Patent Publication Number: US-2023152173-A1

Title: Wheel nut loosening detection device and method of controlling the same

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to and the benefit of Korean Patent Application No. 10-2021-0158633 filed in the Korean Intellectual Property Office on Nov. 17, 2021, the entire contents of which are incorporated herein by reference. 
     BACKGROUND 
     (a) Field of the Disclosure 
     The present disclosure relates to a wheel nut loosening detection device and a method of controlling the same, which are capable of warning a driver of a loosened state of a wheel nut used to fix a wheel and a hub of a vehicle. 
     (b) Description of the Related Art 
     In general, a wheel fixing device includes a hub and a drum installed on an axle configured to receive power of an engine, and the hub and the drum rotate together with the axle. In addition, a wheel is coupled by wheel bolts provided on the hub. Wheel nuts are fastened to the wheel bolts fitted with the wheel, such that the wheel is fixed to the hub. Therefore, the wheel and the axle may be integrally rotated. 
     When the wheel nut for fixing the wheel (i.e., a driving wheel) is loosened while a vehicle having the above-mentioned structure travels, the wheel may be separated from the vehicle, which may cause a large-scale accident. Therefore, a fastening force of the wheel nut is considered important in the corresponding technical field. For this reason, it is necessary to always inspect a fastened state of the wheel nut before and after the vehicle travels. However, it is difficult to recognize the amount of loosening of the wheel nut with the naked eye. Therefore, it is necessary to measure a fastening torque using a separate tool or to tighten the wheel nut at normal times to prevent the wheel nut from being loosened. 
     Therefore, studies have been conducted on a wheel nut loosening detection device capable of checking whether the wheel nut is loosened without using a separate tool or other facilities, where the wheel nut loosening detection device is configured to transmit a warning signal when the wheel nut is loosened. 
     For example, a variable resistor may be used to detect a rotation of the wheel nut based on a change in resistance value. However, there is a problem in that a battery needs to be used to supply power. 
     In addition, where the variable resistor consistently operates, a battery provided in the vehicle cannot cope with the electric power consumption. For this reason, the wheel nut loosening detection device needs to operate only at a particular point in time (e.g., only after the traveling of the vehicle is completed). Accordingly, there is a problem in that it is impossible to detect the loosened state of the wheel nut in real-time while the vehicle travels. 
     The above information disclosed in this Background section is only to enhance understanding of the background of the disclosure. Therefore, the Background section may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. 
     SUMMARY 
     The present disclosure has been made in an effort to provide a wheel nut loosening detection device and a method of controlling the same, which may adopt an electromagnetic induction principle, detect induced current generated in a closed circuit by a change in a magnetic field when a wheel nut including a magnet is loosened, and warn a driver of the loosened state of the wheel nut. 
     An embodiment of the present disclosure provides a wheel nut loosening detection device including: a wheel having a wheel nut fastening unit; a hub; a wheel bolt configured to penetrate the wheel and the hub; a wheel nut fastened to the wheel bolt and configured to fix the wheel and the hub; at least one magnet mounted on the wheel nut; a closed circuit mounted in the wheel nut fastening unit and disposed adjacent to the at least one magnet; a current detector configured to output a corresponding output signal in response to a change in current in the closed circuit; and an output unit configured to output a warning signal in response to the output signal of the current detector. 
     The at least one magnet may include a plurality of magnets, and the plurality of magnets may be disposed at predetermined intervals along a periphery of the wheel nut. 
     According to an embodiment of the present disclosure, the wheel nut loosening detection device may include a memory configured to store an output value and a number of outputs in response to the output signal of the current detector. 
     As mentioned above, the closed circuit may be mounted in the wheel nut fastening unit. 
     The current detector and the output unit may communicate with each other in a wireless manner. 
     The current detector may output a value related to a generation of an induced current in response to the induced current being induced by a rotation of the wheel nut. 
     The output unit may output a warning signal when a measured output value of the induced current exceeds a preset reference value. 
     The output unit may output a warning signal when the measured number of outputs of the induced current exceeds a preset number of outputs. 
