US-12617464-B2 - Sensing device

US12617464B2US 12617464 B2US12617464 B2US 12617464B2US-12617464-B2

Abstract

Disclosed is a sensing device comprising: a stator connected to a first shaft; a first gear rotating in engagement with the stator; a second gear rotating in engagement with the first gear; a magnet coupled to the second gear; and a magnetic element disposed corresponding to the magnet, wherein one surface of the magnet disposed facing 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 the axial direction and thus arranged offset, the sensing device can enhance the precision of a steering angle measurement due to the shape of the magnet.

Inventors

Sung Wook BYUN

Assignees

LG INNOTEK CO., LTD.

Dates

Publication Date: 20260505
Application Date: 20210630
Priority Date: 20200818

Claims (14)

1 . A sensing device comprising: a stator connected to a first shaft; a first gear which rotates in conjunction with the stator; a second gear which rotates 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 has an elliptical shape, wherein the magnet has a peripheral region of which a thickness is greater than a thickness of a central region of the magnet in an axial direction, wherein one surface of the central region includes a flat surface, and wherein one surface of the peripheral region includes an inclined surface.
2 . The sensing device of claim 1 , wherein, with respect to a minor axis of the one surface: an S pole is disposed in one region of the one surface; and an N pole is disposed in an other region of the one surface.
3 . The sensing device of claim 2 , wherein a corner at which the flat surface meets the inclined surface is disposed to be parallel to the minor axis.
4 . The sensing device of claim 2 , wherein a boundary line between the one region and the other region overlaps with the magnetic element in an axial direction of the second gear.
5 . The sensing device of claim 1 , wherein the thickness of the peripheral region decreases toward the central region.
6 . The sensing device of claim 1 , wherein an other surface of the magnet, opposite to the one surface, is a flat surface parallel to the flat surface of the central region.
7 . The sensing device of claim 1 , wherein a sensing point of the magnetic element is disposed to overlap with the flat surface of the central region in an axial direction of the first gear.
8 . The sensing device of claim 1 , wherein one surface of the magnet is a surface facing the magnetic element.
9 . The sensing device of claim 1 , wherein a length of the flat surface of the central region is in the range of 0.2 to 0.8 times a length of a major axis in a major axis direction of the magnet.
10 . The sensing device of claim 1 , wherein a width of the magnetic element in a minor axis direction is greater than a length of a minor axis (A 2 ) of the magnet, and wherein a width of the magnetic element in a major axis direction is smaller than a length of a major axis (A 1 ) of the magnet.
11 . A sensing device comprising: a stator connected to a first shaft; a first gear which rotates in conjunction with the stator; a second gear which rotates 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 includes a flat surface and an inclined surface inclined with respect to the flat surface, wherein the magnet includes a body portion having the flat surface and a protrusion including the inclined surface, wherein the flat surface is disposed between two inclined surfaces, and wherein the magnetic element is disposed to overlap with an end portion of the protrusion in a radial direction of the second gear.
12 . The sensing device of claim 11 , wherein the inclined surface is inclined toward a center of the magnet.
13 . The sensing device of claim 11 , wherein a part of the magnetic element is disposed to overlap with the inclined surface in an axial direction.
14 . A sensing device comprising: a stator connected to a first shaft; a first gear which rotates in conjunction with the stator; a second gear which rotates in conjunction with the first gear; a magnet coupled to the second gear; and a magnetic element disposed to correspond to the magnet, wherein the magnet has a shape in which a ratio for a difference between a maximum value of an X flux and a maximum value of a Y flux has a value within 15% based on an offset of 1 mm, wherein the magnet has a peripheral region of which a thickness is greater than a thickness of a central region of the magnet in an axial direction, wherein one surface of the central region includes a flat surface, and wherein one surface of the peripheral region includes an inclined surface.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application is the National Phase of PCT International Application No. PCT/KR2021/008255, filed on Jun. 30, 2021, which claims priority under 35 U.S.C. 119(a) to Patent Application No. 10-2020-0103339, filed in the Republic of Korea on Aug. 18, 2020, all of which are hereby expressly incorporated by reference into the present application. TECHNICAL FIELD The present embodiment relates to a sensing device. BACKGROUND ART In order to secure steering stability of a vehicle, a steering system which assists steering using separate power can be used in the vehicle, and in particular, an electronic power steering (EPS) system with low power loss and superior accuracy is used. In addition, in the EPS system, an electronic control unit drives a motor according to operating conditions and driver manipulation information detected by a vehicle speed sensor, a torque sensor, an angle sensor, and the like to secure turning stability and quickly provide a restoring force so that a driver can drive safely. In addition, the angle sensor measures a steering angle of a steering handle using a main gear which rotates in conjunction with rotation of a rotor, a sub-gear which rotates by being engaged with the main gear, a magnet coupled to the sub-gear, and a Hall integrated circuit (IC) for detecting a change in magnetic force of the magnet. However, when a center of the magnet fixed to the sub-gear and a center of the Hall IC disposed to correspond to the magnet are not accurately aligned, there is a problem in accurately measuring the steering angle. That is, there is a problem that a degree of measurement accuracy of the angle sensor is degraded due to an offset generated when the center of the magnet and the center of the Hall IC are disposed. For example, due to an assembly error occurring when a substrate in which the Hall IC is disposed is installed in a case, an assembly error occurring when the sub-gear is disposed in the case, and the like, a problem that an offset is generated when the magnet and the Hall IC are disposed occurs. In addition, when two sub-gears, two magnets, and two Hall ICs are used in an angle sensor, since an assembly tolerance is further increased, there is a problem that the reliability of a degree of measurement accuracy is also further degraded. Accordingly, the development of a sensing device which can improve a degree of measurement accuracy of a steering angle even when an assembly tolerance of an angle sensor is generated is required. Technical Problem The present embodiment is directed to providing a sensing device capable of improving a degree of measurement accuracy of a steering angle even when an offset is generated when a magnet fixed to a sub-gear and a magnetic element which detects a change in magnetic field of the magnet are disposed. Objectives to be solved by embodiments are not limited to the objectives described above, and objectives which are not described above will be clearly understood by those skilled in the art from the following descriptions. Technical Solution One aspect of the present invention provides a sensing device including a sensing device including a stator connected to a first shaft, a first gear which rotates in conjunction with the stator, a second gear which rotates 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. Another aspect of the present invention provides a sensing device including a sensing device including a stator connected to a first shaft, a first gear which rotates in conjunction with the stator, a second gear which rotates 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 includes a flat surface and an inclined surface formed to be inclined with respect to the flat surface. Still another aspect of the present invention provides a sensing device including a stator connected to a first shaft, a first gear which rotates in conjunction with the stator, a second gear which rotates in conjunction with the first gear, a magnet coupled to the second gear, and a magnetic element disposed to correspond to the magnet, wherein the magnet has a shape in which a difference between a maximum value of an X flux in an X direction and a maximum value of a Y flux in a Y direction has a value within 15% based on an offset of 1 mm. With respect to a minor axis of the one surface, an S pole may be disposed in one region of the one surface, and an N pole may be disposed in the other region of the one surface. The one surface of the magnet may include a flat surface and an inclined surface inclined with respect to the flat surface, wherein a corner at which the flat surface meets the inclin