087] Referring to FIG. 11, the difference between the X flux and the Y flux can be further clarified through the difference between the maximum values of the X flux and the Y flux. As shown in FIG. 11, it can be confirmed that as the offset increases, the difference between the maximum values of the X flux and the Y flux also increases.

[0088] Referring to FIG. 12, it can be confirmed that the non-linearity increases rapidly as the offset increases. For example, when the offset is about 0.5 mm, it can be confirmed that the non-linearity value is shown to be about 2.6 degrees. Accordingly, as the offset increases, the measurement accuracy of the steering angle also decreases.

[0089] Therefore, as the offset increases, the difference between the maximum values of the X flux and the Y flux increases, and accordingly the non-linearity also increases. Through this, it can be confirmed that as the offset increases, the measurement accuracy of the steering angle decreases.

[0090] Therefore, the sensing device 1 according to the embodiment provides the magnet 500 that minimizes the influence of the offset, so as to be able to provide the measurement accuracy of the steering angle at a certain level or higher.

[0091] FIG. 13 is a perspective view showing a first embodiment of a magnet disposed in the sensing device according to the embodiment, FIG. 14 is a front view showing the first embodiment of the magnet disposed in the sensing device according to the embodiment, FIG. 15 is a plan view showing the first embodiment of the magnet disposed in the sensing device according to the embodiment, and FIG. 16 is a bottom view showing the first embodiment of the magnet disposed in the sensing device according to the embodiment.

[0092] Referring to FIGS. 13 to 16, the magnet 500 may include a facing surface 510 which is a surface disposed to face the magnetic element 600. And the magnet 500 may include a bottom surface 540 which is a surface opposite to the facing surface 510 with reference to the axial direction.

[0093] The facing surface 510 may be formed in a shape having a major axis A1 and a minor axis A2. For example, the facing surface 510 may be formed in an elliptical shape or a polygon with five or more sides. Even when the facing surface 510 is formed in the shape of the polygon, the facing surface 510 may be formed to have the major axis A1 and the minor axis A2. Here, the minor axis A2 may be defined as a line segment having the shortest distance among the line segments connecting two points above around through the rotation center C1 of the magnet 500, and the major axis A1 may be defined as a line segment having the longest distance among the line segments.

[0094] And the minor axis A2 can be a boundary line B that divides one region where the S pole is arranged and another region where the N pole is arranged. Accordingly, one region embodying the S pole can be arranged on one side with reference to the minor axis A2, and another region embodying the N pole can be arranged on the other side. At this time, with reference to the axial direction of the second gear 400, the boundary line B can be arranged to overlap with the magnetic element 600. And due to the overlap of the boundary line B and the magnetic element 600 considering the offset, the radial width of the magnetic element 600 may be larger than the length of the minor axis A2.

[0095] On the other hand, since the magnet 500 can include a body portion 520 and a protruding portion 530 formed to protrude axially on one side of the body portion 520, the opposing surface 510 can include a flat surface 511 and an inclined surface 512 arranged at a predetermined angle θ with respect to the flat surface 511. Here, the protruding portion 530 of the magnet 500 can be called a second protruding portion or a magnet protruding portion.

[0096] The body portion 520 and the protruding portion 530 can be integrally formed. The flat surface 511 can be one axial side surface of the body portion 520, and the inclined surface 512 can be one axial side surface of the protruding portion 530. At this time, a part of the flat surface 511 and the inclined surface 512 can be arranged to face the magnetic element 600.

[0097] Referring to FIGS. 13 to 15, the flat surface 511 can be arranged between two inclined surfaces 512.

[0098] And the rotation center C1 of the magnet 500 can be located on the flat surface 511. Accordingly, the minor axis A2 can also be arranged on the flat surface 511, and the angle 513 where the flat surface 511 and the inclined surface 522 meet can be arranged parallel to the minor axis. Here, the angle 513 can be arranged to axially overlap with the magnetic element 600.

[0099] In addition, the flat surface 511 can be formed to have a predetermined area. At this time, the area of the flat surface 511 can be determined during the design of the magnet 500 such that the sensing point P of the magnetic element 600 overlaps with the flat surface 511 with reference to the axial direction.

