JP2007106347A - Brake control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brake control device capable of suppressing a change in the braking distance associated with the wear of a tire in a braking mode. <P>SOLUTION: The brake control device acquires tire wear information via a deflection detection sensor. An ABS threshold changing unit 42 changes the ABS control timing threshold of the anti-lock brake control based on the acquired tire wear information. The ABS control unit 44 performs the ABS control based on the ABS control timing threshold N during the actual braking. As a result, the ABS control timing threshold is optimized according to the tire wear state, and the change of the braking distance associated with the tire wear in the braking mode can be suppressed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a brake control device, and more particularly to an improvement of a brake control device that suppresses a change in a stop distance due to tire wear during braking.

  An antilock brake system (hereinafter referred to as ABS) is effective for suppressing slip during braking of the vehicle. ABS is a device that prevents wheel lock even when suddenly strong braking is performed, and realizes stable braking. By detecting the tendency of the lock by the wheel speed sensor attached to each wheel, the brake hydraulic pressure is weakened. Prevents wheel locks. A so-called pumping brake is automatically executed at quick intervals. In particular, even on a slippery road surface such as a wet road surface or a frozen road surface, even if a sudden brake is applied, the vehicle can be stopped straight without slipping while keeping the maneuverability by the pumping brake effect.

Various types of vehicles equipped with such an ABS have been proposed in which a device that is devised to improve the performance and safe driving of the vehicle as in Patent Document 1, for example.
JP 2005-138702 A

  By the way, when braking is performed when the tire is worn, the stop distance is shorter on the dry road surface than when it is not worn, and the stop distance tends to be longer on the wet road surface than when it is not worn. The reduction of the stopping distance when driving on a dry road surface results from the fact that the tire wear advances, so that the rigidity of the convex block of the tire tread increases and the coefficient of friction with the road surface increases. That is, the tire is easily gripped on the road surface. On the other hand, the increase in the stopping distance during running on a wet road surface results from a decrease in drainage due to shallow grooves between the convex locks due to wear of the convex blocks of the tire tread. That is, a water film is formed on the tire surface and the idle running distance is extended. As a result, even if the same tire is installed, the difference between the stopping distance when driving on a dry road surface and the stopping distance when driving on a wet road surface increases as the tire wears out. There is a problem of giving a sense of incongruity.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a brake control device that can suppress a change in a stop distance due to tire wear during braking.

  In order to solve the above-mentioned problems, the present invention provides a brake control device capable of anti-lock brake control, comprising: wear information acquisition means for acquiring tire wear information; and Threshold change means for changing the control timing threshold value of the lock brake control, and control execution means for executing anti-lock brake control based on the changed threshold value.

  According to this aspect, the control can be executed by changing the control timing threshold value of the antilock brake control in accordance with the wear state of the tire. For example, when the tire wear exceeds a predetermined value, for example, a value of 50% wear on a new tire, the execution timing of the antilock brake control can be made earlier than the execution timing when the tire is not worn. As a result, the control timing threshold value of the antilock brake control can be optimized according to the tire wear state, and the change in the stop distance due to the tire wear during braking can be suppressed.

  Further, in the above aspect, the vehicle further includes road surface information acquisition means for acquiring road surface information indicating whether a road surface state on which the tire travels is a dry state or a wet state, and the threshold value changing unit includes the dry state according to the road surface state. You may make it change to the control timing threshold value which changes with wet states. For example, when a worn tire is braked on a dry road surface, the stop distance is shortened. However, the antilock brake control execution timing is advanced, so that the braking force can be temporarily reduced to substantially extend the stop distance. That is, the stop distance shortened by tire wear can be corrected and brought close to the stop distance at the time of non-wear. In addition, when a worn tire is braked on a wet road surface, the stopping distance is extended by slipping, but the antilock brake control execution timing is advanced, thereby suppressing the slipping of the tire and substantially reducing the stopping distance. it can. That is, the stop distance extended by tire wear can be corrected and brought close to the stop distance at the time of non-wear. As a result, it is possible to execute the optimum antilock brake control according to the road surface condition and the wear state by suppressing the difference in the stop distance between the dry road surface and the wet road surface from increasing with tire wear. .

