Detection device

Abstract

To provide a detection device capable of detecting deformation of a rotating body while having a simple configuration.SOLUTION: A detection device 100 includes: a magnetic body 1 that is attached to a rotating body (10) that rotates around an axis, and consists of an annular body in which north poles and south poles are alternately arranged in a circumferential direction; a sensor 2 that detects magnetic flux density of the magnetic body; and a processing unit 4 that detects deformation of the rotating body based on a detection result by the sensor. The sensor detects first magnetic flux density (By) emitted from a magnetized surface of the magnetic body in a direction perpendicular to the circumferential direction of the magnetized surface, and the processing unit detects deformation of the rotating body based on a change in the first magnetic flux density.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a detection device that detects deformation of a rotating body by a magnetic body attached to the rotating body that rotates about an axis and a sensor that detects magnetic flux density.

Background Art

[0002] Conventionally, a magnetic body that constitutes a magnetic encoder has been attached to a rotating member in a bearing device of a wheel of an automobile or the like in order to control an anti-lock braking system (ABS) or the like, and the rotational speed and the rotational angle have been detected.

[0003] The following Patent Document 1 discloses a device that includes a sensor that changes an output signal in response to a change in characteristics of a detection surface of a magnetic body and can measure a load applied between an outer ring and a hub without using a load measurement dedicated component such as a displacement sensor. The following Patent Document 2 discloses a device that arranges a first sensor and a second sensor at positions on the outer peripheral surface of a magnetic body where the circumferential phases are different from each other by 180 degrees and measures a radial load based on the phase difference.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, the load applied to the bearing device includes the load due to the weight of the rotating body, the load applied from other components, the load generated by the rotation of the rotating body, etc. If an excessive load is applied, deformation occurs in the rotating body, and if use is continued without noticing, it will lead to breakage of the rotating shaft. Therefore, there is a demand for a device that can detect deformation of a rotating body at an early stage while having a simple configuration.

[0006] This invention has been made in view of the above circumstances, and aims to provide a detection device that can detect deformation of a rotating body despite having a simple configuration. [Means for solving the problem]

[0007] To achieve the above objective, the detection device according to the present invention includes a magnetic material consisting of an annular body mounted on a rotating body that rotates on an axis and having multiple N poles and S poles alternately magnetized in the circumferential direction, and the detection of the magnetic flux density of the magnetic material. and are arranged in close proximity to the magnetized surface of the magnetic material. A detection device comprising a sensor and a processing unit that detects the deformation of the rotating body based on the detection result of the sensor, wherein the sensor detects a first magnetic flux density (By) emitted from the magnetized surface of the magnetic material in a direction perpendicular to the circumferential direction of the magnetized surface, and the processing unit, The rate of change of the value of the first magnetic flux density is calculated, and based on the rate of change The feature is to detect the deformation of the rotating body. In the above configuration, the sensor may detect a second magnetic flux density (Bx) emitted circumferentially from the magnetized surface or a third magnetic flux density (Bz) emitted perpendicular to the magnetized surface, and the processing unit may detect the rotational speed and rotational angle of the rotating body based on the second or third magnetic flux density. Furthermore, in the above configuration, multiple sensors may be provided facing the magnetization surface, spaced apart from each other. Furthermore, in the above configuration, The processing unit detects deformation of the rotating body as an abnormality when the rate of change exceeds a predetermined threshold. That's fine. [Effects of the Invention]

[0008] The detection device according to the present invention, with the above-described configuration, can detect deformation of a rotating body despite its simple configuration. [Brief explanation of the drawing]

[0009] [Figure 1] This figure illustrates a magnetic material constituting a detection device according to one embodiment of the present invention. It is a schematic perspective view showing the mounting state on a rotating body, and shows an example of an axial type magnetic material. [Figure 2]This block diagram shows an example of the configuration of the detection device. [Figure 3] (a) is the measurement diameter of the magnetic material shown in Figure 1. <1> ~ <3> (See Figure 3(b)) This graph shows the waveform of the first magnetic flux density, where (b) is the measurement diameter of the magnetic material. <1> ~ <3> This is a diagram to explain the concept. [Figure 4] (a) and (b) are graphs illustrating the characteristics of the first magnetic flux density (By) emitted by the magnetic material. [Figure 5] As a modified example of the same embodiment, an example of a radial type magnetic material is shown. [Figure 6] (a) to (d) are schematic plan views illustrating examples of the arrangement of magnetic materials and sensors that constitute the detection device. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described below with reference to the drawings. Note that some of the detailed reference numerals used in other figures have been omitted in some of the figures. The detection device 100 according to this embodiment includes a magnetic body 1, which is mounted on a rotating body 10 that rotates on an axis and is an annular body in which multiple N poles and S poles are alternately magnetized in the circumferential direction; a sensor 2 for detecting the magnetic flux density of the magnetic body 1; and a processing unit 4 for detecting the deformation of the rotating body 10 based on the detection result from the sensor 2. The sensor 2 detects a first magnetic flux density (By) emitted from the magnetized surface 1a of the magnetic body 1 in a direction perpendicular to the circumferential direction of the magnetized surface 1a, and the processing unit 4 detects the deformation of the rotating body 10 based on the change in the first magnetic flux density.