[0100] That is, the area of the flat surface 511 can be determined in consideration of assembly tolerances, the range of the offset that can be formed by the assembly tolerances, and the axial overlap with the magnetic element 600. For example, the area of the flat surface 511 may be smaller than the area of one surface of the magnetic element 600 arranged to face the flat surface 511. Accordingly, the width of the flat surface 511 in the major axis direction and the width of the flat surface 511 in the minor axis direction may be smaller than the width of one surface of the magnetic element 600. Specifically, it is preferable that the width of the flat surface 511 in the major axis direction is formed to be smaller than the length in the diagonal direction of one surface of the magnetic element 600.

[0101] In addition, as the flat surface 511 is formed to have a predetermined area, the flat surface 511 has a predetermined length in the major axis direction. At this time, with reference to the major axis direction of the magnet 500, the length L1 of the flat surface 511 in the major axis direction can be formed within a range of 0.2 to 0.8 times the length L2 of the major axis A1. That is, the length L1 of the flat surface 511 in the central region can be 0.2 to 0.8 times the length L2 of the major axis A1 of the magnet 500.

[0102] On the other hand, since the rotation center C1 of the magnet 500 is located on the flat surface 511 and the flat surface 511 is arranged between the inclined surfaces 512, the flat surface 511 can be provided as one surface of the central region. Here, the center of the flat surface 511 can be arranged on the same axis as the rotation center C1 of the magnet 500.

[0103] That is, the magnet 500 can include a central region where the flat surface 511 is arranged and a peripheral region where the inclined surface 512 is arranged, and the flat surface 511 can be provided as a reference for distinguishing the central region and the peripheral region. Accordingly, the central region can include the flat surface 511 as one surface, and the peripheral region can include the inclined surface 512 as one surface.

[0104] The inclined surfaces 512 can be arranged in two on one side and the other side of the flat surface 511 with respect to the major axis direction.

[0105] Also, the inclined surfaces 512 can be arranged so as to have a predetermined gap G with the lower side corners of the magnetic element 600. Accordingly, interference between the inclined surfaces 512 and the magnetic element 600 can be prevented when the magnet 500 rotates.

[0106] Also, the inclined surfaces 512 are arranged to be inclined at a predetermined angle θ with respect to the flat surface 511 and can be arranged to be inclined in the direction of the center C1 of the magnet 500. At this time, the larger the angle θ is, the more advantageous it is for the accuracy, but it is preferably formed within the range where the gap G is formed.

[0107] Also, the inclined surfaces 512 can be provided as one surface of the peripheral region. Accordingly, due to the inclined surfaces 512, the axial thickness of the magnet 500 can increase as it moves away from the center C1 of the magnet 500.

[0108] The body portion 520 can be formed in a columnar shape having a major axis A1 and a minor axis A2. For example, the body portion 520 can be formed in an elliptical columnar shape. At this time, the flat surface 511 can be provided as one surface of the body portion 520.

[0109] Also, the body portion 520 can be formed to have a predetermined axial thickness T1. Here, the axial thickness T1 of the body portion 520 can be called the first thickness and can be the thickness of the central region.

[0110] The protruding portion 530 can be formed to protrude axially on one surface of the body portion 520 having the flat surface 511.

[0111] Also, two protruding portions 530 can be arranged to be spaced apart on one surface of the body portion 520 and can be arranged to be symmetric with respect to the minor axis A2.

[0112] Further, the protruding portion 530 may be formed to have a predetermined axial thickness T2. Here, the axial thickness T2 of the protruding portion 530 may be referred to as the second thickness and may be the thickness of the peripheral region. Accordingly, the thickness of the peripheral region may be even greater than the thickness of the central region with reference to the axial direction.

[0113] Also, the protruding portion 530 may include the inclined surface 512. Accordingly, the thickness of the peripheral region may become smaller as it goes towards the central region.

[0114] Also, an end portion of the protruding portion 530 where the inclined surface 512 is formed may be arranged to overlap with a lower side of the magnetic element 600 with reference to the radial direction of the second gear 400. At this time, a partial region of the magnetic element 600 may be arranged to overlap with the inclined surface 512 with reference to the axial direction of the second gear 400. Accordingly, the angle 513 may be arranged to overlap with the magnetic element 600 in the axial direction.

[0115] The bottom surface 540 may be the other surface located on the opposite side of the opposing surface 510 which is one surface of the magnet 500 with reference to the axial direction. And the bottom surface 540 may be provided as a plane parallel to the plane 511 of the central region.

[0116] FIG. 17 is a drawing showing the maximum values of the X - flux and Y - flux due to the offset of the sensing device including the magnet according to the first embodiment, and FIG. 18 is a drawing showing the relationship between the offset and non - linearity of the sensing device including the magnet according to the first embodiment.

