JP2008100610A - Traveling road surface state detecting system and sensor unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To quickly and precisely detect a traveling road surface state when a vehicle travels at any speed from low speed to high speed. <P>SOLUTION: A micro-vibration superimposed on an acceleration signal in the rotating direction of a tire 2 is detected by a sensor unit 100 provided in the tire 2, and an integrated value obtained by integrating the micro-vibration signal for a predetermined time is transmitted as digital information to a monitor device 200. The monitor device 200 outputs the road surface state information in which the integrated value is made to correspond to the magnitude of friction to a stability control unit 700 by taking the friction between the traveling road surface and the tire 2 to be large when the integrated value is small, and taking the friction between the traveling road surface and the tire 2 to be small when the integrated value is large. The stability control unit 700 conducts braking control based on the road surface state information. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a traveling road surface state detection system that detects a road surface state by detecting minute vibrations generated in wheels during traveling of the vehicle, and a sensor unit thereof.

  Conventionally, matters that must be taken into consideration for safe driving in vehicles include setting the vehicle's tire air pressure to an appropriate level, and paying attention to tire wear and checking the tires. It is done.

  However, when the tires are inspected and the tires are kept in good condition, the brakes are applied when the frictional force between the road surface and the tire decreases, such as when the road surface is wet during rainy weather. Slip into the car and the vehicle may move in an unexpected direction, causing an accident.

  In order to prevent accidents caused by such slips and sudden starts, an anti-lock brake system (hereinafter referred to as ABS), a traction control system, and in addition to these A stability control system equipped with a YAW sensor has been developed.

  For example, ABS is a system that detects the rotational state of each tire and controls the braking force so as to prevent each tire from entering a locked state based on the detection result.

  As the rotation state of the tire, it is possible to detect the number of rotations of each tire, the state of air pressure, distortion, and the like, and use this detection result for control.

  Examples of such a control system include, for example, an automobile brake device disclosed in Japanese Patent Laid-Open No. 05-338528 (hereinafter referred to as Patent Document 1), and brake control disclosed in Japanese Patent Laid-Open No. 2001-018775. Device (hereinafter referred to as Patent Document 2), vehicle control method and apparatus disclosed in Japanese Patent Application Laid-Open No. 2001-182578 (hereinafter referred to as Patent Document 3), and vehicle disclosed in Japanese Patent Application Laid-Open No. 2002-137721 A motion control device (hereinafter referred to as Patent Document 4), a brake device disclosed in JP 2002-160616 A (hereinafter referred to as Patent Document 5), and the like are known.

  In Patent Document 1, negative pressure is supplied from a vacuum tank to a vacuum booster connected to a brake pedal, and negative pressure is supplied from a vacuum pump to the vacuum tank, and the vacuum pump is driven by a pump motor. When the acceleration sensor 14 detects that the deceleration acceleration of the vehicle has reached a predetermined value, the pump motor for operating the vacuum pump is controlled so that the operation fee at the time of a sudden brake operation and the brake operation immediately thereafter is controlled. A brake device for preventing ring changes is disclosed.

  In Patent Document 2, in a brake control device including a control unit that executes ABS control, a lateral acceleration estimation unit that estimates a lateral acceleration generated in a vehicle and an estimation by the lateral acceleration estimation unit are included in the control unit. The lateral acceleration, the estimated lateral acceleration by the vehicle behavior detecting means, and the detected lateral acceleration detected by the lateral acceleration sensor included in the vehicle behavior detecting means are compared, and if the difference between the two is less than a predetermined value, the steering angle is met. Comparing and determining means for determining that the vehicle is turning normally and determining that the vehicle is turning abnormally if the difference is greater than or equal to a predetermined value is provided. Discloses a brake control device that switches control.

  Patent Document 3 discloses a vehicle acceleration method or a vehicle deceleration generated by a traveling road surface inclination in a vehicle control method and apparatus in which a control signal for adjusting a vehicle deceleration and / or acceleration is formed by a corresponding set value. A vehicle control method and apparatus are disclosed that improve the vehicle deceleration and / or acceleration settings by forming a correction factor representative of

In Patent Document 4, the lateral slip angle change speed β ′ of the center of gravity is acquired as the actual yawing motion state quantity of the vehicle having a plurality of wheels, and the absolute value of the change speed β ′ is greater than or equal to the set value β ₀ ′. For example, by applying the brake fluid pressure ΔP to one of the left and right rear brakes, the larger the value of the change speed β ′, the larger the value and the smaller the value of the change speed β ′. During the yawing moment control, it is determined whether or not the slip control is necessary for the wheel to which the brake fluid pressure ΔP is applied. If the slip control is necessary, the brake fluid pressure A vehicle motion control device that performs slip control that keeps the slip ratio within an appropriate range by suppressing ΔP is disclosed.

  Patent Document 5 includes at least two of an acceleration sensor that detects acceleration in the vehicle longitudinal direction, a wheel speed sensor that detects wheel speed of each wheel, and a brake pressure sensor that detects brake pressure. The target brake pressure is calculated by feedback from at least two sensors, and based on the calculation result, the command current is calculated by the command current calculation unit, and the command current is supplied to the brake drive actuator to obtain the magnitude of the command current. A brake device is disclosed that can suppress an output abnormality even if a disturbance occurs or one sensor breaks down by generating a corresponding braking force.

  Further, as disclosed in Japanese Patent No. 3787608 (Patent Document 6), the friction between the traveling road surface and the wheel when the wheel is locked is estimated using the ABS, and the ABS is based on the estimated friction. A technique for changing the control parameter is disclosed.

  In Patent Document 6, road surface friction force information corresponding to a road surface friction force F acting between a vehicle wheel and a traveling road surface, and a brake torque force T acting between the vehicle wheel and a brake device are used. An ABS device having an arbitrary number of first sensors capable of obtaining brake torque information, and calculating a difference parameter M corresponding to a difference between road surface friction force information from the first sensor and brake torque information. A difference parameter calculation means, a wheel speed parameter calculation means for calculating the wheel speed parameter Mω to be zero when the wheel is locked by correcting and integrating the difference parameter M calculated by the difference parameter calculation means; Brake fluid pressure control means for controlling the hydraulic pressure of the brake device using the wheel speed parameter Mω calculated by the speed parameter calculation means. The ABS apparatus characterized by these is disclosed.

  Further, as disclosed in Japanese Patent No. 3448995 (Patent Document 7), a technique for estimating the friction when a wheel slips on a draft road surface during acceleration and controlling the throttle opening based on the estimated friction is known. It has been.

  In Patent Document 7, a second throttle valve that is arranged in series with a throttle valve in an intake passage of an engine and is controlled to be switched in two stages of a fully open position and a fully closed position of a predetermined opening degree, and a drive wheel of a vehicle. Slip state detecting means for detecting a slip state; first driving force reduction control means for reducing the driving force of the vehicle by controlling the second throttle valve to a fully closed position in accordance with the detected slip state; Road surface state detecting means for detecting the state of the friction coefficient of the road surface, second driving force reduction control means for controlling the driving force of the vehicle to decrease more responsively than the first driving force reduction control means, and first driving force Driving force reduction control limiting means for limiting the operation of the reduction control means, and when the road surface condition has a high friction coefficient, the driving force reduction control limiting means limits the operation of the first driving force reduction control means, and the necessary drive Force reduction control for the second drive Driving force control apparatus for a vehicle, characterized in that the cover in force reduction control means is disclosed.

