JP6260474B2 - Tire pressure detector - Google Patents

Description

  The present invention attaches a transmitter provided with a pressure sensor to a wheel to which a tire is attached, transmits a detection result of the pressure sensor from the transmitter, and receives the tire air pressure by a receiver attached to the vehicle body side. The present invention relates to a direct-type tire pressure detection device that performs detection.

  Conventionally, there is a direct type as one of tire pressure detecting devices. In this type of tire pressure detecting device, a transmitter equipped with a sensor such as a pressure sensor is directly attached to a wheel side to which a tire is attached. In addition, an antenna and a receiver are provided on the vehicle body side. When a detection signal from the sensor is wirelessly transmitted from the transmitter, the detection signal is received by the receiver via the antenna, and the tire pressure is detected. Is done.

  In such a direct tire pressure detection device, unique identification information is included in the data transmitted by the transmitter so that it can be determined whether the transmitted data is for the host vehicle or the other vehicle. (Hereinafter referred to as ID information). Further, by making the ID information different for each transmitter, the wheel to which the transmitter is attached can also be identified.

  In order to specify whether or not the transmitter of the host vehicle is based on the ID information included in the transmission data, it is necessary to register the ID information of each transmitter on the receiver side in advance. For this reason, the tire pressure detecting device is provided with an automatic ID registration function, and the ID of the own vehicle is automatically registered from the ID information given to the received data. Specifically, since data from transmitters provided to an unspecified number of vehicles may be received while the vehicle is stopped, the ID information given to the data received while the vehicle is traveling is automatically used. It is registered as a vehicle (see, for example, Patent Document 1).

JP 2012-218672 A

  However, when the host vehicle and the other vehicle are running side by side or running side by side, the data including the ID information from the transmitter attached to the wheels of the other vehicle is received. It becomes indistinguishable from that of your vehicle. As a result, there is a possibility that ID information of the transmitter of the other vehicle is erroneously registered as that of the transmitter of the own vehicle.

  The present invention has been made in view of the above points, and it is an object of the present invention to provide a tire pressure detection device capable of accurately registering the ID information of the transmitter of the own vehicle by distinguishing it from the ID information of the transmitter of the other vehicle. .

  In order to achieve the above object, according to the first aspect of the present invention, the pressure sensor is provided in each of the plurality of wheels (5a to 5d) including the tire and outputs a detection signal related to the tire air pressure of each of the plurality of wheels. The wheel speed is detected from (21a) and a sensing unit (21b) having an acceleration sensor (21b) that outputs a detection signal corresponding to the acceleration caused by the rotation of the wheel, and a detection signal corresponding to the acceleration output from the acceleration sensor. In addition, a first control unit (22) for processing a detection signal output from the pressure sensor and creating a frame storing data on wheel speed and data on tire pressure together with ID information, and a radio wave transmission unit for transmitting the frame A transmitter (2) having (23), a radio wave receiver (32) that is provided on the vehicle body (6) side and receives a frame; Based on the data about the tire pressure is stored in the received frame, a second control unit for detecting a tire air pressure (33), a receiver (3) having a, a.

  In such a configuration, the second control unit acquires the vehicle speed, and the timing at which the vehicle speed is accelerated or decelerated to the predetermined speed from the timing at which the vehicle speed is accelerated or decelerated to the predetermined speed and the data on the wheel speed stored in the frame. Registration means for registering the ID information stored in the frame as the ID information of the host vehicle when it is determined by the determination means (S110, S120, S140, S150) Means (S160).

  As described above, the frame speed data transmitted from the transmitter includes data related to the wheel speed, and the vehicle speed acquired by the receiver is accelerated to the predetermined speed when the wheel speed detected by the transmitter is accelerated or decelerated to the predetermined speed. ID registration is performed for the first time on condition that the timing coincides with the deceleration timing. That is, even if the other vehicle is running side by side next to the host vehicle or running side by side in front and back, the timing at which the wheel speed of the other vehicle exceeds the predetermined speed and the timing at which the vehicle speed of the host vehicle exceeds the predetermined speed. Does not match.

