Steering Angle Sensing Device

Abstract

Disclose a steering angle sensing device. According to one aspect of the present invention, the steering angle sensing device includes: a pinion shaft coupled to a rack cover provided with a rack, having a pinion formed thereon for meshing with the rack; a magnet disposed at one end of the pinion shaft and rotating together with the pinion shaft; a printed circuit board (PCB) having a magnetic sensor disposed at a certain interval from the magnet to sense the rotation angle of a steering wheel connected to the pinion shaft; and a connector connected to the printed circuit board to transmit a sensed value detected by the magnetic sensor to a control unit.

Description

Technical Field

[0001] The present invention relates to a steering angle sensing device, and more particularly, to a steering angle sensing device for sensing the rotation angle of a vehicle's steering wheel. Background Art

[0002] In general, a steering device that is necessarily applied to an automobile is a device that changes the path and traveling direction of the automobile according to the driver's requirements. In addition, as a means of ensuring the safety of the steering state by reducing the steering force of the steering wheel (handle) on the vehicle, a power-assisted steering device is used. As such a power-assisted steering device, a hydraulic power steering system (HPS: Hydraulic Power Steering System) that uses hydraulic pressure has been used in the past. However, in recent years, an electric power steering device (R-EPS: Rack assist type Electric Power Steering) that uses the rotational force of an electric motor to assist the driver's steering has been provided on vehicles.

[0003] Such an electric power steering device may include a device for detecting a steering angle. That is, it is used to detect the steering angle of the vehicle and assist the steering force. A device for detecting a steering angle is disclosed in Patent Publication No. 10-2018-0073970. Referring to the disclosed document, it includes a main gear, two sub-gears, and two sensors provided on a pinion shaft connected to a rack. Magnets are respectively provided on the two sub-gears, and when rotating in engagement with the main gear, the sensors detect a magnetic field change and calculate the rotation angle of the steering wheel.

[0004] However, such an electric power steering device requires a sub-gear, a magnet, and a sensor respectively, so not only does the manufacturing cost increase, but the structure is complex and the installation space is limited. Summary of the Invention

[0005] Technical Problem

[0006] The steering angle sensing device according to an embodiment of the present invention can reduce the manufacturing cost with a simple structure and can also easily detect the steering angle.

[0007] Means for Solving the Technical Problem

[0008] According to an aspect of the present invention, there is provided a steering angle sensing device, which includes: a pinion shaft coupled to a rack housing provided with a rack, having a pinion formed thereon for meshing with the rack; a magnet disposed at one end of the pinion shaft and rotating together with the pinion shaft; a printed circuit board (PCB) having a magnetic sensor disposed at a certain interval from the magnet to sense the rotation angle of a steering wheel connected to the pinion shaft; and a connector connected to the printed circuit board to transmit a sensing value detected by the magnetic sensor to a control unit.

[0009] In addition, the magnet and the magnetic sensor are arranged coaxially with the central axis of the pinion shaft.

[0010] In addition, it further includes: a magnet holder formed in a cylindrical shape with one side open to accommodate and fix the magnet, and the magnet holder is coupled to the pinion shaft.

[0011] In addition, the magnet holder has a stopper protrusion formed protruding from the inner circumferential surface, and at least one or more of the stopper protrusions are formed along the inner circumferential surface of the magnet holder.

[0012] In addition, the stopper protrusion is formed with a predetermined length from the inner bottom of the magnet holder, and the length of the stopper protrusion is longer than the thickness of the magnet.

[0013] In addition, the pinion shaft has a coupling portion at one end, the coupling portion has a diameter smaller than the diameter of the main body formed with the pinion, and the coupling portion is press-fitted and coupled through the open portion of the magnet holder and supported by the stopper protrusion, whereby the end of the coupling portion is disposed at a certain interval from the magnet.

[0014] In addition, a flat surface having a shape corresponding to the stopper protrusion is formed on the outer circumferential surface of the magnet and press-fitted into the magnet holder.

[0015] In addition, the magnet is fixed to the magnet holder by an adhesive.

