CN210618108U

CN210618108U - Anti-cascade locking device

Info

Publication number: CN210618108U
Application number: CN201921321687.3U
Authority: CN
Inventors: 竹森祐一郎
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 2018-10-01
Filing date: 2019-08-15
Publication date: 2020-05-26
Anticipated expiration: 2029-08-15
Also published as: JP6978999B2; JP2020055407A

Abstract

The utility model discloses can detect the cascade locking of various vehicles. The cascade locking prevention device (50) comprises: a brake pressure sensor (17); a braking torque calculation unit (23) that calculates a braking torque from the braking pressure; a wheel speed sensor (18); a wheel deceleration calculation unit (24) that calculates a wheel deceleration from the wheel speed; a moment-of-inertia setting unit (25) that sets the moment of inertia of the wheel and the vehicle; a wheel stopping torque calculation unit (26) that calculates a wheel stopping torque for stopping rotation of the wheel, based on the wheel deceleration and the inertia moment of the wheel; a vehicle stop torque calculation unit (27) that calculates a vehicle stop torque for stopping the vehicle, based on the wheel deceleration and the moment of inertia of the vehicle; a cascade lock detection unit (28) that detects the degree of cascade lock based on the degree of difference between the braking torque and the wheel stopping torque and the vehicle stopping torque; and a travel control unit (29) that controls the travel operation of the vehicle according to the degree of cascade lock.

Description

Anti-cascade locking device

Technical Field

The utility model relates to a prevent cascading locking device of cascading locking (cascade lock) of vehicle.

Background

Conventionally, a method of detecting a cascade lock state in which all wheels of a vehicle are locked and performing anti-lock brake control (anti-lock brake control) is known (for example, see patent document 1). In the method described in patent document 1, in a four-wheel drive vehicle in which a front axle and a rear axle are connected via a differential device, a cascade lock state is detected based on a difference (front-rear difference) between a rotation speed of the front axle and a rotation speed of the rear axle absorbed by the differential device.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. Hei 10-69664

SUMMERY OF THE UTILITY MODEL

Problem to be solved by the utility model

However, the method described in patent document 1 is based on the premise that the differential device absorbs the front-rear difference, and therefore, it is difficult to apply the method to a vehicle other than a four-wheel drive vehicle, and the method is not versatile.

Means for solving the problems

The utility model discloses an embodiment's anti-cascade locking device includes: a brake pressure detection unit for detecting a brake pressure acting on the brake device; a braking torque calculation unit that calculates a braking torque generated by the braking device based on the braking pressure detected by the braking pressure detection unit; a rotational speed detection unit that detects a rotational speed of the wheel; a wheel deceleration calculation unit that calculates a deceleration of the wheel based on the rotation speed of the wheel detected by the rotation speed detection unit; a moment-of-inertia setting unit that sets a moment of inertia of a wheel and a moment of inertia of a vehicle having a travel drive source; a wheel stopping torque calculating unit that calculates a wheel stopping torque for stopping rotation of the wheel, based on the deceleration of the wheel calculated by the wheel deceleration calculating unit and the moment of inertia of the wheel set by the moment of inertia setting unit; a vehicle stopping torque calculation unit that calculates a vehicle stopping torque for stopping the vehicle, based on the deceleration of the wheel calculated by the wheel deceleration calculation unit and the moment of inertia of the vehicle set by the moment of inertia setting unit; a cascade lock detection unit that detects a degree of cascade lock of the vehicle based on a degree of difference between the braking torque calculated by the braking torque calculation unit, the wheel stopping torque calculated by the wheel stopping torque calculation unit, and the vehicle stopping torque calculated by the vehicle stopping torque calculation unit; and a travel control unit that controls a travel operation of the vehicle based on the degree of cascade locking of the vehicle detected by the cascade locking detection unit.

Effect of the utility model

The utility model discloses can be applicable to the detection of the cascade locking of various vehicles, the commonality is high.

Drawings

Fig. 1 is a diagram showing a schematic configuration of a running system of a vehicle to which a cascade lock prevention device according to an embodiment of the present invention is applied.

Fig. 2A is an explanatory diagram showing a state of braking of the vehicle with all tires gripping the ground (grip).

Fig. 2B is an explanatory diagram showing a state during braking of the vehicle in which a part of the tires are slipping (slip).

Fig. 2C is an explanatory diagram showing a state in braking of the vehicle in which a part of tires are locked.

Fig. 2D is an explanatory diagram showing a state in braking of the vehicle in which all tires are locked.

Fig. 3 is a block diagram showing a main part structure of the cascade locking prevention device according to the embodiment of the present invention.

Fig. 4 is an explanatory diagram of processing performed by the braking torque calculation unit of fig. 3.

Fig. 5 is an explanatory diagram of processing performed by the wheel deceleration calculating unit and the wheel-stop torque calculating unit of fig. 3.

Fig. 6 is an explanatory diagram of processing performed by the wheel deceleration calculating section and the vehicle stopping torque calculating section of fig. 3.

Fig. 7 is an explanatory diagram showing a relationship between the degree of cascade lock and the braking torque.

