Abnormality detection device for tire wheel

Abstract

To provide a device capable of detecting abnormality of a mounting state of a tire wheel such as looseness of a nut during traveling of a vehicle.SOLUTION: In one embodiment, a device for detecting an abnormality in a mounted state of a tire wheel (16) includes a light emitting device (20) configured to emit light toward an inner side surface (17) of the tire wheel (16), a light receiving device (20) configured to receive reflected light from the inner side surface (17) of the tire wheel (16), and a processing device (30) connected to the light emitting device (20) and the light receiving device (20). The processing device (30) is configured to acquire a distance (22) to an inner surface (17) of the tire wheel (16) based on the reflected light received by the light receiving device (20) during rotation of the tire wheel (16), and determine that the tire wheel (16) is mounted in an abnormal state when a representative value (24) of the distance (22) exceeds a predetermined value (26).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The technology disclosed in this application relates to a device for detecting an abnormality in the mounting state of a tire wheel. [Background technology]

[0002] A device that uses imaging cameras to assist in the installation of a tire wheel on a vehicle is known. In JP 3-104701 A, two imaging cameras capture images of the hub to which the tire wheel is attached to detect the positions of the hub bolts, and based on the detection data, the tire wheel is installed on the hub by aligning the bolt holes in the tire held by a hand unit with the hub bolts. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 3-104701 Summary of the Invention [Problem to be solved by the invention]

[0004] The method described in the above publication is for detecting hub bolts, etc., when the tire and wheel are assembled during the vehicle manufacturing process (when the vehicle is not running), and cannot be used to detect loose nuts on tire and wheel nuts while the vehicle is running. If it were possible to notify the driver before the tire comes off the wheel, the vehicle could be safely driven and stopped, so there is a demand for a device that can detect abnormalities in the installation condition, such as loose nuts, while the vehicle is running. [Means for solving the problem]

[0005] One aspect of the present technology is an apparatus for detecting an abnormality in the mounting condition of a tire wheel, the apparatus comprising: a light-emitting device that emits light toward the inner surface of the tire wheel; a light-receiving device that receives light reflected from the inner surface of the tire wheel; and a processing device connected to the light-emitting device and the light-receiving device, wherein the processing device is configured to obtain the distance to the inner surface of the tire wheel based on the reflected light received by the light-receiving device while the tire wheel is rotating, and to determine that there is an abnormality in the mounting condition of the tire wheel if a representative value of the distance exceeds a predetermined value.

[0006] Another aspect of the present technology is an apparatus for detecting an abnormality in the mounting condition of a tire wheel, the apparatus comprising: an imaging device that acquires an image of the inner surface of the tire wheel; a marker provided on the inner surface of the tire wheel; and a processing device connected to the imaging device, wherein the processing device is configured to acquire an image of the inner surface of the tire wheel with the imaging device while the tire wheel is rotating, recognize the position of the marker included in the acquired image, and determine that there is an abnormality in the mounting condition of the tire wheel when the amount of deviation of the marker's trajectory exceeds a predetermined range. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic diagram showing a method for detecting an abnormality in the mounting state of a wheel using a distance sensor according to one embodiment; [Figure 2] 10 is a graph showing the change in distance to the inner surface of the wheel when the wheel is properly mounted. [Figure 3] 10 is a graph showing the change in distance to the inner surface of a wheel when a wheel nut is loose. [Figure 4] 10 is a schematic diagram showing a method for detecting an abnormality in the mounting state of a wheel using an imaging device according to another embodiment. FIG. [Figure 5] FIG. 1 is a view of the inner side of a wheel with markers. [Figure 6] 10 is a graph showing the trajectory of the marker when the wheel is properly mounted. [Figure 7] 10 is a graph showing the trajectory of the marker when a wheel nut is loose. DETAILED DESCRIPTION OF THE INVENTION

[0008] Various embodiments will be described below with reference to the drawings.

[0009] [Wheel installation] FIG. 1 shows a wheel 16 with a rubber tire 14 mounted on an axle 12 in a wheel well 10 of the vehicle body. Although not shown, the wheel 16 is typically fixed by inserting a plurality of bolts provided on the hub at the end of the axle 12 into bolt holes 18 (see FIG. 5) in the wheel 16 and tightening them with nuts. Even if the wheel 16 is properly mounted, repeated driving can cause the nuts to loosen and other mounting abnormalities to develop. Such mounting abnormalities can be detected by the method described below.

[0010] Distance to wheel method As shown in FIG. 1, one embodiment uses a laser-type distance sensor 20 equipped with a light-emitting unit and a light-receiving unit. The distance sensor 20 is positioned so that the light-emitting unit emits light toward the inner surface 17 of the wheel 16 (the surface not visible from the outside of the vehicle) and the light-receiving unit detects the light reflected from the inner surface 17 of the wheel 16. Although not shown in FIG. 1, the distance sensor 20 can be fixed to a location that is not affected by the orientation of the wheel 16, for example, to a brake device such as a disc brake or drum brake. Specifically, it can be fixed to the mounting bracket or cylinder body of a disc brake or the back plate of a drum brake. A processing device (processor) 30 is electrically connected to the distance sensor 20 so that the processing device 30 can acquire the distance calculated by the distance sensor. The processing device 30 can be, for example, part of an electronic control unit (ECU) installed in the vehicle. In addition to the processing device 30, the electronic control unit includes a storage device capable of storing data and programs.

