JP2006081304A - Electric power supplying method and its system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric power supplying method and its system that supply electric power efficiently, and that reduce power consumption at electromagnetic wave transmission side. <P>SOLUTION: A monitoring device 200 transmits electromagnetic waves from a transmission antenna to a receiving antenna of a sensor unit 100, when the receiving antenna of the sensor unit 100 is within a prescribed range AR between a rotating shaft 3 and the transmission antenna of the monitoring device 200. Consequently, the electromotive waves can be transmitted from the monitoring device 200 to the receiving antenna of the sensor unit 100 without being attenuated by the rotating shaft 3. Compared with a conventional embodiment, the efficiency of the power supply from the monitoring device 200 to the sensor unit 100 can be improved and wasteful power consumption can be reduced in the monitoring device 200. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a power supply method and system for supplying drive power of a first device that is mounted on a rotating body and rotates from a second device by electromagnetic waves.

  Conventionally, as this type of system, a wide variety of systems are known, and as a very recent system, for example, a system as disclosed in JP-A-2004-133911 is known.

This system is a system for supplying power wirelessly using electromagnetic waves from a power transmission unit provided in a tire house to a sensor unit provided in a tire of a vehicle, as in a system that has been publicly known before. .
JP 2004-133911 A

  However, in the conventional system described above, when the rotation axis of the tire is located between the sensor unit and the power transmission unit, the electromagnetic wave transmitted from the power transmission unit does not reach the sensor unit sufficiently, and the power supply There has been a problem that efficiency is lowered or power cannot be supplied.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a power supply method and system capable of efficiently supplying power and reducing power consumption on the electromagnetic wave transmission side. There is.

  In order to achieve the above object, the present invention comprises means for receiving an electromagnetic wave of a predetermined frequency with a receiving antenna and converting the energy of the electromagnetic wave into electric energy, and means for storing the electric energy. A predetermined direction that is different from the gravitational direction, comprising: a first device that operates using the electric energy as driving power; and a second device that includes means for transmitting electromagnetic waves of the predetermined frequency from the transmitting antenna to the first device. The rotating device rotating about a rotating shaft extending in the direction is fixed to a position at a predetermined distance away from the rotating body with respect to the first device rotating at a predetermined distance from the rotating shaft. A power supply method for supplying the driving power by irradiating the electromagnetic wave from a transmitting antenna, wherein the second device is configured such that the receiving antenna of the first device is in front of the rotating shaft. When within a predetermined range between the transmitting antenna, we propose a method for supplying power for transmitting said electromagnetic wave from said transmitting antenna to the receiving antenna of the first device.

  According to the power supply method of the present invention, when the receiving antenna of the first device is within a predetermined range between the rotating shaft and the transmitting antenna, the second device is connected to the transmitting antenna. Since the electromagnetic wave is transmitted to the receiving antenna of the first device, the electromagnetic wave can be transmitted from the second device to the receiving antenna of the first device without being attenuated by the rotating shaft. For this reason, compared with the prior art, the efficiency of power supply from the second device to the first device can be increased, and wasteful power consumption in the second device can be reduced.

  In order to achieve the above object, the present invention comprises means for receiving electromagnetic waves of a predetermined frequency with a receiving antenna and converting the energy of the electromagnetic waves into electric energy, and means for storing the electric energy, A first device that operates using the stored electrical energy as driving power, and a second device that has means for transmitting the electromagnetic wave of the predetermined frequency from the transmitting antenna to the first device, differing from the direction of gravity A rotating body that rotates about a rotating shaft that extends in a predetermined direction is fixed at a predetermined distance away from the rotating body with respect to the first device that rotates at a predetermined distance from the rotating shaft. A power supply system for supplying the driving power by irradiating the electromagnetic wave from the transmitting antenna, the receiving antenna of the first device with respect to the transmitting antenna Means for detecting that the relative position of the antenna is within a predetermined range between the rotating shaft and the transmitting antenna; and when the relative position of the receiving antenna of the first device is within the predetermined range, A power supply system provided with means for transmitting the electromagnetic wave from the transmitting antenna to the first device is proposed.

  According to the power supply system of the present invention, the second device is configured so that when the receiving antenna of the first device is within a predetermined range between the rotating shaft and the transmitting antenna, Since the electromagnetic wave is transmitted to the receiving antenna of the first device, the electromagnetic wave can be transmitted from the second device to the receiving antenna of the first device without being attenuated by the rotating shaft. For this reason, compared with the prior art, the efficiency of power supply from the second device to the first device can be increased, and wasteful power consumption in the second device can be reduced.