     Another embodiment of the present disclosure provides a method of controlling the wheel nut loosening detection device. The method includes detecting, by the current detector, an induced current in the closed circuit and comparing, by the output unit, an output value outputted by the current detector with a preset reference value of the induced current when the current detector detects the induced current. The method further includes outputting, by the output unit, a warning signal when the output value exceeds the preset reference value of the induced current. 
     The wheel nut loosening detection device, according to an embodiment of the present disclosure, may further include a memory configured to store an output value and the number of outputs in response to the output signal of the current detector. The method of controlling the wheel nut loosening detection device, according to an embodiment of the present disclosure, may further include storing an outputted signal in the memory when the current detector outputs the output signal. 
     The method of controlling the wheel nut loosening detection device, according to an embodiment of the present disclosure, may further include comparing, by the output unit, the measured number of outputs of the induced current with a preset number of outputs. The method of controlling the wheel nut loosening detection device may further include outputting, by the output unit, a warning signal when the measured number of outputs of the induced current exceeds the preset number of outputs. 
     According to the present disclosure, a driver may recognize the generation of the induced current and predict a loosened state of the wheel nut. The driver may recognize the loosened state of the wheel nut even while the vehicle travels. Therefore, it is possible to prevent a safety accident that may occur because of the loosened state of the wheel nut. 
     In addition, the wheel nut loosening detection device may detect the loosened state of the wheel nut without using a separate battery. Therefore, it is possible to detect the loosened state of the wheel nut without using the electric power of the battery of the vehicle. 
     Other effects, which may be obtained or expected by the embodiments of the present disclosure, are directly or implicitly disclosed in the detailed description of the embodiments of the present disclosure. In other words, various effects expected according to the embodiments of the present disclosure are disclosed in the detailed description described below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a view illustrating a wheel nut loosening detection device according to an embodiment of the present disclosure. 
         FIG.  2    is an enlarged view of the wheel nut loosening detection device according to an embodiment of the present disclosure. 
         FIG.  3    is a perspective view of a wheel nut that may be applied to the wheel nut loosening detection device according to an embodiment of the present disclosure. 
         FIG.  4    is a cross-sectional view of the wheel nut that may be applied to the wheel nut loosening detection device according to an embodiment of the present disclosure. 
         FIG.  5    is a partial perspective view illustrating a wheel nut fastening unit including a closed circuit and a current detector according to an embodiment of the present disclosure. 
         FIG.  6    is a view illustrating a process in which the wheel nut loosening detection device, according to an embodiment of the present disclosure, generates induced current. 
         FIG.  7    is a flowchart illustrating a method of controlling the wheel nut loosening detection device according to an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Hereinafter, embodiments of the present disclosure are described in detail with reference to the accompanying drawings so that those with ordinary skill in the art to which the present disclosure pertains may easily carry out the embodiments. However, the present disclosure may be implemented in various different ways and is not limited to the embodiments described herein. 
     A part irrelevant to the description is omitted to clearly describe the present disclosure, and the same or similar constituent elements are designated by the same reference numerals throughout the specification. 
     In the following description, names of constituent elements are classified as a first . . . , a second . . . , and the like so as to discriminate the constituent elements having the same name, and the names are not essentially limited to the order in the description below. 
     When a component, device, element, or the like of the present disclosure is described as having a purpose or performing an operation, function, or the like, the component, device, or element should be considered herein as being “configured to” meet that purpose or to perform that operation or function. 