[0117] Referring to FIGS. 5 and 17, it can be confirmed that as the offset formed between the magnet 500 and the magnetic element 600 of the sensing device 1 according to the embodiment increases, the difference in the maximum values of the X - flux and Y - flux sensed by the magnetic element 600 also increases.

[0118] However, when comparing with the difference between the maximum values of the X - flux and the Y - flux due to the offset of the comparative example shown in FIG. 11, it can be confirmed that the difference between the maximum values of the X - flux (X Flux) and the Y - flux (Y Flux) sensed by the sensing device 1 according to the embodiment is smaller than that of the comparative example. For example, when the offset of the comparative example is 1.00 mm, the difference between the maximum values of the X - flux and the Y - flux is about 8 mT. And when the offset of the sensing device 1 is 1.00 mm, the difference between the maximum values of the X - flux and the Y - flux is about 1.8 mT.

[0119] Referring to FIG. 18, it can be confirmed that the non - linearity increases as the offset of the sensing device 1 according to the embodiment increases.

[0120] When comparing the non - linearity of the sensing device 1 according to the embodiment and the comparative example with reference to FIGS. 12 and 18, it can be confirmed that the line indicating the non - linearity of the sensing device 1 according to the embodiment rises more gently than the line indicating the non - linearity of the comparative example. For example, when the offset of the sensing device 1 is about 0.5 mm, it can be confirmed that the non - linearity value is shown to be about 0.8 degrees. Accordingly, in the case of the sensing device 1, it can be confirmed that as the offset increases, the measurement accuracy of the steering angle is more precise than that of the comparative example.

[0121] However, in the case of the sensing device 1, when considering the relationship with non - linearity, the ratio with respect to the difference between the maximum values of the X - flux and the Y - flux may be limited. Here, the ratio of the difference between the maximum values of the X - flux and the Y - flux can be obtained by the following formula.

[0122]

Equation

[0123] Therefore, the magnet 500 of the sensing device 1 can be formed to have a value such that the ratio of the difference between the maximum values of the X flux and the Y flux with respect to an offset of 1 mm is within 15%. In the unlikely event that the ratio with respect to the difference exceeds 15%, the non-linearity increases and it becomes difficult to provide the measurement accuracy of the steering angle at a certain level or higher. Such a limitation on the ratio can also be applied to the sensing device 1 including the magnet 500a according to the second embodiment described later.

[0124] In summary, since the shape of the magnet 500 of the sensing device 1 minimizes the influence of the offset, the sensing device 1 can sense the measurement accuracy of the steering angle more accurately than in the comparative example. Accordingly, even when the offset is formed, the sensing device 1 can provide the measurement accuracy of the steering angle at a certain level or higher and improve the reliability.

[0125] FIG. 19 is a perspective view showing a second embodiment of the magnet disposed in the sensing device according to the embodiment, FIG. 20 is a front view showing a second embodiment of the magnet disposed in the sensing device according to the embodiment, FIG. 21 is a drawing showing the maximum values of the X flux and the Y flux due to the offset of the sensing device including the magnet according to the second embodiment, and FIG. 22 is a drawing showing the relationship between the offset and the non-linearity of the sensing device including the magnet according to the second embodiment.

[0126] The magnet 500a according to the second embodiment can be disposed in the sensing device 1 instead of the magnet 500 according to the first embodiment.

[0127] When comparing the magnet 500 according to the first embodiment with the magnet 500a according to the second embodiment with reference to FIGS. 13 to 16, 19 and 20, the magnet 500a according to the second embodiment differs from the magnet 500 according to the first embodiment in that it does not include the protruding portion 530 of the magnet 500 according to the first embodiment. That is, the magnet 500a according to the second embodiment differs from the magnet 500 according to the first embodiment in the shape of the opposing surface, which is one surface arranged to face the magnetic element 600.

[0128] Referring to FIGS. 19 and 20, the magnet 500a may include an opposing surface 510a which is one surface arranged to face the magnetic element 600. And the magnet 500a may include a bottom surface 540 which is the opposite surface of the opposing surface 510a with respect to the axial direction.

[0129] The opposing surface 510a may be formed in a shape having a major axis A1 and a minor axis A2. For example, the opposing surface 510a may be formed in an elliptical shape and may be provided as a plane.

