WO2023144942A1 - Fixing member slack detection device and fixing member slack warning device - Google Patents

Abstract

This fixing member slack detection device (31) comprises: a first attachment part (33) configured so as to rotate integrally with a first fixing member (21); a second attachment part (35) configured so as to rotate integrally with a second fixing member (22); and a coupling part (37) that couples the first attachment part (33) and the second attachment part (35). The coupling part (37) deforms due to the rotation of at least one of the first attachment part (33) and the second attachment part (35). A control device (45) determines that slack is present in the fixing members (21, 22) from a detection result of an acceleration sensor (43) provided to the coupling part (37). A transmitting circuit (48) transmits information for enabling recognition of the presence of the slack, to an actuation device (51) for actuating a warning unit (57).

Description

Fixing member looseness detection device and fixing member looseness alarm device

The present disclosure relates to a fixing member looseness detection device and a fixing member looseness alarm device.

The wheel may be provided with a fixing member for fixing the wheel. In order to prevent the fixing member from coming off, the fastening state of the fixing member may be checked. For example, Patent Literature 1 discloses an indicator provided so as to rotate integrally with a fixing member. A person checks the fastening state of the fixing member by looking at the indicator. A person determines whether the indicator has rotated since the previous inspection. A person can determine that the fixing member has become loose if the indicator has been rotating since the previous inspection.

JP 2015-186951 A

When performing visual inspection by a person, there is a risk of overlooking that the fixing member is loose.

According to a first aspect of the present disclosure, a vehicle is provided with a plurality of fixing members for fixing a wheel to an axle, and is configured to detect loosening of at least one of the plurality of fixing members. A configured fixing member looseness detection device is provided. The plurality of fixing members includes a first fixing member and a second fixing member. The fixing member looseness detection device includes: a first mounting portion attached to the first fixing member and configured to rotate integrally with the first fixing member; a second mounting portion that is attached and configured to rotate integrally with the second fixing member; and a connecting portion that connects the first mounting portion and the second mounting portion, a connecting portion configured to be deformed by rotation of at least one of the first mounting portion and the second mounting portion; an acceleration sensor provided in the connecting portion; Information for recognizing that the loosening has occurred is provided to a control device configured to determine that the loosening has occurred and to an actuating device that activates an alarm unit that warns that the loosening has occurred. and a transmission circuit configured to transmit.

When at least one of the first fixing member and the second fixing member is loosened, the connecting portion is deformed. The deformation of the connecting portion changes the detection result of the acceleration sensor. The control device can determine from this change that the fixing member has become loose. The transmission circuit transmits information for recognizing that loosening has occurred to the actuator. As a result, it is possible to warn that the fixing member is loose by means of the warning from the warning unit. It is easier for a person to recognize that the fixing member is loose compared to visual observation by a person.

In the fixing member looseness detection device, the acceleration sensor may have a sensitivity axis, and the sensitivity axis may be oriented in the circumferential direction of the wheel.
In the fixing member looseness detection device, the transmission circuit may transmit the determination result of the control device as information for recognizing that the looseness has occurred.

According to a second aspect of the present disclosure, provided in a vehicle having a plurality of fixing members for fixing a wheel to an axle, looseness of at least one of the plurality of fixing members is detected and an alarm is issued. A fastener looseness alarm device is provided configured to: The plurality of fixing members includes a first fixing member and a second fixing member. The fixing member loosening warning device includes a first mounting portion attached to the first fixing member and configured to rotate integrally with the first fixing member, and a second fixing member. a second mounting portion that is attached and configured to rotate integrally with the second fixing member; and a connecting portion that connects the first mounting portion and the second mounting portion, a connecting portion configured to be deformed by rotation of at least one of the first mounting portion and the second mounting portion; an acceleration sensor provided in the connecting portion; a control device configured to determine that a member and the second fixing member have loosened; an alarm unit configured to warn that the loosening has occurred; and actuating the alarm unit. and a transmission circuit configured to transmit information for making the actuator recognize that the loosening has occurred.

When at least one of the first fixing member and the second fixing member is loosened, the connecting portion is deformed. The deformation of the connecting portion changes the detection result of the acceleration sensor. The control device can determine from this change that the fixing member has become loose. The transmission circuit transmits information for recognizing that loosening has occurred to the actuator. As a result, it is possible to warn that the fixing member is loose by means of the warning from the warning unit. It is easier for a person to recognize that the fixing member is loose compared to visual observation by a person.

