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    • 专利摘要:
    PNEUMATIC AIR PRESSURE MONITORING DEVICE A TPMSCU (4) comprises: a rotating position calculation unit (4a), which detects a rotating position for each wheel, when a wireless signal, including a specific sensor ID, has been transmitted; a wheel position determination unit (4c), which obtains the rotary position of each wheel (1) several times, and accumulates it as the rotary position data of each wheel (1), and determines the position of wheel corresponding to the rotary position data with the least degree of dispersion among all the rotary position data, such as the wheel position of a transmitter (2d), corresponding to the sensor ID; and a rotating position detection inhibition unit (4e), which inhibits the detection of the rotary position of each wheel (1) by the rotating position calculation unit (4a), when a brake control, which controls a pressure wheel wheel cylinder, is running.
    公开号:BR112013027401B1
    申请号:R112013027401-8
    申请日:2012-02-20
    公开日:2021-01-19
    发明作者:Takashi Shima；Syoji Terada；Kazuo Sakaguchi
    申请人:Nissan Motor Co., Ltd.；
    IPC主号:
    专利说明:

    Technical field
    [001] The present invention relates to a pneumatic tire pressure monitoring device. Background
    [002] In a tire pressure or tire pneumatic monitoring device, described in patent document 1, a transmitter sends a wireless signal to a determined, constant rotational position. When wireless signals are received on the vehicle side, the rotational positions of the respective wheels are detected. The wheel position associated with a transmitter corresponding to the rotational position, which is best synchronized with the wireless signal output period, between the rotational positions of the wheels, is determined as the wheel position (wheel position) with which the transmitter is associated. Prior art documents Patent Document
    [003] Patent document 1: publication of Japanese patent application No. 2010-122023. Summary of the invention Problem to be solved by the invention
    [004] According to the prior art described above, the rotational position of the transmitter is determined from the output value of an acceleration sensor, and a wireless signal is transmitted the moment the output value of the acceleration sensor takes over the predetermined value. At this moment, when a brake control, such as an ABS control, is conducted, since the wheel under control is subject to vibrate longitudinally for an extremely short period, disturbing the detected value of the acceleration sensor, the transmitter is able to erroneously determine the rotational position and transmit a wireless signal to a rotational position, different from the determined rotational position. Consequently, due to the determination of the wheel position of the transmitter, based on the erroneous data of the rotational position, the determination of the wheel position is likely to be delayed.
    [005] The purpose or objective of the present invention is to provide a tire pressure monitoring device or tire pneumatics, which can eliminate the delay in determining the wheel position. Mechanism for reaching the object
    [006] To achieve the object described above, according to the present invention, when a brake control, to control a wheel wheel cylinder pressure, is being performed, the detection of each wheel will be inhibited. Effect of the invention
    [007] Consequently, according to the present invention, when the possibility is present when a wireless signal has been transmitted from a transmitter, to a rotational position different from the determined rotational position, the rotational position associated with each wheel, corresponding to this wireless signal, it will not be detected. Therefore, erroneous rotational position data for determining the wheel position is prevented from being used, so that a delay in determining the wheel position can be eliminated. Brief description of the drawings
    [008] Figure 1 is a configuration diagram, illustrating the configuration of the tire pressure monitoring device in a first embodiment.
    [009] Figure 2 is a configuration diagram for a TPMS 2 sensor.
    [010] Figure 3 is a control block diagram, illustrating a control block diagram of a TMPSCU 4, for the execution of the wheel position determination control.
    [011] Figure 4 is a diagram illustrating a process for calculating a rotational position of each wheel 1.
    [012] Figure 5 is a diagram illustrating a process for calculating a characteristic dispersion value.
    [013] Figure 6 is a flow chart illustrating a flow of the wheel position determination control process, in the first embodiment.
    [014] Figure 7 is a diagram illustrating a relationship between the rotational positions (the number of rotor teeth) of each of the 1FL, 1FR, 1RL, 1RR wheels, when the rotational position of the front wheel TPMS 2FL sensor left 1FL assumes the highest point, and the receiving number of the TPMS data.
    [015] Figure 8 is a diagram illustrating a variation of the characteristic value of dispersion X, depending on the number of times of reception times of the TMPS data. Description of reference signals 1 - wheel 2a - pressure sensor (pneumatic tire pressure detection mechanism) 2b - G sensor (acceleration sensor) 2d - transmitter 3 - receiver 4a - rotational position calculation unit (calculation mechanism rotational position) 4c - wheel position determination unit (wheel position determination mechanism) 4e - rotational position detection inhibition unit (rotational position detection inhibition mechanism) Embodiments for implementing the invention
    [016] In the following, the embodiments of the present invention will be described with reference to the embodiments based on the drawings. [First embodiment]
    [017] Figure 1 is a configuration diagram illustrating a tire tire or tire pneumatic monitoring device, in a first embodiment. In this figure, the terminal letters, attached to each reference signal, are intended to indicate the following: FL means for the left front wheel; FR stands for the right front wheel; RL stands for the left rear wheel; and RR stands for the right rear wheel, respectively. In the description presented below, when not specifically necessary, the description of FL, FR, RL and RR will be omitted.