In recent years, more and more passenger cars are equipped with safety equipment using the latest high-tech technology. For example, a millimeter wave radar or infrared camera is used to detect the vehicle ahead and automatically decelerate and stop to prevent rear-end collisions, or to detect pedestrians on dark night roads or to Accident avoidance technology, such as the ability to stop, has also begun to be put into practical use. By using such technology, efforts are being made to avoid the occurrence of serious accidents such as rear-end collisions of vehicles and hitting people walking on the shoulders.
Japanese Patent Laid-Open No. 05-338528 JP 2001-018775 A Japanese Patent Laid-Open No. 2001-182578 JP 2002-137721 A Japanese Patent Laid-Open No. 2002-160616 Japanese Patent No. 3787608 Japanese Patent No. 3442995

  One of the reasons for requiring the anti-lock brake system as described above is a change in the state of the road surface on which the vehicle travels. When the road surface condition changes depending on the weather and the environment, the vibration of the vehicle body and the stability decrease, and further, the change of the braking effect and the slip of the wheel at the time of the brake operation occur. For this reason, technology development for quickly and accurately detecting the road surface state is being performed.

  However, for example, ABS has parameters determined by the standard new car tires selected by automakers at the development stage, but in practice it varies depending on conditions such as tire wear, replacement, number of passengers, weather, road surface, etc. Therefore, it is extremely difficult to achieve optimum control with a single parameter.

  In addition, tire wear, change of clothes, number of passengers, weather, and road surface are dry when braking control of vehicles based on detection results using millimeter wave radars and infrared cameras to prevent rear-end collisions, etc. Depending on the condition of the road surface, such as wet or frozen, the distance traveled from the start of braking to the stop of the vehicle varies, making it difficult to perform appropriate braking control.

  In the technologies disclosed in Patent Documents 6 and 7, the control parameter can be changed at the start of traveling or at low speed traveling, and it is extremely difficult to change the parameter during vehicle traveling, particularly at high speed traveling. That is.

  In view of the above problems, an object of the present invention is to provide a traveling road surface state detection system and a sensor unit thereof that can quickly and accurately detect a traveling road surface state when the vehicle travels at all speeds from low speed to high speed. .

  In order to achieve the above object, the present invention is a system for detecting the state of a road surface on which a vehicle travels, and includes a rotating body provided on a vehicle body of a vehicle for fixing the wheel and rotating the wheel. A vibration detection unit that is provided in the rotation mechanism unit including the vibration detection unit that detects minute vibrations generated in the rotation mechanism unit as the vehicle rotates and converts the vibrations into electric signals, and outputs the electric signals as minute vibration signals; Integrating means for integrating a minute vibration signal output from the vibration detecting unit for a predetermined time and outputting an integrated value, and inputting the integrated value, and the friction between the road surface and the wheel when the integrated value is small Road surface state information output means for outputting road surface state information in which the integrated value is associated with the magnitude of the friction, assuming that the friction between the traveling road surface and the wheel is small when the integral value is large. Running road with It proposes a state detection system.

  According to the traveling road surface state detection system of the present invention, minute vibrations generated in a rotating mechanism unit including wheels such as tires as a vehicle rotates are detected, and a minute electric signal corresponding to the minute vibrations is detected. It is output from the vibration detector as a vibration signal.

  Further, the minute vibration signal is integrated for a predetermined time by the integrating means, and an integrated value of the integration result is output, and when the integrated value is small by the road surface state information output means, the road surface and the wheel are Road surface state information in which the integrated value is associated with the magnitude of the friction is output assuming that the friction between the traveling road surface and the wheel is small when the friction is large and the integral value is large.

  In order to achieve the above object, the present invention provides a sensor unit that is attached to the rotating mechanism unit, a sensor unit that transmits the intensity value of the minute vibration signal as transmission information by radio waves, and transmits the integral value. The present invention proposes a sensor unit that transmits by radio waves as information, and a sensor unit that transmits by radio waves the road surface state information as transmission information.

  According to the traveling road surface state detection system of the present invention, the magnitude of the value obtained by integrating the detected minute vibration intensity value of the rotation mechanism section during vehicle travel varies depending on the friction between the traveling road surface and the wheels. It is possible to detect the state of the traveling road surface, that is, the friction between the traveling road surface and the wheels. By using the detected information on the friction between the road surface and the wheels, it is possible to grasp an appropriate braking start time, a travel distance from the start of braking to the stop of the vehicle, occurrence of slip during braking, and the like. As a result, appropriate braking control can be performed even if the condition of the road surface changes, such as tire wear, change of clothes, number of passengers, weather, road surface is dry, wet, or frozen.

  Furthermore, according to the sensor unit of the present invention, the minute vibration generated by the rotation of the wheel or its integrated value or road surface state information can be obtained only by mounting it at a predetermined position of a rim and wheel, and a rotating body such as a wheel and an axle such as a tire body. Therefore, the traveling road surface state detection system of the present invention can be easily configured.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is an external view showing the arrangement of the monitor device and sensor unit in the first embodiment of the present invention, FIG. 2 is a plan view showing the arrangement of the monitor device and sensor unit in the first embodiment of the present invention, and FIG. The figure explaining the installation place of the sensor unit to the tire in 1st Embodiment of invention, FIG. 4 is a figure which shows the tire in the tire house of 1st Embodiment of this invention, FIG. 5 is 1st Embodiment of this invention. 1 is a configuration diagram showing a vehicle drive control system in FIG. In the present embodiment, a drive control system for a four-wheel vehicle will be described as an example.

  1 and 2, 1 is a vehicle, 2 is a tire (wheel), 100 is a sensor unit, and 200 is a monitor device. In the present embodiment, in each of the sensor unit 100 and the monitor device 200, each electric circuit is housed in a small casing having insulation and electromagnetic wave transmission, and each of the four sensor units 100 is a tire of the vehicle 1. 2, each of the four monitor units 200 is disposed in each tire house 4 so that the sensor unit 100 and the monitor device 200 have a one-to-one correspondence.

  As shown in FIGS. 3 and 4, the tire 2 is, for example, a well-known tubeless radial tire, and includes a wheel and a rim in the present embodiment. The tire 2 includes a tire body 305, a rim 306, and a wheel (not shown). The tire body 305 includes a known cap tread 301, under tread 302, belts 303A and 303B, carcass 304, and the like. It is stored in. Further, each tire house 4 is provided with a monitor device 200. In the present embodiment, as shown in FIG. 3, the tire 2 includes a sensor unit 100, and the sensor unit 100 is fixed to the rim 306. In the present embodiment, the following description will be made assuming that the rotation direction of the tire 2 is the X-axis direction, the rotation axis direction of the tire 2 is the Y-axis direction, and the radial direction centering on the rotation axis of the tire 2 is the Z-axis direction.

  In FIG. 5, 2 is a tire, 3 is an axle, 100 is a sensor unit, 200 is a monitoring device, 410 is an engine, 411 is an accelerator pedal, 412 is a sub-throttle actuator, 413 is a main throttle position sensor, and 414 is a sub-throttle position sensor. , 421 is a steering wheel, 422 is a steering angle sensor, 510 and 520 are sensors for detecting the number of rotations of a tire, 610 is a brake pedal, 620 is a master cylinder for braking, 630 is a pressure control valve for controlling hydraulic pressure for braking, and 640 is The brake driving actuator 700 is a stability control unit.

