Sensing device

Abstract

Disclosed is a sensing device including a stator connected to a first shaft, a first gear engaged in rotation with the stator, a second gear engaged in rotation with the first gear, a magnet coupled to the second gear, and a magnetic element disposed in correspondence with the magnet, wherein one surface of the magnet, which is disposed to face the magnetic element, has an elliptical shape. Accordingly, even when the center of the magnet disposed in the second gear and the center of the magnetic element are not aligned in an axial direction and thus are arranged offset, the sensing device can improve the accuracy of a turning angle measurement due to the shape of the magnet.

Description

Technical Field

[0001] This embodiment relates to a sensing device. Background Technology

[0002] To ensure vehicle steering stability, independent power-assisted steering systems can be used in vehicles, and in particular, electronic power steering (EPS) systems with low power consumption and high precision are used.

[0003] In addition, in the EPS system, the electronic control unit drives the motor based on the operating conditions and driver operation information detected by the vehicle speed sensor, torque sensor, angle sensor, etc., to ensure rotational stability and quickly provide restoring force, so that the driver can drive safely.

[0004] In addition, the angle sensor uses a main gear that rotates with the rotor, a secondary gear that rotates by engaging with the main gear, a magnet connected to the secondary gear, and a Hall integrated circuit (IC) for detecting changes in the magnetic force of the magnet to measure the steering angle of the steering handle.

[0005] However, there are problems with accurately measuring the steering angle when the center of the magnet fixed to the secondary gear and the center of the Hall IC set to correspond to the magnet are not accurately aligned.

[0006] That is, there is a problem that the measurement accuracy of the angle sensor is reduced due to the offset that occurs when setting the center of the magnet and the center of the Hall IC. For example, the offset occurs when setting the magnet and the Hall IC due to assembly errors that occur when mounting the substrate with the Hall IC in the housing, and assembly errors that occur when setting the secondary gear in the housing.

[0007] Furthermore, when two auxiliary gears, two magnets, and two Hall ICs are used in an angle sensor, the reliability of measurement accuracy is further reduced due to the increased assembly tolerances.

[0008] Therefore, there is a need for an improved sensing device that can improve the accuracy of steering angle measurement even when assembly tolerances of the angle sensor are present.

[0009] Technical issues

[0010] This embodiment aims to provide a sensing device that can improve the accuracy of steering angle measurement even when a deflection occurs when a magnet fixed to the auxiliary gear and a magnetic element for detecting changes in the magnetic field of the magnet are installed.

[0011] The objectives to be addressed by the implementation methods are not limited to those described above, and those skilled in the art will clearly understand, based on the following description, objectives not described above.

[0012] Technical solutions

[0013] One aspect of the present invention provides a sensing device comprising a stator connected to a first shaft, a first gear rotating with the stator, a second gear rotating with the first gear, a magnet connected to the second gear, and a magnetic element configured to correspond to the magnet, wherein the magnet is configured such that a surface facing the magnetic element has an elliptical shape.

[0014] Another aspect of the present invention provides a sensing device comprising a stator connected to a first shaft, a first gear rotating with the stator, a second gear rotating with the first gear, a magnet connected to the second gear, and a magnetic element disposed corresponding to the magnet, wherein a surface of the magnet disposed facing the magnetic element comprises a flat surface and an inclined surface formed to be inclined relative to the flat surface.

[0015] Another aspect of the present invention provides a sensing device comprising a stator connected to a first shaft, a first gear rotating with the stator, a second gear rotating with the first gear, a magnet connected to the second gear, and a magnetic element configured to correspond to the magnet, wherein the magnet has a shape in which 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, based on an offset of 1 mm, is within 15%.

[0016] The S pole can be located in one region of a surface relative to its short axis, and the N pole can be located in another region of a surface.

[0017] A surface of the magnet may include a flat surface and an inclined surface that is tilted relative to the flat surface, wherein the corner where the flat surface and the inclined surface intersect may be arranged parallel to the minor axis.

[0018] The boundary line between one region and another region can be set to overlap with the magnetic element in the axial direction of the second gear.

[0019] In addition, the inclined surface can be configured to tilt toward the center of the magnet.

[0020] The thickness of the peripheral region can decrease towards the center region.

[0021] One surface of the central region may include a flat surface, and one surface of the peripheral region may include a sloping surface. In this case, the other surface of the magnet may be a flat surface parallel to the flat surface of the central region.

[0022] The sensing point of the magnetic element can be configured to overlap with the flat surface of the central region in the axial direction of the first gear.

[0023] A surface of a magnet may include a surface in the central region and a surface in the peripheral region, and may be the surface facing the magnetic element.

[0024] The length of the flat surface in the central region along the long axis of the magnet can be in the range of 0.2 to 0.8 times the length of the long axis.

[0025] The magnet may include a body portion having a flat surface and a protrusion including inclined surfaces, the flat surface being disposed between two inclined surfaces, and the magnetic element being configured to overlap with the end portion of the protrusion in the radial direction of the second gear.

[0026] A portion of the magnetic element can be configured to overlap with the inclined surface in the axial direction.

[0027] The width of the magnetic element in the short axis direction can be greater than the length of the short axis (A2) of the magnet, and the width of the magnetic element in the long axis direction can be less than the length of the long axis (A1) of the magnet.

[0028] Another aspect of the present invention provides a sensing device comprising a stator connected to a first shaft, a first gear rotating with the stator, a second gear rotating with the first gear, a magnet connected to the second gear, and a magnetic element configured to correspond to the magnet, wherein the magnet is configured such that a surface facing the magnetic element is formed in a shape having a major axis and a minor axis.

[0029] Beneficial effects

[0030] Even if a misalignment occurs when the center of the magnet on the second gear and the center of the magnetic element are not aligned in the axial direction, the sensing device according to the embodiment can improve the accuracy of the steering angle measurement due to the shape of the magnet.