    [018] The tire pressure monitoring device is, in the first embodiment, equipped with TPMS sensors (tire pressure monitoring system) 2, a receiver 3, a TPMS control unit (TPMSCU) 4, a display 5 and wheel speed sensors 8. The TPMS sensor 2 is installed on each of the wheels 1, and the receiver 3, the TPMSCU 4, the display 5 and the wheel speed sensors 8 are arranged on the side of the vehicle body.
    [019] The TMPS 2 sensor is installed in the position of a pneumatic valve (not shown in the figure) for each tire. Figure 2 is a diagram illustrating the configuration of the TPMS sensor 2. The TPMS sensor 2 comprises a pressure sensor (a tire pressure detection mechanism) 2a, an acceleration sensor (sensor G) 2b, a pressure control unit sensor (sensor CU) 2c, a transmitter 2d and a button battery 2e.
    [020] In the present invention, the pressure sensor 2a detects the tire pressure [kPa] of the tire.
    [021] The G 2b sensor detects acceleration in the centrifugal direction [G] acting on the tire.
    [022] The CU of sensor 2c operates under the energy supplied by the button battery 2e, and the TPMS data, containing the tire pressure information of the tire, detected by the pressure sensor 2a, and the ID (identification information) of the sensor are sent as a wireless signal from the 2d transmitter. In the first embodiment, the sensor IDs are defined by 1 to 4.
    [023] CU of sensor 2c compares the acceleration in the centrifugal direction, detected by the sensor G 2b, with a pre-established threshold, to determine a vehicle's running state. When the acceleration in the centrifugal direction is less than the run-in threshold, a determination is made that the vehicle is being stopped or parked, so that the transmission of TMPS data is interrupted. On the other hand, when the acceleration in the centrifugal direction exceeds the driving threshold, a determination is made that the vehicle is running, and the TMPS data will be transmitted at a specified timing.
    [024] Receiver 3 receives wireless signals transmitted from each TMPS sensor 2, to decode and transmit to TPMSCU 4.
    [025] TPMSCU 4 reads the respective TPMS data, based on the sensor IDs, the TPMS data, and with reference to the correspondence relationship between each of the sensor IDs and the wheel positions stored in a non-volatile memory 4d ( see Figure 3), TPMSCU 4 determines which wheel position the TPMS data corresponds to, and displays on the display 5 a pneumatic tire pressure contained in the TPMS data, such as the pneumatic pressure of the corresponding wheel position. When the pneumatic pressure of a tire falls below a lower limit threshold, the decrease in pneumatic pressure is notified by a variation in the color of the display, by the flashing display, by an alarm sound, or the like.
    [026] Based on the wheel speed pulse current from each of the wheel speed sensors 8, ABSCU 6 detects the wheel speed of each wheel 1, respectively. When a certain wheel has a locking tendency, an ABS actuator, not shown in the figure, is operated, to adjust or maintain a corresponding wheel wheel cylinder pressure, to eliminate the locking tendency. In this way, non-slip brake control (ABS) is conducted. ABSCU 6 transmits the counting value of the wheel speed pulses to the CAN 7 communication line, at each determined time period (for example, 20 ms).
    [027] Each wheel speed sensor 8 is formed into a pulse generator, which generates a chain of wheel speed pulses, producing a determined number z (for example, z = 48) for each cycle of wheel rotation 1 The wheel speed sensor comprises a gear-shaped rotor, rotating in synchronization with wheel 1, and both a permanent magnet and a coil, arranged on the side of the vehicle body and facing the outer periphery of the rotor. As the rotor rotates, the concave-convex or corrugated surface of the rotor passes through the magnetic field, formed at the periphery of the wheel speed sensor 8, so that the density of the magnetic flux varies to generate an electromotive force on the coil, and this variation in voltage is transmitted, as a pulse signal of wheel speed, to ABSCU 6.
    [028] In addition to ABS control, ABSCU 6 performs a vehicle behavior stabilization control, a brake traction control and an LSD brake control, as a control, to control the wheel cylinder pressure of wheel 1. More specifically, by controlling vehicle behavior stabilization, the wheel is provided with a braking force to eliminate a tendency for the vehicle to over-steer, to ensure vehicle running stability. By means of brake traction control, a grip force on the tire's raceway will be increased by eliminating a spin or crazy spin of a driving wheel when one side of the drive wheels slides on a raceway. low μ, and similar. In LSC brake control, a differential is limited by the use of a brake. ABSCU 6 transmits a control indication signal to the CAN 7 communication line and indicates whether or not the brake control, described above, is running. The control indicator is set to "0" when the brake control is not in place, or performed while set to "1" when performed.
    [029] As described above, based on the correspondence relationship between the sensor IDs and the wheel position stored in memory 4d, TPMSCU 4 determines which wheel the received TPMS refers to. Consequently, when a tire rotation is driven while the vehicle is stationary, the matching relationship between the sensor IDs and the wheel position stored in memory 4d is not in line with the effective matching relationship, and it is impossible to find out to which the TPMS data refer. In this case, "tire rotation" refers to the operation of changing the tire installation wheel positions, in order to ensure uniform tire tread wear, and thereby prolong the service life ( tread life). For example, for a passenger vehicle, usually the front / rear tire wheels are switched while with the position of the left / right tire wheels in reverse.