[0130] The bottom surface 540 may be the other surface located on the opposite side of the opposing surface 510 which is one surface of the magnet 500 with respect to the axial direction. And the bottom surface 540 may be provided as a plane parallel to the plane 511 of the central region and may be formed in the same shape as the opposing surface 510a.

[0131] Referring to FIG. 21, it can be confirmed that as the offset formed between the magnet 500a and the magnetic element 600 of the sensing device 1 according to the embodiment increases, the difference between the maximum values of the X flux and the Y flux sensed by the magnetic element 600 also increases.

[0132] When comparing the non-linearity of the sensing device 1 including the magnet 500a according to the second embodiment with that of the comparative example with reference to FIGS. 12 and 22, it can be confirmed that the line indicating the non-linearity of the sensing device 1 according to the embodiment rises more gently than the line indicating the non-linearity of the comparative example. For example, when the offset of the sensing device 1 including the magnet 500a according to the second embodiment is about 0.5 mm, it can be confirmed that the non-linearity value is indicated at about 2.0 degrees. Accordingly, in the case of the sensing device 1 including the magnet 500a according to the second embodiment, it can be confirmed that the measurement accuracy of the steering angle becomes more precise than that of the comparative example as the offset increases.

[0133] The magnetic element 600 may be arranged corresponding to the magnet 500 so as to sense a change in the magnetic field of the magnet 500. For example, one surface of the magnetic element 600 may be arranged to face the opposing surface 510 of the magnet 500. At this time, the sensing point P of the magnetic element 600 may be arranged to overlap with the plane 511 with reference to the axial direction. Here, the magnetic element 600 may be called a magnet sensing element, and a Hall IC may be used. And one surface of the magnetic element 600 arranged to face the opposing surface 510 of the magnet 500 may be called a sensing surface.

[0134] Here, the magnetic elements 600 may be arranged on the circuit board 700 in the same number as the magnets 500, 500a.

[0135] Also, the width of the one surface of the magnetic element 600 may be larger than the length of the short axis A2 and smaller than the length of the long axis A1. For example, the width of the magnetic element 600 in the short-axis direction may be larger than the length of the short axis A2 of the magnet 500, and the width of the magnetic element 600 in the long-axis direction may be smaller than the length of the long axis A1.

[0136] Further, the magnetic element 600 can be disposed between the protrusions 530 with reference to the radial direction of the second gear 400. For example, the width of the one surface of the magnetic element 600 is formed to be smaller than the length of the major axis A1, and since the inclined surface 512 is formed on the protrusion 530, the magnetic element 600 can be disposed between the protrusions 530 with reference to the radial direction of the second gear 400. That is, the magnetic element 600 can be disposed between the inclined surfaces 512 with reference to the radial direction of the second gear 400, and a partial region of the magnetic element 600 can be disposed so as to axially overlap with the inclined surface 512. However, when the magnet 500 rotates, the magnetic element 600 must be disposed so as to have a predetermined gap G from the inclined surface 512 so as to prevent interference between the inclined surface 512 and the magnetic element 600.

[0137] A magnetic element 600 for sensing the magnetization of the magnet 500 can be disposed on the circuit board 700. And a torque sensor 900 for measuring torque can be disposed on the circuit board 700. Here, the circuit board 700 can be a printed circuit board.

[0138] Also, the circuit board 700 can be formed in an arc shape and can be disposed outside the body 220 of the stator 200.

[0139] The collector 800 enables the torque sensor 900 disposed on the circuit board 700 to sense a change in magnetic force generated by a rotational difference due to distortion between the input shaft and the output shaft. Here, the collector 800 can be formed of a metal material and can be fixed to the housing.

[0140] Two collectors 800 can be disposed so as to correspond to each of the pair of stator teeth 230 so as to collect the flux of the stator 200. Here, the collector 800 can be divided into an upper collector and a lower collector depending on the disposed position.

[0141] Referring to FIGS. 1 to 3, the collector 800 may be arranged adjacent to the stator tooth 230. Here, adjacent may mean being arranged in contact or separated by a predetermined interval.

[0142] The collector 800 may include a plate 810 and legs 820.

[0143] The plate 810 may be formed in a plate shape. And the plate 810 may be arranged adjacent to one side of the stator tooth 230.

[0144] The leg 820 may be formed to protrude axially from the plate 810. At this time, the leg 820 may be arranged outside the body 220, and the end of the leg 820 may be bent in the radial direction.

