JP2009280081A - Pressure alarm device and pressure alarm system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology informing the reduction of tire pressure with a simple configuration. <P>SOLUTION: A pressure alarm device 1 informing the reduction of tire pressure with sound is provided with a cylinder 2 attached to a wheel, a sliding member 3 sliding the inside of the cylinder 2 and dividing the inside space of the cylinder 2 into a first space A and a second space B, a communication means 9 communicating the first space A with the inside of a tire 12, and a floating member 4 floating in the second space B. The floating member 4 is fixed by being sandwiched between the sliding member 3 and the inner surface of the cylinder 2 when the sliding member 3 is pressed from the first space A side to the second space B side by the pressure of the tire 12. The cylinder 2 generates the sound by bringing the floating member 4 into contact with the inner surface of the cylinder 2 when the floating member 4 floats in the second space B. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pressure alarm device and a pressure alarm system for notifying a decrease in tire pressure.

  In recent years, with the improvement in performance of vehicles, run-flat tires that can normally travel to a gas station or the nearest maintenance shop are beginning to spread even when the tire pressure drops or punctures. The run-flat tire is configured so that the beat portion does not come off the rim even when the tire pressure is low, and the tread and sidewalls can run without touching each other even when the tire is punctured. Since there is no direct contact with the vehicle, vibration or the like is not transmitted to the vehicle body even in a punctured state, so it is often not known that a driver or a passenger has punctured. However, since runflating is only an emergency measure, it is essential to install an alarm device that notifies the driver of tire pressure abnormalities and punctures. Therefore, run-flat tires are sold on the premise that they are mounted on a vehicle equipped with such an alarm device, and are prohibited from being mounted on a vehicle without the alarm device. Further, not only run-flat tires but also conventional tires, an abnormal decrease in air pressure induces punctures, so an alarm device is desired to be installed.

For example, Patent Document 1 discloses a technique for notifying the lack of air pressure by causing a vehicle block to decenter due to movement of a movable block when the tire air pressure decreases, and causing the vehicle driver to feel a dynamic unbalance. . Further, Patent Document 2 discloses a technique for notifying the driver of an indication that the air pressure has decreased by an indicator lamp or the like when the receiver unit receives a signal generated when the air pressure has decreased from an air pressure sensor installed on the tire. ing. Patent Document 3 discloses a technique for notifying an abnormality in tire air pressure by generating an alarm sound with the spring energy that has been wound up in advance when the tire air pressure decreases. Patent Document 4 discloses a technique for detecting an abnormality in tire air pressure by measuring a noise pattern of a running tire and comparing it with a frequency characteristic of tire pattern noise at the time of abnormal air pressure stored in advance. Has been. Further, Patent Document 5 discloses a technique for generating a warning sound by operating a sound generation circuit by contacting a power source contact when a tire air pressure decreases. In Patent Document 6, a wireless tag having a resonance circuit whose resonance frequency changes depending on pressure is attached to a tire as a pressure sensor, and the pressure of the tire is specified by receiving a radio wave transmitted from the sensor. Technology is disclosed. Further, Patent Document 7 discloses a technique that uses a deformation caused by a decrease in tire air pressure to notify a valve exposed by the deformation by vibrating with the wind pressure during traveling. Patent Document 8 discloses a technique for reducing the output of the engine when the tire air pressure decreases.
JP-A-5-246219 JP 2006-298292 A JP 2000-203220 A JP-A-6-199118 Japanese Patent Laid-Open No. 7-69015 JP 2004-163134 A JP-A-6-278420 JP 2002-59723 A

When pressure sensing means is installed on a tire and the driver is informed of the pressure drop by wired or wireless communication with the pressure sensing means, the system is complicated and expensive, and installation after purchasing the vehicle Have difficulty. In addition, when the driver is notified of a decrease in tire pressure by a sound generated by tire eccentricity or traveling wind, the mounting position and the like are restricted. This invention is made | formed in view of such a subject, and makes it a subject to provide the technique which alert | reports the fall of a tire pressure with a simple apparatus structure.

  In order to solve the above-described problem, the present invention is configured so that when the tire pressure decreases, the sliding member releases the pinching state of the floating member so that the floating member contacts the inner surface of the cylinder and generates sound. did.

  More specifically, a pressure alarm device that informs by sound when the pressure of a tire decreases, and includes a cylinder mounted on a wheel, and a sliding member that slides inside the cylinder, the space inside the cylinder A sliding member that divides the first space and the second space, communication means that communicates the first space with the inside of the tire, and a floating member that floats in the second space, The floating member is sandwiched between the sliding member and the inner surface of the cylinder when the sliding member is pressed from the first space side to the second space side by the pressure of the tire. When the idler member idles in the second space, the idler member comes into contact with the inner surface of the cylinder and generates sound.