[0031] According to the embodiment, since the magnet is configured such that one surface facing the magnetic element has a shape having a short axis and a long axis of different lengths, the accuracy of the rotation angle measurement can be improved. In this case, the short axis can be defined as the imaginary axis with the shortest length among the virtual lines passing through the center of rotation formed on one surface of the magnet, and the long axis can be defined as the imaginary axis with the longest length among the virtual lines.

[0032] According to the implementation, since the inclined surface is formed on a surface of the magnet that is configured to face the magnetic element, the measurement accuracy can be improved.

[0033] The various useful advantages and effects of the embodiments are not limited to those described above, and will be more easily understood from the description of the specific embodiments. Attached Figure Description

[0034] Figure 1 This is a perspective view of a sensing device according to an embodiment.

[0035] Figure 2 This is a perspective view of the bottom of the sensing device according to an embodiment.

[0036] Figure 3 This is an exploded perspective view of a sensing device according to an embodiment.

[0037] Figure 4 This is a view illustrating the arrangement of magnets and magnetic elements in a sensing device according to an embodiment.

[0038] Figure 5 This is a view illustrating the offset caused by the arrangement relationship between the magnet and the magnetic element provided in the sensing device according to the embodiment.

[0039] Figure 6 It is a graph showing the relationship between the X flux in the X direction and the Y flux in the Y direction, based on the magnetic flux detected by the magnetic element.

[0040] Figure 7 This is a view illustrating a magnet and a magnetic element as a comparative example.

[0041] Figure 8 The graph shows the X-flux and Y-flux of the magnet's rotation according to the comparative example.

[0042] Figure 9 This is a graph showing the nonlinearity of flux due to the offset of the comparison example.

[0043] Figure 10 This is a graph showing the X flux and Y flux based on the offset of the comparison example.

[0044] Figure 11 It is a graph showing the maximum values ​​of X flux and Y flux based on the offset of the comparison example.

[0045] Figure 12 The graph shows the relationship between offset and nonlinearity in a comparative example.

[0046] Figure 13 This is a perspective view illustrating a first example of a magnet disposed in a sensing device according to an embodiment.

[0047] Figure 14 This is a front view illustrating a first example of a magnet disposed in a sensing device according to an embodiment.

[0048] Figure 15 This is a top view illustrating a first example of a magnet disposed in a sensing device according to an embodiment.

[0049] Figure 16 This is a bottom view illustrating a first example of a magnet disposed in a sensing device according to an embodiment.

[0050] Figure 17 It is a graph showing the maximum values ​​of the X flux and Y flux based on the offset of the sensing device including the magnet according to the first example.

[0051] Figure 18 It is a graph showing the relationship between the offset and nonlinearity of a sensing device with a magnet according to the first example.

[0052] Figure 19 This is a perspective view illustrating a second example of a magnet disposed in a sensing device according to an embodiment.

[0053] Figure 20 This is a front view illustrating a second example of a magnet disposed in a sensing device according to an embodiment.

[0054] Figure 21 It is a graph showing the maximum values ​​of the X flux and Y flux based on the offset of the sensing device including the magnet according to the second example.

[0055] Figure 22 It is a graph showing the relationship between the offset and nonlinearity of the sensing device including the magnet according to the second example. Detailed Implementation

[0056] In the following, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0057] However, the spirit of the present invention is not limited to the few embodiments described, and can be implemented in various different forms, and at least one or more components in the embodiments can be selectively combined, substituted and used within the scope of the spirit of the invention.

[0058] Furthermore, unless the context explicitly and specifically defines otherwise, all terms used herein (including technical and scientific terms) are to be interpreted as having the meaning commonly understood by those skilled in the art, and the meaning of commonly used terms, such as those defined in common dictionaries, will be interpreted in light of the contextual meaning of the relevant art.

[0059] Furthermore, the terminology used in the embodiments of the present invention is considered in a descriptive sense only and is not intended to limit the invention.

[0060] In this specification, unless the context clearly indicates otherwise, the singular form includes the plural form of the singular form, and in the case of describing “at least one of A, B and C (or one or more of them)”, this may include at least one combination of all possible combinations of A, B and C.

[0061] In addition, in the description of the components of the present invention, terms such as "first", "second", "A", "B", "(a)" and "(b)" may be used.

[0062] These terms are only used to distinguish one element from another, and the nature, order, etc. of the elements are not limited by the terms.

[0063] Additionally, it should be understood that when an element is referred to as “connected” or “linked” to another element, this description can include two cases: the element is directly connected or linked to the other element, and the element is connected or linked to the other element through another element disposed between the element and the other element.

[0064] Additionally, when any element is described as being formed or disposed "on" or "below" another element, this description includes two cases: the two elements are formed or disposed in direct contact with each other, and one or more other elements are placed between the two elements. Furthermore, when an element is described as being formed "on" or "below" another element, this description can include the case where one element is formed on the upper or lower side relative to the other element.

[0065] According to the embodiment, the sensing device can be disposed between the output shaft (not shown) and the input shaft (not shown) of the steering shaft. In this case, the output shaft can be referred to as the first shaft, and the input shaft can be referred to as the second shaft.

[0066] Figure 1 This is a perspective view of a sensing device according to an embodiment. Figure 2 The illustration shows a bottom perspective view of the sensing device according to an embodiment, and Figure 3 This is an exploded perspective view illustrating a sensing device according to an embodiment. In this case, Figures 1 to 3 The Z-direction shown can represent the axial direction, and the R-direction can represent the radial direction. Furthermore, the axial and radial directions can be perpendicular to each other. Figures 1 to 3 The mark "C" shown can indicate the rotation center of each of the rotor 100, stator 200, and first gear 300. Additionally, Figure 2 and Figure 3The mark "C1" shown can indicate the rotation center of each of the second gear 400 and the magnet 500. Additionally, the marks "C" and "C1" can be arranged parallel to each other in the axial direction.