[0016] In addition, the magnet is integrally formed with the magnet holder by insert molding.

[0017] In addition, on the same axis as the pinion shaft, a sensor accommodation portion is provided by opening the lower side of the rack housing, and the steering angle sensing device further includes a plug that is coupled to close the opening of the sensor accommodation portion.

[0018] In addition, a part of the connector is exposed and coupled in such a way as to penetrate the plug and be connected to the control unit.

[0019] In addition, it includes a sealing portion that prevents foreign substances from entering the connector and between the connector exposed from the plug and the plug.

[0020] Advantages of the Invention

[0021] The steering angle sensing device according to an embodiment of the present invention eliminates the conventional main gear, two sub-gears, magnets, and sensors, and can detect the steering angle through a simple structure, thereby reducing manufacturing costs.

[0022] In addition, it can be applied to an existing electric power steering device, so it has practicality, and is configured with a simple structure, so that the installation space can be ensured and the design freedom can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 FIG. is a diagram schematically showing an electric power steering device including the steering angle sensing device according to an embodiment of the present invention.

[0024] Figure 2 FIG. is an exploded perspective view showing the steering angle sensing device according to an embodiment of the present invention.

[0025] Figure 3 is Figure 2 partial combined perspective view of.

[0026] Figure 4 FIG. is a partially cut-away perspective view showing a magnet holder of the steering angle sensing device according to an embodiment of the present invention.

[0027] Figure 5 FIG. is a cross-sectional view showing a state in which a magnet holder of the steering angle sensing device according to an embodiment of the present invention is combined with a pinion shaft.

[0028] Figure 6 FIG. is a perspective view showing a state in which the steering angle sensing device according to an embodiment of the present invention is combined with a rack cover.

[0029] Figure 7 FIG. is a cross-sectional view showing a state in which the steering angle sensing device according to an embodiment of the present invention is combined with a rack cover.

[0030] Figure 8 FIG. is a cross-sectional view showing the steering angle sensing device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0031] Hereinafter, with reference to the drawings, embodiments of the present invention will be described in detail. The following embodiments are for fully conveying the idea of the present invention to those skilled in the art. The present invention is not limited to the embodiments disclosed herein and can be embodied in other forms. Regarding the drawings, for clarity of the present invention, parts irrelevant to the description are omitted from the illustration, and for helping understanding of the present invention, the sizes of the components are shown enlarged somewhat.

[0032] Figure 1 FIG. is a diagram schematically showing an electric power steering apparatus having a steering angle sensing device according to an embodiment of the present invention.

[0033] Referring to Figure 1 , the electric power steering apparatus 1 includes: a steering wheel (handle: not shown) disposed at the driver's seat; a steering shaft 11 connected to the steering wheel; a steering column 12 fixing the steering shaft 11 to the vehicle body; an intermediate shaft 13 connected to the steering column 12 and rotating together with the steering wheel and having a pair of universal joints; a pinion shaft 110 connected to the intermediate shaft 13; and an auxiliary power mechanism 30 supplying steering assist power. Further, the pinion shaft 110 is connected to a rack bar (refer to Figure 5 ‘21’ of ) housed in a rack cover 20, and both ends of the rack bar 21 are connected to wheels of an automobile through tie rods 23 and steering knuckles 24. That is, the rack bar 21 moves left and right by the rotation of the pinion shaft 110, whereby the wheels rotate, and thus the vehicle can be steered.

[0034] The auxiliary power mechanism 30 includes: a control unit (ECU: electronic control unit) that senses a steering torque applied to the steering wheel by a driver and generates a control signal based on an electrical signal transmitted from the sensed steering torque; a motor 31 that generates steering assist power based on the control signal transmitted from the control unit (ECU); and a gear unit that transmits the assist power generated from the motor 31 to the rack bar 21 through a conveyor belt. A motor position sensor (MPS: Motor Positoin Sensor) is provided on such an auxiliary power mechanism 30, whereby the angle of the steering wheel is detected together with the steering angle sensing device 100.