  The pressure warning device is premised on notifying abnormality of a tire during traveling. Further, it is assumed that the tire is of a type in which a gas such as air or nitrogen is used under pressure. Here, since the traveling wheel is rotating, when a housing that is housed inside so as to allow some member to move freely is attached to the wheel, the member collides with the inside of the housing and generates sound. The pressure alarm device is an application of this, and includes a cylinder mounted on a wheel. Inside this cylinder, a floating member is provided that can freely move in the cylinder. The idle member may be any member that can freely move in the cylinder as the wheel rotates, and can generate a sound by colliding with the cylinder. For example, the idle member may be a spherical member or the like. It can be illustrated.

  Here, the pressure alarm device has a sliding member inside the cylinder so that only when the pressure of the tire is lowered is notified by a contact sound between the floating member and the cylinder. The sliding member is a member that slides along the inner peripheral surface of the cylinder, and the internal space of the cylinder is partitioned into two spaces by the sliding member. In the present application, of these two spaces, the space without the floating member is referred to as a first space, and the other space is referred to as a second space. The floating member collides with the cylinder by moving in the second space and generates sound. On the other hand, the first space communicates with the inside of the tire by the communication means. Therefore, when the pressure of the tire is normal, a pressing force in the second space direction is applied to the sliding member, the sliding member slides in the cylinder, and the floating member is pressed against the inner surface of the cylinder. As a result, the floating member is sandwiched and fixed between the sliding member and the inner surface of the cylinder. On the other hand, when the tire pressure decreases, the sandwiched state is released, and the floating member moves freely in the second space and contacts the inner surface of the cylinder, generating sound.

  As described above, according to the pressure alarm device, since the sound is generated by using the rotation of the wheel, the abnormality of the tire can be notified to the driver and the occupant without installing the equipment on the vehicle body side. It is possible to report a decrease in tire air pressure with a simple device configuration.

The pressure alarm device is a pressure alarm device that notifies by sound when the tire pressure is less than a predetermined pressure, and attaches the sliding member from the second space side to the first space side. The urging means further urges the sliding member such that a pressure substantially equal to the predetermined pressure is applied to the surface of the sliding member on the first space side. It may be a thing.

  According to the pressure alarm device, depending on the urging force of the urging means, it is possible to arbitrarily set the pressure at the time of issuing the alarm, and the alarm can be issued with a desired set value. Note that the predetermined pressure is an arbitrarily set pressure, for example, a pressure slightly lower than the rated pressure of the tire. Since the urging means urges the sliding member so that substantially the same pressure as the predetermined pressure is applied to the first space side surface of the sliding member, the first space is equal to or higher than the predetermined pressure, In other words, when the tire pressure is equal to or higher than the predetermined pressure, the pressing force applied to the sliding member by the air pressure overcomes the urging force applied to the sliding member by the urging means, and the sliding member moves to the second space side. The floating member is held. On the other hand, when the first space is less than the predetermined pressure, in other words, when the tire pressure is less than the predetermined pressure, the biasing force on the sliding member by the biasing means overcomes the pressing force on the sliding member by the atmospheric pressure, The sliding member moves to the first space side to release the pinching state of the floating member. As a result, the idler member collides with the inner surface of the cylinder by the rotation of the wheel, and generates a sound.

  Further, the communication means may communicate the first space with the inside of the tire through a hole for an air valve of the wheel. According to this, it is possible to perform mounting | wearing to the wheel of a cylinder and communication with 1st space and the inside of a tire simultaneously.

  Further, the present invention is a pressure alarm system in which any one of the above-described pressure alarm devices is attached to a plurality of wheels, and a notification is given when the tire pressure decreases, and each pressure alarm device attached to each of the plurality of wheels. These cylinders may emit different sounds. According to this, since a different sound is generated at each wheel, it is possible to know which wheel's tire pressure has been reduced by just listening to the sound. Note that different sounds can be generated by appropriately adjusting the shape and material of the floating member and the cylinder.

  In addition, the pressure alarm system includes a microphone that converts sound in the vicinity of the wheel into an electric signal, a detecting unit that processes an electric signal output from the microphone and detects the generation of the cylinder sound, and the detecting unit Is further provided with notification means for notifying a vehicle occupant of a decrease in tire pressure when the sound of the cylinder is detected, and the detection means analyzes the electrical signal of the microphone that changes depending on the difference in sound. The tire whose pressure has decreased may be specified, and the notification means may notify that the tire pressure specified by the detection means among the plurality of wheels has decreased.