[0067] Reference Figures 1 to 3 The sensing device 1 according to the embodiment may include a rotor 100 connected to a second shaft serving as an input shaft, a stator 200 connected to an output shaft serving as a first shaft, a first gear 300 rotating together with the stator 200, a second gear 400 rotating together with the first gear 300, a magnet 500 connected to the second gear 400, and a magnetic element 600 configured to correspond to the magnet 500. In this case, the magnetic element 600 may be provided on a circuit board 700 and may be referred to as a magnetic sensing element. Furthermore, the first gear 300 may be referred to as a main gear, and the second gear 400 may be referred to as a secondary gear.

[0068] In this situation, in the sensing device 1, when the center of the magnet 500 provided on the second gear 400 and the center of the magnetic element 600 provided on the second gear 400 are not aligned in the axial direction due to assembly tolerances, etc., an offset may occur. In this case, due to the gear backlash generated when the first gear 300 and the second gear 400 are engaged, or when the circuit board 700 and the housing (not shown) are connected, an assembly tolerance may occur when the stator 200 and the first gear 300 are connected. Therefore, an offset may occur due to assembly tolerances, etc.

[0069] Therefore, even when a deflection occurs, the sensing device 1 can utilize the shape of the magnet 500 to prevent a decrease in the accuracy of the steering angle measurement. For example, as Figure 3 As illustrated in the figure, in the sensing device 1, the surface of the magnet 500 facing the magnetic element 600 can be formed as an elliptical surface or an inclined surface can be formed on a single surface to minimize the effect of the offset. That is, in the sensing device 1, by utilizing the shape of the magnet 500 to minimize the effect of the offset on the magnetic field change detected by the magnetic element 600, the measurement accuracy of the steering angle can be improved.

[0070] Meanwhile, the sensing device 1 according to the embodiment can also measure the torque of the steering shaft. Therefore, the sensing device 1 may include a collector 800 and a torque sensor 900, which is disposed on the circuit board 700 facing the side of the collector 800.

[0071] Additionally, the sensing device 1 may also include a housing (not shown) that forms the exterior and supports and protects each component.

[0072] The rotor 100 can be rotatably disposed inside the stator 200. Additionally, the rotor 100 can be connected to a second shaft, which serves as the input shaft of the steering shaft. Alternatively, the input shaft can be a steering shaft connected to a vehicle's handle. In this context, the term "inward" refers to a direction radially toward the center C, and the term "outward" refers to the opposite direction.

[0073] The rotor 100 may include a yoke 110 having a cylindrical shape and a magnet 120 disposed on the yoke 110.

[0074] The yoke 110 can be connected to the second shaft. Therefore, the yoke 110 can rotate together with the rotation of the second shaft.

[0075] The magnet 120 can be disposed outside the yoke 110. In this case, the magnet 120 can be fixedly adhered or press-fitted to the outer peripheral surface of the yoke 110. Alternatively, the magnet 120 can be referred to as a rotor magnet or a main magnet.

[0076] The stator 200 can be rotatably mounted outside the rotor 100. Additionally, the stator 200 can be connected to a first shaft, which serves as the output shaft.

[0077] Reference Figure 3 The stator 200 may include a retainer 210 connected to the output shaft, a body 220 disposed on one side of the outer peripheral surface of the retainer 210, and a pair of stator teeth 230 disposed on the body 220.

[0078] The retainer 210 can be connected to a first shaft, which serves as the output shaft of the steering shaft. Therefore, the retainer 210 can rotate with the rotation of the first shaft. In this case, the retainer 210 can be formed of a metallic material, but is not limited to this. For example, the retainer 210 can be formed of other materials with a predetermined strength, such that the first shaft can be fixedly fitted to the retainer 210.

[0079] The body 220 can be disposed on one end portion of the retainer 210. For example, the body 220 can be disposed on one end portion of the retainer 210 by means of resin, such as synthetic resin. In addition, the magnet 120 of the rotor 100 can be rotatably disposed on the body 220.

[0080] Additionally, the body 220 may include a hole formed to connect to the stator tooth portion 230.

[0081] The stator teeth 230 can be fixedly connected to the body 220. In this case, the stator teeth 230 can be formed in pairs and disposed on each of the upper and lower portions of the body 220. In this case, the stator teeth 230 can be referred to as stator rings.

[0082] Additionally, the stator tooth portion 230 may include a plurality of teeth 231, which are arranged to be spaced apart from each other by a distance along the inner peripheral surface of the body 220, and the teeth 231 may be arranged to correspond to the magnet 120. For example, the teeth 231 may be arranged radially outside the magnet 120.

[0083] The first gear 300 can be configured to operate together with the rotation of the stator 200. For example, the first gear 300 can be connected to the body 220 of the stator 200 and rotate together with the rotation of the stator 200.

[0084] The first gear 300 may be formed in a ring shape, and a plurality of gear teeth may be formed on the outer peripheral surface of the first gear 300. In addition, the gear teeth of the first gear 300 may engage with the gear teeth of the second gear 400.

[0085] The second gear 400 can rotate together with the first gear 300. For example, the second gear 400 can engage with the first gear 300. In this case, the second gear 400 can be configured to have a rotation center C1 that is different from the rotation center of the first gear 300.

[0086] Reference Figure 3 The second gear 400 may include a second gear body 410 formed in a disc shape and a boss 420 protruding from the second gear body 410 in an axial direction. In this case, the boss 420 may be referred to as a first protrusion or a second gear protrusion.

[0087] The second gear body 410 may include gear teeth formed on its outer peripheral surface to engage with the gear teeth of the first gear 300.