1 is a schematic configuration diagram of a vehicle in a first embodiment; FIG. FIG. 2 is an exploded perspective view of a hub, a wheel, a fixing member, and a fixing member loosening detection device included in the vehicle of FIG. 1; FIG. 3 is a schematic diagram of the wheel of FIG. 2 as seen from the vehicle width direction; 4 is an enlarged view of a portion of the wheel of FIG. 3; FIG. FIG. 2 is a schematic configuration diagram of a fixing member loosening alarm device provided in the vehicle of FIG. 1; 6 is a flow chart showing transmitter-side control performed by a transmitter provided in the fixing member loosening alarm device of FIG. 5; It is a figure which shows a fixing member looseness detection apparatus when looseness arises in a fixing member. FIG. 4 is a diagram showing acceleration detected by an acceleration sensor when a fixed member is not loosened and acceleration detected by an acceleration sensor when a fixed member is loosened; FIG. 6 is a flowchart showing receiver-side control performed by a receiver included in the fixing member loosening alarm device of FIG. 5; FIG. FIG. 4 is a schematic configuration diagram of a vehicle in a second embodiment; FIG. 9 is a flowchart showing receiver-side control of the second embodiment;

<First embodiment>
A first embodiment of a fixing member looseness detector and a fixing member looseness alarm device will be described.
<Vehicle>
As shown in FIG. 1 , the vehicle 10 includes multiple axles 11 , multiple hubs 12 , multiple wheels 14 , and multiple fixing members 21 and 22 . Vehicle 10 may be of any type, such as a truck, passenger car, or commercial vehicle.

As shown in FIG. 2, one hub 12 is provided at each end of the axle 11 . The hub 12 can rotate integrally with the axle 11 . The hub 12 has a plurality of hub bolts 13 . The plurality of hub bolts 13 are spaced apart from each other in the rotational direction of the axle 11 . There are eight hub bolts 13 in this embodiment. The number of hub bolts 13 may be different from eight. For example, hub bolts 13 may be 4, 6, or 10 in number.

The wheel 14 is fixed to the axle 11 by fastening the fixing members 21 and 22 to the hub bolt 13 passing through the wheel 14 . Wheel 14 is fixed to axle 11 via hub 12 . As an example, a case where one wheel 14 is provided on each end of each axle 11 will be described. good too. That is, each end of the axle 11 may be provided with one wheel for a single tire, or two wheels for a double tire. The wheel 14 rotates integrally with the axle 11 .

The fixing members 21 and 22 are wheel nuts. Fixing members 21 and 22 are fastened to hub bolt 13 . The fixing members 21 and 22 are hexagonal nuts. There are eight fixing members 21 and 22 in this embodiment. The number of fixing members 21, 22 may be different from eight. For example, there may be 4, 6 or 10 fixing members 21,22.

<Fixing member loosening alarm device>
As shown in FIG. 1 , a vehicle 10 is provided with a fixing member loosening warning device 30 . The fixing member looseness alarm device 30 includes a fixing member looseness detection device 31 , a receiver 51 , and an alarm section 57 . The fixing member loosening detection device 31 is configured to detect loosening of at least one of the plurality of fixing members 21 and 22 .

<Fixing member loosening detection device>
As shown in FIGS. 3 and 4 , the fixing member looseness detection device 31 includes an indicator 32 and a transmitter 41 . The indicator 32 includes a first mounting portion 33 , a second mounting portion 35 and a connecting portion 37 . Indicator 32 is made of flexible material. The indicator 32 is made of rubber or resin, for example.

The first mounting portion 33 is cylindrical. The first attachment portion 33 includes a protrusion 34 provided on the inner peripheral surface of the first attachment portion 33 . The protrusions 34 are provided at regular intervals in the circumferential direction of the first mounting portion 33 .

The second mounting portion 35 is cylindrical. The second mounting portion 35 includes a protrusion 36 provided on the inner peripheral surface of the first mounting portion 33 . The protrusions 36 are provided at regular intervals in the circumferential direction of the second mounting portion 35 . In this embodiment, the first attachment portion 33 and the second attachment portion 35 have the same shape. The first attachment portion 33 and the second attachment portion 35 may have different shapes.