Fig. 8 is an explanatory diagram of the anti-cascade lock control performed by the travel control unit in fig. 3.

Fig. 9 is a flowchart showing an example of processing executed by the controller of fig. 3.

Description of the symbols

1: engine

2: speed variator

3: throttle valve

4: ejector

5: torque converter

6: lock-up clutch

7: driving force generating part

13: driving force distribution mechanism

15: brake device

17: brake pressure sensor

18: wheel speed sensor

20: controller

23: brake torque calculation section

24: wheel deceleration calculating section

25: moment of inertia setting section

26: wheel-stop torque calculation unit

27: vehicle stop torque calculation unit

28: cascaded lock-up detection section

29: running control unit

50: anti-cascade locking device

100: vehicle with a steering wheel

FLW, FRW, RLW, RRW: wheel of vehicle

Detailed Description

Hereinafter, an embodiment of the present invention will be described with reference to fig. 1 to 9. The utility model discloses an embodiment's anti-cascade locking device is applicable to the vehicle that drives power and go to the road surface transmission through the wheel. First, the structure of the vehicle will be described.

Fig. 1 is a diagram showing a schematic configuration of a running drive train of a vehicle 100 to which a cascade lock prevention device according to the present embodiment is applied. As shown in fig. 1, the vehicle 100 is a four-wheel drive vehicle in which the front wheels FLW, FRW, rear wheels RLW, and RRW are drive wheels. An engine 1 and a transmission 2 are mounted on a front portion of the vehicle 100.

The engine 1 is an internal combustion engine (e.g., a gasoline engine) that generates rotational power by mixing intake air supplied via a throttle valve (3) and fuel injected from an injector (4) at an appropriate ratio and igniting and combusting the mixture with a spark plug or the like. Various engines such as a diesel engine (diesel engine) may be used instead of the gasoline engine. The intake air amount is adjusted by the throttle valve 3, and the opening degree of the throttle valve 3 is changed by driving a throttle actuator that operates in response to an electric signal. The opening degree of the throttle valve 3 and the injection amount (injection timing, injection time) of the fuel from the injector 4 are controlled by a controller 20 (fig. 3).

The transmission 2 is an automatic transmission that includes a torque converter (torqueconverter)5 to which a running drive force generated by the engine 1 is input, and that changes a speed of the running drive force output from the torque converter 5 to output the changed speed. The transmission 2 is, for example, a stepped transmission in which the transmission ratio can be changed stepwise in accordance with a plurality of gear positions. A continuously variable transmission that can change the transmission ratio without a step can also be used as the transmission 2. The transmission 2 includes an engagement mechanism such as a dog clutch (dog clutch) or a friction clutch, and the speed ratio of the transmission 2 can be changed to the target speed ratio by controlling the flow of oil from a hydraulic source (a hydraulic pump or the like) to the engagement mechanism in accordance with a command from the controller 20 (fig. 3). The target gear ratio is determined according to a predetermined shift map (shift map) based on the vehicle speed and the required driving force.

The torque converter 5 is a torque converter with a lock-up mechanism having a lock-up clutch (lock-up clutch)6 directly coupling an output shaft of the engine 1 and an input shaft of the transmission 2 in an engaged state. The lock-up clutch actuator that drives the lock-up clutch 6 is controlled by the controller 20 (fig. 3).

The engine 1 and the transmission 2 constitute a driving force generation unit 7 that generates a traveling driving force. The traveling driving force generated by the driving force generating unit 7 is transmitted to the left and right front wheels FLW and FRW via a front differential mechanism 8 and a drive shaft (drive draft) 9. The traveling driving force generated by the driving force generating unit 7 can also be transmitted to the left and right rear wheels RLW and RRW via a propeller shaft (propeller shaft)10, a rear differential unit 11, and a drive shaft 12. Alternatively, vehicle 100 may be configured as an electric vehicle or a hybrid vehicle by providing a running motor instead of or in addition to engine 1. That is, the traveling motor can be used as the driving force generating unit.

The differential unit 11 includes: a driving force distribution mechanism 13 for distributing a part of the traveling driving force of the driving force generating unit 7 to the rear wheels RLW and RRW; and a differential mechanism 14 that distributes the running drive force distributed via the drive force distribution mechanism 13 to the left rear wheel RLW and the right rear wheel RRW. The driving force distribution mechanism 13 functions as a driving force distribution mechanism for the front and rear wheels, as well as a differential mechanism that absorbs a rotation difference between the front and rear wheels, a differential limiting mechanism that limits the operation of the differential mechanism during running on a low friction coefficient road (low μ road), and the like. The driving force distribution mechanism 13 includes, for example, a wet-type multi-plate electromagnetic clutch (electronic control coupling) that couples the propeller shaft 10 and the input shaft 14a of the differential mechanism 14. The tightening force of the electromagnetic clutch is controlled by the controller, and by controlling the tightening force of the electromagnetic clutch, the driving forces on the front wheel FLW and front wheel FRW sides and the driving forces on the rear wheel RLW and rear wheel RRW sides can be distributed to 100: 0 (Two-wheel drive (2 WD) mode) to 50: 50 continuously changed within the range of 50. A drive force distribution actuator (electromagnetic clutch or the like) that drives the drive force distribution mechanism 13 is controlled by a controller 20 (fig. 3). The driving force distribution may be arbitrarily changed by a switch operation of the driver or the like.