  Therefore, it is also necessary that the timing at which the wheel speed detected by the transmitter accelerates or decelerates to the predetermined speed matches the timing at which the vehicle speed acquired by the receiver accelerates or decelerates to the predetermined speed. Can be distinguished from the ID information of other vehicles. Thereby, it can be set as the tire air pressure detection apparatus which can distinguish the ID information of the transmitter of the own vehicle from the ID information of the transmitter of another vehicle, and can register it correctly.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows an example of a corresponding relationship with the specific means as described in embodiment mentioned later.

It is the figure which showed schematic structure of the tire pressure monitoring system and remote key system concerning 1st Embodiment of this invention. It is a figure which shows the block configuration of the transmitters 2a-2d. 2 is a block diagram illustrating a receiver 3. FIG. It is a flowchart of the automatic ID registration process which the control part 33 performs.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other will be described with the same reference numerals.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. 1 corresponds to the front of the vehicle 1, the downward direction of the paper corresponds to the rear of the vehicle 1, and the horizontal direction of the paper corresponds to the horizontal direction of the vehicle.

  The tire air pressure detection device shown in FIG. 1 is attached to a vehicle 1 and includes transmitters 2a to 2d, a receiver 3, and a display 4.

  As shown in FIG. 1, the transmitters 2 a to 2 d are attached to the wheels 5 a to 5 d in the vehicle 1, and detect the air pressure of tires attached to the wheels 5 a to 5 d and detect the detection results. The signal data is stored in the frame together with the ID information and transmitted. The receiver 3 is attached to the vehicle body 6 side of the vehicle 1 and receives frames transmitted from the transmitters 2a to 2d, and performs various processes and calculations based on the detection signals stored therein. To detect the tire pressure.

  As shown in FIG. 2A, the transmitters 2a to 2d are configured to include a sensing unit 21, a control unit (first control unit) 22, a radio wave transmission unit 23, a battery 24, and an antenna 25. Each unit is driven based on the power supply from the battery 24.

  The sensing unit 21 includes, for example, a diaphragm type pressure sensor 21a, an acceleration sensor 21b, and the like, and outputs a detection signal corresponding to the tire pressure and a detection signal corresponding to the acceleration, and transmits the detection signal to the control unit 22. Yes. The acceleration sensor 21b is arranged so as to be able to detect acceleration that fluctuates according to tire rotation. For example, the acceleration sensor 21b is arranged so as to be able to detect acceleration in the wheel radial direction and acceleration in the wheel tangential direction. Therefore, when the tire is rotated, the acceleration sensor 21b outputs a detection signal including a centrifugal acceleration component accompanying the rotation.

  Although not shown, the sensing unit 21 is also provided with a temperature sensor, and a detection signal corresponding to the tire internal temperature is also transmitted to the control unit 22.

  The control unit 22 is configured by a known microcomputer including a CPU, a ROM, a RAM, an I / O, and the like, and executes predetermined processing according to a program stored in a memory in the ROM or the like. The memory in the control unit 22 stores ID information including identification information unique to the transmitter for identifying each of the transmitters 2a to 2d and identification information unique to the vehicle for identifying the host vehicle.

  The control unit 22 receives the detection signal output from the sensing unit 21, processes the signal and processes it as necessary, and then includes the ID information of each of the transmitters 2 a to 2 d as data indicating the detection result in the frame. Store the frame and send the frame to the radio wave transmitter 23. Further, the control unit 22 calculates the wheel speed based on the detection signal of the acceleration sensor 21b, and when the wheel speed reaches a predetermined speed (for example, 40 km / h), the data indicating the wheel speed data is described above. It is stored in the frame and sent to the radio wave transmitter 23. For example, if the wheel speed data is referred to as wheel speed data, the wheel speed data (that is, a bit indicating the data) is turned off when the wheel speed is less than a predetermined speed, and the wheel speed data is changed when the wheel speed exceeds the predetermined speed. I try to switch it on.