The connecting portion 37 connects the first mounting portion 33 and the second mounting portion 35 . The connecting portion 37 is, for example, flat. The connecting portion 37 may extend linearly between the first mounting portion 33 and the second mounting portion 35 , or may extend curvedly between the first mounting portion 33 and the second mounting portion 35 . may

The indicator 32 is attached to two fixed members 21 and 22 adjacent to each other in the circumferential direction of the wheel 14 . The first attachment portion 33 is attached to one of the plurality of fixing members 21 and 22 . The second attachment portion 35 is attached to the fixing members 21 and 22 adjacent to the fixing members 21 and 22 to which the first attachment portion 33 is attached. Indicators 32 are attached to all the fixing members 21 and 22 . For example, when eight fixing members 21 and 22 are provided, either the first attachment portion 33 or the second attachment portion 35 is attached to all the fixing members 21 and 22 by the four indicators 32. .

The fixing member 21 to which the first attachment portion 33 is attached is referred to as the first fixing member 21 . The fixing member 22 to which the second attachment portion 35 is attached is referred to as the second fixing member 22 . The protrusion 34 of the first mounting portion 33 is in close contact with the outer peripheral surface of the first fixing member 21 . Thereby, the first attachment portion 33 is configured to rotate integrally with the first fixing member 21 . The protrusion 36 of the second mounting portion 35 is in close contact with the outer peripheral surface of the second fixing member 22 . Thereby, the second mounting portion 35 is configured to rotate integrally with the second fixing member 22 .

The transmitter 41 is provided in the connecting section 37 . The transmitter 41 has a case 42 . The case 42 may be provided integrally with the connecting portion 37 or may be provided separately from the connecting portion 37 . When the case 42 is provided separately from the connecting portion 37, the case 42 is attached to the connecting portion 37 by, for example, a bracket.

As shown in FIG. 5, the transmitter 41 includes an acceleration sensor 43, a transmitter control device 45, a transmission circuit 48, and a transmission antenna 49. The acceleration sensor 43 , transmitter control device 45 , transmission circuit 48 and transmission antenna 49 are housed in the case 42 .

As shown in FIG. 4, the acceleration sensor 43 has a sensitivity axis 44. The acceleration sensor 43 detects acceleration along the sensitivity axis 44 . The acceleration sensor 43 is provided so that the sensitivity axis 44 faces the circumferential direction of the wheel 14 . Specifically, the acceleration sensor 43 is provided so that the sensitivity axis 44 faces the direction D<b>1 in which the centrifugal acceleration acts and the direction perpendicular to the axial direction of the wheel 14 . By providing the acceleration sensor 43 in this manner, the direction D1 in which the centrifugal acceleration acts when the wheel 14 rotates and the direction in which the sensitivity axis 44 faces are perpendicular to each other. Therefore, the centrifugal acceleration when the wheel 14 rotates is no longer detected on the sensitivity axis 44 .

As shown in FIG. 5, the transmitter control device 45 includes a processor 46 and a storage section 47. The processor 46 can be configured by at least one of, for example, an MPU (Micro Processing Unit), a CPU (Central Processing Unit), and a DSP (Digital Signal Processor). The storage unit 47 includes RAM (Random Access Memory) and/or ROM (Read Only Memory). Storage unit 47 stores program code or instructions configured to cause processor 46 to perform processing. The transmitter control device 45 may be configured by a hardware circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). The processing circuitry, transmitter controller 45, may include one or more processors operating according to a computer program, one or more hardware circuits such as ASICs or FPGAs, or a combination thereof. ROM and RAM or computer-readable media include any available media that can be accessed by a general purpose or special purpose computer.

The transmission circuit 48 transmits from the transmission antenna 49 a radio signal modulated according to the transmission data input from the transmitter control device 45 . Thereby, a radio signal is transmitted from the transmission circuit 48 . A radio signal is a signal in a predetermined frequency band. As frequency bands, for example, LF (Low Frequency) band, MF (Medium Frequency) band, HF (High Frequency) band, VHF (Very High Frequency) band, UHF (Ultra High Frequency) band, and 2.4 GHz band can be mentioned.

The receiver 51 includes a receiving antenna 52 , a receiving circuit 53 and a receiver control device 54 . Receiver 51 is mounted on vehicle 10 .
The receiving antenna 52 receives radio signals transmitted from the transmitter 41 . The receiving circuit 53 demodulates the radio signal received via the receiving antenna 52 to obtain transmission data. The receiving circuit 53 outputs transmission data to the receiver control device 54 .