Brake devices 15 such as disc brakes (disc brake) are provided to the wheels FLW, FRW, RLW, and RRW. The brake device 15 is supplied with a hydraulic pressure (brake pressure) corresponding to an operation amount of a brake pedal 16 provided in a vehicle driver seat via a master cylinder (not shown). The brake device 15 generates a braking torque corresponding to the braking pressure. The brake devices 15 of the wheels FLW, FRW, RLW, RRW are provided with brake pressure sensors 17, respectively, and output signals indicating the brake pressures applied to the brake devices 15 of the wheels.

A wheel speed sensor 18 is provided at an appropriate position of each of the wheels FLW, FRW, RLW, and RRW, and outputs a signal indicating the rotational speed of each wheel. When the tire of each wheel grips on the road surface, the vehicle 100 travels at a vehicle speed corresponding to the rotation speed of each wheel.

Fig. 2A to 2D are explanatory views showing a state of the vehicle 100 during braking. As shown in fig. 2A, when the vehicle 100 is braked by an appropriate brake operation according to the state of the road surface RD, each wheel is decelerated with all tires gripping the road surface RD, and the vehicle 100 is decelerated. At this time, the actual vehicle speed V_aAccording to the rotation speed of each wheel (V in the figure)_FRW＝V_RRW) Calculated vehicle speed V_cAnd (5) the consistency is achieved. In this case, vehicle 100 can be appropriately braked while maintaining a stable traveling state of vehicle 100.

As shown in fig. 2B, when braking of vehicle 100 is performed by a sudden braking operation that is out of an appropriate range according to the state of road surface RD, a portion of the tires slip. At this time, the actual vehicle speed V_aAlbeit according to the rotational speed of the non-slipping wheel (V in the figure)_RRW) Calculated vehicle speed V_c(RR)Is uniform but greater than the rotational speed of the wheel according to the slip (V in the figure)_FRW) Calculated vehicle speed V_c(FR). At this time, the traveling state of vehicle 100 becomes unstable, and the braking distance of vehicle 100 increases.

As shown in fig. 2C, when braking of the vehicle 100 is performed by a more abrupt braking operation, a part of the tires (FRW in the drawing) locks. At this time, the traveling state of vehicle 100 becomes more unstable, and the braking distance of vehicle 100 further increases.

As shown in fig. 2D, when the vehicle 100 is braked by an increasingly urgent braking operation, a cascade lock state is established in which all wheels are locked. At this time, the traveling state of vehicle 100 becomes extremely unstable, and braking of vehicle 100 becomes difficult. Such a cascade lock may be generated in all types of vehicles that travel by transmitting a travel driving force to a road surface via wheels. Therefore, it is desired to prevent cascade locking by detecting a state before reaching cascade locking not only in a four-wheel drive vehicle but also in various vehicles including a two-wheel drive vehicle and a two-wheel vehicle.

The state before the cascade lock is reached can be detected based on, for example, the difference in rotation between the front and

rear drive shafts

9 and 12 absorbed by the driving force distribution mechanism 13, but it is difficult to apply the present invention to a four-wheel drive vehicle. It is also possible to calculate an estimated value of the amount of change in deceleration of each wheel from the amount of change in braking pressure detected by the braking pressure sensor 17, calculate an actual value of the amount of change in deceleration of each wheel from the wheel speed detected by the wheel speed sensor 18, and detect the amount of change based on the result of comparison between the estimated value and the actual value. However, when the amount of change in deceleration of each wheel is calculated from the wheel speed, the wheel speed needs to be differentiated twice, and thus it is difficult to obtain an accurate value particularly when the deceleration is small, and it is difficult to reliably detect the state before reaching the cascade lock. Therefore, in the present embodiment, the vehicle control device is configured as follows so that the state of the cascade lock of the vehicle 100 can be detected by a highly versatile method applicable to other four-wheel drive vehicles.

Fig. 3 is a block diagram showing a main part of the cascade locking prevention device 50 according to the present embodiment. As shown in fig. 3, the cascade lock prevention device 50 includes a controller 20, a brake pressure sensor 17, a wheel speed sensor 18, a sensor group 19, a transmission actuator AC1, a lockup clutch actuator AC2, an injector actuator AC3, a throttle actuator AC4, and a drive force distribution actuator AC5, which are connected to the controller 20.

The sensor group 19 is a general term for a plurality of sensors that detect the traveling state of the vehicle 100. For example, the sensor group 19 includes an engine speed sensor that detects the speed of the engine 1, a throttle opening sensor that detects the opening (throttle opening) of the throttle valve 3, and the like.