  The radio wave transmission unit 23 functions as an output unit that transmits the frame transmitted from the control unit 22 through the antenna 25 to the receiver 3 as an RF radio wave. The process of sending a signal from the control unit 22 to the radio wave transmission unit 23 is set to be executed for each predetermined periodical transmission according to the program. That is, since it is not possible to determine whether the ignition switch (IG) is on or off on the transmitters 2a to 2d side, frame transmission is basically performed at every predetermined periodic transmission cycle. Regarding the periodic transmission cycle, the cycle is changed depending on whether the vehicle is stopped or running, and the cycle is shortened when traveling or shorter than when stopped, or after a change from stopping to traveling Some changes can be made as appropriate, such as a shorter period. For example, it is possible to determine whether the vehicle is stopped or traveling based on the wheel speed calculated based on the detection signal of the acceleration sensor 21b, and to change the periodic transmission cycle according to the determination result.

  The battery 24 supplies power to the sensing unit 21, the control unit 22, etc., and receives power supply from the battery 24, collects data related to tire air pressure in the sensing unit 21 and controls the control unit 22. Various calculations are executed.

  The transmitters 2a to 2d configured as described above are attached to air injection valves in the wheels of the wheels 5a to 5d, for example, and are arranged so that the sensing unit 21 is exposed to the inside of the tire. Thereby, the transmitters 2a to 2d detect the tire air pressure of the corresponding wheels, and transmit frames at predetermined intervals through the antennas 25 provided in the transmitters 2a to 2d.

  As shown in FIG. 2B, the receiver 3 operates based on power supply from a battery or the like, and includes an antenna 31, a radio wave reception unit 32, and a control unit 33. .

  The antenna 31 is for receiving frames sent from the transmitters 2a to 2d. In the present embodiment, the antenna 31 is a single common antenna that collectively receives frames transmitted from the transmitters 2 a to 2 d and is fixed to the vehicle body 6.

  The radio wave receiving unit 32 functions as an input unit that receives a frame transmitted from each of the transmitters 2 a to 2 d and receives it by the antenna 31 and sends it to the control unit 33.

  The control unit (second control unit) 33 is configured by a known microcomputer including a CPU, a ROM, a RAM, an I / O, and the like. The control unit 33 performs various processes related to tire air pressure in accordance with a program stored in a ROM or the like. Specifically, the control unit 33 performs automatic ID registration for automatically registering the ID information of the transmitter 2 of the host vehicle. When a frame with the registered ID information is received, Various processes related to tire pressure detection are executed based on the stored data.

  For example, the control unit 33 obtains the tire pressure by performing various signal processing and calculations based on data related to the tire pressure stored in the frame received from the radio wave reception unit 32 as various types of processing related to tire pressure detection. And the electric signal according to the calculated | required tire pressure is output to the indicator 4. FIG. For example, the control unit 33 compares the obtained tire air pressure with a predetermined alarm threshold Th, and when detecting that the tire air pressure has dropped below the predetermined alarm threshold Th, a signal to that effect is displayed on the display 4. Output. In this way, the indicator 4 is informed that the tire air pressure of any of the four wheels 5a to 5d has decreased.

  As shown in FIG. 1, the display 4 is arranged at a place where the driver can visually recognize, and is configured by an alarm lamp or a display installed in an instrument panel in the vehicle 1, for example. For example, when a signal indicating that the tire air pressure has decreased is sent from the control unit 33 in the receiver 3, the display device 4 notifies the driver of the decrease in tire air pressure by displaying that effect.

  As described above, the tire pressure detection device according to the present embodiment is configured. Subsequently, the operation of the tire air pressure detection device of the present embodiment will be described. Since the operation related to basic tire air pressure detection is the same as the conventional one, the automatic ID registration operation different from the conventional one will be described.