  According to the power supply method and the system of the present invention, the second device transmits the signal when the reception antenna of the first device is within a predetermined range between the rotation shaft and the transmission antenna of the second device. Since the electromagnetic wave is transmitted from the antenna to the reception antenna of the first device, the electromagnetic wave can be transmitted from the second device to the reception antenna of the first device without being attenuated by the rotation axis. For this reason, compared with the prior art, the efficiency of power supply from the second device to the first device can be increased, and wasteful power consumption in the second device can be reduced.

  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 (first device), and 200 is a monitor device (second 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. In this embodiment, as shown in FIG. 3, the diamond 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, 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 the tire 2 is locked to prevent slippage. Control automatically.

  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, and the detected acceleration is converted into a digital value. Further, the sensor unit 100 generates and transmits digital information including a digital value of the acceleration of the detection result. The digital information includes identification information unique to each sensor unit 100 in addition to the digital value of the 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 well-known CPU 141, a digital / analog (hereinafter referred to as D / A) conversion circuit 142, and a storage unit 143.

  The CPU 141 operates based on a program stored in the semiconductor memory of the storage unit 143. When the CPU 141 is driven by being supplied with electric energy, the digital value including the digital value of the acceleration detection result acquired from the sensor unit 160 and identification information described later is obtained. A process of generating information and transmitting the digital information to the monitor device 200 is performed. The storage unit 143 stores the identification information unique to the sensor unit 100 in advance. In the present embodiment, the central processing unit 140 is programmed to transmit 0.30 msec at intervals of 0.45 msec and transmit the digital information to the monitor device 200. It is preferable to set appropriately according to the system configuration.

  The storage unit 143 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 143 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 sensor unit 160 includes the acceleration sensor 10 and an A / D conversion circuit 161.

  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 in 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 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 accelerations 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 supports 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 perpendicular 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 Z-axis direction.

  On the other hand, the A / D conversion circuit 171 converts 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 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 (power supply 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 and a transmission unit 212 for radiating electromagnetic waves of a predetermined frequency (the first frequency) in the 2.45 GHz band. Based on an instruction from the control unit 230, the radiation unit 210 performs the above operation. Radiates electromagnetic waves of the first frequency.

  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 the step is detected, and the signal obtained by the detection is converted into a digital signal and 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 calculation unit 240 calculates the acceleration based on the digital signal output from the detection unit 222 and outputs the acceleration to the stability control unit 700. Further, the calculation unit 240 outputs the value of acceleration in the Z-axis direction to the control unit 230 as described later.

  Further, the control unit 230 radiates electromagnetic waves from the radiation unit 210 to the sensor unit 100 only while the acceleration in the Z-axis direction input from the calculation unit 240 is a value within a predetermined range. Details of this will be described later. Thereafter, the control unit 230 repeats the same processing as described above.

  Next, the operation of the system configured as described above will be described with reference to FIGS. 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.

  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 top of the tire 2, the acceleration in the Z-axis direction is obtained by subtracting gravity from the centrifugal force. When the sensor unit 100 is located at the bottom of the tire 2, the acceleration in the Z-axis direction is centrifugal. It is the force plus gravity. Using this phenomenon, the monitor device 200 of the present embodiment detects the rotational position of the sensor unit 100 based on the detected acceleration in the Z-axis direction, and the antenna 110 of the sensor unit 100 with respect to the transmission antenna 211 of the monitor device 200. Is within a predetermined range between the rotating shaft 3 and the transmitting antenna 211, for example, from the radiation unit 210 only when the sensor unit 100 exists within the predetermined range AR above the tire 2 in FIG. Electromagnetic waves are radiated to the sensor unit 100 to supply power to the sensor unit 100.

  In the present embodiment, the electromagnetic wave is radiated from the radiation unit 210 only when the sensor unit 100 exists in the range AR, so that a voltage of 3 V or more is obtained as the electric energy sufficient to drive the sensor unit 100 at all times. Can be charged.

  Thus, the monitor device 200 radiates electromagnetic waves from the radiation unit 210 to the sensor unit 100 when the sensor unit 100 is within the range AR between the rotation shaft 3 of the tire 2 and the monitor device 200. The electromagnetic wave can be sent from the radiation unit 210 to the sensor unit 100 without being attenuated by the rotating shaft 3. Therefore, compared to the conventional example, the efficiency of power supply from the monitor device 200 to the sensor unit 100 can be increased, and wasteful power consumption in the monitor device 200 can be reduced.