  The stability control unit 700 includes a control circuit including a well-known CPU. The stability control unit 700 includes detection results output from sensors 510 and 520 that detect the number of rotations of each tire 2 mounted on the vehicle 1, and throttle position sensors 413 and 414. Stability control is performed by taking in the detection results output from the rudder angle sensor 422 and the monitor device 200.

  That is, at the time of acceleration, by depressing the accelerator pedal 411, the main throttle is opened and fuel is sent to the engine 410, and the rotational speed of the engine 410 is increased.

  Further, at the time of braking, the hydraulic pressure in the master cylinder 620 is increased by depressing the brake pedal 610, etc., and this hydraulic pressure is transmitted to the brake drive actuator 640 of each tire 2 via the pressure control valve. A braking force is applied to the rotation.

  The stability control unit 700 is based on the detection results output from the sensors 510 and 520 that detect the rotational speed of each tire 2, the detection results of the steering angle sensor 422, and the detection results output from the monitor device 200. By electrically controlling the operation state of the actuator 412 and electrically controlling the operation state of each pressure control valve 630, the stability of the vehicle body is maintained and appropriate braking is performed or the tire 2 is locked and slips. Controls automatically so that it does not occur.

  As described above, the sensor unit 100 is fixed to a predetermined position of the rim 306 of the tire 2, and the X, Y, and Z axis directions of each tire 2 are measured by an acceleration sensor described later provided in the sensor unit 100. The acceleration is detected, the gravitational acceleration component is removed from the analog signal of the acceleration in the X-axis direction, and only the minute vibration component is extracted, and the integrated value obtained by integrating the minute vibration component is converted into a digital value. Also, the values of acceleration signals in the X, Y, and Z axis directions are converted into digital values. Further, the sensor unit 100 generates digital information including the digital value of the integral value of the minute vibration component for a predetermined time and the digital value of the acceleration in the X, Y, and Z axis directions, and transmits the digital information every predetermined time. This digital information includes identification information unique to each sensor unit 100 in addition to the integral value and the digital value of acceleration.

  A specific example of the electric circuit of the sensor unit 100 is the circuit shown in FIG. That is, in one specific example shown in FIG. 6, the sensor unit 100 includes an antenna 110, an antenna switch 120, a rectifier circuit 130, a central processing unit 140, a transmission unit 150, and a sensor unit 160.

  The antenna 110 is for communicating with the monitor device 200 using electromagnetic waves, and is matched to a predetermined frequency (first frequency) in the 2.4 GHz band, for example.

  The antenna switch 120 is configured by an electronic switch, for example, and switches between the connection between the antenna 110 and the rectifier circuit 130 and the connection between the antenna 110 and the transmitter 150 under the control of the central processing unit 140.

  The rectifier circuit 130 includes diodes 131 and 132, a capacitor 133, and a resistor 134, and forms a known full-wave rectifier circuit. An antenna 110 is connected to the input side of the rectifier circuit 130 via an antenna switch 120. The rectifier circuit 130 rectifies the high-frequency current induced in the antenna 110 and converts it into a direct current, and outputs this as a drive power source for the central processing unit 140, the transmission unit 150, and the sensor unit 160. As the capacitor 133, a known super capacitor known as a large-capacitance capacitor is used.

  The central processing unit 140 includes a known CPU 141 and a storage unit 142.

  The CPU 141 operates based on a program stored in the semiconductor memory of the storage unit 142. When the CPU 141 is driven by being supplied with electric energy, the integrated value acquired from the sensor unit 160, the digital value of the acceleration detection result, and an identification described later A process of generating digital information including information and transmitting the digital information to the monitor device 200 is performed. Further, the identification information unique to the sensor unit 100 is stored in the storage unit 142 in advance. In the present embodiment, the central processing unit 140 transmits an integral value for 1 second included in the digital information at intervals of 10 seconds, and receives the transmission information from the monitor device 200 when the transmission information is received from the monitor device 200. However, it is preferable to set the integration time and transmission interval as appropriate according to the system configuration. However, the transmission interval is 1 second in consideration of the traveling speed and distance of the vehicle. Is preferably set within 5 minutes.

  The storage unit 142 includes a ROM in which a program for operating the CPU 141 is recorded and an electrically rewritable nonvolatile semiconductor memory such as an EEPROM (electrically erasable programmable read-only memory). The unique identification information is stored in advance in an area designated as non-rewritable in the storage unit 142 at the time of manufacture.

  The transmission unit 150 includes an oscillation circuit 151, a modulation circuit 152, and a high-frequency amplification circuit 153. The transmission unit 150 is configured using a known PLL circuit or the like, and performs central processing on a carrier wave having a frequency of 2.45 GHz oscillated by the oscillation circuit 151. Based on the information signal input from the unit 140, the signal is modulated by the modulation circuit 152, and the frequency of the 2.45 GHz band (second frequency) different from the first frequency is passed through the high frequency amplifier circuit 153 and the antenna switch 120. A high frequency current is supplied to the antenna 110. In the present embodiment, the first frequency and the second frequency are set to different frequencies. However, the first frequency and the second frequency are set to the same frequency, and the sensor unit 100 and the monitor device 200 are set to the same frequency. You may make it synchronize the timing of transmission / reception.

  The frequency of the carrier wave is not limited to the 2.45 GHz band, and any frequency band that is permitted to be used with low power can be used. For example, a frequency such as a 13 MHz band, a 315 MHz band, a 400 MHz band, a 900 MHz band, or a 1200 MHz band may be used.

  The sensor unit 160 includes the acceleration sensor 10, a high-pass filter (HPF) 161, an integration circuit 162, and an A / D conversion circuit 163.

  The acceleration sensor 10 is constituted by a semiconductor acceleration sensor as shown in FIGS.

  7 is an external perspective view showing the semiconductor acceleration sensor according to the first embodiment of the present invention, FIG. 8 is a cross-sectional view taken along line BB in FIG. 7, and FIG. 9 is a cross-sectional view taken along line CC in FIG. 10 and 10 are exploded perspective views.

  In the figure, reference numeral 10 denotes a semiconductor acceleration sensor, which comprises a pedestal 11, a silicon substrate 12, and supports 19A and 19B.

  The base 11 has a rectangular frame shape, and a silicon substrate (silicon wafer) 12 is attached to one opening surface of the base 11. Further, the outer frame portion 191 of the supports 19a and 19B is fixed to the outer peripheral portion of the base 11.

  A silicon substrate 12 is provided at the opening of the pedestal 11, a thin film diaphragm 13 having a cross shape is formed at the center of the wafer outer peripheral frame 12a, and piezoresistors are formed on the upper surfaces of the diaphragm pieces 13a to 13d. (Diffusion resistors) Rx1 to Rx4, Ry1 to Ry4, Rz1 to Rz4 are formed.

  Specifically, one of the diaphragm pieces 13a and 13b arranged on a straight line has a piezoresistor Rx1, Rx2, Rz1, and Rz2 formed on one diaphragm piece 13a, and a piezoresistor Rx3 on the other diaphragm piece 13b. , Rx4, Rz3, and Rz4 are formed. Piezoresistors Ry1 and Ry2 are formed on one diaphragm piece 13c of the diaphragm pieces 13c and 13d arranged on a straight line orthogonal to the diaphragm pieces 13a and 13b, and the piezoresistor is formed on the other diaphragm piece 13d. The bodies Ry3 and Ry4 are formed. Further, these piezoresistors Rx1 to Rx4, Ry1 to Ry4, and Rz1 to Rz4 can configure a resistance bridge circuit for detecting acceleration in the X axis, Y axis, and Z axis directions orthogonal to each other. And connected to a connection electrode 191 provided on the outer peripheral surface of the silicon substrate 12.

