JP2009262817A - Tire wear estimating device, and tire rotation recommending device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tire wear estimating device estimating the wear of a tire with excellent accuracy while suppressing any increase in the manufacturing cost by a simple constitution. <P>SOLUTION: A travel supporting device 1 has a tire wear estimating device for estimating the wear of the tire in a vehicle for executing the small-turn travel control to reduce the turning radius by applying the brake to a rear wheel inside the turning direction when the vehicle makes a turn. The tire wear estimating device has a tire wear estimation unit 8 for estimating the wear of the tire of a front wheel from the turning direction by the small-turn travel control and the small-turn travel control time. The tire wear estimation unit 8 estimates the wear of the tire of the front wheel by considering the wear of each tire of the front wheels different between the outer side and the inner side toward the turning direction during the small-turn travel control, and the wear of the tire of the front wheels is estimated with excellent accuracy. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a tire wear amount estimation device that estimates a tire wear amount of a vehicle that performs small-turn traveling control during turning, and a tire rotation recommendation device that recommends execution of tire rotation.

2. Description of the Related Art Conventionally, a technique for uniformly estimating the amount of wear of each tire based on an accumulated travel distance of a vehicle is known (for example, Patent Document 1). A technique is also known in which a tag is attached to each tire and a system for reading information from the tag on the vehicle side is provided to directly detect the wear amount of each tire.
JP 2007-093434 A JP 2006-151281 A Japanese Patent Laid-Open No. 11-049020

  However, in the technique described in Patent Document 1, since the tire wear amount is calculated based on the accumulated travel distance, there is a problem in that it cannot be accurately estimated when a left-right difference occurs in the tire wear amount. was there. Also, with the technology for tagging each tire, the tag is mounted on each tire, so the tire manufacturing cost will increase, and if the reliability of the tag decreases due to long-term use, it will be accurate. There is a problem that it cannot be estimated.

  In particular, a vehicle that performs small turn traveling control during turning is required to accurately estimate the amount of tire wear and to recommend tire rotation with high accuracy.

  The present invention has been made to solve such a problem, and an object of the present invention is to provide a tire wear amount estimation device capable of accurately estimating the tire wear amount with a simple configuration. .

  Another object of the present invention is to provide a tire rotation recommendation device capable of recommending the execution of tire rotation with a simple configuration with high accuracy. And

  The tire wear amount estimation device according to the present invention is a vehicle that performs small-turn running control that applies braking to shorten the turning radius so that the braking force of the wheels on the inner side in the turning direction becomes larger than the braking force of the wheels on the outer side of the turning direction when turning. A tire wear amount estimating apparatus for estimating a tire wear amount, comprising tire wear amount estimating means for estimating a tire wear amount of a front wheel from a turning direction by a small turning traveling control and a small turning traveling control time.

  According to such a tire wear amount estimation device, the tire wear amount estimation means estimates the tire wear amount of the front wheels from the turning direction by the small turning traveling control and the small turning traveling control time. For this reason, the wear amount of each tire of the front wheel, which is different between the outside and the inside in the turning direction during the small turn traveling control, can be taken into consideration, and the tire wear amount of the front wheel can be accurately estimated. Moreover, since it is not necessary to mount a tag on a tire unlike before, the amount of tire wear can be estimated with a simple configuration with high accuracy.

  Further, the tire wear amount estimation means may estimate the tire wear amount of the front wheels according to the traveling speed of the vehicle during turning by the small turning traveling control. In this way, the amount of tire wear on the front wheels can be estimated more accurately by taking into account the vehicle traveling speed during the small-turn traveling control.

  Moreover, it is good also as a structure further provided with the tire rotation judgment means which judges whether execution of a tire rotation is recommended based on the tire wear amount of a front wheel. Thereby, it is possible to accurately notify the driver that tire rotation is recommended.

  Moreover, it is good also as a structure further provided with the recommended rotation determination means which determines a recommended tire rotation based on the left-right difference of the tire wear amount of a front wheel. Thereby, it is possible to notify the driver of a preferable tire rotation in a timely manner.

  Further, the tire rotation recommendation device according to the present invention is a vehicle that performs small-turn traveling control that shortens the turning radius by applying braking so that the braking force of the inner wheel in the turning direction is larger than the braking force of the outer wheel in turning. Tire rotation recommendation device that recommends the execution of tire rotation in the vehicle, and based on the control time of the small-turn running control, it is determined whether or not the tire rotation needs to be executed, and the tire rotation needs to be executed When it is determined, the recommended tire rotation is determined based on the difference in control time for each turning direction of the small-turn traveling control.