    [030] In the present invention, according to the first embodiment, to update and store the correspondence relationship between each sensor ID and each wheel position, after a tire rotation in the 4d memory, when there is a possibility that a rotation of tire has been driven, the period of transmission of TMPS data, on the side of each TPMS sensor 2, is changed, and, on the side of TPMSCU 4, based on the transmission period of TPMS data and on each pulse of wheel speed , a determination is made with which tire each TPMS 2 sensor is associated with. [Constant position transmission mode]
    [031] When the vehicle stop determination time, before the vehicle starts to run in, is equal to or greater than a determined time (for example, 15 min), the CU of sensor 2c of the TPMS sensor determines that the rotation of the tire may have been driven.
    [032] When the vehicle stop determination time, immediately before the vehicle starts to run in, is less than the determined time, the CU of sensor 2c performs a "normal mode", in which the TPMS data is transmitted at each interval constant or determined (for example, at a one minute interval). On the other hand, when the vehicle stop determination time is equal to or greater than the determined time, the sensor CU performs a "constant position transmission mode", in which, in a shorter interval than the transmission interval in normal mode (for example, at an interval of about 16 seconds), the TPMS data is transmitted at a constant or determined rotational position.
    [033] The constant position transmission mode is executed until the transmission number of the TPMS data reaches a certain number of times (for example, 40 turns). When the number of times the transmission reaches the specified number of times, the constant position transmission mode is switched to normal mode. When a determination has been made that the vehicle stops before the number of times the TPMS data is transmitted reaches the specified number of times, if the vehicle stop determination time is shorter than the determined time (15 min), the constant position transmission mode, before the vehicle stops, is continued until the number of transmission times reaches the specified number of times. When the vehicle stop determination time is longer than the determined time, the continuation of the constant position transmission mode, before the vehicle stops, is canceled, and a new constant position transmission mode is initiated.
    [034] In constant position transmission mode, based on the gravity acceleration-dependent acceleration component, in the centrifugal direction detected by the G 2b sensor, the CU of sensor 2c determines a transmission synchronization of the TPMS data in the transmission mode of constant position. The acceleration in the centrifugal direction, acting on the TPMS sensor 2, varies according to the acceleration / deceleration of the wheels 1, even though the component dependent on gravity acceleration is always constant. That is, the acceleration in the centrifugal direction, acting on the TPMS sensor, shows a waveform with +1 [G] at a top point, -1 [G] at a bottom point, and 0 [G] in the middle position 90 ° between the top point and the bottom point. In other words, by monitoring the magnitude and direction of the gravity acceleration acceleration component in the centrifugal direction, it is possible to understand or identify the rotational position of the TPMS 2 sensor. Therefore, for example, by transmitting TPMS data to a peak from the gravity acceleration-dependent component, TPMS data can be transmitted constantly at the top point. [Self-learning mode]
    [035] When the time has passed from a predetermined (for example, 15 min) or more from the OFF position to the ON position of the ignition key, TPMSCU 4 determines that the tire rotation may have been conducted.
    [036] When the elapsed time from OFF to ON of the ignition key is shorter than the predetermined time, based on the tire pressure information in the TPMS, transmitted from each TPMS 2 sensor, the TPMSCU 4 executes a "mode of monitoring ", in which the pneumatic tire pressure of each wheel 1 is monitored. On the other hand, when the time elapsed from OFF to ON of the ignition key is longer than the predetermined time, TPMSCU 4 performs a "self-learning mode", which will be conducted until the wheel positions of all TPMS sensors 2 are determined, or until a predetermined cumulative travel time (for example, 8 minutes), from the beginning of this mode, has passed. When the wheel positions of all TPMS sensors are determined, or the predetermined cumulative time has passed, control is transferred to monitoring mode.
    [037] Even in the self-learning mode, it is still possible to monitor the pneumatic tire pressure from the pneumatic pressure information contained in the TPMS data. Consequently, the display of the pneumatic pressure and the warning of a lower pneumatic pressure are conducted based on the corresponding relationship between the sensor IDs and the position of the wheels currently stored in memory 4d, during the automatic running mode.
    [038] In self-learning mode, the TPMSCU 4 receives a wheel speed pulse count value from the ABS control unit (ABSCU) 6 via the CAN 7 communication line, and performs the wheel position determination control described below . [Wheel position determination control]
    [039] Figure 3 is a control block diagram of the TPMSCU 4, for carrying out the wheel position determination control. TPMSCU 4 has a rotational position calculation unit (the rotational position detection mechanism) 4a, a dispersion calculation section 4b, a wheel position determination section (the wheel position determination mechanism) 4c, a memory 4d, a detection inhibition unit (detection inhibition mechanism) of rotational position 4e.
    [040] The rotational position calculation unit 4a receives the TPMS data, after being decoded to be transmitted from the receiver 3, and the counting values of the wheel speed pulses transmitted from ABSCU 6 to the CAN 7 communication line, for calculate a rotational position (number of rotor teeth) for each rotor, when the rotational position of each TPMS sensor takes the top point. Note that the "number of teeth" indicates which tooth the wheel speed sensor 8 is counting, and can be obtained by dividing the count value of the wheel speed pulses by a count value per tire rotation (that is, the number of teeth per rotation z = 48). In the first embodiment, when the count value of the wheel speed pulses of the first time, from the self-learning mode is entered, the value obtained by adding 1 to the remainder of the operation of dividing the count value by the number of teeth. 1 cycle or rotation is adopted as the teeth reference value. In the second and subsequent times, based on the counting number of the wheel speed pulses relative to the reference number of teeth (that is, the moment counting value - the counting value in the first half), the number or teeth can be determined.