The receiver control device 54 includes a processor 55 and a storage section 56 . Processors 55 may include, for example, MPUs, CPUs, and DSPs. The storage unit 56 includes ROM and RAM. Storage unit 56 stores program code or instructions configured to cause processor 55 to perform processes. The receiver control device 54 may be configured by a hardware circuit such as ASIC or FPGA. The processing circuitry, receiver controller 54, may include one or more processors operating according to a computer program, one or more hardware circuits such as ASICs or FPGAs, or a combination thereof. ROM and RAM or computer-readable media include any available media that can be accessed by a general purpose or special purpose computer.

The warning unit 57 warns the passengers of the vehicle 10. As the alarm unit 57, for example, a buzzer that gives an alarm by sound, a lamp that gives an alarm by light, a display that gives an alarm by display, or a combination thereof can be used. The alarm unit 57 is activated by the receiver controller 54 . Receiver 51 is an actuator.

<Looseness determination control>
Looseness determination control performed by the fixing member looseness alarm device 30 will be described. The slackness determination control includes transmitter-side control performed by the transmitter 41 and receiver-side control performed by the receiver 51 .

<Transmitter side control>
As shown in FIG. 6, the transmitter control device 45 acquires the detection result from the acceleration sensor 43 in step S1. The detection result of the acceleration sensor 43 is obtained periodically at predetermined time intervals.

Next, in step S<b>2 , the transmitter control device 45 determines whether the first fixing member 21 and the second fixing member 22 are loose based on the detection result of the acceleration sensor 43 .
The sensitivity axis 44 faces the circumferential direction of the wheel 14 when the first fixing member 21 and the second fixing member 22 are not loosened. In this case, the acceleration sensor 43 does not detect centrifugal acceleration. When the first fixing member 21 and the second fixing member 22 are not loosened, the acceleration sensor 43 detects the force component of gravitational acceleration accompanying the rotation of the wheel 14 . As shown in FIG. 8, the acceleration detected by the acceleration sensor 43 sinusoidally changes between +1G and -1G while the wheel 14 rotates once. When the acceleration detected by the acceleration sensor 43 is acquired a plurality of times and the average value of the acceleration acquired during one cycle is calculated, it becomes 0. In practice, the average value may not be 0 due to the timing of acquiring the acceleration, mounting accuracy of the acceleration sensor 43, vibration, and errors, but the average value falls within a predetermined range from 0.

As shown in FIG. 7, when the first fixing member 21 is loosened, the first mounting portion 33 rotates. The connecting portion 37 is deformed by the rotation of the first mounting portion 33 . When the connecting portion 37 is deformed, the orientation of the sensitivity axis 44 deviates from the circumferential direction of the wheel 14 . As a result, the direction D1 in which the centrifugal acceleration acts is no longer perpendicular to the direction in which the sensitivity axis 44 faces, and the acceleration sensor 43 detects the force component of the centrifugal acceleration.

As indicated by the solid line L1 in FIG. 8, when the first fixing member 21 and the second fixing member 22 are not loosened, the acceleration detected by the acceleration sensor 43 changes sinusoidally between +1 G and -1 G. do. As indicated by the dashed line L2 in FIG. 8, when the first fixing member 21 is loosened, the acceleration detected by the acceleration sensor 43 during one rotation of the wheel 14 varies from "component force of centrifugal acceleration +1 G" to " It changes sinusoidally between the centrifugal acceleration component force -1 G'. Acceleration detected by the acceleration sensor 43 is acquired a plurality of times, and the average value of the accelerations acquired during one cycle is calculated to obtain the force component of the centrifugal acceleration. When the first fixing member 21 is loosened in this manner, the acceleration detected by the acceleration sensor 43 is greater than when the first fixing member 21 is not loosened. The transmitter control device 45 can determine looseness of the fixing members 21 and 22 from this change in acceleration.

For example, the transmitter control device 45 determines that the fixing members 21 and 22 have loosened when the average value of the accelerations acquired during one cycle exceeds a threshold. The threshold can be set based on the predetermined range described above. For example, the threshold is set to a value that is higher than the upper limit of a predetermined range that can be taken by the average value of acceleration in one cycle when the first fixing member 21 and the second fixing member 22 are not loosened. . In the above example, the case where the first fixing member 21 is loosened has been described, but when the second fixing member 22 is loosened, or when both the first fixing member 21 and the second fixing member 22 are loosened However, looseness of the fixing members 21 and 22 can be determined by similar control. In the first embodiment, the transmitter controller 45 determines that the fixing members 21 and 22 have become loose. The transmitter controller 45 is the controller.