  According to such a tire rotation recommendation device, the recommended tire rotation is determined according to the left-right difference in the small turn traveling control time. For this reason, it is possible to recommend the execution of tire rotation with high accuracy in consideration of the difference between the left and right tire wear amounts.

  According to the tire wear amount estimation device of the present invention, it is possible to improve the estimation accuracy of the tire wear amount while suppressing an increase in manufacturing cost with a simple configuration.

  Moreover, according to the tire rotation recommendation device of the present invention, it is possible to accurately recommend the execution of tire rotation while suppressing an increase in manufacturing cost with a simple configuration.

  Hereinafter, preferred embodiments of a tire wear amount estimating device and a tire rotation recommendation device according to the present invention will be described with reference to the drawings. In the present embodiment, a travel support device including a tire wear amount estimation device and a tire rotation recommendation device will be described. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. FIG. 1 is a block configuration diagram illustrating a travel support apparatus according to an embodiment of the present invention.

  A travel support device 1 shown in FIG. 1 is provided in a vehicle and performs small-turn travel control, and has a function of estimating tire wear and a function of recommending the execution of tire rotation. Note that the “small turning traveling control” in the present embodiment is to perform traveling control with a shorter turning radius than in a normal turning when a predetermined execution condition is satisfied during turning.

  The travel support apparatus 1 includes a steering angle sensor 2, a vehicle speed sensor 3, a travel support ECU 4, a brake actuator 5, a tire wear amount estimation ECU (tire wear amount estimation means, tire rotation determination means, recommended rotation determination means) 6, and a display. Part 7 is provided. The steering angle sensor 2, the vehicle speed sensor 3, and the brake actuator 5 are electrically connected to the travel support ECU 4, and the display unit 7 is electrically connected to the tire wear amount estimation ECU 6. In addition, the travel support ECU 4 and the tire wear amount estimation ECU 6 are configured to be able to exchange data with each other by being connected by a communication circuit such as CAN (Control Area Network). The driving support ECU 4 and the tire wear amount estimation ECU 6 are electronic control units including a CPU that performs arithmetic processing, a ROM and a RAM that are storage units, an input signal circuit, an output signal circuit, a power supply circuit, and the like.

  The steering angle sensor 2 is provided on, for example, a steering shaft and detects a steering direction and a steering angle based on a steering operation performed by a driver, and transmits the detected steering direction and steering angle to the travel support ECU 4 as a steering signal. .

  The vehicle speed sensor 3 is provided, for example, on the axle shaft, detects the rotation speed of the axle shaft, and calculates the vehicle speed V based on the detected rotation speed of the axle shaft. The vehicle speed sensor 3 transmits the calculated vehicle speed V to the travel support ECU 4 as a vehicle speed signal.

  The travel support ECU 4 controls the travel of the vehicle, and selects the normal travel control or the small travel control with a turning radius shorter than that of the normal travel control based on the steering angle and the vehicle speed V. The storage unit of the travel support ECU 4 stores a selection (start) condition for the small-turn traveling control, a continuation condition for the small-turn traveling control, a program for executing the normal traveling control and the small-turn traveling control, and the like. The selection conditions for the small-turn running control include that the steering angle is 90% or more of the maximum angle, and the vehicle speed is 2 km / h or more and 10 km / h or less. Examples of the continuation condition for the small-turn traveling control include that the steering angle is 80% or more of the maximum angle and the vehicle speed is 15 km / h or less. Note that the selection condition and the continuation condition of the small-turn traveling control may be other values.

  The brake actuator 5 is provided for each wheel, and can apply a braking force independently for each wheel based on a drive signal from the travel support ECU 4. For example, the travel support ECU 4 transmits a drive signal to the brake actuator 5 when the selection condition for the small-turn travel control is satisfied, so that the braking force of the wheel inside the turning direction is larger than the braking force of the wheel outside the turning direction. Control is performed to brake the rear wheel inside the turning direction, and the turning radius of the vehicle is shortened.

  The tire wear amount estimation ECU 6 estimates the wear amount of each tire from the turning direction by the small turn traveling control and the short turn traveling control time, and also based on the estimated wear amount of the tires on the left and right front wheels and the left-right difference of the wear amount. This is to determine the tire rotation timing and recommended rotation of the front and rear wheels. In the tire wear amount estimation ECU 6, a tire wear amount estimation unit 8 and a tire rotation determination unit 9 are constructed by executing a program stored in the storage unit.