  According to this, since the difference in the sound of the pressure alarm device that is different for each wheel is discriminated by electrical processing to notify that a specific tire is abnormal, the position of the wheel is determined by the driver or the occupant. It is possible to know the abnormality of the tire even when it is away from the passenger compartment. As a method for processing the electrical signal output from the microphone by the detection means, for example, a method for detecting the sound generated by the pressure alarm device by analyzing the frequency of the sound generated when the floating member collides with the cylinder. Is mentioned.

  Further, the pressure alarm system according to any one of the above is attached to a wheel, and a pressure alarm system that notifies when a tire pressure decreases, a microphone that converts sound in the vicinity of the wheel into an electric signal, and output from the microphone. Detecting means for processing the electrical signal to detect the generation of the sound of the cylinder, and notifying means for notifying the vehicle occupant of a decrease in tire pressure when the detecting means detects the sound of the cylinder. It may be a thing.

Unlike the above-described pressure alarm system, this pressure alarm system is not limited to one in which a pressure alarm device that emits different sounds is attached to each wheel. That is, this pressure alarm system may be such that the pressure alarm device is attached only to one wheel, and the sound emitted from the pressure alarm device is processed with an electrical signal to notify the driver and the occupant.

  In addition, the microphone is attached in the vicinity of each of a plurality of wheels, the detection means identifies a tire whose pressure has dropped by analyzing an electrical signal output from each microphone, and the notification means Further, it may be notified that the tire pressure specified by the detecting means among the plurality of wheels has decreased.

  This pressure warning system is a system that makes it possible to determine the position of a wheel where an abnormality has occurred in a tire without attaching a pressure warning device that emits a different sound to each wheel, from a microphone attached in the vicinity of each wheel. Based on the output electrical signal, the position of the wheel where the abnormality has occurred is specified. That is, if a sound is emitted from a pressure alarm device attached to any wheel, the sound is input to the microphone corresponding to the wheel, and therefore the sound of the pressure alarm device is input to any microphone. It is possible to identify the position of the wheel where the abnormality has occurred in the tire by determining whether or not the tire has been used.

  It is possible to notify a decrease in tire air pressure with a simple device configuration.

<Embodiment 1>
Hereinafter, a first embodiment of the present invention will be exemplarily described. In the following embodiments, the description will be made on the assumption that the pressure alarm device and the pressure alarm system are attached to a normal passenger car, but the present invention is not limited to this. That is, the present invention can be applied to any vehicle such as a bicycle having a pneumatic tire and a large automobile. Further, in each embodiment shown below, the description will be made on the assumption that a decrease in air pressure of a pneumatic tire is notified, but the present invention is not limited to such an embodiment, for example, nitrogen gas or the like. The present invention may be applied to a tire using a gas other than air.

  FIG. 1 is a structural diagram of a pressure alarm device 1 according to the present embodiment. As shown in FIG. 1, the pressure alarm device 1 includes a housing 2 (corresponding to a cylinder according to the present invention), a piston 3 (corresponding to a sliding member according to the present invention), and a ball 4 (corresponding to the present invention). And a balance spring 5 (corresponding to an urging means in the present invention), a piston seal 6 and a seal 7.

  The housing 2 is a cylinder closed at both ends, and a piston 3 is disposed inside. The piston 3 is a disk-shaped member that slides along the inner peripheral surface of the housing 2, and a piston seal 6 is provided between the piston 3 and the inner peripheral surface of the housing 2. The space inside the housing 2 is thus partitioned into two spaces by the piston 3. The space indicated by the symbol A in FIG. 1 is hereinafter referred to as space A (corresponding to the first space in the present invention), and the space indicated by the symbol B in FIG. 1 is hereinafter referred to as space B (in the present invention, the first space). It corresponds to the second space). The space A and the space B are configured so as not to flow through each other by being blocked by the piston 3 and the piston seal 6. The piston seal 6 is a member that can ensure airtightness between the space A and the space B while maintaining lubricity so that the piston 3 can slide on the inner peripheral surface of the housing 2. It is comprised with elastic members, such as. When there is a difference in air pressure between the space A and the space B, the piston 3 moves to the space side of the space A and the space B where the air pressure is lower.