[0035] The structure of such an electric power steering apparatus 1 is a known structure, and thus a detailed description thereof is omitted.

[0036] Figure 2 FIG. is an exploded perspective view showing a steering angle sensing device according to an embodiment of the present invention, Figure 3 is Figure 2 a partially assembled perspective view of Figure 4 FIG. is a partially cut-away perspective view showing a magnet holder of a steering angle sensing device according to an embodiment of the present invention, Figure 5 FIG. is a cross-sectional view showing a state in which a magnet holder and a pinion shaft of a steering angle sensing device according to an embodiment of the present invention are combined, Figure 6 FIG. is a perspective view showing a state in which a steering angle sensing device according to an embodiment of the present invention is combined with a rack cover, Figure 7 FIG. is a cross-sectional view showing a state in which a steering angle sensing device according to an embodiment of the present invention is combined with a rack cover, Figure 8 FIG. is a cross-sectional view showing a steering angle sensing device according to an embodiment of the present invention.

[0037] Referring to Figures 2 to 8 , a steering angle sensing device 100 according to one aspect of the present invention includes: a pinion shaft 110; a magnet holder 120 coupled to one end of the pinion shaft 110 and having a magnet 122; a printed circuit board 130 having a magnetic sensor 132; a connector 140 connected to the printed circuit board 130 to transmit a sensing value to a control unit (ECU); and a plug 150 coupled to the connector 140.

[0038] The pinion shaft 110 has a predetermined length and rotates together with the steering wheel, and a pinion 111 is formed on an outer circumferential surface. The other end of such a pinion shaft 110 is connected to an intermediate shaft (refer to Figure 1 ‘13’), and a coupling portion 112 is provided at one end, and the coupling portion 112 has a diameter smaller than that of a main body on which the pinion 111 is formed. The coupling portion 112 is coupled to a magnet holder 120 described later. The structure of the coupling between the coupling portion 112 and the magnet holder 120 will be described again below. Such a pinion shaft 110 is coupled to a rack housing 20 so as to mesh with a rack 22 of a rack bar 21.

[0039] On the other hand, a reference numeral ‘115’ (not shown) is a bearing that rotatably supports the pinion shaft 110 on the rack housing 20 to allow the pinion shaft 110 to rotate stably.

[0040] In addition, a reference numeral ‘40’ (not shown) is a rack support device that elastically supports the rack bar 21 on the side of the pinion shaft 110 to keep the rack 22 and the pinion 111 in a tightly meshed state.

[0041] The magnet holder 120 is coupled to the coupling portion 112 and has a magnet 122 therein. The magnet holder 120 has a cylindrical shape with one side open to accommodate the magnet 122. In addition, the magnet holder 120 has a stopper protrusion 124 protruding from an inner circumferential surface. At least one or more stopper protrusions 124 are formed along the inner circumferential surface of the magnet holder 120. More specifically, the stopper protrusion 124 is formed with a predetermined length from an inner bottom portion of the magnet holder 120 and has a flat surface.

[0042] Through the open portion of such a magnet holder 120, the magnet 122 is fixed to the bottom inside the magnet holder 120. As shown in the figure, with the formation of the stopper projection 124 in the magnet holder 120, a flat surface 122a having a shape corresponding to the flat surface of the stopper projection 124 is formed on the outer peripheral surface of the magnet 122. In this regard, after arranging the flat surface 122a of the magnet 122 corresponding to the stopper projection 124, the magnet 122 is press-fitted and joined to the magnet holder 120. This is to prevent the magnet 122 from idling within the magnet holder 120 when the magnet holder 120 is joined to the engagement portion 112 of the pinion shaft 110 and rotates together. On the other hand, in this figure, the case where the flat surface 122a is formed in the magnet 122 and supported by the stopper projection 124 is illustrated and described, but it is not limited thereto. As long as the magnet 122 can be firmly fixed to the magnet holder 120, any assembly structure can be adopted. For example, the magnet 122 is fixed to the magnet holder 120 by an adhesive. In addition, the magnet holder 120 and the magnet 122 are integrally formed by insert molding.