  Further, in the above aspect, the wear information acquisition means includes a deflection detection sensor that detects a deflection amount of the tread portion arranged in the convex block of the tread portion of the tire, and the deflection amount detected by the deflection detection sensor. The tire wear information may be acquired based on the deflection amount change information when the tire is held in advance. The convex block in the tread portion of the tire can be regarded as a kind of cantilever. Therefore, when the vehicle is traveling at a constant speed, the amount of deflection of the convex block of the tire changes corresponding to the height of the convex block. That is, when the new tire is not worn, that is, when the height of the convex block is high, the amount of deflection becomes large. On the other hand, as the wear of the tire progresses and the height of the convex block decreases, the rigidity of the convex block increases, so the amount of deflection decreases. Therefore, tire wear information can be acquired based on the change in the amount of deflection.

  In the above aspect, the wear information acquisition means is embedded in a convex block of the tread portion of the tire, and outputs a potential change signal by contacting the road surface when the convex block is worn and exposed for a predetermined amount. The tire wear information may be acquired based on the potential change. For example, it is arranged so that the potential sensor is exposed when 50% of a new tire is worn. When the potential sensor is exposed from the convex block, the electric charge moves to the ground due to contact with the road surface, and a displacement change occurs. That is, when a potential change of the potential sensor is detected, it can be recognized that the tire has worn a predetermined amount. As a result, tire wear information can be acquired.

  Further, the wear information acquisition means may be an input device that receives wear information from a user. According to this aspect, the user can change the control timing threshold value of the antilock brake control by inputting the tire wear state via the input device based on, for example, the groove depth to the slip sign.

  Further, the road surface information acquisition means may be an input device that receives road surface information from a user. According to this aspect, the control timing threshold value of the antilock brake control can be changed by inputting whether the road surface is in a dry state or a wet state.

  According to the brake control device of the present invention, since the control timing threshold value of the antilock brake control is changed based on the tire wear information, it is possible to suppress the change in the stop distance due to the tire wear during braking.

  Hereinafter, an embodiment of the present invention (hereinafter referred to as an embodiment) will be described with reference to the drawings.

  The brake control device of the present embodiment acquires tire wear information, and changes the control timing threshold for antilock brake control based on the wear information. As a result, since the control timing threshold value of the antilock brake control can be optimized according to the tire wear state, it is possible to suppress the change in the stop distance due to the tire wear during braking.

  FIG. 1 is a conceptual configuration diagram of a vehicle 12 equipped with a brake control device 10 of the present embodiment. The vehicle 12 is equipped with tires 14 at the front wheel position and the rear wheel position. A deflection detection sensor 16 that functions as a wear information acquisition unit that acquires wear information of the convex block 14 a protruding from the tread portion of the tire 14 is disposed inside each tire 14, for example, the tread. The deflection detection sensor 16, which will be described in detail with reference to the following drawings, is a sensor that detects the deflection of a convex block that protrudes from the tread portion of the tire 14, for example, the width direction of the tire 14. One is arranged at a substantially central portion. A plurality of deflection detection sensors 16 may be arranged in the circumferential direction of the tire 14. Furthermore, you may arrange | position in the several position of the width direction of the tire 14, and may arrange in multiple in the width direction and the circumferential direction. A detection signal detected by the deflection detection sensor 16 is provided to the vehicle 12 side via a transmitter 20 disposed in a part of the wheel 18, for example. A detection signal transmitted from the transmitter 20 is provided via a receiver 22 to a control device (hereinafter referred to as ECU) 24 that performs control of an anti-lock brake system (hereinafter referred to as ABS). A wheel speed sensor 26 that detects the rotational speed of the tire 14, that is, the wheel speed, is disposed at a fixed portion of the vehicle 12 at a position facing the tire 14. The wheel speed sensor 26 is a rotation sensor such as an electromagnetic pickup system or a Hall IC system, and detects the rotation of each tire 14 and provides the information to the ECU 24. In addition, an input device 30 that inputs information from the vehicle speed sensor 28 that detects the vehicle speed of the vehicle 12, information on wear of the tire 14, road surface state information, and the like that can be operated by a vehicle occupant as needed. Information from is provided. The input device 30 can be configured by a keyboard, a mouse, a pointer, a voice recognition input device, or the like.