Here, the housing 2 is provided with mounting screws 8 for mounting on the wheels of the vehicle wheels so as to protrude from the lower surface of the housing 2. The mounting screw 8 is a male screw that fits into the female screw, and is provided with a hole 9 (corresponding to the communicating means in the present invention) along the central axis of the screw. The hole 9 is a hole that communicates between the space A and the inside of the tire so as to allow air to pass therethrough, and penetrates the inside and the outside of the housing 2, and a mounting screw 8 is provided on the rim of the wheel. The space A and the inside of the tire communicate with each other by fitting into a female screw that passes through the rim. In the case where the tire is a tube type like a bicycle, it is possible to connect the space A and the inside of the tire by connecting the hole 9 to the air valve of the tire. The attachment screw 8 is provided with a seal 7 for preventing a gap from being generated between the housing 2 and the wheel. The seal 7 is a so-called O-ring and is made of an elastic member such as rubber that can maintain airtightness. The piston seal 6 and the seal 7 have a sealing performance that can sufficiently ensure airtightness at the tire air pressure that is set as standard in ordinary passenger cars. When this pressure alarm device 1 is applied to a high-pressure tire, a member having a sealing performance corresponding to the atmospheric pressure is applied.

  A sphere 4 is disposed in the space B of the housing 2. The sphere 4 is made of any material appropriately selected from all materials such as resin, aluminum, brass, and iron. When the sphere 4 collides with the housing 2, sound is generated from the housing 2 (particularly the upper portion of the housing 2). When the piston 3 moves from the space A side to the space B side, the sphere 4 is sandwiched between the piston 3 and a portion closing the upper end of the housing 2. Further, when the piston 3 moves from the space B side to the space A side and the sandwiched state is released, the piston 3 can move freely in the space B. In the present embodiment, a spherical member is used as the floating member. However, the present invention is not limited to such a member, and by colliding with the casing 2 such as a polyhedron such as a cube or a cylindrical body. Any member capable of generating sound can be applied.

  Further, a balance spring 5 that is a compression spring is provided in the space B of the housing 2, and urges the piston 3 from the space B side to the space A side. The balance spring 5 moves the piston 3 from the space B side to the space A side to release the holding state of the sphere 4 when the tire air pressure decreases to a predetermined pressure at which a decrease in air pressure should be notified to the vehicle occupant. Specifically, the piston 3 is urged so that substantially the same pressure as a predetermined pressure is applied to the space A side surface of the piston 3. That is, the piston 3 is urged so that a value obtained by dividing the urging force of the balance spring 5 by the area of the surface of the piston 3 on the space A side is substantially the same as a predetermined pressure value. Thereby, when the atmospheric pressure in the space A is equal to or higher than a predetermined pressure, the biasing force of the balance spring 5 is overcome and the piston 3 moves from the space A side to the space B side, and the sphere 4 moves between the piston 3 and the housing 2. Sandwiched between. On the other hand, when the atmospheric pressure in the space A is less than a predetermined pressure, the balance spring 5 extends to move the piston 3 from the space B side to the space A side, and the holding state of the sphere 4 is released. The housing 2 is provided with a plurality of air holes 21 for communicating the space B with the atmosphere. FIG. 2 is an external perspective view of the pressure alarm device 1. As shown in FIG. 2, by providing the air hole 21 that communicates the space B with the atmosphere, the air pressure in the space B is always the same as the atmospheric pressure. Therefore, the pinching state of the sphere 4 is released when the tire air pressure is less than a predetermined pressure (gauge pressure) without being affected by the position of the piston 3 or the air pressure around the vehicle.

FIG. 3 is a view showing a mounting position of the pressure alarm device 1. As shown in FIG. 3, the pressure alarm device 1 is fixed to the wheel 10 by attaching a mounting screw 8 to a female screw provided on the wheel 11 of the wheel 10. The screw hole 9 passes through the rim of the wheel 11, and the mounting screw 8 fits into the screw hole 9 so that the inside of the tire (reference numeral C in FIG. 3) communicates with the space A of the housing 2. FIG. 4 is a diagram illustrating the wheel 10 in which the tire 12 is punctured. As shown in FIG. 4, when the tire 12 is punctured or the air pressure becomes less than a predetermined pressure, the air pressure in the space A also decreases, the balance spring 5 extends, and the piston 3 moves from the space B side to the space A side. Thereby, the clamping state of the sphere 4 is released. FIG. 5 is a state diagram of the pressure alarm device 1 when the air pressure in the space A becomes less than a predetermined pressure. As shown in FIG. 5, when the balance spring 5 is extended, the pinched state of the sphere 4 is released. FIG. 6 is a diagram showing the state of the pressure alarm device 1 when the tire 12 has a normal air pressure and the state of the pressure alarm device 1 when the air pressure is less than a predetermined pressure. As shown in FIG. 6, when the space A becomes less than a predetermined pressure due to the tire 12 being punctured or the like, the ball 4 is in a state in which it can move freely in the space B. As a result, the sphere 4 moves in the space B and collides with the housing 2 to generate sound. That is, as the wheel 10 rotates, the sphere 4 vibrates and collides with the housing 2 to generate sound. Therefore, the driver or the occupant can recognize the puncture of the tire 12 or an abnormal decrease in air pressure by stopping the vehicle when detecting the generation of sound due to the vibration of the ball 4 and checking the condition of the tire 12. Become. Note that a sound is generated particularly when the rotational speed of the wheel 10 is relatively slow, such as when the vehicle starts or stops.