Note that in the present embodiment, the sensitivity axis 44 tilts toward the outside in the radial direction of the wheel 14 regardless of whether the first fixing member 21 or the second fixing member 22 is loosened. Therefore, as shown in FIG. 8, the acceleration detected by the acceleration sensor 43 is greater than when the fixing members 21 and 22 are not loosened. In other words, the acceleration detected by the acceleration sensor 43 shifts to the positive side. It can be said that the acceleration detected by the acceleration sensor 43 does not deviate to the negative side even if any of the first fixing member 21 and the second fixing member 22 is loosened.

As shown in FIG. 6, when the determination result of step S2 is affirmative, the transmitter control device 45 performs the process of step S3. If the determination result in step S2 is negative, the transmitter control device 45 terminates transmitter-side control.

In step S<b>3 , the transmitter control device 45 generates transmission data including information indicating that the fixing members 21 and 22 are loose, and outputs the transmission data to the transmission circuit 48 . As a result, information for recognizing that the fixing members 21 and 22 have loosened is transmitted from the transmission circuit 48 . It can be said that the transmitter control device 45 transmits the determination result of step S2 from the transmission circuit 48 . The transmitter controller 45 may include identification information in the transmission data. The identification information is an ID code set for each transmitter 41 . After finishing the process of step S3, the transmitter control device 45 ends the transmitter-side control.

<Receiver side control>
As shown in FIG. 9, in step S11, the receiver control device 54 determines whether or not it has received a radio signal containing information indicating that the fixing members 21 and 22 are loose. If the determination result in step S11 is negative, the receiver control device 54 terminates receiver-side control. If the determination result of step S11 is affirmative, the receiver controller 54 performs the process of step S12.

In step S12, the receiver control device 54 activates the alarm unit 57. If the alarm unit 57 is a lamp, the receiver controller 54 lights or blinks the alarm unit 57 . If the alarm unit 57 is a buzzer, the receiver control device 54 causes the alarm unit 57 to generate a sound. If the alarm unit 57 is a display, the receiver controller 54 displays that the fixing members 21 and 22 are loosened. When the receiver control device 54 grasps the correspondence relationship between the identification information of the transmitter 41 and the position of the wheel 14, it determines which of the fixing members 21 and 22 fixing the wheel 14 is loosened. may be displayed on the display.

<Action>
The operation of the first embodiment will be described.
When at least one of the first fixing member 21 and the second fixing member 22 is loosened, the connecting portion 37 is deformed. The detection result of the acceleration sensor 43 changes due to the deformation of the connecting portion 37 . From this change, the transmitter control device 45 can determine that the fixing members 21 and 22 have loosened. That is, it can be determined that at least one of the plurality of fixing members 21 and 22 that fix the wheel 14 is loosened. Then, when the fixing members 21 and 22 are loosened, the transmitter control device 45 transmits a radio signal including information indicating that the fixing members 21 and 22 are loosened.

<effect>
Effects of the first embodiment will be described.
(1-1) The transmitter controller 45 determines from the detection result of the acceleration sensor 43 that the fixing members 21 and 22 have become loose. Then, the transmitter control device 45 transmits information from the transmission circuit 48 for recognizing that the looseness has occurred. When the receiver controller 54 receives the radio signal containing the information indicating that the fixing members 21 and 22 are loosened, the alarm unit 57 issues an alarm that the fixing members 21 and 22 are loose. I do. It is easier for a person to recognize that the fixing members 21 and 22 are loosened than visually.

(1-2) When visual inspection is performed, it is necessary to perform the inspection while the vehicle 10 is stopped. In contrast, the fixing member looseness detection device 31 can cause the alarm unit 57 to issue an alarm even while the vehicle 10 is running. Even when the fixing members 21 and 22 are loosened while the vehicle 10 is running, the person can be made to recognize that the fixing members 21 and 22 are loosened.

(1-3) The sensitivity axis 44 faces the circumferential direction of the wheel 14 . Centrifugal acceleration due to the rotation of the wheel 14 is less likely to be detected by the acceleration sensor 43 . When the centrifugal acceleration due to the rotation of the wheel 14 is detected by the acceleration sensor 43 , the detection result of the acceleration sensor 43 changes greatly, so it may be difficult to detect the change of the acceleration sensor 43 due to the deformation of the connecting portion 37 . By orienting the sensitivity axis 44 in the circumferential direction of the wheel 14 to reduce the influence of centrifugal acceleration, it is easy to determine from the detection results of the acceleration sensor 43 that the fixing members 21 and 22 have loosened.