  FIG. 2 is a configuration block diagram illustrating the internal configuration of the ECU 24. The ECU 24 includes a deflection detection unit 32, a wear estimation unit 34, a storage unit 36, a road surface friction coefficient estimation unit 38, a road surface determination unit 40, an ABS threshold value change unit 42, an ABS control unit 44, and the like. The deflection detection unit 32 detects the deflection amount of the tire 14 based on the detection value of the deflection detection sensor 16 provided via the receiver 22.

Reference is now made to FIG. FIG. 3 shows the shape of the convex block 14 a formed to protrude from the tread portion of the tire 14 and the arrangement state of the deflection detection sensor 16 inside the convex block 14 a. As shown in FIG. 3, the convex block 14 a of the tire 14 has a width b in the circumferential direction A of the tire 14, a width h in the width direction B of the tire 14, and a height L in the height 14. Between the plurality of convex blocks 14 a is a so-called groove 46. When the vehicle 12 equipped with the tire 14 having the convex block 14a is traveling at a constant speed, for example, at 40 km / h without acceleration / deceleration, the frictional force F received by the convex block 14a from the road surface is as follows. Can be considered constant regardless of the road surface condition. Further, the convex block 14 a can be regarded as a cantilever beam fixed in a cantilever state on the tread surface of the tire 14. Therefore, the running deflection δ generated in the convex block 14a can be obtained by δ = FL ³ / 3EI. ^{Here, I = bh 3/12,} E is the modulus of longitudinal elasticity. Therefore, a proportional relationship as shown in FIG. 4 is established between the amount of deflection of the convex block 14a and the height L of the convex block 14a during constant speed traveling. Therefore, when the value falls below the predetermined threshold A, it can be estimated that the convex block 14a is also worn below a predetermined height. Further, it can be considered that a similar proportional relationship exists between the deflection amount detected by the deflection detection sensor 16 and the height L of the convex block 14a. Therefore, when the value falls below the predetermined threshold A, it can be estimated that the convex block 14a is also worn below a predetermined height. In addition, the shape of the convex block 14a shown in FIG. 3 is simplified for the description of the present embodiment, and the actual shape of the convex block 14a has various shapes in consideration of wear strength and drainage capacity. .

  Returning to FIG. 2, the wear estimation unit 34 uses the deflection amount of the convex block 14 a detected by the deflection detection unit 32 and a table indicating the relationship between the deflection amount stored in the storage unit 36 and the height of the convex block 14 a. The actual height of the convex block 14a, in other words, the amount of wear of the tire 14 is estimated. In addition, the table memorize | stored in the memory | storage part 36 can be produced previously, for example using the measuring apparatus etc. by the abrasion state of the convex block 14a, and the deflection amount detected by the deflection | deviation detection sensor 16 at that time. Further, the road surface friction coefficient estimation unit 38 estimates the road surface friction coefficient by a known method based on the vehicle speed provided from the vehicle speed sensor 28 of the vehicle 12 and the wheel speed provided from the wheel speed sensor 26. The road surface determination unit 40 determines whether the road surface on which the vehicle 12 is currently traveling is a dry road surface or a wet road surface based on the road surface friction coefficient estimated by the road surface friction coefficient estimation unit 38. The determination result is provided to the ABS threshold value changing unit 42. The ABS threshold value changing unit 42 changes the ABS control timing threshold value stored in advance in the storage unit 36 based on the wear amount of the tire 14 estimated by the wear estimation unit 34. The changed ABS control timing threshold value is provided to the ABS control unit 44 and used for actual ABS control.