[0011] <First Embodiment> First, the detection device 100 according to the first embodiment will be described with reference to Figures 1 to 4. As shown in Figures 1 and 2, the detection device 100 comprises a magnetic body 1 attached to a rotating body that rotates on an axis, a sensor 2 for detecting magnetic flux density, and a computing device 30 having a processing unit 4 for detecting deformation of the rotating body based on the detection result from the sensor 2. Below, an example of the application of the detection device 100 will be described, specifically its application to a vehicle bearing device. The bearing device is provided to support a wheel (not shown) so that it can rotate (rotate on an axis), and comprises an outer ring (not shown) which is the outer fixed side member, and an inner ring 10 which is the inner rotating side member. Therefore, in this embodiment Hey Furthermore, the inner ring 10 is a rotating body, and a detection device 100 is provided to detect deformation of the inner ring 10 at an early stage due to loads applied to the inner ring 10.

[0012] The magnetic material 1 is an annular body with multiple N and S poles alternately magnetized in the circumferential direction and a through hole in the center, and is magnetized in the radial or planar direction of the disk. The composition of the magnetic material 1 is not particularly limited, but rubber magnets, sintered magnets, plastic magnets, etc., in which magnetic powders such as ferrite and neodymium are bonded with rubber material are used. The magnetic material 1 is attached to the inner ring 10 via a core metal member 11. The core metal member 11 is formed by press-forming a steel plate such as SPCC so that the cross-section on one side is substantially L-shaped. The core metal member 11 has a cylindrical portion 12 that fits onto the end of the inner ring 10, and a disk portion 13 that extends radially outward from one end of the cylindrical portion 12 in the axial direction A. The magnetic material 1 is vulcanized and bonded, or post-bonded, to the outer surface 13a of the disk portion 13 in the axial direction A. The shape of the magnetic material 1 and the manner in which it is fixed to the core metal member 11 are not limited to the illustrated example, but in this embodiment, the outer surface 13a of the disk portion 13 and the disk portion 13 It is positioned to cover the outer end 13b in the radial direction R. This allows the magnetic material 1 to be firmly fixed to the core metal member 11, and it can withstand long-term use. The pole widths of the N pole and S pole are not particularly limited and may be equally spaced as shown in the figure example, or the boundary between the poles may be a spiral shape with an oblique curve.

[0013] The sensor 2 used to detect the magnetic flux density of the magnetic material 1 will be described using an example of a magnetic sensor. The sensor 2 is positioned in close proximity to the magnetized surface 1a of the magnetic material 1, and is fixed to a fixing member (not shown). The magnetic flux density detected by the sensor 2 from the magnetic material 1 changes with the rotation of the inner ring 10, and the sensor 2 is electrically connected to the computing unit 30. To detect the deformation of the inner ring 10, which is a rotating body, the sensor 2 detects a first magnetic flux density (By) emitted from the magnetized surface 1a of the magnetic material 1 in a direction perpendicular to the circumferential direction of the magnetized surface 1a, as shown in Figure 1. The sensor 2 also detects a second magnetic flux density (Bx) emitted in the circumferential direction from the magnetized surface 1a and a third magnetic flux density (Bz) emitted from the magnetized surface 1a in a direction perpendicular to the magnetized surface 1a, in order to detect the rotational speed and rotational angle (rotational position) of the inner ring 10. As the detection element used in sensor 2, Hall elements, MR elements (magnetoresistive element), etc., are used, and a highly sensitive element that can detect not only the second magnetic flux density (Bx) emitted in the circumferential direction from the magnetized surface 1a and the third magnetic flux density (Bz) emitted from the magnetized surface 1a perpendicular to the magnetized surface 1a, but also the first magnetic flux density (By) emitted from the magnetized surface 1a perpendicular to the circumferential direction of the magnetized surface 1a is preferred. For example, in the case of a Hall element, in addition to a Hall element for detecting the strength Bx of the X-axis component of the magnetized surface 1a or a Hall element for detecting the strength Bz of the Z-axis component, a Hall element for detecting the strength By of the Y-axis component of the magnetized surface 1a is required in order to detect load and displacement.