The transmission actuator AC1 controls the flow of oil to the engagement mechanism of the transmission 2 to change the transmission ratio of the transmission 2. The lock-up clutch actuator AC2 drives the lock-up clutch 6 to be engaged or disengaged. The injector actuator AC3 adjusts the injection amount (injection timing, injection time) of the injector 4 of the engine 1. The throttle actuator AC4 adjusts the opening degree (throttle opening degree) of the throttle valve 3 of the engine 1. The driving force distribution mechanism 13 is driven by a driving force distribution actuator (electromagnetic clutch or the like) AC 5.

The controller 20 includes an Electronic Control Unit (ECU). Note that a plurality of ECUs having different functions, such as an engine control ECU and a transmission control ECU, may be provided, but the controller 20 is shown as a set of these ECUs in fig. 3 for convenience. The controller 20 is configured to include a computer having: a calculation Unit 21 such as a Central Processing Unit (CPU) that performs Processing related to travel control; a storage unit 22 such as a Read Only Memory (ROM), a Random Access Memory (RAM), and a hard disk; and other peripheral circuits not shown.

The storage unit 22 stores the weight WV of the vehicle 100, the weight WW of each wheel including the tire and the wheel, and the radius RW. The storage unit 22 also stores information such as a shift map (shift line map) serving as a reference of the shifting operation, programs of various controls, and thresholds used in the programs.

The calculation unit 21 has a functional configuration of a braking torque calculation unit 23, a wheel deceleration calculation unit 24, an inertia moment setting unit 25, a wheel stopping torque calculation unit 26, a vehicle stopping torque calculation unit 27, a cascade lock detection unit 28, and a travel control unit 29.

Fig. 4 is an explanatory diagram of the processing performed by the braking torque calculation unit 23. As shown in fig. 4, the braking torque calculation unit 23 is based on the braking pressure P of the brake device 15 of each wheel detected by the braking pressure sensor 17 of each wheel FLW, FRW, RLW, RRW_FLWBraking pressure P_FRWBraking pressure P_RLWBraking pressure P_RRWCalculating braking torque T generated by the braking device 15 of each wheel_FLWBraking torque T_FRWBraking torque T_RLWBraking torque T_RRW. The braking torque of each wheel can be calculated based on the braking torque characteristics that are set in advance and stored in the storage unit 22. Further, the braking torque calculation unit 23 calculates the braking torque T of each wheel_FLWBraking torque T_FRWBraking torque T_RLWBraking torque T_RRWAs the total value of the vehicleBraking torque T of vehicle 100_B。

Fig. 5 is an explanatory diagram of processing performed by the wheel deceleration calculating unit 24 and the wheel stopping torque calculating unit 26, and fig. 6 is an explanatory diagram of processing performed by the wheel deceleration calculating unit 24 and the vehicle stopping torque calculating unit 27. As shown in fig. 5 and 6, the wheel deceleration calculating section 24 calculates the wheel speed V of each wheel based on the wheel speed V of each wheel detected by the wheel speed sensor 18 of each wheel FLW, FRW, RLW, RRW_FLWWheel speed V_FRWWheel speed V_RLWWheel speed V_RRWCalculating the deceleration D of each wheel_FLWDeceleration D_FRWDeceleration D_RLWDeceleration D_RRW. The deceleration of each wheel can be calculated by time-differentiating the wheel speed of each wheel.

The moment of inertia setting unit 25 sets the moment of inertia I of each wheel that rotates about the rotation axis based on the weight WW (e.g., 12.5kg) and the radius RW of each wheel stored in the storage unit 22_W. Moment of inertia I of each wheel_WFor example, each wheel is assumed to be a disk-shaped rotating body having a uniform mass distribution, and can be set as the following expression (i) using an appropriate constant C (for example, C is 0.8).

I_W＝WW×(RW×C)＾2…(i)

The inertia moment setting unit 25 sets the inertia moment I of the vehicle 100 based on the weight WV (e.g., 1500kg) of the vehicle 100 and the radius RW of each wheel stored in the storage unit 22_V. Moment of inertia I about vehicle 100_VThe vehicle 100 may be assumed to be a disk-shaped rotating body that rotates around the rotation axis of each wheel and has a uniform mass distribution, and may be set as the following expression (ii) using an appropriate constant C (for example, C is 0.8).

I_V＝WV×(RW×C)＾2…(ii)

As shown in fig. 5, the wheel-stopping-torque calculating unit 26 is based on the deceleration of each wheel calculated by the wheel-deceleration calculating unit 24 and the moment of inertia I of each wheel set by the moment-of-inertia setting unit 25_WAnd a wheel stopping torque T for stopping the rotation of all the wheels of the vehicle 100, that is, for locking is calculated₁. Specifically, the wheel-stop torque calculation unit 26 is provided for the vehicleThe deceleration D of each wheel calculated by the wheel deceleration calculating section 24_FLWDeceleration D_FRWDeceleration D_RLWDeceleration D_RRWEach multiplied by the moment of inertia I of each wheel set by the moment of inertia setting section 25_WCalculating a wheel stopping torque T for locking each wheel_1FLWWheel stopping torque T_1FRWWheel stopping torque T_1RLWWheel stopping torque T_1RRW. Further, the wheel-stopping-torque calculating unit 26 calculates a wheel-stopping torque T for locking each wheel_1FLWWheel stopping torque T_1FRWWheel stopping torque T_1RLWWheel stopping torque T_1RRWAs the wheel stopping torque T for locking all the wheels of the vehicle 100₁. Wheel stopping torque T₁Is a braking torque to a transition state of a cascade lock-up state in which all wheels of the vehicle 100 are locked.