  According to the pressure alarm device, it is possible to easily notify a driver or an occupant of a puncture of a running tire or an abnormal drop in air pressure simply by being attached to a wheel. In particular, it is difficult to detect a tire puncture and it is difficult to detect a tire abnormality. Even if it is not installed, it is possible to notify the driver and passengers of tire abnormalities. As a result, the spread of run-flat tires is expected, and the reduction of emergency tires that are hardly used is expected. In particular, even an existing vehicle can be attached by a simple operation such as simple processing of a wheel or replacement of an existing air valve.

<Embodiment 2>
Hereinafter, a second embodiment of the present invention will be exemplarily described. In the first embodiment described above, the material of the sphere 4 is not particularly limited, but in this embodiment, the pressure alarm device 1 using the spheres 4 of different materials is attached to each of the plurality of wheels 10. The punctured wheel 10 can be specified by sound. FIG. 7 is a configuration diagram of the pressure alarm system 13 according to the present embodiment. In the present embodiment, it is assumed that the pressure alarm system 13 is applied to a four-wheeled vehicle. As shown in FIG. 7, the pressure alarm system 13 according to this embodiment is configured by mounting the pressure alarm device 1 according to Embodiment 1 described above on four wheels, and the materials of the balls of the pressure alarm device 1 are mutually different. Configured differently. That is, as shown in FIG. 7, a resin ball is used for the left front wheel, an aluminum ball is used for the right front wheel, and a brass ball is used for the left rear wheel. An iron ball is used for the right rear wheel. Thus, by changing the material or the like so that the pressure alarm device 1 of each wheel 10 generates a different sound, it becomes possible to identify a punctured tire or a tire whose air pressure is abnormally lowered by sound. This is because the frequency of sound when the sphere vibrates changes because the specific gravity differs if the material is different. The specific gravity (relative to water) is 1.2 for resin, 2.7 for aluminum, 7.8 for iron, and 8.4 for brass. Therefore, even with a sphere of the same size, the weight is “resin <aluminum <iron <brass”. In this way, by making the frequency of the sound change according to the position of the tire, it becomes possible for the driver and the occupant to specify the position of the tire where the abnormality has occurred. In addition, although this embodiment demonstrated the case where it applied to a four-wheeled motor vehicle, the application form of this embodiment is not limited to a four-wheeled motor vehicle, a two-wheeled motor vehicle, a bicycle, or six wheels or more. It is also possible to apply to a vehicle having a tire.

<Embodiment 3>
Hereinafter, the third embodiment of the present invention will be exemplarily described. In the first and second embodiments described above, it is assumed that the driver or the occupant directly hears the sound emitted from the pressure alarm device 1 attached to the wheel 10, but the present invention may be configured as follows. That is, the sound generated by the pressure alarm device 1 may be converted into an electrical signal and processed to notify the driver or occupant of tire puncture or a decrease in air pressure. Hereinafter, the pressure alarm system according to the present embodiment will be described in detail.

FIG. 8 is a diagram showing the processing circuit 14 of the pressure alarm system according to the present embodiment. The pressure alarm system according to the present embodiment is a system in which a processing circuit 14 is added to the pressure alarm system 13 according to the second embodiment described above, and the processing circuit 14 processes the sound signal of the pressure alarm device 1 that is different for each wheel. By doing so, the driver and the passenger are notified of the tire puncture or abnormal decrease in air pressure.

As shown in FIG. 8, the processing circuit 14 includes a microphone 15, an amplifier 16, a filter bank 18 in which a plurality of BPFs 17 (Band-pass filters) are combined, a CPU 19 (Central Processing Unit), and a display 20. The microphone 15 is a device that converts sound into an electrical signal, and includes, for example, a condenser microphone. The microphone 15 is attached to a position where the sound generated by the pressure alarm device 1 attached to each wheel 10 can be picked up, for example, near the center of the chassis. The amplifier 16 is a circuit that amplifies the audio signal of the microphone 15, amplifies the fine electrical output of the microphone 15, and sends it to the filter bank 18.