[0014] Figure 2 is a block diagram showing an example of the detection device 100 according to this embodiment. As described above, the detection device 100 includes a magnetic body 1 attached to the inner ring 10, a sensor 2 capable of detecting the magnetic flux density generated from the magnetic body 1, and an arithmetic unit 30. The arithmetic unit 30 includes a control unit 3 configured by a CPU that executes various controls, a processing unit 4 that performs various arithmetic processes based on various magnetic flux densities (Bx to Bz) detected by the sensor 2, a storage unit 5 that stores various programs and data necessary for executing the arithmetic processes in the processing unit 4, a reception unit 6 that receives signals from the sensor 2, an operation unit 7 that operates the arithmetic unit 30, a display unit 8 that displays measurement and calculation results, a notification unit 9 that notifies, such as lighting or flashing a warning sound or a lamp when an abnormality such as deformation of the inner ring 10 is detected, and the like. The storage unit 5 is composed of memories such as ROM and RAM and HDD, and appropriately stores various arithmetic results. The processing unit 4 includes a load / deformation amount calculation unit 40 and a speed / angle calculation unit 41. The load / deformation amount calculation unit 40 calculates using the change rate of the first magnetic flux density (By) due to the change in the measured diameter. Specifically, based on the characteristics described later of the first magnetic flux density (By) and the measured diameter (see FIG. 3(b)) shown in FIGS. 4(a) and 4(b), the change rate of the value of the first magnetic flux density (By) detected by the sensor 2 is calculated, and the deformation amount is calculated therefrom. Then, the load is calculated from the deformation amount. The speed / angle calculation unit 41 converts two magnetic patterns of the second magnetic flux density (Bx) and the third magnetic flux density (Bz) into digital signals, performs arithmetic processing, and calculates rotation position (rotation angle) information from absolute position detection. Further, the speed / angle calculation unit 41 calculates the distance from the two-phase pulse signals of the second magnetic flux density (Bx) and the third magnetic flux density (Bz), and also executes the calculation of the rotation speed of the inner ring 10.

[0015] Next, referring to FIGS. 3 and 4, the analysis results regarding the characteristics of the first magnetic flux density (By) emitted from the magnetization surface 1a used for detecting the deformation of the inner ring 10, which is a rotating body, in a direction perpendicular to the circumferential direction of the magnetization surface 1a will be described. Here, the measurement was performed using a ferrite rubber magnet.

[0016] The graph in Fig. 3(a) shows the result of detecting the first magnetic flux density (By) at the positions of the measured diameters <1> to <3> of the magnetic body 1 shown in Fig. 3(b). Here, the horizontal axis represents the rotation angle (°), and the vertical axis represents the magnetic flux density (mT). As shown in Fig. 3(b), the measured diameter <1> is the smallest among the three measured diameters, and the measured diameter <3> is the largest among the three measured diameters. According to Fig. 3(a), for any of the measured diameters <1> to <3>, although the amplitude of the magnetic flux density varies, a sine wave is confirmed, and it can be confirmed that a sine signal is generated one cycle per rotation.

[0017] The graph in Fig. 4(a) shows the result of detecting the first magnetic flux density (By) at the same measured diameters <1> to <3> for the same magnetic body 1 that shows the sine wave in Fig. 3(a). Here, the horizontal axis represents the measured diameter (mm), the vertical axis represents the magnetic flux density (mT), and not only the first magnetic flux density (By) but also the second magnetic flux density (Bx) and the third magnetic flux density (Bz) were measured at the positions of the measured diameters <1> to <3>. From this measurement result, it was found that the second magnetic flux density (Bx) and the third magnetic flux density (Bz) show almost the same measured values at any position, while the first magnetic flux density (By) shows a large change rate that rapidly decreases at the measured diameter <1>.

[0018] Fig. 4(b) is a graph that more clearly shows the change rate of each magnetic flux density. Here, the horizontal axis is the measured diameter (mm), and the vertical axis is the ratio of the measurement result in Fig. 4(a). The vertical axis uses the measured diameter <1> with the largest change rate as the reference ("1") and shows how much it has changed from that reference. It is clear that there is almost no change in the second magnetic flux density (Bx) and the third magnetic flux density (Bz) when compared. On the other hand, it can be said that the change rate of the magnetic flux density of the first magnetic flux density (By) is very large with respect to the change in the radial direction. From the above, by detecting the first magnetic flux density (By), that is, the strength By of the Y-axis component of the magnetization surface 1a, with the sensor 2, when a change in the radial direction of the rotating body is applied, a large change occurs in the first magnetic flux density (By). Therefore, the load and the amount of deformation can be detected from this characteristic.