  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. 19 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, the amount of distortion of the tire 2 caused by this acceleration, the side slip state of the vehicle body, the idling state of the tire 2, etc. can be estimated. Based on this, the pressure control valve during vehicle braking can be controlled.

  Therefore, according to the vehicle drive control system described above, it is possible to detect accelerations in the X, Y, and Z axis directions that are orthogonal to each other and generated in each of the four tires 2 of the vehicle when the vehicle is traveling. Furthermore, since it is possible to estimate the grip and lift of the tire 2 from the acceleration in the Z-axis direction, it is possible to estimate the amount of distortion of the tire 2 that occurs when the vehicle travels, the side slip state of the vehicle body, the idling state of the tire, and the like. The above-described actuators can be controlled so as to be able to travel stably based on these.

  Further, as described above, the monitor device 200 radiates electromagnetic waves from the radiation unit 210 to the sensor unit 100 when the sensor unit 100 is within the range AR between the rotation shaft 3 of the tire 2 and the monitor device 200. Therefore, the electromagnetic wave can be sent from the radiation unit 210 to the sensor unit 100 without being attenuated by the rotating shaft 3. Therefore, compared to the conventional example, the efficiency of power supply from the monitor device 200 to the sensor unit 100 can be increased, and wasteful power consumption in the monitor device 200 can be reduced.

  In the present embodiment, the range AR in which electromagnetic waves for power supply from the monitor device 200 to the sensor unit 100 are radiated is determined based on the acceleration in the Z-axis direction. It goes without saying that a physical quantity other than the acceleration in the direction may be detected, and the range AR may be determined based on the detection result.

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

  FIG. 28 is a block diagram showing an electric circuit of the monitor device 200A in the second 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 second embodiment and the first embodiment is that in the second embodiment, the presence position of the sensor unit 100 is detected based on the intensity of electromagnetic waves radiated from the sensor unit 100, and the sensor unit 100 is a tire. The electromagnetic wave is radiated from the radiation unit 210 to the sensor unit 100 when it is within the range AR between the second rotation shaft 3 and the monitor device 200.

  That is, the monitor device 200A in the second embodiment includes a wave receiving unit 220A having an intensity detection unit 223.

  The intensity detecting unit 223 is for detecting the intensity of the electromagnetic wave received by the receiving unit 220A. Specifically, the intensity detecting unit 223 detects the value of the high frequency voltage or high frequency current obtained by the detection by the detecting unit 222. This value is converted into digital data and output to the control unit 230.

  The intensity of the electromagnetic wave received by the monitor device 200A from the sensor unit 100 varies depending on the position of the sensor unit 100. That is, when the sensor unit 100 exists in the range AR between the rotating shaft 3 of the tire 2 and the monitor device 200, the electromagnetic waves radiated from the sensor unit 100 are not attenuated by the rotating shaft 3 without causing attenuation. The monitor device 200A can receive a wave. However, if the rotating shaft 3 of the tire 2 is positioned between the monitoring device 200A and the sensor unit 100, the electromagnetic wave radiated from the sensor unit 100 is attenuated by the rotating shaft 3, and is received by the monitoring device 200A. The strength of is reduced.

  Therefore, the monitor device 200A detects the intensity of the electromagnetic wave received from the sensor unit 100, and when the sensor unit 100 is within the range AR between the rotating shaft 3 of the tire 2 and the monitor device 200, the sensor unit 100 Radiates electromagnetic waves. Thus, similarly to the first embodiment, the electromagnetic wave can be transmitted from the radiation unit 210 to the sensor unit 100 without being attenuated by the rotating shaft 3, so that the sensor unit 200 can be compared with the sensor unit compared to the conventional example. The efficiency of power supply to 100 can be increased, and unnecessary power consumption in the monitor device 200 can be reduced.

  In the first and second embodiments, information on the acceleration generated in the tire 2 is transmitted from the sensor unit 100 to the monitoring devices 200 and 200A. However, physical quantities other than the acceleration that change according to the state of the tire 2, For example, a sensor that detects a physical quantity such as air pressure or temperature may be provided in the sensor unit 100, and the detection result may be transmitted from the sensor unit 100 to the monitoring devices 200 and 200A.

  Further, the transmitting antenna and the receiving antenna in the monitor devices 200 and 200A may be shared by one antenna.

  In the sensor unit 100, a transmitting antenna and a receiving antenna may be provided separately.

  In each of the above embodiments, the case where power is supplied from the monitoring devices 200 and 200A to the sensor unit 100 provided in the tire 2 of the vehicle has been described as an example. However, the sensor unit 100 is used as a rotating body other than the tire 2. It goes without saying that the same effects as described above can be obtained even if the provided system is configured.