[0043] On the other hand, the stopper projection 124 has a predetermined length in the longitudinal direction of the magnet holder 120. At this time, the length l2 of the stopper projection 124 is longer than the thickness l1 of the magnet 122.

[0044] The engagement portion 112 is press-fitted and joined through the open portion of the magnet holder 120 as described above. At this time, the end of the engagement portion 112 is blocked by the stopper projection 124. That is, when the engagement portion 112 is press-fitted and joined to the magnet holder 120, the engagement portion 122 is blocked by the stopper projection 124 and restricted from moving, so that the end of the engagement portion 112 is spaced apart from the magnet 122 by a certain interval. In this regard, the engagement portion 112 is prevented from being over-press-fitted and joined, thereby preventing the magnet 122 from being damaged.

[0045] On the other hand, in this figure, the case where the engagement portion 112 is spaced apart from the magnet 122 by a certain interval and supported by the stopper projection 124 to be joined to the magnet holder 120 is illustrated and described, but it is not limited thereto. The length of the engagement portion 112 may also have a length that does not contact the magnet 122 joined to the magnet holder 120 and is joined to the magnet holder 120.

[0046] The printed circuit board 130 is provided with a magnetic sensor 132 for sensing the rotation angle of the steering wheel. The printed circuit board 130 is disposed at a certain interval from the magnet holder 120. Specifically, various electrical components and circuit wirings are arranged on the printed circuit board 130, and the magnetic sensor 132 is provided on the surface facing the magnet 122. That is, the magnetic sensor 132 provided on the printed circuit board 130 is disposed opposite to the magnet 122, and the magnet 122 and the magnetic sensor 132 are separated by a certain interval. Such a magnetic sensor 132 is located at a position opposite to the magnet 122 fixed to the magnet holder 120. The magnetic sensor 132 is, for example, an AMR (Anisotropic Magneto Resistive) sensor, a GMR (Giant Magneto Resistance) sensor, a Hall sensor, or the like. The magnetic sensor 132 senses the magnetic field change of the magnet 122 generated according to the rotation of the pinion shaft 110, and the printed circuit board 130 processes the sensing signal of the magnetic field change of the magnetic sensor 132.

[0047] On the other hand, the magnet 122 and the magnetic sensor 132 are arranged coaxially with the central axis of the pinion shaft 110.

[0048] The connector 140 is connected to the printed circuit board 130 to transmit the sensed value detected by the magnetic sensor 132 of the printed circuit board 130 to the control unit (ECU). The connector 140 is connected to the printed circuit board 130 through the connection terminal 143 by a press fit method or electrically connected by soldering. One end of such a connector 140 is connected to the printed circuit board 130, and the other end is connected to the electronic control device or the control unit (ECU) of the auxiliary power mechanism 30 through a separately provided socket or the like. In this regard, the sensing signal detected by the magnetic sensor 132 is transmitted to the control unit (ECU) through the connector 140, and the rotation angle of the steering wheel is calculated by another algorithm for control. Such a connector 140 is combined with a plug 150 described later.

[0049] The plug 150 will be locked and joined to the lower side of the opening of the rack cover 20 arranged coaxially with the pinion shaft 110. The lower side of the rack cover 20 is open to have a sensor accommodating portion for accommodating the connector 140 joined to the printed circuit board 130. In this regard, the plug 150 joined to the connector 140 will lock and join the lower side opening of the rack cover 20. When the plug 150 is press-fitted and joined to the lower side opening of the rack cover 20, it is press-fitted and joined in such a way that there is a certain interval between the magnetic sensor 132 and the magnet holder 120. This is to smoothly sense the magnetic field change of the magnet 122 through the magnetic sensor 132. In addition, the plug 150 is formed by being screwed to the rack cover 20. That is, the plug 150 is screwed to the rack cover 20, and the position of the magnetic sensor 132 is adjusted according to the degree of the screw joining, thereby adjusting the interval between the magnetic sensor 132 and the magnet holder 120.