[0088] The boss 420 can be formed in a cylindrical shape. Additionally, the magnet 500 can be disposed inside the boss 420. Therefore, the magnet 500 can also rotate together with the rotation of the second gear 400. In this case, an example of a boss 420 formed in a cylindrical shape and to which the magnet 500 is fixed has been described, but the invention is not necessarily limited to this. For example, the boss 420 can be formed in any shape as long as it can prevent movement of the magnet 500 and can also be connected to the magnet 500.

[0089] like Figures 1 to 3As illustrated, the two second gears 400 can be configured to improve the accuracy of steering angle measurement. Therefore, the second gears 400 can include a 2-1 gear 400a and a 2-2 gear 400b. In this case, both 2-1 gear 400a and 2-2 gear 400b are configured to engage with the first gear 300, but the invention is not necessarily limited thereto. For example, 2-1 gear 400a can also engage with the first gear 300, and 2-2 gear 400b can also be configured to engage with 2-1 gear 400a.

[0090] Magnet 500 can be connected to the second gear 400. Therefore, magnet 500 can share the rotation center C1 with the second gear 400 and can rotate together with the second gear 400. For example, magnet 500 can be connected to the boss 420 of the second gear 400 and rotate together with the second gear 400. In this case, magnet 500 can be referred to as an angular magnet or a sub-magnet.

[0091] Figure 4 This is a view illustrating the arrangement of magnets and magnetic elements in a sensing device according to an embodiment.

[0092] Reference Figure 4 When the magnet 500 and the magnetic element 600 are arranged such that the center of rotation of the magnet 500 and the center of the magnetic element 600 are aligned in the axial direction, the steering angle can be measured accurately. For example, when the center of the magnetic element 600 is located on and aligned with the center of rotation C1 of the magnet 500, the steering angle can be measured accurately.

[0093] Figure 5 This is a view illustrating the offset caused by the arrangement relationship between the magnet and magnetic element provided in the sensing device according to the embodiment. Figure 5 In the diagram, the mark "C2" can be the center of magnetic element 600.

[0094] Reference Figure 5 The magnet 500 and the magnetic element 600 can be configured such that the center of the magnet 500 and the center of the magnetic element 600 disposed on the second gear 400 are not aligned in the axial direction due to assembly tolerances, etc.

[0095] For example, when “C1”, representing the rotation center of magnet 500, and “C2”, representing the center of magnetic element 600, are arranged parallel in the axial direction, an offset can occur between “C1” and “C2”. That is, relative to the rotation center C1 of magnet 500 in the radial direction, an offset can occur between the rotation center C1 of magnet 500 and the center C2 of magnetic element 600.

[0096] Therefore, in the sensing device 1, even if a misalignment occurs when the center of the magnet 500 disposed on the second gear 400 and the center of the magnetic element 600 disposed on the second gear 400 are not aligned in the axial direction, the shape of the magnet 500 can minimize the effect caused by the misalignment.

[0097] Therefore, in order to examine the difference in the effect of the shape of the magnet 500 according to the sensing device 1 of the embodiment, a comparative example of a magnet having a different shape from that of the magnet 500 can be proposed. Additionally, the flux detected by the magnetic element of the comparative example can be used to examine the effect of the offset on the measurement accuracy of the steering angle.

[0098] Figure 6 It is a graph showing the relationship between the X-flux in the X direction and the Y-flux in the Y direction, based on the magnetic flux detected by the magnetic element. Figure 7 This is a view illustrating a magnet and a magnetic element as a comparative example. Figure 8 It shows graphs of the X-flux and Y-flux of the magnet's rotation according to a comparative example, and Figure 9 This is a graph showing the nonlinearity of flux due to the offset of the comparison example. Figure 6 In a plane, the X and Y directions can be perpendicular to each other. Additionally, Figure 6 The mark “P” shown can be placed on line C2 that passes through the center of the magnetic element.

[0099] Reference Figure 6 The magnetic flux detected by the magnetic element can be divided into X-flux in the X direction and Y-flux in the Y direction. In this case, the arctangent Atan can be calculated to determine the angle, but errors in angle calculation may occur due to the difference between the maximum values ​​of the X-flux and Y-flux caused by offset. Therefore, a nonlinearity arises that is associated with the measurement accuracy of the steering angle. In this case, the center of the magnetic element can be the sensing center and can be referred to as the sensing point P. In this case, the magnetic element can be a Hall integrated circuit (IC).

[0100] Reference Figure 7 As a comparative example, the sensing device may include a magnetic element 10, a counter gear 20, and a magnet 30 fixed to the counter gear 20 and arranged to face the magnetic element 10. In this case, the magnetic element 10 and the magnet 30 may be offset to a certain extent due to assembly tolerances, etc.

[0101] In this case, the magnet 30 of the sensing device used as a comparative example can be formed in a cylindrical shape, and the surface 31 of the magnet 30 facing the magnetic element 10 can be formed in a circular shape with a predetermined radius r. Therefore, when a displacement occurs, the sensing device used as a comparative example is difficult to respond to the displacement.

[0102] Reference Figure 8 Relative to the virtual line passing through the center C1, the S pole can be positioned on one side of the magnet 30, and the N pole can be positioned on the other side. In this case, the sensing point P of the magnetic element 10 can be positioned on a surface 31 of the magnet 30, spaced a certain distance from the rotation center C1 of the magnet 30 due to offset. Figure 8 As shown in the figure, the actual measured values ​​of X flux and Y flux can be represented as waveforms based on the rotation angle of magnet 30.

[0103] When reference Figure 8 When comparing actual measurements of flux X and flux Y with ideal values, discrepancies can arise between the actual and ideal values ​​due to offset. For example, in Figure 8 At 45 degrees, a difference can be seen between the actual measured values ​​of the X flux and the Y flux and their ideal values. In this case, the actual measured values ​​can be those that reflect the offset and are actually measured by the magnetic element, while the ideal values ​​can be the theoretical values ​​calculated when the center of the magnet and the center of the magnetic element are aligned.