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 block diagram which shows the electric system circuit of the monitor apparatus in 2nd Embodiment of this invention

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Vehicle, 2 ... Tire, 3 ... Axle, 4 ... Tire house, 100 ... Sensor unit, 110 ... Antenna, 120 ... Antenna switch, 130 ... Rectifier circuit, 131, 132 ... Diode, 133 ... Capacitor, 134 ... Resistor, 140 ... Central processing unit, 141 ... CPU, 142 ... D / A conversion circuit, 143 ... Storage unit, 150 ... Transmission unit, 151 ... Oscillation circuit, 152 ... Modulation circuit, 153 ... High frequency amplification circuit, 160 ... Sensor unit, 161 ... A / D conversion circuit, 200,200A ... monitor device, 210 ... radiation unit, 211 ... antenna, 212 ... transmitting unit, 220,220A ... receiving unit, 221 ... antenna, 222 ... detection unit, 223 ... intensity detection unit, 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, 510,520 ... Rotation speed sensor, 610 Brake pedal, 620 ... Master cylinder, 630 ... Pressure control valve, 640 ... Brake drive actuator, 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 part tip, 31A- 31C: Voltage detector, 32A to 32C: DC power supply, Rx1 to Rx4, Ry1 to Ry4, Rz1 to Rz4: Piezoresistors (diffusion resistors).

Claims (7)

First means for receiving an electromagnetic wave of a predetermined frequency with a receiving antenna and converting the energy of the electromagnetic wave into electric energy and means for storing the electric energy, and operating the stored electric energy as driving power. Equipment,
A second device having means for transmitting electromagnetic waves of the predetermined frequency from a transmitting antenna to the first device;
A predetermined distance away from the rotating body with respect to the first device rotating at a predetermined distance from the rotating shaft of the rotating body rotating about a rotating shaft extending in a predetermined direction different from the gravitational direction. A power supply method for supplying the driving power by irradiating the electromagnetic wave from the transmitting antenna fixed in position,
The second device is configured such that when the receiving antenna of the first device is within a predetermined range between the rotation axis and the transmitting antenna, the transmitting antenna to the receiving antenna of the first device An electric power supply method characterized by transmitting electromagnetic waves. First means for receiving an electromagnetic wave of a predetermined frequency with a receiving antenna and converting the energy of the electromagnetic wave into electric energy and means for storing the electric energy, and operating the stored electric energy as driving power. Equipment,
A second device having means for transmitting electromagnetic waves of the predetermined frequency from a transmitting antenna to the first device;
A predetermined distance away from the rotating body with respect to the first device rotating at a predetermined distance from the rotating shaft of the rotating body rotating about a rotating shaft extending in a predetermined direction different from the gravitational direction. A power supply system that supplies the driving power by irradiating the electromagnetic wave from the transmitting antenna fixed in position,
Means for detecting that the relative position of the receiving antenna of the first device with respect to the transmitting antenna is within a predetermined range between the rotating shaft and the transmitting antenna;
And a means for transmitting the electromagnetic wave from the transmitting antenna to the first device when the relative position of the receiving antenna of the first device is within the predetermined range. The first device includes:
Means for detecting a predetermined physical quantity that changes according to the direction in which gravity is applied;
Means for transmitting information relating to the detected physical quantity to the second device,
The second device includes:
Means for receiving information on the physical quantity transmitted from the first device;
Means for detecting a rotational position of the first device based on the received information;
The power supply system according to claim 2, further comprising: a unit that detects that the relative position is within the predetermined range based on the detected rotational position. The first device has means for transmitting an electromagnetic wave having a predetermined frequency to the second device from either the receiving antenna or a transmitting antenna disposed in the vicinity of the receiving antenna,
The second device includes:
Means for receiving the electromagnetic wave transmitted from the first device and detecting the intensity of the electromagnetic wave by either the transmitting antenna of the second device or the receiving antenna disposed in the vicinity of the transmitting antenna;
The power supply system according to claim 2, further comprising means for detecting that the relative position is within the predetermined range based on the detected electromagnetic wave intensity. The power supply system according to claim 3, wherein the first device includes a unit that detects, as the physical quantity, acceleration in a predetermined direction that changes according to a direction in which gravity is applied. The rotary body is a tire of a vehicle, the first device is fixed to the tire, and the transmitting antenna of the second device is fixed to a tire house of the tire. 6. The power supply system according to any one of items 5. The power supply system according to claim 6, wherein the first device includes means for detecting a predetermined physical quantity that changes in accordance with a tire condition and transmitting the detection result by electromagnetic waves.

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