(1-4) The transmission circuit 48 transmits a radio signal containing information indicating that slackness has occurred as information for making the receiver 51 recognize that slackness has occurred. Compared to the case where the detection result of the acceleration sensor 43 is transmitted as information for making the receiver 51 recognize that loosening has occurred, the data length of the transmission data can be shortened. Further, when the radio signal is transmitted only when the fixing members 21 and 22 are loosened, it is possible to reduce the transmission frequency of the radio signal.

<Second embodiment>
A second embodiment of the fixing member looseness detector and the fixing member looseness alarm device will be described. Hereinafter, points different from the first embodiment will be described, and descriptions of points similar to the first embodiment will be omitted.

<ABS>
As shown in FIG. 10 , vehicle 10 includes ABS 60 . ABS 60 is an anti-lock braking system. The ABS 60 has a rotation angle detector 61 and an ABS controller 62 . One rotation angle detection unit 61 is provided corresponding to the mounting position of each wheel 14 . It can also be said that one rotation angle detection unit 61 is provided corresponding to each wheel 14 . The rotation angle detection unit 61 is arranged to face a gear provided to rotate integrally with the wheel 14 . As the gear rotates, a pulse is generated in the rotation angle detector 61 . As the wheel 14 rotates once, a pulse corresponding to the number of teeth of the gear is generated in the rotation angle detection section 61 .

The ABS controller 62 is composed of, for example, a microcomputer. The ABS controller 62 counts pulses from each rotation angle detector 61 . The ABS controller 62 counts the rise and fall of pulses. The ABS controller 62 calculates the remainder obtained by dividing the counted number of pulses by the counted number of pulses for one rotation of the gear as a pulse count value. By dividing 360 degrees by the number of pulses generated by one rotation of the gear, it is possible to grasp how many times the gear has rotated for each pulse count value. With these, the rotation angle of the wheel 14 can be obtained from the pulse count value.

<Transmitter side control>
In the second embodiment, the transmitter control device 45 acquires the detection result of the acceleration sensor 43 at predetermined time intervals. Then, the transmitter control device 45 generates transmission data including the detection result of the acceleration sensor 43 and outputs the transmission data to the transmission circuit 48 . Thereby, a radio signal including the detection result of the acceleration sensor 43 is transmitted toward the receiver 51 .

<Receiver side control>
As shown in FIG. 11, the receiver controller 54 receives the radio signal from the transmitter 41 in step S21. Thereby, the receiver control device 54 acquires the detection result of the acceleration sensor 43, that is, the acceleration from the radio signal.

Next, in step S22, the receiver control device 54 acquires the rotation angle from the ABS controller 62 each time the acceleration is acquired. The receiver controller 54 associates the rotation angle obtained from the ABS controller 62 with the acceleration obtained from the radio signal. This association is performed for each piece of identification information, that is, for each fixing member looseness detection device 31 . As a result, it is possible to associate the acceleration with the rotation angle.

Next, in step S23, the receiver control device 54 determines whether or not the fixing members 21 and 22 are loosened. As indicated by the dashed line L2 in FIG. 8, when the fixing members 21 and 22 are loosened, a phase shift θ1 occurs from the acceleration when the fixing members 21 and 22 are not loosened. The receiver control device 54 determines that the fixing members 21 and 22 are loosened when the phase difference from the acceleration when the fixing members 21 and 22 are not loosened exceeds a threshold value. The threshold is set so as to allow a phase shift that occurs when the first fixing member 21 and the second fixing member 22 are not loosened. The pulse count value is reset when the ignition of the vehicle 10 is turned off. Therefore, after the ignition of the vehicle 10 is turned on, the receiver control device 54 associates the acceleration with the rotation angle, and uses this as an initial value. Then, it is determined whether or not the fixing members 21 and 22 are loosened based on the phase difference from the initial value. If the determination result of step S23 is affirmative, the receiver control device 54 performs the process of step S24. The processing of step S24 is the same as that of step S12. If the determination result in step S23 is negative, the receiver control device 54 terminates receiver-side control.

In the second embodiment, the receiver controller 54 determines that the fixing members 21 and 22 have become loose. Receiver controller 54 is the controller. The information for making the receiver 51 recognize that loosening has occurred is the detection result of the acceleration sensor 43 .