  The tire wear amount estimation unit 8, when the small turn traveling control is executed, information on the turning direction by the small turn traveling control and the time during which the small turn traveling control is executed (hereinafter referred to as “small turn traveling control time”). Receive more. Then, the tire wear amount estimation unit 8 compares the received turning direction and the small turn traveling control time with a wear amount conversion map described later, and sets the small turn traveling control time for each turning direction by the small turn traveling control to the tires on the left and right front wheels and Convert to the amount of tire wear on the left and right rear wheels. Then, every time the small-turn traveling control is performed, the tire wear amount is converted, and an integrated value of the wear amount is calculated for each tire and stored in the storage unit 10 of the tire wear amount estimation ECU 6.

  The storage unit 10 of the tire wear amount estimation ECU 6 stores in advance a wear amount conversion map for calculating the wear amount of the tires of the four wheels of the vehicle based on the small turning traveling control time. A plurality of types of wear amount conversion maps are prepared in accordance with traveling conditions such as vehicle speed and steering angle during small-turn traveling control. The tire wear amount estimation unit 8 recognizes the travel state during the small turn travel control, and estimates the wear amount for each tire with reference to the wear amount conversion map close to the recognized travel state.

  Further, the storage unit 10 of the tire wear amount estimation ECU 6 stores a small-turn traveling control time, an integrated value for each tire of the tire wear amount estimated by conversion, and the like. The storage unit 10 of the tire wear amount estimation ECU 6 stores in advance a determination threshold value for determining whether or not to recommend tire rotation.

  FIG. 3 is a diagram showing an example of a wear amount conversion map used in the tire wear amount estimating apparatus shown in FIG. 1, where (a) shows a case where the vehicle speed is 10 km / h, and (b) shows a case where the vehicle speed is 15 km / h. FIG. In the wear amount conversion map when the vehicle speed V in FIG. 3A is 10 km / h, the wear amount of the front turning direction outer wheel (Fr outer wheel) is about 0.8 mm / 3650 seconds, and the front wheel turning direction inner wheel ( Fr inner ring) wear amount and rear wheel turning direction outer ring (Rr outer ring) wear amount is about 0.15 mm / 3650 seconds, and rear wheel turning direction inner ring (Rr inner ring) wear amount is about 0.18 mm / 3650 seconds. Further, in the wear amount conversion map when the vehicle speed V in FIG. 3B is 15 km / h, the wear amount of the front turning direction outer wheel (Fr outer wheel) is about 0.92 mm / 3650 seconds, and the turning direction of the front wheel The wear amount of the inner ring (Fr inner ring) is about 0.11 mm / 3650 seconds, the wear amount of the rear turning outer ring (Rr outer ring) is about 0.15 mm / 3650 seconds, and the rear turning inner ring (R The wear amount of the Rr inner ring is about 0.09 mm / 3650 seconds.

  The tire rotation determination unit 9 has an integrated value of the tire wear amount of any of the left and right front wheels estimated by the tire wear amount estimation unit 8 (hereinafter referred to as “integrated wear amount”) equal to or greater than a determination threshold (reference wear value). It is determined whether or not tire rotation is recommended when the accumulated wear amount of any of the left and right front wheels is equal to or greater than a determination threshold value.

  Further, when the tire rotation determining unit 9 determines to recommend the execution of the tire rotation, the tire rotation determining unit 9 obtains a difference between the accumulated wear amounts of the left and right front wheels, and determines a recommended tire rotation pattern (recommended rotation) based on the left / right difference. to decide. Specifically, the tire rotation determination unit 9 selects the cross rotation as the recommended rotation when the difference between the accumulated wear amounts of the left and right front wheels is equal to or greater than a predetermined determination threshold (allowable wear difference), and the accumulated wear of the left and right front wheels. When the amount difference is not equal to or greater than the predetermined determination threshold, parallel rotation is selected as the recommended rotation. Then, the tire wear amount estimation ECU 6 transmits information indicating the selected recommended rotation to the display unit 7. Note that the parallel rotation in the present embodiment is to rotate the front and rear tires on the same side.

  Based on the information output from the tire wear amount estimation ECU 6, the display unit 7 displays, for example, a light-up display to notify the driver of tire rotation recommendation. For example, when the display unit 7 displays rotation information, as shown in FIG. 2, cross rotation is recommended by turning on the first indicator 21 provided on the combination meter 20 disposed in front of the driver's seat, By turning on the second indicator 22, parallel rotation is recommended.

  The tire wear amount estimation ECU 6 is electrically connected to an indicator release switch (not shown) operated by a driver (operator). This indicator release switch is operated when tire rotation is executed. When the indicator release switch is operated, the tire wear amount estimation ECU 6 recognizes that the tire rotation has been executed, and releases the lighting display by the indicators 21 and 22.