[0104] Therefore, when using a sensing device to measure the steering angle, the offset affects the accuracy. (Refer to...) Figure 9 The impact can be seen more clearly.

[0105] Figure 9 This is a view showing the comparison between the actual and ideal values ​​of flux due to the offset of the comparison example to check the measurement accuracy of the steering angle, and the ideal value can be represented in a linear shape. Alternatively, the difference between the actual and ideal values ​​can be represented in a non-linear shape (waveform) and can be referred to as non-linearity. In this case, the non-linearity can be expressed in angular units.

[0106] Reference Figure 9 As can be seen, the nonlinearity of the actual measured value due to the offset increases due to the difference from the ideal value. In this case, the nonlinearity can be expressed as the maximum value of the difference between the ideal value and the actual measured value. Therefore, the value at the point farthest from the ideal value can be set as the nonlinear value, and the nonlinearity value can have a maximum value when the rotation angle of magnet 30 is 45 degrees, 135 degrees, 225 degrees, or 315 degrees.

[0107] Therefore, it can be seen that the accuracy of steering angle measurement due to offset is related to nonlinearity. For example, it can be seen that the accuracy of steering angle measurement decreases as the nonlinearity value increases.

[0108] At the same time, due to various factors, such as the accumulation of assembly tolerances, the offset length can change. Therefore, it will be referred to Figure 7 The comparative examples shown in the figure illustrate the impact of increased offset on measurement accuracy.

[0109] Figure 10 This is a graph showing the X flux and Y flux with offsets based on a comparative example. Figure 11 It is a graph showing the maximum values ​​of X flux and Y flux based on the offset of the comparison example, and Figure 12 The graph shows the relationship between offset and nonlinearity in a comparative example.

[0110] Reference Figure 10 As can be seen, the maximum value of the Y flux increases as the offset in the sensing device according to the comparative example increases. Therefore, in Figure 10 At approximately 45 degrees, the difference between the X flux and the Y flux also increases.

[0111] Reference Figure 11 The difference between flux X and flux Y can be further explained by the difference between the maximum values ​​of flux X and flux Y. For example... Figure 11 As shown in the diagram, the difference between the maximum values ​​of the X flux and the Y flux increases with the increase of the offset.

[0112] Reference Figure 12 As can be seen, the nonlinearity increases sharply with increasing offset. For example, when the offset is approximately 0.5 mm, the nonlinearity is approximately 2.6 degrees. Therefore, the accuracy of the steering angle measurement decreases as the offset increases.

[0113] Therefore, as the offset increases, the difference between the maximum values ​​of the X flux and the Y flux increases, and thus the nonlinearity also increases. Consequently, it can be seen that the accuracy of the steering angle measurement decreases as the offset increases.

[0114] Therefore, in the sensing device 1 according to the embodiment, a magnet 500 is provided to minimize the effect of the offset, and thus can provide measurement accuracy of the turning angle above a predetermined level.

[0115] Figure 13 This is a perspective view illustrating a first example of a magnet disposed in a sensing device according to an embodiment. Figure 14 This is a front view illustrating a first example of a magnet disposed in a sensing device according to an embodiment. Figure 15 This is a top view illustrating a first example of a magnet disposed in a sensing device according to an embodiment, and Figure 16 This is a bottom view illustrating a first example of a magnet disposed in a sensing device according to an embodiment.

[0116] Reference Figures 13 to 16 The magnet 500 may include a facing surface 510, which is a surface configured to face the magnetic element 600. Additionally, the magnet 500 may include a lower surface 540, which is the axially opposite surface to the facing surface 510.

[0117] The facing surface 510 can be formed in a shape having a major axis A1 and a minor axis A2. For example, the facing surface 510 can be formed in an elliptical shape or a polygonal shape with five or more corners. Even when the facing surface 510 is formed in a polygonal shape, it can still be formed with a major axis A1 and a minor axis A2. In this case, the minor axis A2 can be defined as the shortest line segment among the line segments passing through the rotation center C1 and connecting two points on the circumference of the magnet 500, and the major axis A1 can be defined as the longest line segment.

[0118] Furthermore, the short shaft A2 can be a boundary line B separating one region with an S pole from another region with an N pole. Therefore, relative to the short shaft A2, one region with an S pole can be located on one side, and the other region with an N pole can be located on the other side. In this case, the boundary line B can be positioned to overlap with the magnetic element 600 in the axial direction of the second gear 400. Additionally, considering offset, for the overlap between the boundary line B and the magnetic element 600, the width of the magnetic element 600 in the radial direction can be greater than the length of the short shaft A2.

[0119] Meanwhile, since the magnet 500 may include a body portion 520 and a protrusion 530 formed to protrude axially from one side of the body portion 520, the facing surface 510 may include a flat surface 511 and an inclined surface 512 disposed at a predetermined angle θ relative to the flat surface 511. In this case, the protrusion 530 of the magnet 500 may be referred to as a second protrusion or a magnet protrusion.

[0120] The body portion 520 and the protrusion 530 can be integrally formed. The flat surface 511 can be a surface of the body portion 520 on one side in the axial direction, and the inclined surface 512 can be a surface of the protrusion 530 in the axial direction. In this case, a portion of the flat surface 511 and a portion of the inclined surface 512 can be configured to face the magnetic element 600.

[0121] Reference Figures 13 to 15 The flat surface 511 can be disposed between two inclined surfaces 512.

[0122] Furthermore, the rotation center C1 of the magnet 500 can be positioned on the flat surface 511. Therefore, the short axis A2 can also be provided on the flat surface 511, and the corner 513 where the flat surface 511 intersects the inclined surface 522 can be provided parallel to the short axis. In this case, the corner 513 can be provided to overlap with the magnetic element 600 in the axial direction.

[0123] Additionally, the flat surface 511 can be formed with a predetermined area. In this case, 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 can overlap with the flat surface 511 in the axial direction.