  The change of the ABS control timing threshold will be described with reference to the schematic diagram of FIG. FIG. 5 shows a graph a showing the tire wear coefficient and slip ratio when running on a dry road surface when not worn (new article), and a graph b showing the tire wear coefficient and slip ratio when running on a dry road surface when worn. Has been. In addition, a graph c indicating the tire wear coefficient and slip rate when running on a wet road surface when not worn (when new) and a graph d showing the tire wear coefficient and slip rate when running on a dry road surface when worn are shown. . As described above, when the tire 14 is being worn on the dry road surface, the rigidity of the convex block 14a of the tire 14 increases and the tire friction coefficient increases. On the other hand, when the vehicle is traveling on a wet road surface, the groove 46 becomes shallow due to a decrease in the height of the convex block 14 a, the drainage performance is lowered, and a water film is formed between the road surface and the tire 14. As a result, the tire wear coefficient decreases. When the tire 14 is in a non-wearing state, the ABS control timing threshold value is set after the peak of the tire friction coefficient for safety (point P in the case of graph a). That is, the ABS is operated after the slipping of the tire 14 is detected. As shown in FIG. 5, when the ABS control timing threshold value is shared for both dry road driving and wet road driving, the ABS control timing threshold M functions well for both dry road driving and wet road driving. Set to do.

  By the way, as the wear of the tire 14 progresses, as described above, the tire friction coefficient increases on the dry road surface and the stop distance decreases, and the stop distance decreases on the wet road surface and the stop distance increases. Therefore, in the present embodiment, the ABS is operated earlier by correcting the ABS control timing threshold M to the ABS control timing threshold N as shown in FIG. As a result, when traveling on a dry road surface, it is possible to control so that the stopping distance shortened with the wear of the tire 14 is returned to the stopping distance when the tire 14 is not worn. On the other hand, when running on a wet road surface, by operating the ABS early, control is performed so that the idle running distance that has become longer due to the formation of a water film accompanying the wear of the tire 14 is returned to the stop distance when the tire 14 is not worn. Can do.

  FIG. 6 shows a flowchart showing a control procedure of the brake control device 10 of the present embodiment. FIG. 6 illustrates a basic process for detecting wear of the tire 14 and changing the ABS control timing threshold. In this case, in the configuration of the ECU 24 in FIG. 2, the road surface friction coefficient estimating unit 38 and the road surface determining unit 40 are not used for the ABS control timing threshold changing process, and can be omitted. The ECU 24 determines whether or not the vehicle speed has become a constant speed at Vkm / h (for example, 40 km / h) via the vehicle speed sensor 28 (Y or N in S100). If Vkm / h has not been reached, or if acceleration / deceleration is being performed (N in S100), the amount of deflection is not stable, so detection processing is not performed and vehicle speed monitoring is continued. If the vehicle speed is Vkm / h (for example, 40 km / h) and the vehicle speed is constant (Y in S100), the deflection detection unit 32 performs deflection detection based on the detection information provided from the deflection detection sensor 16 ( S101). When the detection of the deflection amount is completed, the wear estimation unit 34 performs wear estimation and determines whether or not the wear value is worn by a predetermined value, for example, 50% of the new tire 14 (S102). If the wear state does not exceed the predetermined value (N in S102), the process returns to S101 and the deflection amount detection process is performed again. On the other hand, when it is determined that the wear estimation unit 34 has worn beyond a predetermined value (Y in S102), the wear estimation unit 34 provides wear information to the ABS threshold value changing unit 42, and the ABS threshold value changing unit 42 is shown in FIG. As described above, the ABS control timing threshold value M is corrected to the ABS control timing threshold value N (S103). Then, the corrected ABS control timing threshold value N is provided to the ABS control unit 44, and ABS control is executed based on the ABS control timing threshold value N during actual braking (S104).

  In this way, by detecting the wear of the tire 14 and changing the ABS control timing threshold M to the ABS control timing threshold N, the stop distance at the time of dry travel and the stop distance at the time of wet travel spread by the wear of the tire 14 are increased. The difference can be controlled to return to the difference when the tire 14 is not worn. As a result, it is possible to reduce a sense of discomfort related to the stop distance of the passenger of the vehicle 12 due to wear of the tire 14.