  Next, a tire wear amount estimation process in the travel support device 1 having such a configuration and including a tire wear amount estimation device will be described with reference to the flowchart of FIG. 4. FIG. 4 is a flowchart showing an estimation process executed by the tire wear amount estimation apparatus according to the present embodiment.

  First, the vehicle speed sensor 3 compares whether or not the current vehicle speed V is within a certain range between the lower limit speed Va (2 km / h) and the upper limit speed Vb (10 km / h) at which the small turn traveling control is performed (S1). As a result of the comparison in step S1, if the vehicle speed V is within a certain range, the process proceeds to step S2, and if the vehicle speed V is not within the certain range, the small-turn running control is not performed, and the process returns to step S1.

In step S2, it is compared whether or not the absolute value of the steering angle δ _SW detected by the steering angle sensor 2 is equal to or greater than a predetermined threshold value δ _C (90% of the maximum angle). If the absolute value of the steering angle [delta] _SW predetermined threshold value [delta] _C or more, the process proceeds to step S3, because it does not perform the small turn running control smaller, the flow returns to step S1. In step S3, the rotation direction of the steering, that is, the turning direction of the vehicle is detected. If the turning direction is clockwise, the process proceeds to step S4. If the turning direction is counterclockwise, the process proceeds to step S6.

  When the turning direction is clockwise, the travel support ECU 4 starts the right small turn travel control (S4), and continues the right small turn travel control until the end condition of the right small turn travel control is met (S5). On the other hand, when the end condition of the right turn traveling control is met in step S5, the right turn turning control is finished and the control time for performing the turn turning control is measured (S8).

  When the turning direction is counterclockwise, the travel support ECU 4 starts the counterclockwise travel control (S6), and continues the counterclockwise travel control until the end condition of the counterclockwise travel control is met (S7). On the other hand, if the end condition of the left turn control is met in step S7, the left turn control is terminated and the control time for performing the turn control is measured (S8).

  Subsequently, the respective small turning control times measured by the driving support ECU 4 are transmitted to the tire wear amount estimation unit 8 of the tire wear amount estimation ECU 6, and the tire wear amount estimation unit 8 uses the tire wear amount conversion map to perform the small turn control time. Is converted into the wear amount of each tire (S9). Then, the newly converted wear amount is added to the accumulated wear amount of each tire stored in the storage unit 10 of the tire wear amount estimation ECU 6 to update the accumulated wear amount (S10).

  If the cumulative wear amount of each tire is updated in step S10, it is next determined whether any of the cumulative wear amounts of the left and right tires of the front wheels is equal to or greater than a reference wear value (S11). If the accumulated wear amount of any tire is equal to or greater than the reference wear value, it is determined that tire rotation is necessary, and the process proceeds to step S12. On the other hand, if none of the accumulated wear amounts of the left and right tires has reached the reference wear value, the process returns to step S1 and the wear amount estimation process is continued.

  In step S12, a difference value, which is a left-right difference in the accumulated wear amount of the left and right tires of the front wheels, is calculated (S12). Then, it is determined whether or not the difference value is equal to or greater than the allowable wear difference (S13). If the difference value is equal to or greater than the allowable wear difference, the tires on the left and right of the front wheels are worn unevenly, and the tire cross rotation is referred to as the recommended rotation. The information indicating that cross rotation should be performed is transmitted to the display unit 7 and the indicator 21 of the display unit 7 is turned on to guide the driver (S14).

  On the other hand, if the difference value, which is the difference between the left and right cumulative wear amounts of the front and left tires, is smaller than the allowable wear difference, the front and left tires are worn in a well-balanced manner, and the parallel rotation of the tires is judged as the recommended rotation. Then, information indicating that parallel rotation should be performed is transmitted to the display unit 7, and the indicator 22 of the display unit 7 is turned on to guide the driver (S15). The lighting of the indicator 21 or the indicator 22 is released by operating the indicator release switch.

  According to such a travel support device 1, the tire wear amount estimation unit 8 estimates the tire wear amount of the front wheels by comparing the turning direction by the small turn travel control and the short turn travel control time with the wear amount conversion map. Yes. For this reason, the wear amount of each tire of the front wheel, which is different between the outside and the inside in the turning direction during the small turn traveling control, can be taken into consideration, and the tire wear amount of the front wheel can be accurately estimated.

  Further, according to the travel support device 1, the tire wear amount estimation unit 8 estimates the tire wear amount of the rear wheel by comparing the turning direction by the small turn travel control and the short turn travel control time with the wear amount conversion map. Yes. For this reason, not only the front wheel but also the tire wear amount of the rear wheel can be accurately estimated.