    [041] Figure 4 is a diagram showing a process for calculating the rotational position of each wheel 1.
    [042] In Figure 4, t1 represents the time when the wheel speed pulse count value is entered, t2 represents the time when the rotational position of the TPMS 2 sensor reaches the top point, t3 represents the time when reception of the TPMS data by the TPMSCU 4 is completed, and t5 represents the time when the wheel speed pulse count value is entered. In this case, t1, t4 and t5 can actually be measured, t3 can be calculated by subtracting the data extension (nominal value, for example, about 10 ms) from the TPMS data of t4, and t2 can be calculated by subtracting from a time delay in transmission (t2 can be determined in advance by experiment or similar) of t3.
    [043] Consequently, suppose that the number of teeth in t1 is zt1, the number of teeth in t2 is zt2, and the number of teeth in t5 is zt5, respectively, the following equation is established: (t2-t1) / (t5-t1) = (zt2-zt1) / (zt5-zt1) Because zt2 = zt1 + (zt5-zt1) * (t2-t1) / (t5-t1)
    [044] the number of teeth zt2 is expressed as follows, when the PAM of the TPMS 2 sensor is at the top point: zt2 = zt1 + (zt5-zt1) * (t2-t1) / (t5-t1)
    [045] Scatter computation section 4b accumulates a rotational position of each wheel 1, which is calculated in the rotational position calculation unit 4a for each sensor ID, to obtain rotational position data, and calculates a degree of dispersion in each rotational position data, for each sensor ID, as a characteristic dispersion value. The characteristic dispersion value is calculated each time the rotational position for identical sensor ID is calculated by the rotational position calculation unit 4a.
    [046] Figure 5 is a diagram illustrating a process for calculating the characteristic dispersion value. According to the first embodiment, a unitary circle (a circle with radius of 1), with the origin (0, 0) in the two-dimensional plane, is assumed, and the rotational position θ [°] (= 360 x (the number of rotor teeth / 48)) of each wheel 1 is converted into the circumferential coordinates (cos θ, sin θ) in the unit circle. More specifically, the rotational position of each wheel 1 is calculated as follows: consider a vector having the origin (0, 0) as the starting point and the coordinates (cos θ, sin θ) with the end with an extension of 1 , the average vectors (ave_cos θ, ave_sin θ) of each vector of the same rotational position data are obtained, and the scalar quantity of the average vector is calculated as the characteristic dispersion value X of the rotational position data: cos θ, sin θ) = (cos ((zt2 + 1) * 2π / 48), sin ((zt2 + 1) * 2π / 48))
    [047] Consequently, suppose that the number of times the TPMS data is received with respect to the identical sensor ID as n (n is a positive integer), the mean vectors (ave_cos θ, ave_sin θ) are expressed below: ( ave_cos θ, ave_sin θ) = ((∑ (cos θ)) / n, (∑ (sin θ)) / n)
    [048] The characteristic dispersion value X can therefore be represented as follows: X = ave_cos θ2 + ave_sin θ2
    [049] The wheel position determination unit 4c works as follows. The characteristic values of dispersion X of each of the rotational position data of the same and identical sensor ID, calculated by the dispersion calculation unit 4b are compared. When the highest value of the characteristic dispersion values X is greater than a first threshold (for example, 0.57) and the remaining 3 characteristic values of dispersion X are all less than a second threshold (for example, 0.37), a determination is made that the wheel position of the rotational position data, corresponding to the characteristic dispersion value X with the highest value, that is, the wheel position of the wheel speed sensor 8 that has detected the rotational position data corresponding, is the wheel position of the TPMS 2 sensor corresponding to the sensor ID of the rotational position data. This determination is carried out for all sensor IDs; the correspondence relationship between each sensor ID and each wheel position is obtained as being registered in memory 4d, in the update process.
    [050] The rotational position detection inhibition unit 4e inhibits or prevents the rotational position calculation unit 4a from calculating the rotational position of each wheel 1, when any wheel 1 is under a brake control, in which a wheel cylinder pressure is controlled (for anti-lock brake control, vehicle behavior stability control, brake traction control and LSD brake control) by ABSCU 6. The determination of whether the brake control is in place or in progress it can be done based on a value of the control indication, which is entered by the CAN 7 communication line; [Wheel position determination control process]
    [051] Figure 6 is a flow chart illustrating the flow of the wheel position determination control process, according to the first embodiment. In the following, the respective operating steps will be described. In the description presented below, the case of the sensor ID being "1" is considered. However, for the other IDs (ID = 2, 3, 4), the wheel position determination control process is also conducted in parallel.
    [052] In step S1, the rotational position calculation unit 4a receives the TPMS data with the sensor ID being 1.
    [053] In step S2, the rotational position detection inhibition unit 4e determines whether or not a brake control is in progress, and, if YES, the control returns to step S1, if NO, control continues to step S3.
    [054] In step S3, the rotational position calculation section 4a calculates the rotational position of each wheel 1.