     In general, a bolt and a nut are installed to connect and fix an object. When the nut is loosened, it may cause the occurrence of an accident and may cause damage to devices. Therefore, the fastened state between the bolt and the nut must always be checked for safety. 
     The present disclosure is described below, focusing on a means for detecting a loosened state of the bolt and the nut used to connect a wheel and a hub in a wheel structure of a vehicle. The present disclosure may be applied not only to the wheel structure of the vehicle, but also to all devices using the bolt and the nut. 
       FIG.  1    is a view illustrating a wheel nut loosening detection device according to an embodiment of the present disclosure.  FIG.  2    is an enlarged view of the wheel nut loosening detection device according to an embodiment of the present disclosure. 
     Referring to  FIGS.  1  and  2   , the wheel nut loosening detection device, according to the embodiment of the present disclosure, includes: a wheel  10  including a wheel nut fastening unit  11 ; a wheel bolt  100  configured to penetrate the wheel  10  and a hub  20 ; and a wheel nut  200  fastened to the wheel bolt  100  and configured to fix the wheel  10  and the hub  20 . The wheel nut  200  has at least one magnet  210 . A closed circuit  220  is mounted in the wheel nut fastening unit  11  and is disposed adjacent to the at least one magnet  210 . The wheel nut fastening unit  11  may be disposed at any position on the wheel  10  of the vehicle at which the wheel nut  200  and the wheel bolt  100  are fastened to each other. 
     For example, the closed circuit  220  may be a conductive wire made of copper or the like. 
     As described below, when the wheel nut  200  is loosened, the magnet  210  mounted on the wheel nut  200  moves together with the wheel nut  200 . Therefore, a change in magnetic flux occurs on the closed circuit  220 . The change in magnetic flux generates induced current in the closed circuit  220 . 
     The wheel nut loosening detection device, according to an embodiment of the present disclosure, may include: a current detector  300  configured to output a corresponding signal in response to the change in current in the closed circuit  220 ; and an output unit  400  configured to output a current detection signal or a warning signal in response to an output signal of the current detector  300 . 
     The current detector  300  and the closed circuit  220  may be electrically connected. The connection method is not particularly limited. The current detector  300  and the output unit  400  may communicate with each other. As an example, the current detector  300  and the output unit  400  may communicate with each other in a wireless manner (e.g., wirelessly). 
     The current detector  300  and the closed circuit  220  are electrically connected to each other. The current detector  300  is operated by the induced current when the induced current is generated in the closed circuit  220 . Further, the current detector  300  may output a current amount signal of the corresponding induced current to the output unit  400 . 
     The output unit  400  may be implemented by one or more microprocessors configured to be operated by a preset program. The preset program may include a series of commands for performing the method according to an embodiment of the present disclosure. 
     The wheel nut loosening detection device, according to an embodiment of the present disclosure, is not particularly limited by the method of outputting the current detection signal or the warning signal by the output unit  400 . As an example, the output unit  400  may be disposed on an instrument panel in the vehicle and output the current detection signal or the warning signal in the form of an image. As another example, the output unit may output the current detection signal or the warning signal by turning on a light-emitting lamp when the output signal of the current detector  300  is implemented in the form of a light-emitting lamp (not illustrated). Therefore, a driver in the vehicle may recognize the loosened state of the wheel nut  200 . 
     As an example, the output unit  400  may include a separate warning unit  410  configured to output a corresponding warning signal. As an example, the warning unit  410  may output the warning signal in the form of a warning sound or an image. 
     The wheel nut loosening detection device, according to an embodiment of the present disclosure, may further include a memory  420  configured to store an output value of the current detector  300  and/or the number of signal outputs of the current detector  300 . 
       FIG.  3    is a perspective view of a wheel nut that may be applied to the wheel nut loosening detection device according to an embodiment of the present disclosure.  FIG.  4    is a cross-sectional view of the wheel nut that may be applied to the wheel nut loosening detection device according to an embodiment of the present disclosure. 