[0124] That is, the area of ​​the flat surface 511 can be determined by taking into account assembly tolerances, the range of offsets that may occur due to assembly tolerances, and the overlap of the magnetic elements 600 in the axial direction. For example, the area of ​​the flat surface 511 can be smaller than the area of ​​a surface of the magnetic element 600 that is positioned facing the flat surface 511. Therefore, each of 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 can be smaller than the width of a surface of the magnetic element 600. Specifically, the width of the flat surface 511 in the major axis direction can be smaller than the length of a surface of the magnetic element 600 in the diagonal direction.

[0125] Furthermore, since the flat surface 511 is formed with a predetermined area, it also has a predetermined length along its major axis. In this case, based on the major axis direction of the magnet 500, the length L1 of the flat surface 511 along its major axis can be formed in the range of 0.2 to 0.8 times the length L2 of the major axis A1. That is, the length L1 of the central region of the flat surface 511 can be in the range of 0.2 to 0.8 times the length L2 of the major axis A1 of the magnet 500.

[0126] Meanwhile, since the rotation center C1 of the magnet 500 is located on the flat surface 511, and the flat surface 511 is disposed between the inclined surfaces 512, the flat surface 511 can be set as a surface of the central region of the magnet 500. In this case, the center of the flat surface 511 can be set coaxially with the rotation center C1 of the magnet 500.

[0127] That is, the magnet 500 may include a central region provided with a flat surface 511 and a peripheral region provided with an inclined surface 512, and the flat surface 511 may be configured as a reference for distinguishing the central region from the peripheral region. Therefore, the central region may include the flat surface 511 as a surface, and the peripheral region may include the inclined surface 512 as a surface.

[0128] Two inclined surfaces 512 can be disposed on one side and the other side of the flat surface 511 in the long axis direction.

[0129] Furthermore, the inclined surface 512 can be configured to have a predetermined gap G with the lower edge of the magnetic element 600. Therefore, when the magnet 500 rotates, interference between the inclined surface 512 and the magnetic element 600 can be prevented.

[0130] Furthermore, the inclined surface 512 can be inclined relative to the flat surface 511 at a predetermined angle θ and can be inclined toward the center C1 of the magnet 500. In this case, the larger the angle θ, the more advantageous it is in terms of accuracy, but the angle θ can be formed within the range where the gap G is formed.

[0131] Additionally, the inclined surface 512 can be configured as a surface in the peripheral region. Therefore, due to the inclined surface 512, the thickness of the magnet 500 in the axial direction can be increased away from the center C1 of the magnet 500.

[0132] The body portion 520 can be formed in a cylindrical shape having a major axis A1 and a minor axis A2. For example, the body portion 520 can be formed in an elliptical cylindrical shape. In this case, a flat surface 511 can be provided as a surface of the body portion 520.

[0133] Furthermore, the body portion 520 may be formed to have a predetermined thickness T1 in the axial direction. In this case, the thickness T1 of the body portion 520 in the axial direction may be referred to as the first thickness, and this thickness T1 may be the thickness of the central region.

[0134] The protrusion 530 can be formed to protrude axially from one surface of the body portion 520 having a flat surface 511.

[0135] In addition, two protrusions 530 may be provided on one surface of the body portion 520 and spaced apart from each other, and the two protrusions 530 may be arranged symmetrically with respect to the minor axis A2.

[0136] Furthermore, the protrusion 530 can be formed to have a predetermined thickness T2 in the axial direction. In this case, the thickness T2 of the protrusion 530 in the axial direction can be referred to as a second thickness, and this thickness T2 can be the thickness of the peripheral region. Therefore, the thickness of the peripheral region in the axial direction can be greater than the thickness of the central region in the axial direction.

[0137] Additionally, the protrusion 530 may include an inclined surface 512. Therefore, the thickness of the peripheral region can decrease towards the central region.

[0138] Furthermore, the end portion of the protrusion 530 with the inclined surface 512 can be configured to overlap with the lower side of the magnetic element 600 in the radial direction of the second gear 400. In this case, a portion of the magnetic element 600 can be configured to overlap with the inclined surface 512 in the axial direction of the second gear 400. Therefore, the corner portion 513 can be configured to overlap with the magnetic element 600 in the axial direction.

[0139] The lower surface 540 may be another surface located on the opposite side of the facing surface 510, which is a surface of the magnet 500 in the axial direction. Alternatively, the lower surface 540 may be configured as a flat surface parallel to the flat surface 511 of the central region.

[0140] Figure 17 It shows a graph illustrating the maximum values ​​of the X flux and Y flux based on the offset of the sensing device including the magnet according to the first example, and Figure 18 It is a graph showing the relationship between the offset and nonlinearity of a sensing device with a magnet according to the first example.

[0141] Reference Figure 5 and Figure 17 As can be seen, as the offset between the magnet 500 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 detected by the magnetic element 600 also increases.

[0142] However, when the difference between the maximum values ​​of the X flux and Y flux at the offset of the comparison example is plotted in... Figure 11 As can be seen, the difference between the maximum values ​​of the X flux and Y flux detected by the sensing device 1 according to the embodiment is smaller than the difference between the maximum values ​​of the X flux and Y flux detected by the sensing device according to 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 Y flux is approximately 8 mT. Furthermore, when the offset of the sensing device 1 is 1.00 mm, the difference between the maximum values ​​of the X flux and Y flux is approximately 1.8 mT.

[0143] Reference Figure 18As can be seen, the nonlinearity increases as the offset of the sensing device 1 according to the embodiment increases.

[0144] When reference Figure 12 and Figure 18 When comparing the nonlinearity of the sensing device 1 according to the embodiment with that of the comparative example, it can be seen that the line indicating the nonlinearity of the sensing device 1 according to the embodiment rises slowly compared to the line indicating the nonlinearity of the comparative example. For example, it can be seen that when the offset of the sensing device 1 is about 0.5 mm, the nonlinearity value is about 0.8 degrees. Therefore, in the case of the sensing device 1, it can be seen that as the offset increases, the measurement accuracy of the steering angle is higher than that of the comparative example.