    [055] In step S4, the dispersion calculation unit 4b calculates the characteristic dispersion values X of the rotational position data for each wheel 1.
    [056] In step S6, a determination is made as to whether the TPMS data, with the sensor ID being equal to 1, is received a specified number of times (for example, 10 times) or more. If the determination result is YES, the operation goes to step S6. If the determination is NO, the operation returns to step S1.
    [057] In step S6, the wheel position determination section 4c determines whether the larger value of the characteristic dispersion value is greater than the first threshold of 0.57, and whether the value of the remaining characteristic dispersion values is less than the second threshold of 0.37. If the determination is YES, the operation goes to step S7; if the determination result is NO, the operation goes to step S8.
    [058] In step S7, the wheel position determination section 4c determines the wheel position of rotational position data corresponding to the highest baffle retention channel as the wheel position of the sensor ID. Then, the self-learning mode ends.
    [059] In step S8, the wheel position determination section 4c determines whether a predetermined cumulative or cumulative run time (for example, 8 min) has passed from the start of the self-learning mode. If the result of the determination is YES, the self-learning mode is ended. If the result of the determination is NO, the operation returns to step S1.
    [060] When the wheel position determination section 4c can determine the wheel positions for all sensor IDs within the determined cumulative travel time, the matching relationship between the sensor ID and the wheel position is updated and stored in 4d memory for registration. On the other hand, when it is impossible to determine the wheel position for all sensor IDs within the determined accumulated travel time, the correspondence relationship between the sensor IDs and each wheel position, currently stored in memory 4d, is continued to be used.
    [061] Next, the operation will be explained. [Operation of the determination of wheel position by the degree of dispersion in the rotational position data]
    [062] The TPMS 2 sensor works as follows: when the vehicle stop determination time, immediately before the vehicle starts to run in, is equal to or greater than 15 min, a determination is made that there is a possibility that the tire rotation has been conducted, and the operation goes from the normal mode to the constant position transmission mode. In the constant position transmission mode, after 16 seconds of the previous transmission time has passed and the rotational position of the TPMS sensor itself reaches the top point, each TPMS sensor 2 transmits the TPMS data.
    [063] On the other hand, when the time between OFF and ON of the ignition key is 15 min, or longer, TPMSCU 4 goes from the monitoring mode to the self-learning mode. In self-learning mode, each time TPMS data is received from each TPMS sensor 2, TPMSCU 4 calculates the rotational position (the number of rotor teeth) of each wheel 1, when the rotational position of the TPMS sensor 2 reaches the top point, based on the time of input of the counting value of the wheel speed pulses, time of completion of receiving the TPMS and similar data. This is conducted repeatedly for 10 or more times and accumulated like the rotational position data. Among the rotational position data, the wheel position at which the rotational position data, with the least degree of dispersion, is determined as the wheel position of that TPMS 2 sensor.
    [064] When the vehicle is traveling or rotating, the rotation speeds of each wheel 1 may be different from each other, due to the difference in the tracks between the internal and external wheels, the locking and sliding of the wheels 1 and the difference in pressure pneumatic tires. Even when the vehicle rotates straight, as the driver can still make minor corrections to the steering wheel, and there is a certain difference in the bearing surface between the right and left sides, the difference in rotation still develops between the front and rear 1FL wheels. and 1FR, and between the left and right wheels 1RL and 1RR. That is, even though there is a difference in the speed of rotation of each wheel, according to the vehicle's rolling state, since the TPMS sensor 2 and the wheel speed sensor 8 (the teeth of its rotor) rotate fully , for the exit period of a specific TPMS 2 sensor, the exit period of the wheel speed sensor 8, associated with the same wheel, is kept being synchronized (in association), regardless of the travel distance and travel status. .
    [065] Consequently, by observing the degree of dispersion in the rotational position data of each wheel 1, with respect to a transmission period of the TPMS data, it is possible to make a highly accurate determination in the wheel positions of each TPMS sensor 2.
    [066] Figure 7 illustrates the relationship between the rotational positions (the number of rotor teeth) of the 1FL, 1FR, 1RL and 1RR wheels, when the rotational position of the TPMS 2 2FL sensor of the left front wheel reaches the top point and the number of times the TPMS data is received. In this case, (a) corresponds to the 8FL wheel speed sensor on the left front wheel 1FL, (b) corresponds to the 8FR wheel speed sensor on the right front wheel 1FR, (c) corresponds to the wheel speed sensor 8RL on the left wheel left rear 1RL, and (d) corresponds to the 8RR wheel speed sensor on the right rear wheel 1RR.
    [067] As will be evident from Figure 7, while the degrees of dispersion are high with respect to the wheel positions (the number of teeth), obtained from the wheel speed sensors 8FR, 8RL and 8RR, with respect to the other wheels (the right front wheel 1FR, the left rear wheel 1RL and the right rear wheel 1RR), the degree of dispersion of the wheel position, obtained from the wheel speed sensor 8FL with respect to the wheel itself (the left front wheel 1FL), is the smallest or minimum, so the output period of the TPMS 2 2FL sensor and the output period of the 8FL wheel speed sensor are almost synchronized with each other.