  FIG. 7 is a flowchart showing another control procedure of the brake control device 10 of the present embodiment. FIG. 7 shows an example in which the wear of the tire 14 is detected and the ABS control timing threshold is changed depending on whether the road surface is in a dry state or a wet state. In this case, the processing is performed by the configuration of the ECU 24 in FIG. The ECU 24 determines whether or not the vehicle speed has reached a constant speed of Vkm / h (for example, 40 km / h) via the vehicle speed sensor 28 (Y or N in S200). If Vkm / h has not been reached, or if acceleration / deceleration is being performed (N in S200), the vehicle speed is continuously monitored because the amount of deflection is not stable. If the vehicle speed is Vkm / h (for example, 40 km / h) and the vehicle speed is constant (Y in S200), the deflection detection unit 32 performs deflection detection based on the detection information provided from the deflection detection sensor 16 (S201). ). When the detection of the deflection amount is completed, the wear estimation unit 34 performs wear estimation, and determines whether or not the wear value is worn at a predetermined value, for example, 50% of the new tire 14 (S202). When the wear state does not exceed the predetermined value (N in S202), the process returns to S201, and the deflection amount detection process is performed again. On the other hand, when it is determined that the wear estimation unit 34 has worn more than a predetermined value (Y in S202), the wear estimation unit 34 provides wear information to the ABS threshold value changing unit 42. Further, the road surface friction coefficient estimating unit 38 performs estimation of the road surface friction coefficient based on information from the wheel speed sensor 26 and the vehicle speed sensor 28. The road surface determination unit 40 determines whether the road surface on which the vehicle 12 is currently traveling is a dry road surface or a wet road surface based on the road surface friction coefficient estimated by the road surface friction coefficient estimation unit 38 (Y in S203). Or N). Whether the road surface is a dry road surface or a wet road surface can be determined to be a wet road surface, for example, when the road surface friction coefficient is equal to or lower than a set value. Then, the result is provided to the ABS threshold value changing unit 42. When it is determined that the vehicle 12 is traveling on a dry road surface (Y in S203), the ABS threshold value changing unit 42 changes the ABS control timing threshold value for the dry road surface based on the wear information provided from the wear estimation unit 34. (S204).

  FIG. 8A shows a graph showing the change of the ABS control timing threshold value for the dry road surface. FIG. 8 (a) shows a graph a showing the tire wear coefficient and slip ratio when running on a dry road surface when not worn (new article), and a graph showing the tire wear coefficient and slip ratio when running on a dry road surface when worn. b is shown. Further, an ABS control timing threshold value M suitable for dry running when the tire 14 is in a non-wearing state and an ABS control timing threshold value N suitable for dry running when the tire 14 is in a worn state are shown. The ABS threshold value changing unit 42 determines that the tire 14 is worn beyond a predetermined value (for example, 50% of the new tire 14 is worn) based on information from the wear estimating unit 34, and the current vehicle. When it is determined that 12 is traveling on a dry road surface, switching control is executed. That is, the ABS control timing threshold value M is switched to the ABS control timing threshold value N. Then, the ABS threshold changing unit 42 provides the changed ABS control timing threshold N to the ABS control unit 44, and executes ABS control based on the ABS control timing threshold N during actual braking (S205). As a result, the ABS is used so that the stopping distance at the time of braking is shortened more than necessary due to the increase in rigidity of the convex block 14a due to the wear of the tire 14 is returned to the stopping distance when the tire 14 is not worn. Operate early to achieve a comfortable brake.