  This automatic ID registration operation will be described with reference to the flowchart of the automatic ID registration process shown in FIG. The automatic ID registration process shown in this figure is executed at predetermined control cycles by the control unit 33 when, for example, the IG is turned on.

  First, as shown in step 100, it is determined whether or not the receiver 3 has received a frame with ID information. At this time, regardless of whether it belongs to the own vehicle or the other vehicle, if a frame with ID information is received, an affirmative determination is made and the routine proceeds to step 110, where no frame is received. If not, the process ends.

  In the subsequent step 110, it is determined whether or not the vehicle speed has accelerated to a predetermined speed (for example, 40 km / h). For example, by acquiring vehicle speed information from an electronic control device (hereinafter referred to as meter ECU) that performs meter control (not shown) through the in-vehicle LAN wiring, it is determined whether or not the vehicle speed has accelerated until it exceeds a predetermined speed. Can do.

  If the determination is affirmative, the routine proceeds to step 120 where it is determined whether or not the wheel speed data stored in the frame has changed from off to on. If an affirmative determination is made here as well, the timing at which the vehicle speed obtained on the receiver 3 side reaches the predetermined speed coincides with the timing at which the wheel speed reaches the predetermined speed at the transmitter 2 and is stored in that frame. The confirmation that the ID information is that of the transmitter 2 of the host vehicle is high. Therefore, it progresses to step 130 and ID information provided to the received frame is ID-registered as a candidate that belongs to the transmitter 2 of the own vehicle.

  Thereafter, the routine proceeds to step 140, where it is determined whether or not the vehicle speed has been reduced to a predetermined speed (for example, 40 km / h). For example, similarly to step 110 described above, by acquiring vehicle speed information from a meter ECU (not shown), it can be determined whether or not the vehicle has been decelerated until the vehicle speed becomes a predetermined speed or less.

  If the determination is affirmative, the routine proceeds to step 150, where it is determined whether or not the wheel speed data stored in the frame has changed from on to off. If an affirmative determination is made here as well, the timing at which the vehicle speed obtained at the receiver 3 is reduced to a predetermined speed coincides with the timing at which the wheel speed is reduced to the predetermined speed at the transmitter 2 and is stored in that frame. The confirmation that the ID information is that of the transmitter 2 of the host vehicle is high. Therefore, it progresses to step 160 and ID registration provided to the received flame | frame is ID-registered as a candidate which is the transmitter 2 of the own vehicle. In this way, the automatic ID registration process is completed. Here, although ID registration is performed as a candidate for the transmitter 2 of the own vehicle, it may be registered as the transmitter 2 of the own vehicle as it is, or the ID information listed as a candidate in step 120 or step 160. When the IDs match, the ID may be officially registered for the first time. Further, when the number of candidates equal to or greater than the number of wheels of the host vehicle is gathered, the above process is repeated again, and when the number of candidates matches the number of wheels of the host vehicle, the ID may be officially registered. .

  As described above, in this embodiment, in addition to the vehicle running, the timing at which the wheel speed detected by the transmitter 2 is accelerated to a predetermined speed is the same as the vehicle speed acquired by the receiver 3 is the predetermined speed. The ID is registered as a condition that it coincides with the accelerated timing. Alternatively, it is also a condition that the timing at which the wheel speed detected by the transmitter 2 is reduced to a predetermined speed matches the timing at which the vehicle speed acquired by the receiver 3 is reduced to the predetermined speed. For this reason, it is possible to suppress ID registration of the ID information of the transmitter of the other vehicle as that of the transmitter 2 of the own vehicle.

  That is, in the conventional case, when the receiver 3 receives the frame to which the ID information is added, the receiver 3 determines whether or not the vehicle is running. ID registration is automatically performed for the transmitter. Thus, since automatic ID registration is performed only during traveling, ID registration of the transmitter of the own vehicle can be basically performed. However, if other vehicles are running side by side or running side by side, the ID information of the other vehicles may be registered as that of the own vehicle.