  Further, a thick film portion 14 is formed on one surface side of the central portion of the diaphragm 13 at the intersection of the diaphragm pieces 13a to 13d, and the surface of the thick film portion 14 has a rectangular parallelepiped shape made of, for example, glass. A weight 15 is attached.

  On the other hand, the support members 18A and 18B are provided so as to connect the outer frame portion 181 having a rectangular frame shape, the four support columns 182 standing at the four corners of the fixed portion, and the tip portions of the support columns. A cross-shaped beam portion 183, and a conical projection portion 184 provided at a central intersection of the beam portion 183.

  The outer frame portion 181 is fitted and fixed to the outer peripheral portion of the pedestal 11 so that the protruding portion 184 is located on the other surface side of the diaphragm 13, that is, on the side where the weight 15 does not exist. Here, the tip 184a of the protrusion 184 is set to be located at a distance D1 from the surface of the diaphragm 13 or the weight 15. This distance D1 causes the diaphragm pieces 13a to 13d to extend even when acceleration occurs in a direction perpendicular to the surface of the diaphragm 13 and a force of a predetermined value or more is applied to both surfaces of the diaphragm 13 due to this acceleration. The displacement is set to a value that can be limited by the protrusion 184 so as not to occur.

  When the semiconductor acceleration sensor 10 having the above configuration is used, three resistance bridge circuits are configured as shown in FIGS. That is, as a bridge circuit for detecting the acceleration in the X-axis direction, as shown in FIG. 12, the positive electrode of the DC power supply 32A is connected to the connection point between one end of the piezoresistor Rx1 and one end of the piezoresistor Rx2. The negative electrode of the DC power supply 32A is connected to the connection point between one end of the piezoresistor Rx3 and one end of the piezoresistor Rx4. Further, one end of the voltage detector 31A is connected to the connection point between the other end of the piezoresistor Rx1 and the other end of the piezoresistor Rx4, and the other end of the piezoresistor Rx2 and the other end of the piezoresistor Rx3 are connected. The other end of the voltage detector 31A is connected to the point.

  As a bridge circuit for detecting the acceleration in the Y-axis direction, as shown in FIG. 13, the positive electrode of the DC power supply 32B is connected to the connection point between one end of the piezoresistor Ry1 and one end of the piezoresistor Ry2. The negative electrode of the DC power supply 32B is connected to the connection point between one end of the piezoresistor Ry3 and one end of the piezoresistor Ry4. Further, one end of the voltage detector 31B is connected to the connection point between the other end of the piezoresistor Ry1 and the other end of the piezoresistor Ry4, and the connection between the other end of the piezoresistor Ry2 and the other end of the piezoresistor Ry3. The other end of the voltage detector 31B is connected to the point.

  As a bridge circuit for detecting the acceleration in the Z-axis direction, as shown in FIG. 14, the positive electrode of the DC power supply 32C is connected to the connection point between one end of the piezoresistor Rz1 and one end of the piezoresistor Rz2. The negative electrode of the DC power source 32C is connected to the connection point between one end of the piezoresistor Rz3 and one end of the piezoresistor Rz4. Further, one end of the voltage detector 31C is connected to a connection point between the other end of the piezoresistor Rz1 and the other end of the piezoresistor Rz3, and a connection between the other end of the piezoresistor Rz2 and the other end of the piezoresistor Rz4. The other end of the voltage detector 31C is connected to the point.

  According to the semiconductor acceleration sensor 10 having the above-described configuration, when the force generated along with the acceleration applied to the sensor 10 is applied to the weight 15, the diaphragm pieces 13a to 13d are distorted, thereby causing the piezoresistors Rx1 to Rx4, The resistance values of Ry1 to Ry4 and Rz1 to Rz4 change. Accordingly, by forming a resistance bridge circuit by the piezoresistors Rx1 to Rx4, Ry1 to Ry4, Rz1 to Rz4 provided on the diaphragm pieces 13a to 13d, accelerations in the X axis, Y axis, and Z axis directions orthogonal to each other are formed. Can be detected.

  Further, as shown in FIGS. 15 and 16, when acceleration is applied such that forces 41 and 42 including force components in a direction perpendicular to the surface of the diaphragm 13 are applied, a predetermined value is applied to the other surface side of the diaphragm 13. When the above force is applied, the diaphragm 13 is distorted and extended in the direction in which the forces 41 and 42 are applied, but the displacement is supported and limited by the apex 184a of the protrusion 184, so that each diaphragm piece 13a to 13d is maximum. There is no limit. Thereby, even when a force of a predetermined value or more is applied to the other surface side of the diaphragm 13, the position of the weight 15 is displaced with the vertex 184 a of the projection 184 serving as a fulcrum, so that it is parallel to the surface of the diaphragm 13. Acceleration in any direction can be detected.

  As shown in FIG. 2, the semiconductor acceleration sensor 10 detects accelerations in the X, Y, and Z axis directions orthogonal to each other generated in each of the four tires 2 of the vehicle when the vehicle is running. be able to. Further, the grip of the tire 2 can be estimated from the acceleration in the X-axis direction.

  A high-pass filter (HPF) 161 removes the gravitational acceleration component from the analog signal of acceleration in the X-axis direction and extracts and outputs only the minute vibration component.

  The integrating circuit 162 integrates the analog signal of the minute vibration component output from the high-pass filter 161, and outputs an analog signal of this integrated value. In this embodiment, the voltage of the analog signal of the minute vibration component is integrated using a well-known RC integration circuit including a resistor and a capacitor as the integration circuit. In addition, a switching element is connected in parallel with the capacitor of the integrating circuit, and after the central processing unit 140 acquires the integration result, the switching element is turned on by the central processing unit 140 at the start of the next integration, and both ends of the capacitor are short-circuited. As a result, the integral value is reset.

  In this embodiment, a single-stage RC integration circuit is used as the integration circuit 162. However, a ladder-type RC integration circuit having two or more stages is used to increase the impedance on the input side, or the RC integration circuit. Alternatively, a high impedance input amplifier may be provided on the input side to reduce the load on the output side of the acceleration sensor 10. In the present embodiment, the RC integration circuit having the simplest configuration is used. However, the present invention is not limited to this, and an integration circuit using an operational amplifier or the like may be used.

  On the other hand, the A / D conversion circuit 163 converts the analog electrical signal output from the integration circuit 162 and the analog electrical signal output from the acceleration sensor 10 into a digital signal and outputs the digital signal to the CPU 141. This digital signal corresponds to the integral value and the acceleration values in the X, Y, and Z axis directions.

  In addition, as the acceleration generated in the X, Y, and Z axis directions, there are a positive acceleration and a negative acceleration. In the present embodiment, both accelerations can be detected.

  In this embodiment, as described above, the frequency of the 2.45 GHz band is used as the first and second frequencies so that the metal is hardly affected. Thus, in order to make it less susceptible to the influence of metal, it is preferable to use a frequency of 1 GHz or more as the first and second frequencies.

  The monitor device 200 is connected to the stability control unit 700 by a cable and operates by electric energy sent from the stability control unit 700.