<effect>
Effects of the second embodiment will be described.
(2-1) The receiver control device 54 determines from the detection results of the acceleration sensor 43 that the fixing members 21 and 22 are loosened. When the receiver control device 54 determines that the fixing members 21 and 22 are loosened, the warning unit 57 issues an alarm that the fixing members 21 and 22 are loose. It is easier for a person to recognize that the fixing members 21 and 22 are loosened than visually.

<Modification>
Embodiments can be modified and implemented as follows. The embodiments and the following modifications can be implemented in combination with each other within a technically consistent range.

· In the first embodiment, if the determination result in step S2 is negative, the transmitter control device 45 may transmit from the transmission circuit 48 a radio signal including information indicating that there is no looseness.

· The fixing member looseness alarm device 30 of the first embodiment may include a fixing member looseness detection device 31 and a mobile communication terminal. A passenger of the vehicle 10 possesses the portable communication terminal. A mobile communication terminal includes an alarm unit, an actuating device for activating the alarm unit, and a receiving circuit. The alarm unit includes at least one of a display for visual alarm, a speaker for alarm by sound, and a vibrator for alarm by vibration. The activation device is a computer that activates the alarm. The receiving circuit receives radio signals from the transmitter 41 . The transmitter control device 45 transmits information indicating that the looseness has occurred from the transmission circuit 48 to the portable communication terminal. Upon receiving the wireless signal by the receiving circuit, the actuator provides at least one of a visual alert, an audible alert, and a vibration alert.

Similarly, the fixing member looseness alarm device 30 of the second embodiment may include a fixing member looseness detection device 31 and a mobile communication terminal. The transmitter control device 45 transmits a radio signal including the detection result of the acceleration sensor 43 from the transmission circuit 48 to the mobile communication terminal. The mobile communication terminal performs the receiver-side control of the second embodiment.

· The fixing member looseness alarm device 30 of the first embodiment may include a fixing member looseness detection device 31, a receiver 51, and a mobile communication terminal. In this case, the receiver controller 54 is configured to be able to communicate with the mobile communication terminal. When the receiver control device 54 receives the radio signal including the information indicating that the looseness has occurred, the receiver control device 54 transmits the information to the mobile communication terminal. As a result, the mobile communication terminal issues an alarm. It can be said that the receiver 51 functions as a repeater between the transmitter 41 and the mobile communication terminal.

Similarly, the fixing member looseness alarm device 30 of the second embodiment may include a fixing member looseness detection device 31, a receiver 51, and a mobile communication terminal. In this case, receiver-side control may be performed by the receiver 51 . When the receiver control device 54 determines that the fixing members 21 and 22 have become loose, it transmits information indicating that the looseness has occurred to the mobile communication terminal. As a result, the mobile communication terminal issues an alarm. Also, receiver-side control may be performed by the mobile communication terminal. In this case, when the receiver control device 54 receives the radio signal including the detection result of the acceleration sensor 43, it transmits the detection result of the acceleration sensor 43 to the mobile communication terminal. The mobile communication terminal performs the receiver-side control of the second embodiment.

· In the first embodiment, the alarm unit and the actuating device may be provided integrally with the fixing member looseness detection device 31 . In this case, the transmitter circuit 48 and the actuator may be in wired communication.

- The alarm part 57 may be provided in arbitrary positions, such as the outer surface of the vehicle 10 .
- In the second embodiment, the sensitivity axis 44 of the acceleration sensor 43 may face in a direction different from the circumferential direction of the wheel 14 . In this case, in step S23, the receiver control device 54 determines whether or not the fixing members 21 and 22 have loosened based on the relationship between the acceleration and the vehicle speed. Vehicle speed can be obtained from the ABS controller 62 . A case where the sensitivity axis 44 of the acceleration sensor 43 faces the direction D1 in which the centrifugal acceleration acts will be described as an example.

The acceleration detected by the acceleration sensor 43 increases as the vehicle speed increases. A correspondence relationship between the acceleration detected by the acceleration sensor 43 and the vehicle speed is stored in the storage unit 56 of the receiver control device 54 . Correspondence may be stored as a formula or as a map. When at least one of the first fixing member 21 and the second fixing member 22 is loosened, the connecting portion 37 is deformed. When the orientation of the sensitivity axis 44 shifts due to the deformation of the connecting portion 37, the acceleration detected by the acceleration sensor 43 decreases. The receiver controller 54 uses the correspondence to find the acceleration corresponding to the vehicle speed. If the difference between the acceleration obtained from the correspondence relationship and the acceleration obtained from the acceleration sensor 43 is equal to or greater than a threshold, the receiver control device 54 determines that the fixing members 21 and 22 are loose. The threshold is set so as to allow deviation in acceleration that occurs when the first fixing member 21 and the second fixing member 22 are not loosened.