    [068] As one of the conventional pneumatic tire pressure devices, an inclination sensor is arranged for each TPMS sensor, and the relationship between the wheel position of the TPMS sensor and the angle of inclination is used to determine the wheel position of the TPMS sensor. For this type of pneumatic tire pressure monitoring device, corresponding to the vehicle's running-in, the difference in rotation speed occurs between the 4 wheels, so that the correspondence between the wheel position of the TPMS sensor and the angle of inclination varies . It is therefore impossible to make a highly accurate determination of the wheel position of each TPMS sensor.
    [069] Like another conventional tire pneumatic pressure monitoring device, the same number of receivers, as those of the TPMS sensors, are arranged next to the sensors, respectively; based on the intensity of the electromagnetic wave of the received wireless signals, the wheel position of each TPMS sensor is determined. In this case, it is necessary to consider the sensor output, the dispersion of sensitivity of the receiver and the effect of the antenna in harp for the disposition of the receivers, and the physical environment and the disposition of reception determine the performance. In addition, 4 receivers must be arranged. Consequently, the cost is higher.
    [070] On the other hand, for the pneumatic tire pressure monitoring device in the first embodiment, the wheel position of each TPMS 2 sensor can be specified without using the electromagnetic wave intensity, so that it is possible to determine the position of wheel of each TPMS 2 sensor, regardless of the physical environment and reception arrangement. In addition, one receiver 3 is sufficient, which will eliminate the cost for additional sensors.
    [071] In addition, according to the first embodiment, TPMSCU 4 calculates and determines that the rotational position of each wheel 1 is positioned at the top point, based on the gravity-dependent component of an acceleration in the centrifugal direction, that is detectable from the G 2b sensor. Since the G 2b sensor is used in the existing pneumatic tire pressure monitoring device, for detecting vehicle stop and travel, the existing TPMS sensor can be used commonly so that there is no need to add new sensors on the side of the vehicle. The cost can therefore be reduced. [Operation in determining the degree of dispersion of the characteristic dispersion value]
    [072] Because the rotational position of wheel 1 is indicated by the angular data with periodicity, the degree of dispersion of the rotational position cannot be determined using the general dispersion formula defined by the mean of the "square of the difference of the mean or mean value ".
    [073] Thus, in the first embodiment, the dispersion calculation unit 4b works as follows. The rotational position θ of each wheel 1, obtained from each wheel speed sensor 8, is converted into the circumferential coordinates (cos θ, sin θ) of a unit circle having the origin (0, 0) in the center. The coordinates (cos θ, sin θ) are considered as vectors, the mean vectors (ave_cos θ, ave_sin θ) of the vectors of the same rotational position data are obtained, and the scalar quantity of the mean vector is calculated as the characteristic dispersion value. X. Therefore, it is possible to avoid periodicity in determining the degree of dispersion of the rotational position.
    [074] Figure 8 shows a diagram illustrating a variation in the characteristic dispersion value X, according to the number of receipt of the TPMS data. In Figure 8, the wheel itself presents the characteristic dispersion value X, calculated in the rotational position data of the wheel speed sensor 8, on the same wheel on which the TPMS sensor is installed, while the other wheels show the characteristic value of dispersion X, calculated in the rotational position data of the route speed sensor 8, in a different wheel from those in which the TPMS sensors are installed.
    [075] As shown in Figure 8, as the number of TPMS data receipts in the same sensor ID increases, this trend is indicated when the dispersion characteristic X approaches "1", while the characteristic value of dispersion X for the other wheel approaches "0". In this way, it may be ideal to select the maximum value (that is, the characteristic dispersion value closest to "1") on reaching a sufficient number of receptions (about several dozen times). However, since it is impossible to inform the driver with accurate information on the condition of the tires, during the period of determining the wheel position, immediately after a tire rotation, the delay in the determination time will not be preferable. On the other hand, in the insufficient number of receptions (such as several times), no difference in the characteristic dispersion value, with respect to itself and to the other wheels, is detectable and the decrease in the detection accuracy will be anticipated.
    [076] Thus, in the first embodiment, the wheel position determination unit 4c compares the characteristic dispersion values in each of the rotational position data, with respect to a specific sensor ID, when receiving the TPMS data with respect to that specific sensor ten times or more, and detects that the maximum value of the characteristic dispersion values X exceeds a first threshold value 0.57, while the remaining three characteristic dispersion values are below a second threshold value 0.37, then, the wheel position of the rotational position data, corresponding to the characteristic maximum dispersion value V, will be identified as the wheel position of that sensor ID.
    [077] Not only by selecting the maximum value of the characteristic dispersion values, by comparison with the first threshold value (0.57), a certain degree of determination accuracy can be guaranteed. In addition, by comparing characteristic dispersion values, different from the maximum value, with the second threshold value (0.37), a predetermined difference (of 0.2 or more) can be confirmed, which further improves the accuracy of determination. Therefore, with a relatively small number of receipts, such as ten times, both the determination accuracy and the decrease in the determination time can be obtained. [Operation of intermittent transmission of TPMS data]
    [078] Each TPMS 2 sensor transmits TPMS data after 16 seconds have elapsed from the previous TPMS data transmission time, and in synchronization in which the rotational position itself reaches the top point. In the first embodiment, since the characteristic values of dispersion X of each of the rotational position data are compared with each other, to determine the wheel position, with respect to the TPMS 2 sensor, which has transmitted the TPMS data, a certain amount cumulative travel distance will be necessary to cause a difference in the characteristic values of dispersion X, between the wheel itself (the same wheel) and the other wheel (another vehicle wheel).