  As shown in FIG. 17, the electrical circuit of the monitor device 200 includes a radiation unit 210, a wave receiving unit 220, a control unit 230, and a calculation unit 240. Here, the control unit 230 and the calculation unit 240 are configured by a memory circuit including a known CPU, a ROM storing a program for operating the CPU, a RAM necessary for performing calculation processing, and the like.

  The radiation unit 210 includes an antenna 211 for radiating an electromagnetic wave signal having a predetermined frequency in the 2.45 GHz band (the above first frequency) and a transmission unit 212. Based on an instruction from the control unit 230, the antenna unit 211 The electromagnetic wave having the first frequency is radiated.

  As an example of the transmission unit 212, similarly to the transmission unit 150 of the sensor unit 100, a configuration including an oscillation circuit 151, a modulation circuit 152, and a high frequency amplification circuit 153 can be given. As a result, an electromagnetic wave of 2.45 GHz is radiated from the antenna 211. The high frequency power output from the transmitter 212 is set to a value that can supply electric energy to the sensor unit 100 from the electromagnetic wave radiation antenna 211 of the monitor device 200.

  The wave receiving unit 220 includes an antenna 221 for receiving an electromagnetic wave having a predetermined frequency (the second frequency) in the 2.45 GHz band, and a detection unit 222. Based on an instruction from the control unit 230, the antenna 221 The electromagnetic wave having the second frequency received by is detected, and a digital signal obtained by the detection is output to the arithmetic unit 250. An example of the detection unit 222 includes a circuit including a diode and an analog / digital converter that converts a signal detected by the diode into digital data.

  When electric energy is supplied from the stability control unit 700 and the operation is started, the control unit 230 always drives the detection unit 222 and causes the detection unit 222 to output a digital signal to the calculation unit 240. The control unit 230 transmits an information transmission command to the sensor unit 100 via the transmission unit 212 when receiving an instruction from the calculation unit 240.

  The calculation unit 240 calculates the acceleration in the X, Y, and Z axis directions based on the digital signal output from the detection unit 222 and outputs the acceleration to the stability control unit 700, and based on the integrated value, A friction evaluation value corresponding to the value of friction with the tire is obtained and output to the stability control unit 700. As will be described later, the friction evaluation value becomes a small value when the integral value is large and becomes a large value when the integral value is small. The friction evaluation value is obtained by an experiment in advance and is associated with the integral value in the calculation unit 240. It is remembered. Further, when the arithmetic unit 240 detects a change in driving operation based on information received from the stability control unit 700, for example, the driver has stepped on the accelerator pedal, has stepped on the brake pedal, or has steered beyond a certain angle. When a change in driving operation such as turning off is detected, the controller 230 is instructed to transmit an information transmission command to the sensor unit 100 via the oscillator 212. Thereby, when the friction between the traveling road surface and the tire changes due to the change of the driving operation, this can be detected quickly.

  Next, the operation of the system configured as described above will be described with reference to the drawings. 18 to 20 are actual measurement results of acceleration in the Z-axis direction, FIGS. 21 to 23 are actual measurement results of acceleration in the X-axis direction, FIGS. 24 and 25 are actual measurement results of acceleration in the Y-axis direction, and FIG. 27 shows the actual measurement result of the acceleration in the X-axis direction when applied, and FIG. 27 shows the actual measurement result of the acceleration in the Z-axis direction when the brake is applied. In addition, the minute vibration component which generate | occur | produces by the friction between a driving | running | working road surface and the tire 2 is superimposed on the signal waveform of each figure.

  18 to 20, FIG. 18 is an actual measurement value of acceleration in the Z-axis direction when traveling at a speed of 2.5 km, FIG. 19 is an actual measurement value of acceleration in the Z-axis direction when traveling at a speed of 20 km, and FIG. This is an actual measurement value of acceleration in the Z-axis direction when traveling at a speed of 40 km / h. Thus, since the centrifugal force of the wheel increases as the traveling speed increases, the acceleration in the Z-axis direction also increases. Therefore, the traveling speed can be obtained from the acceleration in the Z-axis direction.

  In the figure, the measured value has a sine wave shape because it is influenced by gravitational acceleration. That is, when the sensor unit 100 is located at the front part of the tire 2 (position at 90 degrees on the vehicle traveling direction side), the acceleration in the X-axis direction is obtained by subtracting the gravitational acceleration from the acceleration due to the rotation, and the rear part of the tire 2 ( When the vehicle is located at a position 90 degrees opposite to the vehicle traveling direction), the acceleration in the X-axis direction is obtained by adding gravitational acceleration to acceleration due to rotation.

  In the present embodiment, by radiating electromagnetic waves from the radiation unit 210, a voltage of 3 V or more can be stored in the capacitor 133 as electrical energy sufficient to drive the sensor unit 100 at all times.

  21 to FIG. 23, FIG. 21 is an actual measurement value of acceleration in the X-axis direction when traveling at a speed of 2.5 km, FIG. 22 is an actual measurement value of acceleration in the X-axis direction when traveling at a speed of 20 km, and FIG. This is an actual measurement value of acceleration in the X-axis direction when traveling at a speed of 40 km / h. Thus, since the rotation speed of the wheel increases as the traveling speed increases, the cycle in which the acceleration in the X-axis direction changes becomes shorter. Therefore, it is possible to obtain the rotational speed of the wheel from the acceleration in the X-axis direction. In the figure, the reason why the actually measured value has a sine wave shape is that it is affected by the gravitational acceleration as described above.

  FIG. 24 shows measured values of acceleration in the Y-axis direction when the steering wheel is turned to the right during traveling, and FIG. 25 shows measured values of acceleration in the Y-axis direction when the steering wheel is turned to the left during traveling. Thus, when the steering wheel is turned and the tire 2 (wheel) is swung left and right, the acceleration in the Y-axis direction appears remarkably. Needless to say, the acceleration in the Y-axis direction is similarly generated when the vehicle body slides. The reason why the reverse acceleration occurs in the actual measured values of the acceleration in the Y-axis direction is that the driver unconsciously turns the steering wheel slightly in the reverse direction.

  Further, as shown in FIGS. 26 and 27, the time from when the brake is applied (when the brake is turned on: when the brake pedal is depressed) to when the rotation of the tire 2 (wheel) stops is about 0.2 seconds. It was also possible to detect accurately.

  By detecting the acceleration generated when the brake pedal 610 is depressed in this way, it is possible to estimate the amount of distortion of the tire 300 caused by this acceleration, the side slip state of the vehicle body, the idling state of the tire, and the like. Thus, the pressure control valve during vehicle braking can be controlled.

  Further, the state of the acceleration signal in the X-axis direction (acceleration in the wheel rotation direction) changes depending on the road surface state during vehicle travel. That is, the minute vibration component superimposed on each acceleration detection signal described above changes depending on the state of the traveling road surface. For example, FIGS. 28 to 30 all extract only the change of the minute vibration component superimposed on the acceleration detection signal in the X-axis direction (wheel rotation direction) when traveling at a vehicle traveling speed of 60 km / h. Recorded. However, FIG. 28 shows a change in acceleration signal on a dry paved road during clear weather, and FIG. 29 shows a change in acceleration signal on a paved road with a water film having a depth of 2 to 3 mm in rainy weather. FIG. 30 shows the recorded change in acceleration signal on a paved road (including a snow-capped road) where the entire surface of the road surface is frozen.