As shown in fig. 6, the vehicle stopping torque calculating unit 27 is based on the deceleration of each wheel calculated by the wheel deceleration calculating unit 24 and the moment of inertia I of the vehicle 100 set by the moment of inertia setting unit 25_VAnd a vehicle stopping torque T for stopping, i.e., braking, the vehicle 100 is calculated₂. Specifically, the vehicle stopping torque calculating unit 27 calculates the deceleration D of each wheel calculated by the wheel deceleration calculating unit 24_FLWDeceleration D_FRWDeceleration D_RLWDeceleration D_RRWEach multiplied by the moment of inertia I of the vehicle 100 set by the moment of inertia setting unit 25_V1/4, and calculates a vehicle stopping torque T for braking the vehicle 100 by each wheel_2FLWVehicle stop torque T_2FRWVehicle stop torque T_2RLWVehicle stop torque T_2RRW. That is, assuming that the weight of the vehicle 100 is shared equally among the wheels, the vehicle stopping torque for braking 1/4 of the vehicle 100 by each wheel is calculated. Further, the vehicle stopping torque calculating unit 27 calculates the vehicle stopping torque T for braking the vehicle 100 by each wheel_2FLWVehicle stop torque T_2FRWVehicle stop torque T_2RLWVehicle stop torque T_2RRWAs a total value forVehicle stopping torque T for overall braking of vehicle 100₂. Vehicle stopping torque T₂Is a braking torque when the vehicle 100 is braked with all the tires in a state of being caught on the road surface.

The cascade lock detection unit 28 calculates the braking torque T based on the braking torque calculated by the braking torque calculation unit 23_BAnd the wheel stopping torque T calculated by the wheel stopping torque calculating unit 26₁And the vehicle stopping torque T calculated by the vehicle stopping torque calculating unit 27₂The degree of the difference, the degree of cascade locking of the vehicle 100 is detected.

FIG. 7 is a graph showing the degree of cascade lock-up and the braking torque T_BAn explanatory diagram of the relationship (A) shows the actual braking torque T_BBraking torque (wheel stopping torque) T to transition state to cascade lock state₁And a braking torque (vehicle stopping torque) T when the vehicle 100 is braked with the tire gripped₂. Actual braking torque T_BThe closer to the tire grip state ((T)₂－T_B) The smaller) the lower the degree of cascade locking. On the other hand, the actual braking torque T_BCloser to cascade lock-up transition state ((T)_B－T₁) The smaller) the higher the degree of cascade locking. The cascade lock detection unit 28 calculates the degree R of cascade lock as shown in the following formula (iii), for example.

R＝(T_B－T₁)/(T₂－T₁)…(iii)

Further, the cascade lock detection unit 28 detects cascade lock when the degree R of cascade lock is smaller than a predetermined value R_TH(e.g., 0.5), the state is determined as a transition state to the cascade lock state. When the cascade lock detection unit 28 determines that the vehicle 100 is in a transition state to the cascade lock state, the travel control unit 29 performs travel control for preventing cascade lock.

The travel control unit 29 controls the actuators AC1 to AC5 to perform cascade lock prevention control for controlling the travel operation of the vehicle 100 to prevent cascade lock. For example, the travel control unit 29 controls the shift actuator AC1 such that the gear ratio of the transmission 2 is on the Overspeed (OD) side (high side). This reduces the running drive force generated by the drive force generation unit 7, and reduces the running drive force transmitted to each wheel, thereby preventing each wheel from locking.

Fig. 8 is an explanatory diagram of the cascade lock prevention control performed by the travel control unit 29, and shows a change in the engine speed during the cascade lock prevention control. In the anti-cascade lock control, the speed ratio of the transmission 2 is shifted to the OD side with the engine speed NE at the time of releasing the accelerator with the D range as a target value in the normal control, for example. Further, as shown in fig. 8, an upshift (up shift) is performed at a speed faster than that in the normal control, and the transition to the target engine speed NE is performed in a shorter time (t2 < t 1).

Then, the travel control unit 29 controls the lock-up clutch actuator AC2 to release the lock-up clutch 6. By releasing the lock-up clutch 6 to release the direct connection between the engine 1 and the transmission 2 and switching to torque transmission using the torque converter 5, the driving force for running transmitted to each wheel is reduced, and locking of each wheel is prevented.

The travel control unit 29 controls the injector actuator AC3 so that the injector 4 of the engine 1 injects fuel. In a fuel cut state where fuel injection is stopped during deceleration of vehicle 100, engine 1 may rub and each wheel may lock. By controlling the injector actuator AC3 so as to inject fuel, the running driving force generated by the driving force generation unit 7 is maintained so that the idle rotation speed of the engine 1 becomes a predetermined value (for example, 1000rpm) or more, thereby preventing locking of each wheel. The throttle actuator AC4 may be controlled so that the intake air amount of the engine 1 increases, and the idle speed of the engine 1 may be set to a predetermined value or more. The target value of the idle rotation speed in the anti-cascade lock control is higher than the idle rotation speed in the normal control, and is set to be equal to or lower than the initial idle rotation speed immediately after the engine is started.