    [079] Considering that the TPMS data will be transmitted each time the rotational position of the TPMS data reaches a top point, no substantial difference in the characteristic dispersion value will be expected between the wheel itself and another, so it can be difficult make a determination of wheel position.
    [080] Thus, by adjusting a transmission interval to 16 seconds + α, a certain amount of cumulative travel distance will be obtained, until the TPMS data is received ten times or more. Therefore, a sufficient difference in the characteristic dispersion value X, between the wheel itself and another, can be created to ensure an accurate determination of the wheel position. [Operation to eliminate energy consumption]
    [081] By transmitting TPMS data forty (40) times during the constant position transmission mode, the TPMS sensor 2 transfers to normal mode. The TPMS 2 sensor consumes the power of the button battery 2e, in the transmission of the TPMS data, so that the battery life time of the button battery 2e will be shorter as the constant position transmission mode continues. . Thus, when each wheel position may not be determined, in spite of sufficient cumulative travel time, the constant position transmission mode will be terminated to transfer to normal mode, which can eliminate the decrease in time. battery life.
    [082] On the other hand, when TPMSCU 4 cannot determine the correspondence between each sensor ID and each wheel position, regardless of the elapsed time of cumulative eight (8) minute travel, the self-learning mode will be terminated and the process goes into monitoring mode. The total number of TPMS data is thirty (30) times or less, when the cumulative travel time has passed eight minutes, the self-learning mode will be substantially ended in synchronization with the completion of the constant position transmission mode of the TPMS sensor. 2. [Delay operation for determining the position of the wheel]
    [083] The sensor CU 2c of the TPMS sensor 2 detects the rotational position of the TPMS sensor 2, based on the gravity-dependent component of the centrifugal acceleration detected by the G 2b sensor, during the constant position transmission mode, and transmits the TPMS data at the peak of the gravity acceleration-dependent component, so that the TPMS data is transmitted at the top point during transmission. Although the centrifugal acceleration exerted on the TPMS 2 sensor may be subject to variation, due to the acceleration / deceleration of wheel 1, the gravity-dependent component of gravity establishes a waveform of constant width (-1 to 1 [G]) and it varies in an extremely shorter period, compared to the speed of variation in the centrifugal acceleration, accompanied by the acceleration / deceleration of the vehicle. Therefore, it is easy to impose the variation in the gravity acceleration-dependent component based on centrifugal accelerations.
    [084] However, when a brake control, such as an ABS control and a brake traction control, is being performed, wheel 1, under control, is subjected to vibrating longitudinally in an extremely short period, due to this control, the centrifugal acceleration detected by the G 2b sensor will be affected and fluctuates in an extremely short period, with a large width or amplitude (several tens of [G] or more). In this way, the CU of sensor 2c may erroneously determine the tremor or fluctuations as the peak in the gravity acceleration-dependent component, so that the probability exists that the TPMS data will be transmitted at a different rotational position than the peak.
    [085] Thus, the rotational position calculation unit 4a of TPMSCU 4 calculates the rotational position of each wheel 1, in synchronization in which the rotational position of each TPMS sensor 2 has reached its peak, based on the receiving synchronization the TPMS data and the wheel speed pulse count value for each wheel, in this synchronization. Therefore, the rotational position calculation unit 4a calculates the rotational position of each wheel 1, which has been transmitted at the rotational position other than the top point, such as that transmitted at the top point, and the dispersion calculation unit 4b is for calculate the characteristic dispersion value X for each wheel 1, by including this rotational position in the rotational position data. Consequently, due to the inclusion of false rotational position data in the rotational position data for each wheel, the creation of the difference between the maximum value and the other values, for each characteristic dispersion value X, will be delayed and the determination of position of wheel will be slowed.
    [086] In comparison, in the first embodiment, the rotational position detection inhibition unit 4e inhibits the rotational position calculation unit 4a from detecting the rotational position for each wheel, when a brake control, such as an ABS control, is running.
    [087] More specifically, when there is a probability that the transmission synchronization of the TPMS data is different from the normal or common transmission synchronization, by inhibiting the calculation of the rotational position of each wheel, based on the TPMS data, the calculation of the value dispersion characteristic X, using erroneous or false data, will be eliminated.
    [088] Exposed in another way, when there is a probability that the transmission synchronization of the TPMS data has been made in a different synchronization than the normal or common synchronization, then, by inhibiting the calculation of the rotational position of each wheel 1, the data Rotational position errors will be prevented from being included in the rotational position data for each wheel. Therefore, a delay in determining the wheel position will be eliminated, and the correspondence ratio between each sensor ID and each wheel position can be determined prematurely.
    [089] A description of the effects will then be made.