[0145] Also, the end of the leg 820 may be arranged to face the torque sensor 900. Accordingly, the torque sensor 900 may be arranged between the legs 820 of the upper collector and the lower collector, respectively.

[0146] The torque sensor 900 may be arranged on the circuit board 700. Here, the torque sensor 900 may be arranged to correspond to the leg 820 of the collector 800.

[0147] When a strain occurs between the input shaft and the output shaft, a rotational difference may occur between the rotor 100 and the stator 200. And such a rotational difference is sensed as a change in magnetic force through the collector 800 and the torque sensor 900. Accordingly, the torque sensor 900 can measure the torque that can smoothly adjust the steering handle.

[0148] Although the above has been described with reference to preferred embodiments of the present invention, it will be understood by those skilled in the relevant art that the present invention can be variously modified and changed without departing from the spirit and scope of the present invention described in the following claims.

Explanation of Reference Numerals

[0149] 1: Sensing device 100: Rotor 200: Stator 300: First gear 400: Second gear 500, 500a: Magnet 510: Opposing surface 511: Plane 512: Inclined plane 600: Magnetic element 700: Circuit board 800: Collector 900: Torque sensor

Claims

1. A stator connected to a first shaft, a first gear that rotates in conjunction with the stator, a second gear that rotates in conjunction with the first gear, a magnet coupled to the second gear, including a magnetic element arranged to correspond to the magnet, one surface of the magnet has an elliptical shape, a sensing device, wherein the width of the magnetic element in the minor axis direction is greater than the length of the minor axis (A2) of the magnet, and the width in the major axis direction is smaller than the length of the major axis (A1) of the magnet.

2. A stator connected to a first shaft, a first gear that rotates in conjunction with the stator, a second gear that rotates in conjunction with the first gear, a magnet coupled to the second gear, including a magnetic element arranged to correspond to the magnet, one surface of the magnet includes a flat surface and an inclined surface inclined with respect to the flat surface, the magnet includes a body portion including the flat surface and a protruding portion including the inclined surface, the flat surface is arranged between two inclined surfaces, a sensing device, wherein the magnetic element is arranged to overlap with an end portion of the protruding portion with reference to the radial direction of the second gear.

3. A stator connected to a first shaft, a first gear that rotates in conjunction with the stator, a second gear that rotates in conjunction with the first gear, a magnet coupled to the second gear, including a magnetic element arranged to correspond to the magnet, a sensing device, wherein the magnet has a shape such that the ratio of the difference between the maximum value of the X flux and the maximum value of the Y flux with reference to an offset of 1 mm is within 15%.

4. A stator connected to a first shaft, a first gear that rotates in conjunction with the stator, a second gear that rotates in conjunction with the first gear, a magnet coupled to the second gear, including a magnetic element arranged to correspond to the magnet, a sensing device, wherein the thickness of the peripheral region of the magnet is greater than the thickness of the central region with reference to the axial direction.

5. The sensing device according to claim 1, wherein an S pole is arranged in one region of the one surface and an N pole is arranged in another region with reference to the minor axis of the one surface.

6. One surface of the magnet includes a flat surface and an inclined surface inclined with respect to the flat surface, The sensing device according to claim 5, wherein the angle at which the flat surface and the inclined surface meet is arranged parallel to the minor axis.

7. The sensing device according to claim 5, wherein a boundary line between the one region and the other region overlaps with the magnetic element with reference to an axial direction of the second gear.

8. The sensing device according to claim 2, wherein the inclined surface is inclined in a central direction of the magnet.

9. The sensing device according to claim 4, wherein a thickness of the peripheral region becomes smaller as it goes toward the central region.

10. One surface of the central region has a flat surface, The sensing device according to claim 4, wherein one surface of the peripheral region includes an inclined surface.

11. The sensing device according to claim 10, wherein the other surface of the magnet is a plane parallel to the flat surface of the central region.

12. The sensing device according to claim 4, wherein a sensing point of the magnetic element is arranged so as to overlap with the flat surface of the central region with reference to an axial direction of the first gear.

13. One surface of the magnet includes one surface of the central region and one surface of the peripheral region, The sensing device according to claim 4, which is a surface facing the magnetic element.

14. The sensing device according to claim 4, wherein a length of the flat surface of the central region is within 0.2 to 0.8 of a length of the major axis with reference to a major axis direction of the magnet.

15. The sensing device according to claim 2, wherein a part of the magnetic element is arranged so as to overlap with the inclined surface with reference to an axial direction.

Images