  On the other hand, when it is determined in S203 that the vehicle 12 is not traveling on the dry road surface, that is, the vehicle 12 is traveling on the wet road surface (N in S203), the ABS threshold value changing unit 42 wears the wear provided from the wear estimating unit 34. Based on the information, the ABS control timing threshold for the wet road surface is changed (S206). FIG. 8B shows a graph showing the change of the ABS control timing threshold value for the wet road surface. FIG. 8B shows a graph c showing the tire wear coefficient and slip ratio when running on a wet road surface when not worn (new article), and a graph showing the tire wear coefficient and slip ratio when running on a wet road surface when worn. d is shown. In addition, an ABS control timing threshold value M suitable for wet running when the tire 14 is in a non-wearing state and an ABS control timing threshold value N suitable for wet running when the tire 14 is in a worn state are shown. The ABS threshold value changing unit 42 determines that the tire 14 is worn beyond a predetermined value (for example, 50% of the new tire 14 is worn) based on information from the wear estimating unit 34, and the current vehicle. When it is determined that 12 is traveling on a wet road surface, switching control is executed. That is, the ABS control timing threshold value M is switched to the ABS control timing threshold value N. Then, the ABS threshold changing unit 42 provides the changed ABS control timing threshold N to the ABS control unit 44, and executes ABS control based on the ABS control timing threshold N during actual braking (S205). As a result, the ABS operates earlier so that the stopping distance at the time of braking due to idle running due to wear of the tire 14 is returned to the stopping distance when the tire 14 is not worn, and the discomfort is felt. Realize no braking.

  In the flowcharts shown in FIGS. 6 and 7, the deflection determination timing is set to a predetermined vehicle speed (for example, at a constant vehicle speed of 40 km / h), but at a plurality of vehicle speeds (for example, at a constant vehicle speed of 80 km / h). By performing deflection detection, it is possible to perform deflection detection with higher accuracy.

  FIG. 9 shows an example including another configuration that functions as a wear information acquisition unit of the present embodiment. In the example shown in FIG. 9, a potential sensor 48 is arranged in the convex block 14 a instead of the deflection detection sensor 16 inside the convex block 14 a of the tire 14. When the convex block 14a is worn and exposed to the surface of the tire 14, the potential sensor 48 comes into contact with the road surface and discharges electric charges to the ground. The potential change at that time is sent to the ECU 24 side via the transmitter 20. The potential sensor 48 is disposed at a predetermined depth of the convex block 14a, for example, a depth that is exposed when the convex block 14a is worn 50% with respect to a new tire 14. In the example of FIG. 9, three are arranged in the width direction of the tire 14, but the number of arrangement is arbitrary and may be one, or four or more. A plurality of tires 14 may be arranged in the circumferential direction of the tire 14. The potential change signal output from the potential sensor 48 is wear information indicating that the wear of the tire 14 has reached a predetermined value as it is. Therefore, in the configuration of the ECU 24 shown in FIG. 2, the deflection detection unit 32 and the wear estimation unit 34 are unnecessary, and information provided from the tire 14 side via the receiver 22 is directly provided to the ABS threshold value changing unit 42. Is done.

  FIG. 10 is a flowchart for explaining the procedure for correcting the ABS control timing threshold when the road surface determination is not performed. In this case, in the configuration of the ECU 24 in FIG. 2, the road surface friction coefficient estimating unit 38 and the road surface determining unit 40 are not used for the ABS control timing threshold changing process, and can be omitted. The ABS threshold value changing unit 42 confirms whether or not a potential change signal from the potential sensor 48 is acquired via the receiver 22 (Y or N in S301). If the potential change signal cannot be acquired (N in S301), that is, if the potential sensor 48 is not yet exposed on the surface of the tire 14, the presence or absence of acquisition is continued. On the other hand, when the potential change signal can be acquired (Y in S301), the ABS threshold value changing unit 42 determines that the wear of the tire 14 has progressed to a predetermined value, and sets the ABS control timing threshold value M as shown in FIG. The ABS control timing threshold value N is corrected (S302). Then, the corrected ABS control timing threshold value N is provided to the ABS control unit 44, and ABS control is executed based on the ABS control timing threshold value N during actual braking (S303).

  In this way, by detecting the wear of the tire 14 and changing the ABS control timing threshold M to the ABS control timing threshold N, the stop distance at the time of dry travel and the stop distance at the time of wet travel spread by the wear of the tire 14 are increased. The difference can be controlled to return to the difference when the tire 14 is not worn. As a result, it is possible to reduce a sense of discomfort related to the stop distance of the passenger of the vehicle 12 due to wear of the tire 14. In this case, since it is directly detected that the wear of the tire 14 has progressed to a predetermined value, the detection reliability is high and the ECU 24 can be configured simply.

