JP2006224706A - Braking force controlling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To assist a turning operation during traveling of a vehicle without using a power transmission mechanism with a complicated structure. <P>SOLUTION: Load sensors 80 and 81 are provided at right and left positions of a steering 82, and a steering assist request of a driver is detected by a load applied to the steering 82 by the driver. According to the steering assist request of the driver, an actuator 50 for controlling liquid pressure of a brake is driven, and a braking force larger than a turning outer wheel side is applied to a turning inner wheel side, so as to generate an inward yaw moment. When the inward yaw moment acts as a force for assisting the operation of the steering 82 and the driver operates the steering 82 to turn the vehicle, the steering 82 becomes easy to turn as if the steering 82 becomes light. Accordingly, the steering operation can be made easily as the driver wishes, so as to improve a kinetic performance. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a braking force control device for a vehicle that applies a braking force to specific wheels in order to assist a turning operation in traveling of the vehicle.

  2. Description of the Related Art Conventionally, there has been a demand for improvement in motion performance by making it possible to perform a steering operation more easily as intended by a driver in accordance with the traveling state of a vehicle. For example, there is a demand for making it easier to perform an operation of turning sharply when the vehicle turns at a low speed.

In response to such demands, for example, a four-wheel drive force control system that adjusts the drive force distribution of each wheel has been proposed as a device for improving exercise performance (see, for example, Patent Document 1). In this four-wheel drive force free control system, by adjusting the drive force for each wheel, the yaw moment around the vehicle rotation axis generated in the vehicle can be freely controlled from the inside to the outside. This four-wheel drive force control system is provided with a power transmission mechanism for smoothly distributing the drive force to each wheel, and the drive force applied to a specific wheel is adjusted using this power transmission mechanism. ing.
JP-A-5-294157

  However, when the power transmission mechanism is used as described above, a power transmission mechanism having a very complicated structure is required.

  SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to assist a turning operation in traveling of a vehicle without using a power transmission mechanism having a complicated structure.

  In order to achieve the above object, according to the first aspect of the present invention, a load detecting means (80) for detecting a load protruding in the vehicle forward direction applied to the steering (82) on each of the left and right sides of the steering (82). 81), and in the electronic control unit (70), based on the detection signal of the load detection means (80, 81), the load applied to the left side of the steering (82) and the load applied to the right side are calculated. By requesting, a steering assist request by the driver is detected. That is, when the load applied to the left side of the steering (82) is larger than the load applied to the right side, an electric signal is output to the pressure generating means (50), and the wheel cylinders (14, 15, 34, 35) for the left wheel (FL, RL) by generating a pressure higher than that corresponding to the right wheel (FR, RR) for the left wheel (FL, RL). Braking force larger than that of the right wheel (FR, RR) is generated. When the load applied to the right side of the steering (82) is larger than the load applied to the left side, an electric signal is output to the pressure generating means (50), and the wheel cylinders (14, 15, 34, 35) for the right wheel (FR, RR) by generating a pressure higher than that corresponding to the left wheel (FL, RL) against the right wheel (FR, RR). This is characterized in that a braking force larger than that of the left wheel (FL, RL) is generated.

  Thus, the load detection means (80, 81) is provided on both the left and right sides of the steering (82), and the load applied to the left and right of the steering (82) is determined based on the detection result of the load detection means (80, 81). The braking force distribution between the right wheel (FR, RR) and the left wheel (FL, RL) is adjusted based on the magnitude of the applied load.

  As a result, an inward yaw moment due to the difference in braking force between the right wheel (FR, RR) and the left wheel (FL, RL) can be generated, and the steering (82) can be easily turned off. As a result, the steering operation can be performed easily as intended by the driver, and the exercise performance can be improved. Such improvement in motion performance is performed only by adjusting the pressure generated by the pressure generating means (50) in the wheel cylinders (14, 15, 34, 35), so there is no complicated power transmission mechanism. However, it is possible to improve athletic performance.