· In each embodiment, the fixing members 21 and 22 may be wheel bolts. When the fixing members 21 and 22 are wheel bolts, the hub 12 has bolt holes instead of the hub bolts 13 . Wheel bolts are inserted into the bolt holes. The wheel bolt is thereby fastened to the hub 12 . Wheel 14 is fixed to axle 11 by a wheel bolt. The wheel bolt has a shaft and a head. The shaft is inserted into the bolt hole. The first attachment portion 33 and the second attachment portion 35 are attached to the head of the wheel bolt.

- In each embodiment, the fixing member looseness detection device 31 is provided so that the sensitivity axis 44 faces radially inward of the wheel 14 when at least one of the first fixing member 21 and the second fixing member 22 becomes loose. may have been For example, if at least one of the first fixing member 21 and the second fixing member 22 is loosened depending on the shape of the connecting portion 37 , the sensitivity axis 44 faces radially inward of the wheel 14 . Further, when the fixing members 21 and 22 are tightened counterclockwise, the sensitivity axis 44 faces radially inward of the wheel 14 when the fixing members 21 and 22 become loose. In this case, if the fixing members 21 and 22 become loose, the acceleration detected by the acceleration sensor 43 shifts to the negative side. In the first embodiment, the transmitter control device 45 may determine that the fixing members 21 and 22 have loosened when the average value of the accelerations acquired during one cycle is below the threshold. Further, the transmitter control device 45 may make the determination from the absolute value of the acceleration.

DESCRIPTION OF SYMBOLS 10... Vehicle 21... 1st fixing member 22... 2nd fixing member 30... Fixing member loosening alarm device 31... Fixing member looseness detection apparatus 33... First attachment part 35... Second attachment part 37... Connection part 43 Acceleration sensor 44 Sensitivity axis 45 Control device for transmitter which is control device 48 Transmitting circuit 51 Receiver which is operating device 54 Control device for receiver which is control device , 57 . . . alarm unit.

Claims (4)

A fixing member loosening detection device provided in a vehicle having a plurality of fixing members for fixing a wheel to an axle, and configured to detect loosening of at least one of the plurality of fixing members, ,
the plurality of fixing members includes a first fixing member and a second fixing member;
The fixing member looseness detection device includes:
a first mounting portion attached to the first fixing member and configured to rotate integrally with the first fixing member;
a second mounting portion attached to the second fixing member and configured to rotate integrally with the second fixing member;
a connecting portion that connects the first mounting portion and the second mounting portion, the connecting portion configured to be deformed by rotation of at least one of the first mounting portion and the second mounting portion;
an acceleration sensor provided at the connecting portion;
a control device configured to determine that the fixing member has become loose from the detection result of the acceleration sensor;
a transmission circuit configured to transmit information for recognizing that the loosening has occurred to an operating device that activates an alarm unit that warns that the loosening has occurred. Device. The acceleration sensor has a sensitivity axis,
2. The fixing member loosening detection device according to claim 1, wherein the sensitivity axis is oriented in the circumferential direction of the wheel. The fixing member looseness detection device according to claim 1 or 2, wherein the transmission circuit transmits the determination result of the control device as information for recognizing that the looseness has occurred. A fixing member loosening alarm provided in a vehicle having a plurality of fixing members for fixing a wheel to an axle, and configured to detect loosening of at least one of the plurality of fixing members and issue an alarm. a device,
the plurality of fixing members includes a first fixing member and a second fixing member;
The fixing member loosening alarm device includes:
a first mounting portion attached to the first fixing member and configured to rotate integrally with the first fixing member;
a second mounting portion attached to the second fixing member and configured to rotate integrally with the second fixing member;
a connecting portion that connects the first mounting portion and the second mounting portion, the connecting portion configured to be deformed by rotation of at least one of the first mounting portion and the second mounting portion;
an acceleration sensor provided at the connecting portion;
a control device configured to determine that the first fixing member and the second fixing member have loosened based on the detection result of the acceleration sensor;
an alarm unit configured to alarm that the loosening has occurred;
an activation device configured to activate the alarm;
and a transmission circuit configured to transmit information for recognizing that the loosening has occurred to the actuator.

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