Further, the running control unit 29 allocates the driving forces to the front wheels FLW, FRW side, the rear wheels RLW, RRW side to 100: in the 2WD mode of 0, the drive force distribution actuator AC5 is controlled so as to be switched to the 4WD mode. For example, the driving force distribution between the front wheels FLW, FRW, and the rear wheels RLW, RRW is 50: the driving force distribution actuator AC5 is controlled in the manner of 50. By switching to the 4WD mode, the running state of the vehicle 100 is stabilized, and locking of the wheels is prevented.

Fig. 9 is a flowchart showing an example of processing executed by the CPU of the controller 20 of fig. 3 according to a program stored in advance in the storage unit 22. The processing shown in the above-described flowchart is started when the operation of the brake device 15 is detected by, for example, a brake switch, and is repeated at a predetermined cycle.

First, in step S1, the braking torque T of the vehicle 100 is calculated by reading the detection value of the braking pressure sensor 17 through the processing performed by the braking torque calculation unit 23_B. Next, in step S2, the detection value of the wheel speed sensor 18 is read by the processing performed by the wheel deceleration calculating unit 24, and the deceleration D of each wheel is calculated_FLWDeceleration D_FRWDeceleration D_RLWDeceleration D_RRW. Next, in step S3, the weight WW and the radius RW of the wheel and the weight WV of the vehicle 100 stored in the storage unit 22 are read by the processing performed by the inertia moment setting unit 25, and the inertia moment I of the wheel is set_WAnd moment of inertia I of vehicle 100_V. Then, in step S4, the wheel-stopping-torque calculating unit 26 performs the processing based on the deceleration of each wheel calculated in step S2 and the moment of inertia I of the wheel set in step S3_WAnd the wheel stopping torque T is calculated₁. Next, in step S5, the wheel-stopping-torque calculating unit 26 performs a process based on the deceleration of each wheel calculated in step S2 and the moment of inertia I of the vehicle set in step S3_VAnd calculates the vehicle stop torque T₂. Next, in step S6, the brake torque T calculated in step S1 is based on the processing performed by the cascade lock detection unit 28_BThe wheel-stop torque T calculated in step S4₁And the vehicle stop torque T calculated in step S5₂And detects the degree R of cascade locking of the vehicle 100.

In step S7, it is determined whether the degree R of cascade lock detected in step S6 is less than a predetermined value R or not by the processing performed by the cascade lock detection unit 28_TH. If a positive determination is made in step S7, it is determined that the vehicle 100 is in the transition state to the cascade lock state, and the process proceeds to stepStep S8 is a cascade locking prevention control. On the other hand, the processing ends when no in step S7. In step S8, the process performed by the travel control unit 29 controls the shift actuator AC1 to shift the gear ratio of the transmission 2 to the OD side. Next, in step S9, the lock-up clutch actuator AC2 is controlled to release the lock-up clutch 6. Then, in step S10, the injector actuator AC3 is controlled to inject the fuel of the engine 1. Next, in step S11, it is determined whether or not the mode is the 2WD mode. If affirmative in step S11, the flow proceeds to step S12, and if negative, the processing is ended. In step S12, the driving force distribution actuator AC5 is controlled to switch to the 4WD mode.

The actual braking torque T generated by the braking device 15_BAnd a wheel stopping torque T for locking the wheel₁Difference of (d) and actual braking torque T_BWith vehicle stopping torque T for braking the vehicle₂By comparing the differences, it is possible to detect whether the actual state of the vehicle 100 is in a transient state close to the cascade lock or in a braking state close to the tire grip (steps S1 to S6). When it is determined that the vehicle 100 is in the transition state to the cascade lock state (step S7), the driving force transmitted from the driving force generation unit 7 to each wheel is reduced (steps S8 and S9), or the driving force generated by the driving force generation unit 7 is maintained (step S10), whereby the locking of each wheel can be prevented, and the cascade lock can be prevented. When the vehicle is traveling in the 2WD mode, the traveling state of vehicle 100 can be stabilized by switching to the 4WD mode, and cascade locking can be prevented (step S11 and step S12).

According to the present embodiment, the following operational effects can be exhibited.