[0145] However, in the case of sensing device 1, considering the relationship with nonlinearity, the ratio of the difference between the maximum values ​​of X flux and Y flux can be limited. In this case, the ratio of the difference between the maximum values ​​of X flux and Y flux can be obtained using the following equation:

[0146] [Equation]

[0147]

[0148] Therefore, the magnet 500 of the sensing device 1 can be configured such that the ratio of the difference between the maximum values ​​of the X flux and the Y flux based on a 1 mm offset is within 15%. When the ratio of the difference is greater than 15%, nonlinearity increases, and it is therefore difficult to provide measurement accuracy of the steering angle above a predetermined level. The ratio limitation can also be applied to the sensing device 1 including the magnet 500a according to the second example described below.

[0149] In summary, because the shape of the magnet 500 of the sensing device 1 minimizes the effects of offset, the sensing device 1 can detect the steering angle with higher measurement accuracy compared to the comparative example. Therefore, even when offset occurs, the sensing device 1 can improve reliability by providing measurement accuracy of the steering angle above a predetermined level.

[0150] Figure 19 This is a perspective view illustrating a second example of a magnet disposed in a sensing device according to an embodiment. Figure 20 This is a front view illustrating a second example of a magnet disposed in a sensing device according to an embodiment. Figure 21 It shows a graph illustrating the maximum values ​​of the X flux and Y flux based on the offset of the sensing device including the magnet according to the second example, and Figure 22 It is a graph showing the relationship between the offset and nonlinearity of the sensing device including the magnet according to the second example.

[0151] The sensing device 1 may be equipped with a magnet 500a according to the second example, instead of a magnet 500 according to the first example.

[0152] When reference Figures 13 to 16 , Figure 19 and Figure 20 When comparing the magnet 500 according to the first example with the magnet 500a according to the second example, the difference between the magnet 500a according to the second example and the magnet 500a according to the first example is that the magnet 500a according to the second example does not include the protrusion 530 of the magnet 500 according to the first example. That is, the shape of the facing surface of the magnet 500a according to the second example—that is, the surface configured to face the magnetic element 600—is different from the shape of the facing surface of the magnet 500 according to the first example.

[0153] Reference Figure 19 and Figure 20 The magnet 500a may include a facing surface 510a, which is a surface configured to face the magnetic element 600. Additionally, the magnet 500a may include a lower surface 540, which is the opposite surface to the facing surface 510a in the axial direction.

[0154] The facing surface 510a can be formed in a shape having a major axis A1 and a minor axis A2. For example, the facing surface 510a can be formed in an elliptical shape and can be set as a flat surface.

[0155] The facing surface 510 can be one surface of the magnet 500 in the axial direction, and the lower surface 540 can be another surface located on the opposite side of the facing surface 510. In addition, the lower surface 540 can be configured as a flat surface parallel to the flat surface 511 of the central region, and can be formed with the same shape as the facing surface 510a.

[0156] Reference Figure 21 As can be seen, as the offset 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 Y flux detected by the magnetic element 600 also increases.

[0157] When reference Figure 12 and Figure 22When comparing the nonlinearity of the sensing device 1 including the magnet 500a according to the second example with the nonlinearity of the comparative example, it can be seen that the line indicating the nonlinearity of the sensing device 1 according to the embodiment rises slowly compared to the line indicating the nonlinearity of the comparative example. For example, it can be seen that when the offset of the sensing device 1 including the magnet 500a according to the second example is approximately 0.5 mm, the nonlinearity value is approximately 2.0 degrees. Therefore, in the case of the sensing device 1 including the magnet 500a according to the second example, it can be seen that as the offset increases, the measurement accuracy of the steering angle is higher than that of the comparative example.

[0158] The magnetic element 600 can be configured to correspond to the magnet 500 to detect changes in the magnetic field of the magnet 500. For example, one surface of the magnetic element 600 can be configured to face the facing surface 510 of the magnet 500. In this case, the sensing point P of the magnetic element 600 can be configured to overlap with the flat surface 511 in the axial direction. In this case, the magnetic element 600 can be referred to as a magnetic sensing device, and a Hall IC can be used as the magnetic element 600. Additionally, the surface of the magnetic element 600 that faces the facing surface 510 of the magnet 500 can be referred to as a detection surface.

[0159] In this case, the same number of magnetic elements 600 as magnets 500 or 500a can be provided on the circuit board 700.

[0160] Additionally, the width of one surface of the magnetic element 600 can be greater than the length of the minor axis A2 and less than the length of the major axis A1. For example, the width of the magnetic element 600 in the minor axis direction can be greater than the length of the minor axis A2 of the magnet 500, and the width of the magnetic element 600 in the major axis direction can be less than the length of the major axis A1.

[0161] Furthermore, the magnetic element 600 can be disposed between the protrusions 530 along the radial direction of the second gear 400. For example, since the width of one surface of the magnetic element 600 is less than the length of the major axis A1, and the inclined surface 512 is formed on the protrusions 530, the magnetic element 600 can be disposed between the protrusions 530 along the radial direction of the second gear 400. That is, the magnetic element 600 can be disposed between the inclined surfaces 512 along the radial direction of the second gear 400, and a portion of the magnetic element 600 can be configured to overlap with the inclined surface 512 in the axial direction. However, when the magnet 500 rotates, the magnetic element 600 should be configured to have a predetermined gap G with the inclined surface 512 to prevent interference between the inclined surface 512 and the magnetic element 600.

[0162] A magnetic element 600 for detecting the magnetization of magnet 500 can be mounted on a circuit board 700. Additionally, a torque sensor 900 for measuring torque can be mounted on the circuit board 700. In this case, the circuit board 700 can be a printed circuit board.