     Referring to  FIGS.  3  and  4   , in the wheel nut loosening detection device, according to an embodiment of the present disclosure, the at least one magnet  210  is inserted into the wheel nut  200 . As an example, the at least one magnet  210  may be a plurality of magnets provided in the wheel nut  200 . The plurality of magnets  210  may be disposed at predetermined intervals along a periphery of the wheel nut  200 . Typically, the wheel nut  200  may have a hexagonal cross-sectional shape and be variously manufactured in accordance with the required torque and design. As an example, one side of the wheel nut  200  may be closed, but the present disclosure is not particularly limited to the configuration in which one side of the wheel nut  200  is closed. 
     As an example, the wheel nut  200  may include a nut body  201  configured to define an external shape of the wheel nut  200 . A screw thread  203  may be formed in the nut body  201  and fastened to the wheel bolt  100 . 
     The plurality of magnets  210  may be inserted into the nut body  201  and disposed at predetermined intervals along the periphery of the wheel nut  200 . 
     In general, the wheel nut  200  and the wheel bolt  100  are kept fastened. However, the wheel nut  200  may be loosened by external factors or the vibration of the vehicle. Hereinafter, the process in which the induced current is generated in the closed circuit  220  is described in detail. 
       FIG.  5    is a partial perspective view illustrating the wheel nut fastening unit, including the closed circuit  220  and the current detector  300 , according to an embodiment of the present disclosure.  FIG.  6    is a view illustrating a process in which the wheel nut loosening detection device, according to an embodiment of the present disclosure, generates induced current. 
     Referring to  FIGS.  1 - 6   , the closed circuit  220  may be mounted in the wheel nut fastening unit  11  disposed at any position on the wheel  10  at which the wheel nut  200  and the wheel bolt  100  are fastened to each other. As an example, the closed circuit  220  may be disposed on the wheel nut fastening unit  11  and mounted at the position at which the magnetic force of the magnet  210  is applied. 
     The wheel nut  200  may be loosened by external factors or vibrations of the vehicle, and a relative position between the closed circuit  220  and the magnet  210  mounted on the wheel nut  200  is changed by the loosened state of the wheel nut  200 . More specifically, when a relative position of at least any one of the magnets  210 , which apply the magnetic force to the closed circuit  220 , is changed with respect to the position of the closed circuit  220 , a change in magnetic flux occurs in the closed circuit  220 . The change in magnetic flux generates the induced current in the closed circuit  220 . 
     In other words, referring to  FIG.  6   , the change in the relative position of the magnet  210  (for example, at least any one of the plurality of magnets  210   a ,  210   b , and  210   c ), changes the magnetic fields B 1 , B 2 , or B 3 . Therefore, the induced current ( 1 ) is generated in the closed circuit  220 . 
     In other words, when the relative position of the magnet  210  is changed with respect to the position of the closed circuit  220  by the loosened state of the wheel nut  200 , the induced current ( 1 ) is generated. Based on Fleming&#39;s right-hand rule, the induced current ( 1 ) flows in a direction in which the induced current ( 1 ) restricts an increase in magnetic flux in the closed circuit  220 . As an example, based on  FIG.  6   , the induced current may flow clockwise on the closed circuit  220 . 
     In other words, when the relative position of the magnet  210  with respect to the closed circuit  220  is changed by the loosened state of the wheel nut  200 , the induced current ( 1 ) is generated. The induced current ( 1 ) flows in a direction in which the induced current ( 1 ) restricts a decrease in magnetic flux in the closed circuit  220 . 
     As illustrated in  FIG.  6   , where the plurality of magnets  210   a ,  210   b , and  210   c  is disposed at predetermined intervals in the wheel nut  200 , the respective magnets  210  affect the change in the magnetic flux of the closed circuit  220  when the wheel nut  200  is loosened. For example, when the wheel nut  200  is loosened, any one of the magnets  210  may become distant from the closed circuit  220 , but another magnet  210  may become closer to the closed circuit  220 . A total change in magnetic flux may be determined collectively in consideration of the values of changes of the plurality of magnets  210 . 
     Hereinafter, a method of controlling the wheel nut loosening detection device, according to an embodiment of the present disclosure, is described. 
       FIG.  7    is a flowchart illustrating a method of controlling the wheel nut loosening detection device according to an embodiment of the present disclosure. 
     Referring to  FIG.  7   , first, a step S 100  of detecting, by the current detector  300 , the induced current in the closed circuit  220  is performed. 
     The wheel nut  200  may be loosened by external factors or vibrations of the vehicle while rotating relative to the wheel bolt  100 . The single magnet  210  or the plurality of the magnets  210  mounted in the wheel nut  200  rotate. Therefore, the induced current ( 1 ) is generated in the closed circuit  220 . 