(1) The anti-cascade locking device 50 includes: a brake pressure sensor 17 for detecting a brake pressure P applied to the brake device 15_FLWBraking pressure P_FRWBraking pressure P_RLWBraking pressure P_RRW(ii) a A braking torque calculation part 23 for calculating the braking torque T generated by the braking device 15 based on the braking pressure detected by the braking pressure sensor 17_B(ii) a A wheel speed sensor 18 for detecting a wheel FLW, a wheel FRW, a wheel RLW, and a vehicleWheel speed V of wheel RRW_FLWWheel speed V_FRWWheel speed V_RLWWheel speed V_RRW(ii) a The wheel deceleration calculating section 24 calculates the deceleration D of the wheel based on the wheel speed detected by the wheel speed sensor 18_FLWDeceleration D_FRWDeceleration D_RLWDeceleration D_RRW(ii) a A moment of inertia setting unit 25 for setting the moment of inertia I of the wheel_WAnd moment of inertia I of vehicle 100 having engine 1_V(ii) a The wheel-stopping-torque calculating unit 26 calculates the deceleration of the wheel based on the deceleration calculated by the wheel-deceleration calculating unit 24 and the moment of inertia I of the wheel set by the moment-of-inertia setting unit 25_WAnd a wheel stopping torque T for stopping the rotation of the wheel is calculated₁(ii) a The vehicle stopping torque calculating section 27 calculates the deceleration of the wheel based on the deceleration calculated by the wheel deceleration calculating section 24 and the moment of inertia I of the vehicle 100 set by the moment of inertia setting section 25_VAnd calculates a vehicle stop torque T for stopping the vehicle 100₂(ii) a A cascade lock detection unit 28 based on the braking torque T calculated by the braking torque calculation unit 23_BAnd the wheel stopping torque T calculated by the wheel stopping torque calculating unit 26₁And the vehicle stopping torque T calculated by the vehicle stopping torque calculating unit 27₂Detecting a degree R of cascade locking of the vehicle 100; and a travel control unit 29 that controls a travel operation of the vehicle 100 based on the degree R of cascade lock of the vehicle 100 detected by the cascade lock detection unit 28 (fig. 3).

That is, the actual braking torque T generated by the braking device 15_BAnd a wheel stopping torque T for locking the wheel₁Difference of (d) and actual braking torque T_BWith vehicle stopping torque T for braking the vehicle₂Is compared to detect whether the actual vehicle 100 state is approaching a transition state to cascade lock or a braking state with tire grip. This makes it possible to apply the present invention to all types of vehicles that travel by transmitting the travel driving force to the road surface via the wheels. Also, the wheel stopping torque T₁And vehicle stopping torque T₂Based on first differentiation by wheel speedThe deceleration of each wheel and the moment of inertia of each wheel and the vehicle are calculated, and therefore, even when the deceleration of each wheel is small, the deceleration can be accurately calculated. Therefore, the cascade lock state can be detected even when the deceleration of each wheel is small.

(2) The moment-of-inertia setting unit 25 sets the moment of inertia I of the wheel in advance based on the weight of the wheel_WAnd the moment of inertia I of the vehicle 100 is set in advance based on the weight of the vehicle 100_V. Thus, the moment of inertia I for detecting cascade lock can be easily set_WMoment of inertia I_VThereby enabling to reduce the calculation load.

(3) The vehicle 100 further has: the transmission 2 transmits the traveling driving force generated by the engine 1 to the wheels (fig. 1). When the degree R of cascade lock of the vehicle 100 detected by the cascade lock detection unit 28 exceeds the predetermined value R, the travel control unit 29 controls the vehicle to travel in a state where the degree R of cascade lock of the vehicle 100 exceeds the predetermined value R_THThe transmission 2 is controlled so as to reduce the running drive force transmitted from the engine 1 to the wheels. This prevents the wheels from locking.

(4) The engine 1 is an internal combustion engine. When the degree R of cascade lock of the vehicle 100 detected by the cascade lock detection unit 28 exceeds the predetermined value R, the travel control unit 29 controls the vehicle to travel in a state where the degree R of cascade lock of the vehicle 100 exceeds the predetermined value R_THIn this case, the engine 1 is controlled so that the idling rotation speed of the engine 1 becomes equal to or higher than a predetermined value. This can maintain the running driving force generated by the engine 1 and prevent each wheel from being locked.

(5) The vehicle 100 further has: the driving force distribution mechanism 13 is selectively switchable between a 4WD mode and a 2WD mode (fig. 1) according to the traveling state of the vehicle 100. When the 2WD mode is selected by the driving force distribution mechanism 13, the travel control unit 29 detects that the degree R of cascade lock of the vehicle 100 exceeds the predetermined value R by the cascade lock detection unit 28_THAt this time, the driving force distribution mechanism 13 is controlled to switch to the 4WD mode. This stabilizes the traveling state of vehicle 100 and prevents each wheel from being locked.

The embodiment can be modified in various ways. Hereinafter, a modified example will be described. In the above embodiment, the cascade locking prevention device 50 is applied to the four-wheel drive vehicle 100, but the cascade locking prevention device of the present invention can be applied to all types of vehicles including two-wheel drive vehicles or two-wheel vehicles that travel by transmitting a driving force to a road surface via wheels.

In the above embodiment, the inertia moment setting unit 25 sets the inertia moment I of the wheel in advance based on the weight WW of each wheel and the weight WV of the vehicle 100 stored in the storage unit 22_WAnd moment of inertia I of vehicle 100_VHowever, the inertia moment setting unit that sets the inertia moments of the wheels and the vehicle is not limited to this type of inertia moment setting unit. For example, the moment of inertia of the wheel or the vehicle may be corrected based on the deceleration of the wheel or the vehicle during normal running. In this case, the cascade lock can be detected in consideration of the influence of the amount of accumulation or the wear of the tire.