  The filter bank 18 is a filter bank in which four BPFs 17 (f1 to f4) are combined. The filter bank 18 filters the audio signal input from the amplifier 16 and sends it to the CPU 19. Each BPF 17 (f1 to f4) passes audio signals in different predetermined frequency bands and attenuates audio signals in other frequency bands. The predetermined frequency band is a frequency band substantially the same as the frequency of the sound emitted from the pressure alarm device 1 attached to each wheel 10. For example, the BPF 17 (f1) is a pressure alarm device 1 to which a resin ball is applied. Is passed through the sound signal (ie, the sound of the left front wheel), and the sound signal of another frequency band (for example, the sound signal of the right front wheel, road noise, ambient noise, etc.) is attenuated. Further, the BPF 17 (f2) passes a signal of a sound (that is, a sound of the right front wheel) emitted from the pressure alarm device 1 to which an aluminum ball is applied, and attenuates a sound signal in another frequency band. The BPF 17 (f3) passes a signal of a sound (that is, a sound of the left rear wheel) emitted from the pressure alarm device 1 to which a brass ball is applied, and attenuates a sound signal of another frequency body. Further, the BPF 17 (f4) transmits a signal of a sound (that is, a sound of the right rear wheel) emitted from the pressure alarm device 1 to which an iron ball is applied, and attenuates a sound signal of another frequency body. By detecting which BPF 17 (f1 to f4) passes the audio signal, it is possible to identify a tire in which the puncture or the air pressure has abnormally decreased. The BPF 17 (f1 to f4) is a combination of a high-pass filter and a low-pass filter. The BPF 17 (f1-f4) is a low-pass filter that passes a signal in a band of a predetermined frequency band or higher and a high-pass filter that passes a signal in a band of a predetermined frequency band or lower. An audio signal in a predetermined frequency band is allowed to pass through in combination with a filter.

  The CPU 19 is an arithmetic processing unit that realizes a predetermined function by executing a computer program stored in a storage medium such as a ROM (Read Only Memory) (not shown), and based on a signal sent from the filter bank 18 Judgment processing of puncture and air pressure drop. The processing content of the CPU 19 will be described in detail in the processing flow described later.

Hereinafter, the flow of signal processing of the processing circuit 14 according to the present embodiment will be described. FIG. 9 is a flowchart showing the flow of signal processing. When the tire punctures or the air pressure drops abnormally, the ball 4 vibrates and a sound is generated from the pressure alarm device 1 (S101). The sound generated from the pressure alarm device 1 is input to the microphone 15 and converted into an electrical sound signal (S102). The audio signal output from the microphone 15 is amplified by the amplifier 16 (S103). The audio signal amplified by the amplifier 16 is input to the filter bank 18 composed of four types of BPFs 17, and the audio signal is filtered (S104). That is, the sound signal generated from the pressure alarm device 1 due to the vibration of the sphere 4 passes through the filter, and other sound signals are removed as noise. Based on the audio signal filtered by the filter bank 18, the CPU 19 performs the following determination process. That is, when an audio signal that has passed through the filter bank 18 is input, the CPU 19 determines the intensity of the audio signal (S105). If the audio signal sent from the filter bank 18 exceeds a predetermined threshold value, the CPU 19 executes the next step S106. Further, if the audio signal sent from the filter bank 18 is equal to or less than a predetermined threshold, the CPU 19 repeatedly executes the process of step S105. The predetermined threshold value determines whether the sound signal that has passed through the filter bank 18 is due to vibration of the sphere 4 of the pressure alarm device 1 or due to noise of the same frequency from other sources. For example, a value arbitrarily set according to the distance between the microphone 15 and the pressure alarm device 1. When the CPU 19 detects that the intensity of the audio signal sent from the filter bank 18 exceeds a predetermined threshold value in the process of step S105, the CPU 19 determines whether or not the audio signal continues for a predetermined time (S106). ). CPU19 will perform the process of following step S107, if an audio | voice signal continues for a fixed time. If the audio signal has not continued for a certain period of time, the CPU 19 repeatedly executes the process of step S106. Here, the certain time is determined whether the sound signal that has passed through the filter bank 18 is due to vibration of the sphere 4 of the pressure alarm device 1 or due to temporary noise from other sources. For example, it is a preset time that is slightly longer than the duration of noise generated by a sound source other than the pressure alarm device 1. When the CPU 19 detects a tire abnormality by the processes in steps S105 and S106, the CPU 19 identifies the position of the tire where the abnormality has occurred (S107). That is, the CPU 19 identifies the position of the tire where the abnormality has occurred by detecting which BPF 17 of the BPF 17 (f1 to f4) of the filter bank 18 has the strongest audio signal. The intensity of the signal sent from each BPF 17 (f1 to f4) is measured to identify the BPF 17 sending the strongest signal. Next, the CPU 19 displays on the display device 20 that an abnormality has occurred in the tire (S108). When displaying the abnormality of the tire on the display device 20, the CPU 19 specifies and displays the position of the tire where the abnormality occurs based on which BPF 17 the abnormality signal is sent from. Specifically, if the signal sent from the BPF 17 (f1) is the strongest, the CPU 19 displays on the display 20 that an abnormality has occurred in the tire of the left front wheel, and is sent from the BPF 17 (f2). If the signal is the strongest, the display 20 indicates that an abnormality has occurred in the tire on the right front wheel. If the signal sent from the BPF 17 (f3) is the strongest, an abnormality has occurred in the tire on the left rear wheel. Is displayed on the display 20, and if the signal sent from the BPF 17 (f4) is the strongest, the display 20 indicates that an abnormality has occurred in the tire of the right rear wheel.