    [090] In the pneumatic tire pressure monitoring device in the first embodiment, the following effects are achieved. (1) In the pneumatic tire pressure monitoring device, which monitors the pneumatic pressure of each tire, a pressure sensor 2a is provided, which detects the pneumatic pressure of the tire and which is installed in the tire of each wheel 1; a pressure sensor 2a, to detect the pneumatic pressure of each tire; a G 2b sensor, which is installed on the tire of each wheel 1 and detects centrifugal acceleration acting on the tire; and a transmitter 2d, which is installed on each wheel 1 and detects the rotational position of the wheel, based on the detected value of the G 2b sensor, to transmit, as a wireless signal, the pneumatic pressure at the determined rotational position, together with the Sensor ID; a receiver 3, which is arranged on the side of the vehicle body and receives the wireless signal; a rotational position calculation unit 4a, which is installed on the side of the vehicle body and to detect the rotational position of each wheel 1, when the wireless signal includes a specific sensor ID; a wheel position determination unit 4c, which determines the wheel position of the transmitter, corresponding to that specific sensor ID, based on the rotational position of each wheel 1; and a rotational position detection inhibition unit 4e, which inhibits the detection of the rotational position of each wheel 1 by the rotational position calculation unit 4a.
    [091] In this way, the delay in determining the wheel position, due to the vibration of the wheel 1, caused by a brake control, can be eliminated, and the correspondence between each sensor ID and each wheel position can be established according to beforehand. 2)) The wheel position determination unit 4c obtains the rotational position for each wheel 1 several times, accumulates the rotational position data for each wheel, and determines the wheel position corresponding to the rotational position data, with the lowest degree of dispersion between the rotational position data, such as the wheel position of transmitter 3 corresponding to the specific sensor ID.
    [092] In this way, the correspondence ratio between each TPMS 2 sensor and each wheel position can be precisely determined. 3)) The G 2b sensor detects the centrifugal acceleration exerted on a tire, while the TPMS 2 sensor detects the rotational position of the wheel based on the gravity-dependent component of the centrifugal acceleration gravity.
    [093] Thus, even in a vehicle acceleration / deceleration state, the rotational position of the wheel can be detected with good precision. [Other embodiments]
    [094] Although the best embodiments have been described to implement the present invention, the specific configuration is not limited to these embodiments. Instead, a design variation or changes that do not depart from the essence of the present invention can be included in the present invention.
    [095] For example, the G sensor can detect the acceleration exerted in a rotational direction of the tire and detect the rotational position in this detected acceleration. During a constant vehicle travel, in which no acceleration / deceleration is taking place in the tire's rotational direction, the accelerations acting on the tire are "0" [G], on a top or bottom part of the tire, while considering " 1 "[G] or" -1 "[G] in the forward and backward direction, respectively. Therefore, by transmitting TPMS data in synchronization when the detection value of the acceleration sensor assumes "1" or "-1", the TPMS data can be transmitted to a constant rotational position.
    权利要求:
    Claims (2)
    [0001]
    1) Pneumatic tire pressure monitoring device (4), comprising: a pneumatic tire pressure sensor (2a) installed on a tire on each wheel (1), to detect a pneumatic tire pressure acting on the tire; an acceleration sensor (2b) installed on the tire of each wheel (1), to detect acceleration in a given direction acting on the tire; a transmitter (2d) arranged on each wheel (1), to detect a rotational position of the wheel (1), based on a detected value of the acceleration sensor (2b), to transmit the pneumatic pressure together with information of unique specific identification for each transmitter (2d), by means of a wireless signal; a receiver (3), installed in a vehicle body, to receive the wireless signal; and a rotational position detection unit (4a), installed in the vehicle body, to detect the rotational position of each wheel (1), when the specific identification information has been transmitted; CHARACTERIZED by the fact that a wheel position determination unit (4c), which obtains the rotational position of each wheel (1) a plurality of times, to accumulate the rotational position data for each wheel (1), and determine a wheel position corresponding to the rotational position data with the least degree of dispersion between the rotational position data of the transmitter wheel position (2d) corresponding to the specific identification information; and a detection inhibition unit (4e), which inhibits the accumulation of the rotational position data of each wheel (1) by the rotational position detection unit (4a), when a brake control, to control a cylinder pressure of wheel wheel (1), is being executed, in which the wheel position determination unit (4c) converts the rotational position of the wheel (1) into a vector in a two-dimensional plane, with its origin as a starting point and a circumferential point of a unit circle as a termination point; calculate a scalar quantity of an average vector of each rotational position data as a characteristic dispersion value; and determining a maximum value for each characteristic dispersion value as the one with the lowest degree of dispersion.
    [0002]
    2) Pneumatic tire pressure monitoring device (4), according to claim 1, CHARACTERIZED by the fact that: the acceleration sensor (2b) detects a centrifugal acceleration that acts on the tire and the transmitter (2d) detects the rotational position of the wheel (1) based on the component dependent on the gravitational acceleration of the centrifugal acceleration.
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    法律状态:
    2018-12-18| B06F| Objections, documents and/or translations needed after an examination request according [chapter 6.6 patent gazette]|
    2019-11-19| B06U| Preliminary requirement: requests with searches performed by other patent offices: procedure suspended [chapter 6.21 patent gazette]|
    2020-11-17| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|
    2021-01-19| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 20/02/2012, OBSERVADAS AS CONDICOES LEGAIS. |
    优先权:
    申请号 | 申请日 | 专利标题
    JP2011-096674|2011-04-25|
    JP2011096674A|JP5853402B2|2011-04-25|2011-04-25|Tire pressure monitoring device|
    PCT/JP2012/053972|WO2012147395A1|2011-04-25|2012-02-20|Tire air pressure monitor device|
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