[0050] On the other hand, a part of the connector 140 is exposed to penetrate the plug 150 and be connected to the control unit (ECU) to be joined. According to the illustration, the connector 140 is joined and fixed to the plug 150, and the lower part is exposed from the plug 150 and connected to the electronic control device or the control unit (ECU) provided in the auxiliary power unit 30. In this regard, as described above, the accurate steering wheel angle is detected by calculating the rotation angle of the pinion shaft 110 detected by the magnetic sensor 132 on one side of the present invention and the rotational speed of the motor detected by the MPS provided in the auxiliary power unit 30 using another algorithm.

[0051] In addition, a sealing portion (not shown) is provided, and this sealing portion prevents foreign substances from flowing into the connector 140 and between the connector 140 and the plug 150 as the connector 140 is exposed from the plug 150. The sealing portion is composed of a sealing member or silicon, etc. Through such a sealing portion, the gap between the connector and the plug is finished to prevent the inflow of foreign substances.

[0052] As described above, the steering angle sensing device 100 can use the existing pinion shaft 110, magnet 112, printed circuit board 130, connector 140, and plug 150, and only manufacture the magnet holder 120 separately for use. Therefore, the assembly of the electric power steering device 1 is simpler, the number of components is reduced, and thus the manufacturing cost can be reduced.

[0053] As described above, although the present invention has been described through limited embodiments and drawings, the present invention is not limited thereto, and those skilled in the art can clearly make various modifications and deformations within the scope equivalent to the technical idea of the present invention and the following claims.

Claims

1. A steering angle sensing device, comprising: A pinion shaft coupled to a rack housing provided with a rack, and formed with a pinion for meshing with the rack; A magnet disposed at one end of the pinion shaft and rotating together with the pinion shaft; A printed circuit board (PCB) having a magnetic sensor disposed at a certain interval from the magnet, and sensing the rotation angle of a steering wheel connected to the pinion shaft; A connector connected to the printed circuit board and transmitting a sensed value measured by the magnetic sensor to a control unit; and A magnet holder formed in a cylindrical shape with one side open to accommodate and fix the magnet, and the magnet holder is coupled to the pinion shaft, The magnet holder has a stopper protrusion formed protruding on the inner circumferential surface, At least one or more of the stopper protrusions are formed along the inner circumferential surface of the magnet holder, The stopper protrusion is formed to have a predetermined length from the inner bottom of the magnet holder and has a flat surface, The length of the stopper protrusion is longer than the thickness of the magnet, The pinion shaft has a coupling portion at one end, and the coupling portion has a diameter smaller than the diameter of the main body formed with the pinion, The coupling portion is arranged to be press-fitted and supported by the stopper protrusion through the open portion of the magnet holder, whereby the end of the coupling portion is spaced apart from the magnet by a certain interval.

2. The steering angle sensing device according to claim 1, wherein The magnet and the magnetic sensor are arranged coaxially with the central axis of the pinion shaft.

3. The steering angle sensing device according to claim 1, wherein A flat surface having a shape corresponding to the stopper protrusion is formed on the outer circumferential surface of the magnet, whereby the magnet is press-fitted and coupled to the magnet holder.

4. The steering angle sensing device according to claim 1, wherein The magnet is fixed to the magnet holder by an adhesive.

5. The steering angle sensing device according to claim 1, wherein The magnet is integrally formed with the magnet holder by insert molding.

6. The steering angle sensing device according to claim 1, wherein On the same axis as the pinion shaft, a sensor accommodation portion is provided with an opening on the lower side of the rack housing, The steering angle sensing device further includes a plug that is coupled to close the opening of the sensor accommodation portion.

7. The steering angle sensing device according to claim 6, wherein A part of the connector is exposed and coupled in such a way as to penetrate the plug and be connected to the control unit.

8. The steering angle sensing device according to claim 7, comprising: A sealing portion that prevents foreign substances from flowing into the connector and between the connector exposed from the plug and the plug.

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