  As described above, according to the present embodiment, an abnormality occurs when the processing circuit 14 analyzes the sound signals emitted from the pressure alarm devices 1 while adopting the pressure alarm devices 1 that emit different sounds from each wheel 10. Therefore, the driver or the occupant can easily identify a punctured tire or a tire with an abnormally decreased air pressure. In particular, according to the pressure alarm system according to the present embodiment, since the processing circuit 14 detects a tire abnormality based on the sound picked up by the single microphone 15, only one microphone 15 is installed. Thus, it is possible to grasp the abnormality of the four-wheel tire, and it is possible to mount the pressure alarm system on the vehicle very easily.

<Embodiment 4>
Hereinafter, the fourth embodiment of the present invention will be exemplarily described. This embodiment is a modification of the above-described third embodiment. Therefore, only differences from the third embodiment will be described mainly. Points that are not particularly mentioned are the same as in the third embodiment described above. In the third embodiment described above, the pressure alarm devices attached to the four wheels are configured to emit different sounds. However, in this embodiment, the pressure alarm devices of the respective wheels are configured to emit substantially the same sound. It is configured. Then, the sound is picked up by microphones attached in the vicinity of each wheel.

FIG. 10 is a diagram showing the processing circuit 114 of the pressure alarm system according to the present embodiment. As shown in FIG. 10, the processing circuit 114 includes a filter bank 118 in which four microphones 15 and an amplifier 16 are combined with four BPFs corresponding thereto. The processing circuit 114 includes a CPU 19 and a display device 20. The microphones 15 are mounted in the vicinity of the respective wheels 10, and each microphone 15 picks up a sound generated by the pressure alarm device 1 attached to each wheel 10. Four amplifiers 16 are provided independently corresponding to the four microphones 15, amplify the signals of the microphones 15, and send them to the corresponding BPFs 117. The filter bank 18 is a filter bank in which four BPFs 117 (fx) are combined. The filter bank 18 filters the audio signal input from the amplifier 16 and sends it to the CPU 19. Here, each BPF 117 (fx) passes audio signals in the same predetermined frequency band, and attenuates audio signals in other frequency bands. The signal processing flow of the processing circuit 114 according to the present embodiment is the same as the signal processing flow of the processing circuit 14 according to the above-described third embodiment.

  As described above, according to the present embodiment, the microphone 15 installed in the vicinity of each wheel 10 picks up the sound emitted from the pressure alarm device 1, and the processing circuit 14 analyzes the sound signal to identify the tire in which the abnormality has occurred. Therefore, it becomes possible for a driver or an occupant to easily identify a punctured tire or a tire with an abnormally decreased air pressure. In particular, since the pressure alarm device 1 that emits the same sound is installed on each wheel 10, even if the wheel 10 is replaced in front, rear, left and right, even if you forget to replace the pressure alarm device 1, Abnormality is not reported. The configuration of the third embodiment and the configuration of the fourth embodiment may be used in combination with a pressure alarm device that is attached to each wheel and emits a different sound.

<Embodiment 5>
Hereinafter, a method for attaching the pressure alarm device and the pressure alarm system according to each of the above-described embodiments will be exemplarily described. FIG. 11 is a diagram illustrating an example of a method for attaching the pressure alarm device 1. As shown in FIG. 11, the pressure alarm device 1 is configured by inserting a mounting screw 8 through a hole provided in the rim of the wheel 11 and tightening from the air chamber side of the tire (that is, the outer peripheral side of the rim) with a mounting nut 22. It is possible to attach.

  As another aspect, as shown in FIG. 12, the air valve and the pressure alarm device 1 are integrated, and the pressure alarm device 1 integrated with the air valve is attached to a hole in which the air valve provided in the wheel 11 is fitted. It may be. That is, a hollow branch pipe 23 that is mounted in an air valve hole provided in the wheel 11 and that has a pipe branching in three directions is prepared. Is connected to the hole of the wheel 11, the second port is connected to the mounting screw 8 of the pressure alarm device 1, and the third port is connected to the air valve. If the hole for the existing air valve is used in this way, the wheel 11 is not processed, and as shown in FIG. 13, it can be directly attached to a wheel that has already been distributed or used.