  Further, according to the driving support device 1, two types of wear amount conversion maps corresponding to the vehicle speed V are prepared in the storage unit 10 of the tire wear amount estimation ECU 6, and the tire wear amount estimation unit 8 corresponds to the vehicle speed V. The tire wear amount is estimated using these two types of wear amount conversion maps. Thus, by considering the vehicle speed V at the time of the small turn traveling control, the tire wear amount of the front wheel or the rear wheel can be estimated with higher accuracy.

  Moreover, according to the driving assistance device 1, the tire rotation determination unit 9 determines whether or not to recommend the tire rotation based on the accumulated wear amount of the front tire. As a result, it is sufficient to determine the recommended rotation for the first time when the reference wear value is exceeded, and the processing process is simplified.

  Further, according to the driving support device 1, the tire rotation determination unit 9 determines the recommended tire rotation based on the left-right difference in the accumulated wear amount of the front tire. Thereby, the required rotation can be easily known.

  As mentioned above, although this invention was concretely demonstrated based on the embodiment, this invention is not limited to the said embodiment. For example, in the above-described embodiment, the tire integrated wear amount estimated by the tire wear amount estimation ECU 6 of the driving support apparatus 1 is used when determining the recommended rotation of the tire. However, the tire integrated wear amount is estimated. It is determined whether or not tire rotation needs to be performed based on the small turn traveling control time that is the basis for this, and the recommended rotation is determined based on the difference in the small turn traveling control time for each turning direction You may do it.

  Moreover, in the said embodiment, although the integrated wear amount of the tire estimated by tire wear amount estimation ECU6 of the driving assistance apparatus 1 is utilized when judging the recommended rotation of a tire, this invention is used for such a use. The present invention is not limited to this, and it can be applied to various uses such as displaying the accumulated wear amount of each tire as it is on the display unit 7 and prompting the driver to replace the worn tire.

  In the above embodiment, two types of wear amount conversion maps corresponding to the vehicle speed V in the small turn traveling control are prepared and used when converting the small turn traveling control time into the wear amount. The map may be composed of one representative type of wear amount conversion map, or may be composed of more wear amount conversion maps. With one type of wear amount conversion map, the wear amount can be easily converted. On the other hand, with more wear amount conversion maps, more accurate wear amount conversion is possible.

It is a block block diagram which shows the driving assistance apparatus which concerns on embodiment of this invention. It is a figure which shows an example of the display part in the driving assistance apparatus shown in FIG. It is a figure which shows an example of an abrasion amount conversion map, (a) is a figure in case a vehicle speed is 10 km / h, (b) is a figure in case a vehicle speed is 15 km / h. It is a flowchart which shows the estimation process of the abrasion amount performed with the driving assistance apparatus shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Driving assistance device, 2 ... Rudder angle sensor, 3 ... Vehicle speed sensor, 4 ... Driving assistance ECU, 5 ... Brake actuator, 6 ... Tire wear amount estimation ECU, 7 ... Display part, 8 ... Tire wear amount estimation part, 9 ... tire rotation determination unit, 10 ... storage unit.

Claims (5)

Estimating the amount of tire wear in a vehicle that performs small-turn running control that shortens the turning radius by applying braking so that the braking force of the wheels inside the turning direction is greater than the braking force of the wheels outside the turning direction during turning A device,
A tire wear amount estimating device comprising tire wear amount estimating means for estimating a tire wear amount of a front wheel from a turning direction by the small turn traveling control and a small turn traveling control time.   The tire wear amount estimation device according to claim 1, wherein the tire wear amount estimation means estimates the tire wear amount of the front wheels according to a traveling speed of the vehicle at the time of turning by the small turn traveling control.   The tire wear amount estimation device according to claim 1, further comprising tire rotation determination means for determining whether or not to recommend the execution of tire rotation based on the tire wear amount of the front wheels.   The tire wear amount estimation device according to any one of claims 1 to 3, further comprising a recommended rotation determination unit that determines a recommended tire rotation based on a left-right difference in the tire wear amount of the front wheels. Tire rotation is recommended to perform tire rotation in vehicles that perform small-turn running control that shortens the turning radius by applying braking so that the braking force of the wheels inside the turning direction is greater than the braking force of the wheels outside the turning direction when turning A device,
Based on the control time of the small-turn traveling control, it is determined whether or not the tire rotation needs to be performed, and when it is determined that the tire rotation needs to be performed, the small-turn traveling control is performed for each turning direction. A tire rotation recommendation device that determines a recommended tire rotation based on a difference in control time.

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