  In contrast, in the present embodiment, wheel speed data is included in the frame transmitted from the transmitter 2 so that the timing at which the wheel speed detected by the transmitter 2 reaches a predetermined speed can be confirmed by the receiver 3. I have to. The ID registration is made for the first time on the condition that the timing at which the wheel speed detected by the transmitter 2 is accelerated or decelerated to a predetermined speed coincides with the timing at which the vehicle speed acquired by the receiver 3 is accelerated or decelerated to the predetermined speed. Has been done. In other words, even if another vehicle is running side by side next to the host vehicle or running side by side in front and back, the timing at which the wheel speed of the other vehicle accelerates or decelerates to a predetermined speed and the vehicle speed of the host vehicle are the predetermined speed. The timing to accelerate or decelerate until does not match.

  Therefore, on the condition that the timing at which the wheel speed detected by the transmitter 2 is accelerated or decelerated to a predetermined speed coincides with the timing at which the vehicle speed acquired by the receiver 3 is accelerated or decelerated to the predetermined speed, The ID information of the own vehicle can be distinguished from the ID information of other vehicles. Thereby, it can be set as the tire air-pressure detection apparatus which can register ID information of the transmitter 2 of the own vehicle separately from ID information of the transmitter of other vehicles, and can register exactly.

(Other embodiments)
The present invention is not limited to the embodiment described above, and can be appropriately changed within the scope described in the claims.

  For example, in the above-described embodiment, the step that the timing at which the wheel speed detected by the transmitter 2 is accelerated or decelerated to a predetermined speed coincides with the timing at which the vehicle speed acquired by the receiver 3 is accelerated or decelerated to the predetermined speed is performed. 110, 120, 140, 150. That is, when it is determined that the vehicle speed acquired by the receiver 3 has been accelerated or decelerated to a predetermined speed, it is determined whether or not the wheel speed detected by the transmitter 2 has been accelerated or decelerated to the predetermined speed. . However, the timing at which the vehicle speed acquired by the receiver 3 is accelerated or decelerated to a predetermined speed may be slower than the wheel speed detected by the transmitter 2 is accelerated or decelerated to the predetermined speed. In that case, even if an affirmative determination is made in steps 110 and 140, an affirmative determination is not made in steps 120 and 150.

  Therefore, for example, by taking into account an error between the vehicle speed and the wheel speed, the predetermined speed used in the determinations at steps 110 and 140 may be made smaller by an error than the predetermined speed when the wheel speed data is turned on. Alternatively, it may be a condition that both affirmative determination is made in steps 110 and 120 within a predetermined period, or both are affirmatively determined in steps 140 and 150. Even in this case, it can be determined whether the timing at which the wheel speed detected by the transmitter 2 is accelerated or decelerated to a predetermined speed matches the timing at which the vehicle speed acquired by the receiver 3 is accelerated or decelerated to the predetermined speed.

  The timing at which the wheel speed data is switched from OFF to ON matches the timing at which the vehicle speed is accelerated to a predetermined speed, or the timing at which the wheel speed data is switched from ON to OFF matches the timing at which the vehicle speed is decelerated to the predetermined speed. It is determined whether or not. This is a method for determining whether or not the timing at which the vehicle speed is accelerated or decelerated to a predetermined speed matches the timing at which the wheel speed obtained from the data relating to the wheel speed stored in the frame is accelerated or decelerated to the predetermined speed. One is shown. In addition, the transmitter 2 can store data indicating the wheel speed itself as data relating to the wheel speed in a frame. In that case, comparing the wheel speed obtained from the data indicating the wheel speed and the vehicle speed, the timing at which the wheel speed is accelerated or decelerated to the predetermined speed matches the timing at which the vehicle speed is accelerated or decelerated to the predetermined speed. What is necessary is just to determine.