[0019] According to the detection device 100 of this embodiment, by utilizing the characteristics of the first magnetic flux density (By) and detecting the first magnetic flux density (By) with the sensor 2, the deformation (tilt) of the inner ring 10 can be detected. Therefore, from the detection result by the detection device 100, it can be inferred that an excessive (radial) load has been applied to the inner ring 10. Furthermore, by setting a threshold for the calculation result of the load / deformation amount calculation unit 40 based on the detection result of the first magnetic flux density (By), and considering it an abnormality in the load / deformation amount when the threshold is exceeded, the notification unit 9 of the detection device 100 will notify with a warning sound, etc., thereby preventing damage to the rotating shaft, etc. Furthermore, with the above configuration, in addition to the deformation of the inner ring 10, the rotation speed and rotation angle of the inner ring 10 can be detected using a single magnetic material 1.

[0020] Figure 5 shows an example of a radial type magnetic material 1A. Common reference numerals are used for parts common to the above embodiment, and explanations of common items are omitted. In the above embodiment, an axial type magnetic material 1 was described, but it is not limited to this, and can be applied as a magnetic material 1A provided on one side surface 10b of the inner ring 10 as shown in Figure 5. In this case as well, similar to the axial type, not only the second magnetic flux density (Bx) emitted in the circumferential direction from the magnetized surface 1a and the third magnetic flux density (Bz) emitted from the magnetized surface 1a perpendicular to the magnetized surface 1a are detected, but also the first magnetic flux density (By) emitted from the magnetized surface 1a perpendicular to the circumferential direction of the magnetized surface 1a. Based on the change in the first magnetic flux density, the processing unit 4 detects the axial deformation of the inner ring 10, which is a rotating body.

[0021] Next, with reference to Figures 6(a) to 6(d), examples of the arrangement of the magnetic body 1 and sensor 2 that constitute the detection device 100 will be described. As shown in Figure 1, the sensor 2 is positioned opposite the magnetized surface 1a of the magnetic body 1. As shown in Figure 6(a), one sensor 2 may be used to perform the above detection for one annular magnetic body 1, or, as shown in Figure 6(b), a sensor 2 may be placed at a position 90° different from the position of the sensor 2 provided in Figure 6(a), for example. Furthermore, as shown in Figure 6(c), in addition to the example in Figure 6(b), a sensor 2 may be placed at a position 180° different. Furthermore, as shown in Figure 6(d), two sensors 2,2 may be installed at the same position in the circumferential direction of the magnetic body 1, facing each other in the width direction on the edge of the magnetic body 1. The placement of the sensors 2 is not limited to the examples shown, and multiple sensors may be installed at equal intervals. By arranging multiple sensors 2 at intervals opposite the magnetized surface 1a in this manner, deformation of the rotating body (such as the inner ring 10) can be detected at multiple locations, thereby improving detection accuracy.

[0022] As described above, the configuration and manner of the detection device 100 according to the embodiment are not limited to the above embodiment. For example, the shape of the magnetic body 1 is not limited to a thin annular body as shown in the figure example, but may be a cylindrical body. Also, the object for detecting the deformation of a rotating body is not limited to the inner ring 10 of a bearing device, but can be applied to rotating members of mechanical devices that rotate on an axis, such as sheet winding equipment. [Explanation of Symbols]

[0023] 100 detection device 10 Inner ring (rotating body) 1,1A magnetic material 1a Magnetized surface 2 sensors By 1st Magnetic Flux Density Bx Second Magnetic Flux Density B z Third magnetic flux density

Claims

1. A detection device comprising: a magnetic body consisting of an annular body attached to a rotating body that rotates on an axis and having multiple N poles and S poles alternately magnetized in the circumferential direction; a sensor that detects the magnetic flux density of the magnetic body and is positioned in close proximity to the magnetized surface of the magnetic body; and a processing unit that detects the deformation of the rotating body based on the detection result from the sensor, The sensor detects a first magnetic flux density emitted from the magnetized surface of the magnetic material in a direction perpendicular to the circumferential direction of the magnetized surface, The detection device is characterized in that the processing unit calculates the rate of change of the value of the first magnetic flux density and detects the deformation of the rotating body based on the rate of change.

2. In claim 1, The sensor detects a second magnetic flux density emitted circumferentially from the magnetized surface or a third magnetic flux density emitted perpendicular to the magnetized surface. The detection device is characterized in that the processing unit detects the rotational speed and rotational angle of the rotating body based on the second magnetic flux density or the third magnetic flux density.

3. In claim 1 or claim 2, The detection device is characterized in that a plurality of sensors are provided opposite the magnetized surface, spaced apart from each other.

4. In claim 1 or claim 2, The detection device is characterized in that the processing unit detects the deformation of the rotating body as an abnormality when the rate of change exceeds a predetermined threshold.

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