  As shown in FIG. 28, on a dry paved road in fine weather, the amplitude and period of the minute vibration component superimposed on the acceleration signal in the X-axis direction are substantially constant. In addition, as shown in FIG. 29, on a paved road where the road surface is covered with a water film having a depth of 2 to 3 mm during rainy weather, the tire may slip due to the water film, so it is superimposed on the acceleration signal in the X-axis direction. Disturbance occurs in the amplitude and period of the minute vibration component. Further, as shown in FIG. 30, on a paved road (including a snowy road) whose surface is frozen, the tire is always slipping, so the amplitude of the minute vibration component superimposed on the acceleration signal in the X-axis direction. Is smaller than the dry paved road in fine weather and has a longer period.

  Thus, the state of the minute vibration component superimposed on the acceleration signal in the X-axis direction clearly changes depending on the road surface state. When the PP (peak to peak) value of the minute vibration component is integrated for a predetermined time, the integrated value changes corresponding to the friction between the running road surface and the tire. That is, the integral value decreases as the friction between the traveling road surface and the tire increases, and the integral value increases as the friction between the traveling road surface and the tire decreases. This is because when the friction between the road surface and the tire is large, the tire tread rubber and the road surface slip little, so the regular vibration at the moment of tire contact and kicking is dominant and the vibration level is also small. This is because when the friction between the running road surface and the tire becomes small, slippage occurs between the tread rubber and the road surface, and irregular fine vibrations are added to the tire.

  Therefore, the calculation unit 240 of the monitor device 200 specifies the friction evaluation value based on the information received from the sensor unit 100 and the information stored in the calculation unit 240, and the specified friction evaluation value (road surface state information). Can be output. As a result, the stability control unit 700 can grasp the appropriate braking start timing, the travel distance from the start of braking to the vehicle stop, the occurrence of slip during braking, and the like by using the friction evaluation value. Therefore, appropriate braking control can be performed even if the road surface condition changes such as tire wear, change of clothes, number of passengers, weather, road surface is dry, wet, or frozen.

  Further, by using the sensor unit 100 of the present embodiment, the minute vibrations generated by the rotation of the wheel or the rim and the wheel and the wheel body such as the tire main body and the like only by attaching the sensor unit 100 to a predetermined position of the rotating body such as the axle, Since the integral value or the friction evaluation value (road surface state information) can be easily detected, the traveling road surface state detection system of the present embodiment can be easily configured.

  In the present embodiment, the sensor unit 100 is configured to obtain the integral value of the minute vibration component, transmit the integral value to the monitor device 200, and the monitor device 200 is configured to obtain the friction evaluation value from the integral value. There is no limit. For example, the friction evaluation value may be obtained in the sensor unit 100, or the data of the minute vibration component is transmitted from the sensor unit 100 to the monitor device 200, and the integral value and the friction evaluation value are obtained in the monitor device 200. May be.

  In the present embodiment, the driving power of the sensor unit 100 is covered by the electric energy of the radio wave received from the monitor device 200. However, a battery is provided in the sensor unit 100, and the sensor unit 100 is powered by the power supplied from the battery. May be driven.

  Next, a second embodiment of the present invention will be described.

  The configurations of the sensor unit 100 and the monitor device 200 in the second embodiment are substantially the same as those in the first embodiment described above. In the second embodiment, the central processing unit 140 of the sensor unit 100 detects the vehicle travel speed from the change in the acceleration in the X-axis direction or the change in the acceleration in the Z-axis direction, and when the travel speed is 20 km / h or less. The transmission process was not performed. By doing so, the power consumption of the sensor unit 100 can be suppressed while the necessity of braking control using the friction evaluation value in the stability control unit 700 is low. Also in the configuration of the present embodiment, the same effects as those of the first embodiment described above can be obtained.

  Next, a third embodiment of the present invention will be described.

  The configurations of the sensor unit 100 and the monitor device 200 in the third embodiment are substantially the same as those in the first embodiment described above, but in the third embodiment, the information transmission interval in the sensor unit 100 is not the time but the rotation of the wheel. Set by number. In other words, in the present embodiment, the CPU 141 of the central control unit 140 counts the number of rotations of the tire by an acceleration signal in the X-axis direction or the Z-axis direction, and resets the count value to 0 when this count value reaches 100. At the same time, the digital value including the digital value of the integral value of the minute vibration component for a predetermined time, the digital value of the acceleration in the X, Y, and Z axis directions and the identification information is generated and transmitted. As described above, when information is transmitted every 100 rotations of the tire, information is transmitted at equal distance intervals for every predetermined travel distance. The information transmission interval is preferably set to a rotational speed between 10 and 1000 rotations of the tire in consideration of the traveling speed of the vehicle. Also in the configuration of the present embodiment, the same effects as those of the first embodiment described above can be obtained.

  Next, a fourth embodiment of the present invention will be described.

  FIG. 31 is a block diagram showing a configuration of an electric circuit of the sensor unit 100A in the fourth embodiment. In the figure, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. Further, the difference between the fourth embodiment and the first embodiment is that in the fourth embodiment, the integration of the minute vibration component superimposed on the acceleration signal in the X-axis direction is performed by the arithmetic processing of the central processing unit 140. It is that.

  That is, the sensor unit 160 in the fourth embodiment includes the acceleration sensor 10 and the A / D conversion circuit 163, and only the digital values of acceleration signals in the X, Y, and Z axis directions from the sensor unit 160 to the central processing unit 140. Is entered.

  The CPU 141 of the central processing unit 140 operates based on a program stored in the semiconductor memory of the storage unit 142. When the CPU 141 is driven by being supplied with electric energy, the acceleration of gravity is obtained from the acceleration signal in the X-axis direction acquired from the sensor unit 160. The component is removed and only the minute vibration component is extracted, and the minute vibration component is integrated for one second at intervals of 10 seconds to obtain an integrated value. Further, the CPU 141 generates digital information including the calculated integral value, the digital value of the acceleration detection result, and the identification information, and performs processing for transmitting the digital information to the monitor device 200. In addition, the CPU 141 is programmed to transmit an integral value for 1 second included in the digital information at intervals of 10 seconds and to transmit the digital information to the monitor device 200 when a transmission command is received from the monitor device 200. Yes. These integration time and transmission interval are preferably set as appropriate according to the system configuration, but the transmission interval is preferably set between 1 second and 5 minutes.

  Also in the present embodiment, the calculation unit 240 of the monitor device 200 specifies the friction evaluation value based on the information received from the sensor unit 100 and the information stored in the calculation unit 240, and the specified friction evaluation value ( Road surface condition information) can be output. As a result, the stability control unit 700 can grasp the appropriate braking start timing, the travel distance from the start of braking to the vehicle stop, the occurrence of slip during braking, and the like by using the friction evaluation value. Therefore, appropriate braking control can be performed even if the condition of the road surface changes, such as tire wear, change of clothes, number of passengers, weather, road surface is dry, wet, or frozen.

  In the present embodiment, the sensor unit 100 is configured to obtain the integral value of the minute vibration component, transmit the integral value to the monitor device 200, and the monitor device 200 is configured to obtain the friction evaluation value from the integral value. There is no limit. For example, the friction evaluation value may be obtained in the sensor unit 100, or the data of the minute vibration component is transmitted from the sensor unit 100 to the monitor device 200, and the integral value and the friction evaluation value are obtained in the monitor device 200. May be.

  In the present embodiment, the driving power of the sensor unit 100 is covered by the electric energy of the radio wave received from the monitor device 200. However, a battery is provided in the sensor unit 100, and the sensor unit 100 is powered by the power supplied from the battery. May be driven.