     When the induced current ( 1 ) is generated in the closed circuit  220 , the current detector  300  electrically connected to the closed circuit  220  outputs a signal corresponding to a current value of the induced current ( 1 ). In this case, the induced current ( 1 ) is operation energy (or electric power) for the current detector  300 . 
     Based on the output signal of the current detector  300 , the output unit  400  determines whether the induced current ( 1 ) is generated in the closed circuit  220 . When the induced current ( 1 ) is detected by the current detector  300 , the output unit  400  compares the output values of the induced current ( 1 ). 
     As an example, the output unit  400  may compare the output value ( 1 ) outputted by the current detector  300  with a preset reference value (Is) of the induced current (S 200 ). The output unit  400  may output a warning signal to the driver when the output value ( 1 ) exceeds the preset reference value (Is) of the induced current (S 300 ). 
     The reference value (Is) may be any one of a total amount of induced current ( 1 ) generated by the loosened state of the wheel nut  200 , an average value of the generated induced current ( 1 ), and a total sum of absolute values of the generated induced current ( 1 ). However, the present disclosure is not particularly limited to the calculation method or type. 
     As an example, the reference value (Is) of the induced current may be a total amount of the induced current ( 1 ) generated when the wheel nut  200  is loosened by a preset limit rotation angle of the wheel nut  200 , for example, 180 degrees or more. Therefore, the driver may indirectly recognize that the loosened state of the wheel nut  200  exceeds a predetermined level and may warn a user of this situation (S 300 ). 
     When the current detector  300  outputs the signal, the memory  420  may store the outputted signal (S 150 ). 
     The output unit  400  may compare the measured number of outputs (In) of the induced current ( 1 ) with a preset number of outputs (In_s) (S 250 ). When the measured number of outputs (In) of the induced current ( 1 ) exceeds the preset number of outputs (In_s), the output unit  400  may output a warning signal (S 300 ). 
     In other words, when the measured number of outputs (In) of the induced current ( 1 ), which are stored in the memory  420 , exceeds the preset number of outputs (In_s), the output unit  400  may generate a warning signal indicating that the wheel nut  200  may be separated as the wheel nut  200  is repeatedly loosened. 
     The total amount of the induced current ( 1 ), the average value of the induced current ( 1 ), the total sum of the absolute values of the generated induced current ( 1 ), or the reference number (In_s) of outputs of the measured induced current ( 1 ), which is used to warn of the loosened state, may be determined in advance through experiments and stored in the memory  420 . 
     According to the wheel nut loosening detection device, according to an embodiment of the present disclosure, the driver may recognize the generation of the induced current ( 1 ) and predict a loosened state of the wheel nut. The driver may recognize the loosened state of the wheel nut even while the vehicle travels. Therefore, it is possible to prevent a safety accident that may occur because of the loosened state of the wheel nut. 
     In addition, according to an embodiment of the present disclosure, the wheel nut loosening detection device may detect the loosened state of the wheel nut without using a separate battery. Therefore, it is possible to detect the loosened state of the wheel nut without using the electric power of the battery of the vehicle. 
     While this disclosure has been described in connection with what is presently considered practical embodiments, it is to be understood that the disclosure is not limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. 
     DESCRIPTION OF SYMBOLS 
       
     
       
         
           
               
               
               
             
               
                   
                   
               
             
            
               
                   
                 10: Wheel 
                 11: Wheel nut fastening unit 
               
               
                   
                 20: Hub 
                 100: Wheel bolt 
               
               
                   
                 200: Wheel nut 
                 201: Nut body 
               
               
                   
                 203: Screw thread 
                 210: Magnet 
               
               
                   
                 220: Closed circuit 
                 300: Current detector 
               
               
                   
                 400: Output unit 
                 410: Warning unit 
               
               
                   
                 420: Memory