  The flowchart shown in FIG. 11 shows an example in which the wear of the tire 14 is detected by the potential sensor 48 and the ABS control timing threshold is changed according to whether the road surface is in a dry state or a wet state. In this case, the ECU 24 in FIG. 2 performs processing with a configuration excluding the deflection detection unit 32 and the wear estimation unit 34. The ABS threshold value changing unit 42 confirms whether or not a potential change signal from the potential sensor 48 is acquired via the receiver 22 (Y or N in S401). When the potential change signal cannot be acquired, that is, when the potential sensor 48 is not yet exposed on the surface of the tire 14 (N in S401), the monitoring of the acquisition is continued. On the other hand, when the potential change signal can be acquired (Y in S401), the road surface friction coefficient estimation unit 38 estimates the road surface friction coefficient based on information from the wheel speed sensor 26 and the vehicle speed sensor 28. Then, the road surface determination unit 40 determines whether the road surface on which the vehicle 12 is currently traveling is a dry road surface or a wet road surface based on the road surface friction coefficient estimated by the road surface friction coefficient estimation unit 38 (Y in S402). Or, the result is provided to the ABS threshold value changing unit 42. When it is determined that the vehicle 12 is traveling on the dry road surface (Y in S402), the ABS threshold value changing unit 42 performs the ABS control for the dry road surface based on the potential change signal that is the wear information provided from the potential sensor 48. The timing threshold value is changed (S403). That is, as shown in FIG. 8A, the ABS threshold value changing unit 42 indicates that the tire 14 is worn by a predetermined value or more based on information from the potential sensor 48 (for example, 50% of the new tire 14 is worn). When it is determined that the vehicle has occurred and it is determined that the vehicle 12 is currently traveling on a dry road surface, switching control is executed. That is, the ABS control timing threshold value M is switched to the ABS control timing threshold value N. Then, the ABS threshold change unit 42 provides the changed ABS control timing threshold N to the ABS control unit 44, and executes ABS control based on the ABS control timing threshold N during actual braking (S404). As a result, the ABS is used so that the stopping distance at the time of braking is shortened more than necessary due to the increase in rigidity of the convex block 14a due to the wear of the tire 14 is returned to the stopping distance when the tire 14 is not worn. Operate early to achieve a comfortable brake.

  On the other hand, if it is determined in S402 that the vehicle 12 is not traveling on a dry road surface, that is, a vehicle is traveling on a wet road surface (N in S402), the ABS threshold value changing unit 42 wear information provided from the potential sensor 48. Based on the potential change signal, the ABS control timing threshold value of the wet road surface is changed (S405). That is, as shown in FIG. 8B, the ABS threshold value changing unit 42 indicates that the tire 14 wears more than a predetermined value based on information from the potential sensor 48 (for example, 50% wear with respect to the new tire 14). When it is determined that it has occurred and it is determined that the vehicle 12 is currently traveling on a wet road surface, switching control is executed. That is, the ABS control timing threshold value M is switched to the ABS control timing threshold value N. Then, the ABS threshold change unit 42 provides the changed ABS control timing threshold N to the ABS control unit 44, and executes ABS control based on the ABS control timing threshold N during actual braking (S404). As a result, the ABS operates earlier so that the stopping distance at the time of braking due to idle running due to wear of the tire 14 is returned to the stopping distance when the tire 14 is not worn, and the discomfort is felt. Realize no braking. In this case, since it is directly detected that the wear of the tire 14 has progressed to a predetermined value, the detection reliability is high and the ABS control timing threshold suitable for the road surface condition can be changed. Brake can be realized suitable for the tire condition. Further, the ECU 24 can be configured simply.

  Note that when the potential sensor 48 is used, the vehicle 12 does not need to be traveling, so the ABS control timing threshold can be changed at an arbitrary timing.

  In the above-described example, the case where the deflection detection sensor 16 or the potential sensor 48 is used as a means for acquiring the wear state of the tire 14 has been described. Fourteen wear information may be input. For example, the wear state of the tire 14 can be input based on the groove depth to the slip sign provided on the tire 14. Since the slip sign indicates the limit of wear of the tire 14, the slip sign may be used in two stages as a sign for changing the ABS control timing threshold. In this case, since the information from the input device 30 is directly provided to the ABS threshold value changing unit 42, the configuration of the ECU 24 is the same as that when the potential sensor 48 is used.