[0163] In addition, the circuit board 700 can be formed in an arc shape and can be disposed outside the body 220 of the stator 200.

[0164] Collector 800 allows torque sensor 900, mounted on circuit board 700, to detect changes in magnetic force caused by the rotational difference based on the torsion of the input and output shafts. In this case, collector 800 can be formed of a metallic material and fixed to the housing.

[0165] Two collectors 800 can be configured to correspond to each of a pair of stator teeth 230 to collect the flux of the stator 200. In this case, depending on the arrangement, the collectors 800 can be divided into an upper collector and a lower collector.

[0166] Reference Figures 1 to 3 The collector 800 can be positioned close to the stator teeth 230. In this case, the term "close" can mean "in contact with each other or spaced a predetermined distance apart".

[0167] Collector 800 may include plate 810 and legs 820.

[0168] The plate 810 can be formed in a plate shape. In addition, the plate 810 can be positioned close to one side of each stator tooth 230 in the stator tooth portion 230.

[0169] The leg 820 can be formed to protrude from the plate 810 in the axial direction. In this case, the leg 820 can be disposed outside the body 220, and the end portion of the leg 820 can be bent in the radial direction.

[0170] Additionally, the end portion of the leg 820 can be configured to face the torque sensor 900. Therefore, the torque sensor 900 can be positioned between the leg 820 of the upper collector and the leg 820 of the lower collector.

[0171] A torque sensor 900 can be mounted on a circuit board 700. In this case, the torque sensor 900 can be configured to correspond to the leg 820 of the collector 800.

[0172] When torsion occurs between the input and output shafts, a rotational difference may occur between the rotor 100 and the stator 200. This rotational difference is detected as a change in magnetic force by the collector 800 and the torque sensor 900. Therefore, the torque sensor 900 can measure the torque to smoothly adjust the steering handle.

[0173] Although the invention has been described above with reference to exemplary embodiments, those skilled in the art will understand that various modifications and alterations can be made to the invention without departing from the spirit and scope of the invention as defined by the appended claims.

[0174] <Figure Labels>

[0175] 1: Sensing device; 100: Rotor; 200: Stator; 300: First gear; 400: Second gear; 500, 500a: Magnet; 510: Facing surface; 511: Flat surface; 512: Inclined surface; 600: Magnetic element; 700: Circuit board; 800: Collector; 900: Torque sensor

Claims

1. A sensing device, comprising: Stator, the stator being connected to the first shaft; The first gear rotates together with the stator; The second gear rotates together with the first gear; A magnet, the magnet being connected to the second gear; as well as A magnetic element, wherein the magnetic element is configured to correspond to the magnet. One surface of the magnet has an elliptical shape. Wherein, the width of the magnetic element in the short axis direction is greater than the length of the short axis (A2) of the magnet; and Wherein, the width of the magnetic element in the long axis direction is smaller than the length of the long axis (A1) of the magnet.

2. A sensing device, comprising: Stator, the stator being connected to the first shaft; The first gear rotates together with the stator; The second gear rotates together with the first gear; A magnet, the magnet being connected to the second gear; as well as A magnetic element, wherein the magnetic element is configured to correspond to the magnet. One surface of the magnet includes a flat surface and an inclined surface that is tilted relative to the flat surface. The magnet includes a body portion having the flat surface and a protrusion including the inclined surface; The flat surface is disposed between the two inclined surfaces; and The magnetic element is configured to overlap with the end portion of the protrusion in the radial direction of the second gear.

3. A sensing device, comprising: Stator, the stator being connected to the first shaft; The first gear rotates together with the stator; The second gear rotates together with the first gear; A magnet, the magnet being connected to the second gear; as well as A magnetic element, wherein the magnetic element is configured to correspond to the magnet. The magnet has a shape in which the ratio of the difference between the maximum value of the X flux and the maximum value of the Y flux, based on an offset of 1 mm, is within 15%. The magnet includes a body portion having a flat surface and a protrusion including an inclined surface; The flat surface is disposed between the two inclined surfaces; and The magnetic element is configured to overlap with the end portion of the protrusion in the radial direction of the second gear.

4. A sensing device, comprising: Stator, the stator being connected to the first shaft; The first gear rotates together with the stator; The second gear rotates together with the first gear; A magnet, the magnet being connected to the second gear; as well as A magnetic element, wherein the magnetic element is configured to correspond to the magnet. The magnet has a peripheral region, and in the axial direction, the thickness of the peripheral region is greater than the thickness of the central region of the magnet. The thickness of the peripheral region decreases towards the central region.

5. The sensing device of claim 1, wherein, Relative to the minor axis of the aforementioned surface: The S-pole is disposed in a region of the surface; and The N pole is located in another region of the surface.

6. The sensing device according to claim 5, wherein, The one surface of the magnet includes: Flat surface; and An inclined surface, which is inclined relative to the flat surface. The corner where the flat surface intersects the inclined surface is arranged to be parallel to the short axis.

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

8. The sensing device according to claim 2, wherein, The inclined surface is tilted toward the center of the magnet.

9. The sensing device according to claim 4, wherein: One surface of the central region includes a flat surface; and One surface of the peripheral region includes a sloping surface.

10. The sensing device according to claim 9, wherein, The other surface of the magnet is a flat surface parallel to the flat surface of the central region.

11. The sensing device according to claim 4, wherein, The sensing point of the magnetic element is configured to overlap with the flat surface of the central region in the axial direction of the first gear.

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

13. The sensing device according to claim 4, wherein, The length of the flat surface of the central region along the long axis of the magnet is in the range of 0.2 to 0.8 times the length of the long axis.

14. The sensing device according to claim 2, wherein, A portion of the magnetic element is configured to overlap the inclined surface in the axial direction.

Images