  Further, a technique for identifying whether the transmitter 2 is attached to the front, rear, left, or right wheels based on the reception intensity or RSSI value when the radio wave transmitted from the transmitter 2 is received by the receiver 3. Have been proposed (see, for example, Japanese Patent Laid-Open No. 2013-086661). Similarly, various techniques for specifying which of the front, rear, left, and right wheels the transmitter 2 is attached based on the detection signal of the acceleration sensor 21b have been proposed (for example, JP 2013-001220 A). reference). When the present invention is applied together with these technologies, not only the ID information of the transmitter 2 of the own vehicle and the ID information of the transmitter of the other vehicle but also the position of the wheel to which each transmitter 2 of the own vehicle is attached. It becomes possible to specify. Therefore, ID registration of each transmitter 2 becomes possible in association with each wheel 5a-5d.

  The steps shown in each figure correspond to means for executing various processes. That is, the part that executes the processing of steps 110, 120, 140, and 150 corresponds to the determination unit, and the part that executes the processing of steps 130 and 160 corresponds to the registration unit.

DESCRIPTION OF SYMBOLS 1 Vehicle 2a-2d Transmitter 3 Receiver 4 Indicator 5a-5d Wheel 6 Car body 21 Sensing part 22, 33 Control part

Claims (4)

A plurality of wheels (5a to 5d) provided with tires, each of which is provided with a pressure sensor (21a) for outputting a detection signal relating to tire air pressure of each of the plurality of wheels, and according to acceleration generated with the rotation of the wheels The wheel speed is detected from a sensing unit (21) having an acceleration sensor (21b) that outputs the detected signal and a detection signal corresponding to the acceleration output from the acceleration sensor, and the detection signal output from the pressure sensor is signaled. A first control unit (22) for processing and creating a frame storing data on the wheel speed and data on the tire air pressure together with identification information; and a radio wave transmission unit (23) for transmitting the frame. A transmitter (2)
A radio wave receiving unit (32) that is provided on the vehicle body (6) side and receives the frame, and a second control unit (33) that detects tire pressure based on the received tire pressure data stored in the frame. And a receiver (3) having
The second controller is
Whether the vehicle speed is acquired and the timing at which the vehicle speed is accelerated or decelerated to a predetermined speed and the timing at which the wheel speed is accelerated or decelerated from the data relating to the wheel speed stored in the frame is coincident. Determination means for determining (S110, S120, S140, S150);
A tire pressure detecting device comprising: a registration unit (S160) that registers the identification information stored in the frame as the identification information of the host vehicle when the determination unit determines that they match. The first control unit turns off data indicating the wheel speed when the wheel speed is less than the predetermined speed, and indicates data indicating the wheel speed when the wheel speed is equal to or higher than the predetermined speed. Turn on
The determination means determines whether the timing at which the data indicating the wheel speed is switched from OFF to ON matches the timing at which the vehicle speed is accelerated to a predetermined speed, or the timing at which the data indicating the wheel speed is switched from ON to OFF. The tire pressure detection device according to claim 1, wherein it is determined whether or not a timing at which the vehicle speed is reduced to a predetermined speed coincides with each other. The determination means matches the timing at which the vehicle speed is accelerated or decelerated to a predetermined speed and the timing at which the wheel speed is accelerated or decelerated from the data relating to the wheel speed stored in the frame within a predetermined time. The tire pressure detecting device according to claim 1 or 2, wherein it is determined whether or not to do so. The predetermined speed as a first predetermined speed,
The determination means accelerates the wheel speed to the first predetermined speed based on the timing at which the vehicle speed is accelerated or decelerated to a second predetermined speed that is lower than the first predetermined speed and the data on the wheel speed stored in the frame. The tire pressure detection device according to any one of claims 1 to 3, wherein it is determined whether or not the deceleration timing coincides.

Images