  In addition, the road surface state may also be input using the input device 30 by the passenger of the vehicle 12 as to whether the currently running road surface is in a dry state or a wet state. In this case, since the road surface friction coefficient estimating unit 38 and the road surface determining unit 40 can be omitted, the configuration of the ECU 24 is simplified.

  In the present embodiment, an example in which the ABS control timing threshold value is changed from the ABS control timing threshold value M to the ABS control timing threshold value N according to the wear state of the tire 14 is shown, but a plurality of ABS control timing threshold values are prepared. In addition, the tire 14 can be changed according to the wear state of the tire 14, and more detailed ABS control is possible.

  The present invention is not limited to the above-described embodiments, and various modifications such as design changes can be added based on the knowledge of those skilled in the art. The configuration shown in each figure is for explaining an example, and any configuration that can achieve the same function can be changed as appropriate, and the same effect can be obtained.

It is a composition conceptual diagram of vehicles which mount a brake control device of this embodiment. It is a block diagram explaining the structure of ECU of the brake control apparatus of this embodiment. In the brake control apparatus of this embodiment, it is explanatory drawing explaining the example of arrangement | positioning of a deflection | deviation detection sensor, and the shape of a convex block. It is explanatory drawing explaining the relationship between a convex block and a deflection amount. It is explanatory drawing explaining the change of an ABS control timing threshold value. It is a flowchart explaining the example of control of the brake control apparatus of this embodiment. It is a flowchart explaining the other example of control of the brake control apparatus of this embodiment. It is explanatory drawing explaining the change of an ABS control timing threshold value in the case of controlling separately a dry road surface and a wet road surface in control of the brake control apparatus of this embodiment. In the brake control device of this embodiment, it is explanatory drawing explaining the structure of the tire in the case of using an electric potential sensor. It is a flowchart explaining the control procedure in the case of using an electric potential sensor. It is a flowchart explaining the other control procedure in the case of using an electric potential sensor.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Brake control apparatus, 12 Vehicle, 14 Tire, 14a Convex block, 16 Deflection detection sensor, 18 Wheel, 20 Transmitter, 22 Receiver, 24 ECU, 26 Wheel speed sensor, 28 Vehicle speed sensor, 30 Input device, 32 Deflection detection Part, 34 wear estimation part, 36 storage part, 38 road surface friction coefficient estimation part, 40 road surface judgment part, 42 ABS threshold value changing part, 44 ABS control part, 46 groove part, 48 potential sensor.

Claims (6)

A brake control device capable of anti-lock brake control,
Wear information acquisition means for acquiring tire wear information;
Threshold changing means for changing a control timing threshold of the antilock brake control based on the tire wear information;
Control execution means for executing antilock brake control based on the changed threshold;
A brake control device comprising: Road surface information acquisition means for acquiring road surface information indicating whether the road surface state where the tire travels is a dry state or a wet state;
The brake control device according to claim 1, wherein the threshold value changing unit changes a control timing threshold value that differs between the dry state and the wet state according to a road surface state.   The wear information acquisition means includes a deflection detection sensor that detects a deflection amount of the tread portion disposed in a convex block of the tread portion of the tire, and the deflection amount detected by the deflection detection sensor and the tire held in advance. The brake control device according to claim 1, wherein wear information of the tire is acquired based on deflection amount change information during wear of the tire.   The wear information acquisition means includes a potential sensor that is embedded in a convex block of the tread portion of the tire, and outputs a potential change signal by contacting the road surface when the convex block is worn and exposed by a predetermined amount, The brake control device according to claim 1, wherein wear information of the tire is acquired based on the potential change.   The brake control device according to claim 1, wherein the wear information acquisition unit is an input device that receives wear information from a user.   The brake control device according to claim 2, wherein the road surface information acquisition means is an input device that receives road surface information from a user.

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