  Further, among the processing circuits of the pressure alarm system according to each of the above embodiments, the amplifier, the filter bank, the CPU, and the indicators are arranged in one unit and are arranged near the driver's seat as shown in FIG. Also good. Then, the microphone connected to the unit by cable is installed on the underside of the chassis or on the tire house. According to this, it is easy to take out the operation power supply and the like, and the driver and the passenger can easily operate the unit.

FIG. 3 is a structural diagram of a pressure alarm device. The external appearance perspective view of a pressure alarm device. The figure which shows the attachment position of a pressure alarm apparatus. The figure which shows the wheel 10 in which the tire was punctured. The state diagram of a pressure alarm device when it becomes less than a predetermined pressure. The figure which compared two states of the pressure alarm apparatus. The block diagram of a pressure alarm system. The figure which shows the processing circuit of a pressure alarm system. The flowchart which shows the flow of signal processing. The figure which shows the processing circuit of a pressure alarm system. The figure which shows an example of the attachment method of a pressure alarm apparatus. The figure which shows an example of the attachment method of a pressure alarm apparatus. The figure which shows an example of the attachment method of a pressure alarm apparatus. The figure which shows an example of the attachment method of a pressure alarm system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Pressure alarm device 2 ... Housing 3 ... Piston 4 ... Ball 5 ... Balance spring 6 ... Piston seal 7 ... Seal 8 ... Mounting screw 9 ... Hole 10 ... Wheel 11 ... Wheel 12 ... Tire 13 ... Pressure alarm system 14, 114 ... Processing circuit 15 ... Microphone 16 ... Amplifier 17, 117 ... BPF
18, 118 ... Filter bank 19 ... CPU
20 ... Display 21 ... Air hole 22 ... Mounting nut 23 ... Branch pipe

Claims (7)

It is a pressure alarm device that notifies by sound when the pressure of the tire falls,
A cylinder mounted on the wheel;
A sliding member that slides inside the cylinder, wherein the sliding member divides a space inside the cylinder into a first space and a second space;
Communicating means for communicating the first space with the inside of the tire;
A floating member that floats in the second space,
The floating member is fixed by being sandwiched between the sliding member and the inner surface of the cylinder when the sliding member is pressed from the first space side to the second space side by the pressure of the tire. And
The cylinder generates a sound when the floating member contacts the inner surface of the cylinder when the floating member moves in the second space.
Pressure alarm device. The pressure alarm device is a pressure alarm device that notifies by sound when the tire pressure is less than a predetermined pressure,
A biasing means for biasing the sliding member from the second space side to the first space side;
The biasing means biases the sliding member so that a pressure substantially equal to the predetermined pressure is applied to the surface of the sliding member on the first space side;
The pressure alarm device according to claim 1. The communication means communicates the first space and the inside of the tire through a hole for an air valve of the wheel.
The pressure alarm device according to claim 1 or 2. A pressure alarm system that attaches the pressure alarm device according to any one of claims 1 to 3 to each of a plurality of wheels, and notifies that the tire pressure decreases,
The cylinders of the pressure alarm devices attached to the plurality of wheels respectively emit different sounds.
Pressure alarm system. A microphone that converts sound in the vicinity of the wheel into an electrical signal;
Detection means for processing the electrical signal output from the microphone to detect the generation of the sound of the cylinder;
When the detection means detects the sound of the cylinder, further comprising notification means for notifying the vehicle occupant of a decrease in tire pressure.
The detection means identifies a tire whose air pressure has dropped by analyzing an electric signal of the microphone that changes due to a difference in sound,
The notifying means notifies that the tire pressure specified by the detecting means among the plurality of wheels has decreased,
The pressure alarm system according to claim 4. A pressure alarm system that attaches the pressure alarm device according to any one of claims 1 to 3 to a wheel and notifies that the pressure of the tire decreases,
A microphone that converts sound in the vicinity of the wheel into an electrical signal;
Detecting means for processing the electrical signal output from the microphone to detect the generation of sound of the cylinder;
When the detection means detects the sound of the cylinder, a notification means for notifying a vehicle occupant of a decrease in tire pressure,
Pressure alarm system. The microphone is attached in the vicinity of each of a plurality of wheels,
The detection means identifies a tire whose air pressure has dropped by analyzing an electrical signal output from each microphone,
The notifying means notifies that the tire pressure specified by the detecting means among the plurality of wheels has decreased,
The pressure alarm system according to claim 6.

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