  Each of the above embodiments is a specific example of the present invention, and the present invention is not limited only to the configuration of the above embodiment. For example, the configurations of these embodiments may be combined.

1 is an external view showing the arrangement of a monitor device and a sensor unit in the first embodiment of the present invention. The top view which shows arrangement | positioning of the monitor apparatus and sensor unit in 1st Embodiment of this invention The figure explaining the installation place of the sensor unit to the tire in 1st Embodiment of this invention The figure which shows the tire in the tire house of 1st Embodiment of this invention. The block diagram which shows the vehicle drive control system in 1st Embodiment of this invention. The block diagram which shows the electric system circuit of the sensor unit in 1st Embodiment of this invention. 1 is an external perspective view showing a semiconductor acceleration sensor according to a first embodiment of the present invention. BB direction arrow sectional view in FIG. CC sectional view taken along line CC in FIG. The disassembled perspective view which shows the semiconductor acceleration sensor in 1st Embodiment of this invention. The block diagram which shows the electric system circuit of the semiconductor acceleration sensor in 1st Embodiment of this invention. The figure which shows the bridge circuit which detects the acceleration of a X-axis direction using the semiconductor acceleration sensor in 1st Embodiment of this invention. The figure which shows the bridge circuit which detects the acceleration of the Y-axis direction using the semiconductor acceleration sensor in 1st Embodiment of this invention. The figure which shows the bridge circuit which detects the acceleration of a Z-axis direction using the semiconductor acceleration sensor in 1st Embodiment of this invention. The figure explaining operation | movement of the semiconductor acceleration sensor in 1st Embodiment of this invention. The figure explaining operation | movement of the semiconductor acceleration sensor in 1st Embodiment of this invention. The block diagram which shows the electric system circuit of the monitor apparatus in 1st Embodiment of this invention The figure which shows the actual measurement result of the acceleration of a Z-axis direction in 1st Embodiment of this invention. The figure which shows the actual measurement result of the acceleration of a Z-axis direction in 1st Embodiment of this invention. The figure which shows the actual measurement result of the acceleration of a Z-axis direction in 1st Embodiment of this invention. The figure which shows the actual measurement result of the acceleration of a X-axis direction in 1st Embodiment of this invention. The figure which shows the actual measurement result of the acceleration of a X-axis direction in 1st Embodiment of this invention. The figure which shows the actual measurement result of the acceleration of a X-axis direction in 1st Embodiment of this invention. The figure which shows the actual measurement result of the acceleration of the Y-axis direction in 1st Embodiment of this invention. The figure which shows the actual measurement result of the acceleration of the Y-axis direction in 1st Embodiment of this invention. The figure which shows the actual measurement result of the acceleration of a X-axis direction when a brake is applied in 1st Embodiment of this invention. The figure which shows the actual measurement result of the acceleration of a Z-axis direction when a brake is applied in 1st Embodiment of this invention. The figure which shows the actual measurement result of the acceleration of a wheel rotation direction in the dry paved road at the time of fine weather in 1st Embodiment of this invention. The figure which shows the actual measurement result of the acceleration of a wheel rotation direction in the paved road where the road surface was covered with the water film of the depth of 2-3 mm at the time of rain in 1st Embodiment of this invention. The figure which shows the actual measurement result of the acceleration of a wheel rotation direction in the paved road where the whole surface is frozen in 1st Embodiment of this invention. The block diagram which shows the electric system circuit of the sensor unit in 4th Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Vehicle, 2 ... Tire, 3 ... Axle, 4 ... Tire house, 100,100A ... Sensor unit, 110 ... Antenna, 120 ... Antenna switch, 130 ... Rectifier circuit, 131, 132 ... Diode, 133 ... Capacitor, 134 ... Resistor 140 ... Central processing unit 141 ... CPU 142 ... Storage unit 150 ... Transmission unit 151 ... Oscillation circuit 152 ... Modulation circuit 153 ... High frequency amplification circuit 160 ... Sensor unit 161 ... High pass filter (HPF) , 162 ... integration circuit, 163 ... A / D conversion circuit, 200 ... monitoring device, 210 ... radiation unit, 211 ... antenna, 212 ... transmission part, 220 ... reception unit, 221 ... antenna, 222 ... detection part, 223 ... Strength detector 230 ... Control unit 240 ... Calculation unit 410 ... Engine, 411 ... Accelerator pedal, 412 ... Sub throttle actuator, 413 ... Main throttle position sensor, 414 ... Sub throttle position sensor, 421 ... Handle, 422 ... Rudder Angle sensor, 5 10,520 ... rotational speed sensor, 610 ... brake pedal, 620 ... master cylinder, 630 ... pressure control valve, 640 ... actuator for brake drive, 700 ... stability control unit, 10 ... semiconductor acceleration sensor, 11 ... pedestal, 12 ... silicon substrate , 13 ... Diaphragm, 13a-13d ... Diaphragm piece, 14 ... Thick film part, 15 ... Weight, 18A, 18B ... Support, 181 ... Outer frame part, 182 ... Post, 183 ... Beam part, 184 ... Projection part, 184a: Projection tip, 31A to 31C: Voltage detector, 32A to 32C: DC power supply, Rx1 to Rx4, Ry1 to Ry4, Rz1 to Rz4: Piezoresistor (diffusion resistor).

Claims (22)