[0011] As shown in FIGS. 2 and 3, the processing device 30 determines that there is an abnormality in the mounting condition of the wheel 16 when the average value 24 of the acquired distances 22 exceeds a predetermined threshold value 26 while the vehicle is running (i.e., while the wheels are rotating). These figures show graphs plotting the distance (D) from the distance sensor 20 to the wheel 16 against time (T). If the wheel 16 is mounted properly, the average value 24 of the distances 22 to the wheel 16 is considered to be less than some threshold value 26 (FIG. 2). On the other hand, if the average value 24 of the distances 22 exceeds the threshold value 26, it is considered that there is some abnormality in the mounting condition of the wheel 16, such as a loose nut (FIG. 3). In another embodiment, instead of the average value 24 of the distances 22, the maximum or minimum value of the distance, or some representative value that takes these into account, can be used.

[0012] The radial position of the wheel 16 to be used as the distance can be determined for each specific vehicle model. The radial position can be a position where the undulations are as small as possible in the circumferential direction, such as a portion close to the rim, that is, a position where the fluctuation in the distance from the distance sensor 20 is as small as possible even when the wheel 16 rotates. However, even if there are some undulations, detection is possible by using the average distance per rotation of the wheel 16.

[0013] In another embodiment, a non-laser type distance sensor can be used instead of the laser type distance sensor 20. In yet another embodiment (not shown), a separate light emitting device and light receiving device can be provided instead of using the distance sensor 20. In this case, the processing device 30 calculates the distance from the light emitting device or light receiving device (or some other reference point) to the inner surface 17 of the wheel 16 based on, for example, the time it takes for the laser to be reflected and returned and the angle at which it returns (triangulation).

[0014] [Marker trajectory-based method] As shown in Figures 4 and 5, another embodiment may use an imaging device 40, such as an infrared camera, that captures an image of the inner surface 17 of the wheel 16, and at least one marker 42 provided as a mark on the inner surface 17 of the wheel 16. In one embodiment, multiple markers 42 having a uniform shape and dimensions may be arranged at the same radial position at equal angular intervals. Each marker 42 may be, for example, a reflective flat surface with a clear outline. The marker 42 may be, for example, recessed or protruding from its surroundings. The method for forming the marker 42 is not limited, but may be formed by stamping, for example. Like the light-emitting device and light-receiving device described above, the imaging device 40 is fixed in a location that is not affected by the orientation of the wheel 16. A processing device 50 is electrically connected to the imaging device 40. The processing device 50 may be part of an electronic control unit (ECU) installed in the vehicle. The electronic control unit includes, in addition to the processing device 50, a storage device capable of storing data and programs.

[0015] As shown in FIGS. 6 and 7, the processing device 50 recognizes the positions of the markers 42 included in the images captured by the imaging device 40. If the amount of deviation in the trajectory of the markers 42 exceeds a predetermined range 44, the processing device 50 determines that the mounting condition of the wheel 16 is abnormal. These figures show the positions of the markers 42 recognized from multiple images captured by the imaging device 40, superimposed on one another. If the wheel 16 is properly mounted, the trajectory of the markers 42 is considered to fall within the predetermined range (FIG. 6). On the other hand, if there are markers 42 (A) that are within the predetermined range 44 and markers 42 (B) that are outside the predetermined range 44, and the trajectory of the markers 42 varies, it is considered that an abnormality has occurred in the mounting condition of the wheel 16, such as a loose nut (FIG. 3: the deviation in the trajectory is exaggerated). Note that the amount of deviation in the trajectory of the markers 42 can be an appropriate value, such as the maximum deviation, average deviation, or standard deviation of the radial position of the markers 42. Correspondingly, the predetermined range 44 can be a range defined relative to a fixed reference value, average value, or other statistically representative value.

[0016] [Use of judgment results] If an abnormality is detected, the driver can be notified, for example, by radio. This allows the driver to know that there is an abnormality, such as a loose nut, before the wheel 16 comes off the road, and allows the driver to take measures such as safely stopping the vehicle.

[0017] Although various embodiments have been described above, the present technology is not limited to these embodiments, and various changes, substitutions, and improvements can be made by those skilled in the art. [Explanation of symbols]

[0018] 10 Tire House 12 axles 14 Rubber Tires 16 wheels 17 Inner surface 18 bolt holes 20 Distance Sensor 22 distance 24 average 26 Threshold 30 Processing equipment 40 Imaging device 42 Markers 44 Prescribed range 50 Processing equipment

Claims

1. A device for detecting an abnormality in the mounting state of a tire wheel, a light emitting device that emits light toward an inner surface of the tire wheel; a light receiving device that receives light reflected from an inner surface of the tire wheel; a processing device connected to the light emitting device and the light receiving device, the processing device acquires a distance to an inner surface of the tire wheel based on the reflected light received by the light receiving device while the tire wheel is rotating, The device is configured to determine that there is an abnormality in the mounting condition of the tire / wheel when the representative value of the distance exceeds a predetermined value.

2. A device for detecting an abnormality in the mounting state of a tire wheel, an imaging device for acquiring an image of the inner surface of the tire wheel; a marker provided on an inner surface of the tire wheel; a processing device connected to the imaging device, the processing device acquires an image of the inner surface of the tire wheel with the imaging device while the tire wheel is rotating, Recognizing the position of the marker included in the acquired image; The device is configured to determine that there is an abnormality in the mounting condition of the tire wheel when the amount of deviation of the marker's trajectory exceeds a predetermined range.

Images