In the above embodiment, the formula (iii) is exemplified as the calculation formula for calculating the degree R of cascade lock by the cascade lock detection unit 28, but the calculation method is not limited to the above method as long as the cascade lock detection unit detects the degree of cascade lock based on the degree of difference between the braking torque and the wheel stopping torque and the vehicle stopping torque.

In the above embodiment, when the degree of cascade locking R exceeds the predetermined value R_THIn this case, the travel control unit 29 performs the cascade lock prevention control, but the travel control unit that controls the travel operation of the vehicle according to the degree of cascade lock is not limited to this type of travel control unit. For example, the running driving force may be reduced in stages according to the degree of cascade lock. Then, the value R is determined_THThe example is 0.5, but the predetermined value is not limited thereto. The predetermined value R may be set to plural values_THAnd the driver can select it appropriately.

In the above embodiment, the travel control unit 29 shifts the gear ratio of the transmission 2 to the OD side or releases the lock-up clutch 6, but the travel control unit that controls the torque transmission unit so as to reduce the travel driving force transmitted from the travel driving source to the wheels is not limited to this type of travel control unit. The travel control unit 29 controls the injector 4 to inject fuel into the engine 1 or controls the throttle valve 3 to increase the intake air amount of the engine 1, but the travel control unit that controls the internal combustion engine so that the idle rotation speed becomes equal to or higher than a predetermined value is not limited to this type of travel control unit.

The above description is merely an example, and the present invention is not limited to the embodiment and the modifications described above unless the features of the present invention are lost. One or more of the above-described embodiments and modifications may be arbitrarily combined, and modifications may be combined with each other.

Claims

1. An anti-cascading locking device, comprising:

a brake pressure detection unit for detecting a brake pressure acting on the brake device;

a braking torque calculation unit that calculates a braking torque generated by the braking device based on the braking pressure detected by the braking pressure detection unit;

a rotational speed detection unit that detects a rotational speed of the wheel;

a wheel deceleration calculation unit that calculates a deceleration of the wheel based on the rotation speed of the wheel detected by the rotation speed detection unit;

a moment-of-inertia setting unit that sets a moment of inertia of the wheel and a moment of inertia of a vehicle having a travel drive source;

a wheel stopping torque calculating unit that calculates a wheel stopping torque for stopping rotation of the wheel based on the deceleration of the wheel calculated by the wheel deceleration calculating unit and the moment of inertia of the wheel set by the moment of inertia setting unit;

a vehicle stopping torque calculating unit that calculates a vehicle stopping torque for stopping the vehicle, based on the deceleration of the wheel calculated by the wheel deceleration calculating unit and the moment of inertia of the vehicle set by the moment of inertia setting unit;

a cascade lock detection unit that detects a degree of cascade lock of the vehicle based on a degree of difference between the braking torque calculated by the braking torque calculation unit, the wheel stopping torque calculated by the wheel stopping torque calculation unit, and the vehicle stopping torque calculated by the vehicle stopping torque calculation unit; and

and a travel control unit that controls a travel operation of the vehicle based on the degree of cascade locking of the vehicle detected by the cascade locking detection unit.

2. The cascade lock prevention device according to claim 1, wherein the moment of inertia setting portion sets the moment of inertia of the wheel in advance based on a weight of the wheel, and sets the moment of inertia of the vehicle in advance based on the weight of the vehicle.

3. The cascade locking prevention device according to claim 1 or 2, wherein the vehicle further has: a torque transmission portion that transmits a travel driving force generated by the travel driving source to the wheel,

the running control unit controls the torque transmission unit to reduce the running driving force transmitted from the running drive source to the wheel when the degree of cascade lock of the vehicle detected by the cascade lock detection unit exceeds a predetermined value.

4. The cascade lock prevention device according to claim 1 or 2, wherein the travel drive source is an internal combustion engine,

the running control unit controls the internal combustion engine such that an idle rotation speed of the internal combustion engine becomes equal to or higher than a predetermined value when the degree of cascade locking of the vehicle detected by the cascade lock detection unit exceeds the predetermined value.

5. The cascade locking prevention device according to claim 1 or 2, wherein the vehicle further has: a mode switching unit that can selectively switch between a four-wheel drive mode and a two-wheel drive mode according to a running state of the vehicle,

the running control unit controls the mode switching unit to switch to the four-wheel drive mode when the degree of cascade lock of the vehicle detected by the cascade lock detection unit exceeds a predetermined value when the two-wheel drive mode is selected by the mode switching unit.

6. The anti-cascade locking apparatus according to claim 3, wherein the vehicle further has: a mode switching unit that can selectively switch between a four-wheel drive mode and a two-wheel drive mode according to a running state of the vehicle,

7. The anti-cascade locking apparatus according to claim 4, wherein the vehicle further has: a mode switching unit that can selectively switch between a four-wheel drive mode and a two-wheel drive mode according to a running state of the vehicle,