A system for detecting the state of a road surface on which a vehicle travels,
A minute vibration generated in the rotation mechanism unit that is provided in a rotation mechanism unit that is provided on a vehicle body and includes a rotating body that fixes the wheel and rotates the wheel, and the wheel, and that rotates with the rotation of the wheel during vehicle travel. Is detected and converted into an electric signal, and a vibration detection unit that outputs the electric signal as a minute vibration signal;
Integrating means for integrating a minute vibration signal output from the vibration detection unit for a predetermined time and outputting an integrated value;
When the integral value is input, the friction between the traveling road surface and the wheel is large when the integral value is small, and the friction between the traveling road surface and the wheel is small when the integral value is large, Road surface state information output means for outputting road surface state information in which an integrated value and the magnitude of the friction are associated with each other. A sensor unit provided in the rotation mechanism, and a monitor device provided on the vehicle body side excluding the rotation mechanism,
The sensor unit includes the vibration detection unit, and a transmission unit that transmits information on the intensity value of the minute vibration signal output from the vibration detection unit as a transmission information by radio waves of a predetermined frequency every predetermined time,
The monitor device receives the information transmitted from the transmitting means of the sensor unit, acquires the intensity value of the minute vibration signal from the information received by the receiving means, and integrates the intensity value for a predetermined time. The said integration means which outputs an integrated value in this way, and the said road surface state information output means which inputs the integral value acquired by this integration means, and outputs the said road surface state information. Road surface condition detection system. A sensor unit provided in the rotation mechanism, and a monitor device provided on the vehicle body side excluding the rotation mechanism,
The sensor unit includes the vibration detection unit, the integration unit, and a transmission unit that transmits information of an integral value output from the integration unit as transmission information by radio waves of a predetermined frequency every predetermined time,
The monitoring device includes: a receiving unit that receives information transmitted from the transmitting unit of the sensor unit; an integration value acquiring unit that acquires the integral value from the information received by the receiving unit; and an acquisition unit that acquires the integrated value. The road surface state detection system according to claim 1, further comprising: a road surface state information output unit that inputs the integrated value and outputs the road surface state information. A sensor unit provided in the rotation mechanism, and a monitor device provided on the vehicle body side excluding the rotation mechanism,
The sensor unit uses the road surface state information output from the vibration detection unit, the integration unit, the road surface state information output unit, and the road surface state information output unit as transmission information by radio waves of a predetermined frequency every predetermined time. Transmission means for transmitting,
The traveling road surface state detection system according to claim 1, wherein the monitor device includes a reception unit that receives and outputs road surface state information transmitted from the transmission unit of the sensor unit. The travel road surface condition detection system according to claim 3 or 4, wherein the information transmission interval in the transmission means is set to a predetermined time between 1 second and 5 minutes. A sensor unit provided in the rotation mechanism, and a monitor device provided on the vehicle body side excluding the rotation mechanism,
The sensor unit includes the vibration detection unit, the integration unit,
Means for detecting the rotational speed of the wheel;
Transmitting means for transmitting the information of the integral value output from the integrating means as transmission information by radio waves of a predetermined frequency for each predetermined number of rotations of the wheel;
The monitoring device includes: a receiving unit that receives information transmitted from the transmitting unit of the sensor unit; an integration value acquiring unit that acquires the integral value from the information received by the receiving unit; and an acquisition unit that acquires the integrated value. The road surface state detection system according to claim 1, further comprising: a road surface state information output unit that inputs the integrated value and outputs the road surface state information. A sensor unit provided in the rotation mechanism, and a monitor device provided on the vehicle body side excluding the rotation mechanism,
The sensor unit includes the vibration detection unit, the integration unit,
Means for detecting the rotational speed of the wheel;
The road surface state information output means, and a transmission means for transmitting the road surface state information output from the road surface state information output means as a transmission information by radio waves of a predetermined frequency for each predetermined number of rotations of the wheel,
The traveling road surface state detection system according to claim 1, wherein the monitor device includes a reception unit that receives and outputs road surface state information transmitted from the transmission unit of the sensor unit. The travel road surface state detection system according to claim 6 or 7, wherein an information transmission interval in the transmission means is set to a predetermined number of rotations between 10 rotations and 1000 rotations of the wheels. The sensor unit includes an acceleration detection means for detecting an acceleration generated in the rotation direction of the wheel, and the transmission means when an acceleration value detected by the acceleration detection means is an acceleration value of a vehicle traveling speed of 20 km / h or less. The travel road surface state detection system according to any one of claims 2 to 8, further comprising: a unit that stops transmission of the transmission information by the control unit. The monitor device is
Means for obtaining driving operation change information indicating that the driver has changed the driving operation;
Transmission means for transmitting an information transmission command by radio waves of a predetermined frequency to the sensor unit when the driving operation change information is acquired;
The sensor unit is
Receiving means for receiving an information transmission command transmitted from the monitor device;
The travel road surface condition detection system according to any one of claims 2 to 8, further comprising: a unit that transmits the transmission information when the information transmission command is received by the reception unit. A sensor unit provided in a rotating mechanism unit including a rotating body that is provided on a vehicle body and rotates the wheel by fixing the wheel,
A vibration detection unit that detects minute vibrations generated in the rotation mechanism unit as the vehicle rotates and converts the vibrations into electric signals, and outputs the electric signals as minute vibration signals;
Transmitting means for transmitting information on the intensity value of the minute vibration signal output from the vibration detection unit as transmission information by radio waves of a predetermined frequency every predetermined time;
A sensor unit characterized by that. A sensor unit provided in a rotating mechanism unit including a rotating body that is provided on a vehicle body and rotates the wheel by fixing the wheel,
A vibration detection unit that detects minute vibrations generated in the rotation mechanism unit as the vehicle rotates and converts the vibrations into electric signals, and outputs the electric signals as minute vibration signals;
Integrating means for integrating a minute vibration signal output from the vibration detection unit for a predetermined time and outputting an integrated value;
A sensor unit, comprising: transmission means for transmitting the integration value output from the integration means as transmission information by radio waves of a predetermined frequency every predetermined time. A sensor unit provided in a rotating mechanism unit including a rotating body that is provided on a vehicle body and rotates the wheel by fixing the wheel,
A vibration detection unit that detects minute vibrations generated in the rotation mechanism unit as the vehicle rotates and converts the vibrations into electric signals, and outputs the electric signals as minute vibration signals;
Integrating means for integrating a minute vibration signal output from the vibration detection unit for a predetermined time and outputting an integrated value;
When the integral value is input, the friction between the traveling road surface and the wheel is large when the integral value is small, and the friction between the traveling road surface and the wheel is small when the integral value is large, Road surface state information output means for outputting road surface state information that associates the integrated value with the magnitude of the friction, and road surface state information output from the road surface state information output means as transmission information by radio waves of a predetermined frequency every predetermined time A sensor unit comprising a transmitting means for transmitting. The sensor unit according to claim 12 or 13, wherein an information transmission interval in the transmission unit is set to a predetermined time between 1 second and 5 minutes. A sensor unit provided in a rotating mechanism unit including a rotating body that is provided on a vehicle body and rotates the wheel by fixing the wheel,
A vibration detection unit that detects minute vibrations generated in the rotation mechanism unit as the vehicle rotates and converts the vibrations into electric signals, and outputs the electric signals as minute vibration signals;
Integrating means for integrating a minute vibration signal output from the vibration detection unit for a predetermined time and outputting an integrated value;
A sensor unit, comprising: transmission means for transmitting, as transmission information, information on the integration value output from the integration means by radio waves having a predetermined frequency for each predetermined rotation speed of the wheel. A sensor unit provided in a rotating mechanism unit including a rotating body that is provided on a vehicle body and rotates the wheel by fixing the wheel,
A vibration detection unit that detects minute vibrations generated in the rotation mechanism unit as the vehicle rotates and converts the vibrations into electric signals, and outputs the electric signals as minute vibration signals;
Integrating means for integrating a minute vibration signal output from the vibration detection unit for a predetermined time and outputting an integrated value;
When the integral value is input, the friction between the traveling road surface and the wheel is large when the integral value is small, and the friction between the traveling road surface and the wheel is small when the integral value is large, Road surface state information output means for outputting road surface state information associating the integrated value with the magnitude of the friction, and road surface state information output from the road surface state information output means as transmission information predetermined for each predetermined number of rotations of the wheel A sensor unit comprising: a transmission means for transmitting by radio waves of a frequency. The sensor unit according to claim 15 or 16, wherein an information transmission interval in the transmission unit is set to a predetermined number of rotations between 10 and 1000 rotations of the wheel. Acceleration detecting means for detecting acceleration generated in the rotation direction of the wheel;
And a means for stopping transmission of the transmission information by the transmission means when the acceleration value detected by the acceleration detection means is an acceleration value of a vehicle traveling speed of 20 km / h or less. Item 18. The sensor unit according to any one of Items 11 to 17. Receiving means for receiving an information transmission command;
The sensor unit according to any one of claims 11 to 17, further comprising: a unit that transmits the transmission information when the information transmission command is received by the reception unit. A storage means storing identification information unique to itself;
18. The sensor unit according to claim 11, further comprising: a unit that transmits the identification information stored in the storage unit in the transmission information. The sensor unit according to any one of claims 11 to 17, further comprising a semiconductor acceleration sensor having a silicon piezo diaphragm to detect the minute vibrations. The sensor unit according to claim 18, further comprising a semiconductor acceleration sensor having a silicon piezo-type diaphragm for detecting the acceleration in the rotation direction.

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