  When the driver's steering assist request can be detected by such load detection means (80, 81), the braking force difference between the left and right wheels is independently generated separately from the steering operation, so that only the inward moment is generated. It is also possible to manipulate the direction of travel.

  In the second aspect of the invention, in the electronic control unit (70), the larger the difference in load between the left and right of the steering (82), the greater the difference between the right wheel (FR, RR) and the left wheel (FL, RL). An electric signal is output to the pressure generating means (50) so as to increase the braking force difference, and the pressure generated in the wheel cylinders (14, 15, 34, 35) is adjusted.

  Thus, the braking force difference between the right wheel (FR, RR) and the left wheel (FL, RL) can be increased according to the difference in load between the left and right of the steering (82).

  In the invention according to claim 3 or 4, in the electronic control unit (70), when the load applied to the left side of the steering (82) is larger than the load applied to the right side, or the steering (82) When the load applied to the right side of the cylinder is greater than the load applied to the left side, an electric signal is output to the pressure generating means (50), and the wheel cylinders (14, 15, 34, 35) are output. The front wheels (FL, FR) with respect to the rear wheels (RL, RR) are generated against the rear wheels (RL, RR) by generating a pressure higher than that corresponding to the front wheels (FL, FR). It is characterized by generating a greater braking force.

  Thus, the inward yaw moment can also be generated by making the braking force of the rear wheels (RL, RR) higher than that of the front wheels (FL, FR). Thereby, the same effect as that of claim 1 can be obtained. Further, as in the invention described in claim 3, the control of increasing the braking force of the rear wheels (RL, RR) to the invention described in claim 1 further than that of the front wheels (FL, FR). If this is done, a larger inward yaw moment can be generated, and the above effect can be obtained.

  In the invention according to claim 5, in the electronic control unit (70), the larger the difference in load between the left and right of the steering (82), the more the control between the rear wheels (RL, RR) and the front wheels (FL, FR). In order to increase the power difference, an electrical signal is output to the pressure generating means (50) to adjust the pressure generated in the wheel cylinders (14, 15, 34, 35).

  Thus, the braking force difference between the braking force difference between the rear wheels (RL, RR) and the front wheels (FL, FR) can be increased in accordance with the difference in load between the left and right of the steering (82).

  According to the sixth aspect of the present invention, the steering angle detecting means (84) for detecting the angle of the steering (82) by the operation of the driver is provided, and the electronic control device (70) detects the steering angle detecting means (84). Based on the signal, the driver's steering assistance request is detected, and an electric signal is output based on at least one of the steering angle and the steering angular velocity obtained from the detection signal of the steering angle detection means (84), and the wheel cylinders (14, 15) are output. , 34, 35), the brake force corresponding to the turning inner wheel is generated by generating a higher braking force on the turning inner wheel than the turning outer wheel by generating a higher pressure than that corresponding to the turning outer wheel. It is said.

  In this way, assuming that at least one of the steering angle and the steering angular velocity indicates a driver's steering assistance request, based on these, by generating a braking force larger than the turning outer wheel for the turning inner wheel, Generates an inward yaw moment. Thereby, the same effect as that of claim 1 can be obtained.

  In the invention according to claim 7, in the electronic control unit (70), the pressure is generated so that the larger the steering angle and the steering angular velocity are, the larger the braking force is generated on the turning inner wheel than the turning outer wheel. An electric signal is output to the means (50), and the pressure generated in the wheel cylinder (14, 15, 34, 35) is adjusted.

  Thus, the braking force difference between the turning inner wheel and the turning outer wheel can be increased in accordance with the magnitude of at least one of the steering angle and the steering angular velocity.

  In the invention according to claim 8 or 9, the electronic control device (70) outputs an electrical signal based on at least one of the steering angle and the steering angular velocity obtained from the detection signal of the steering angle detection means (84), Of the wheel cylinders (14, 15, 34, 35) corresponding to the rear wheels (RL, RR), a higher pressure is generated than that corresponding to the front wheels (FL, FR) to generate the rear wheels ( RL, RR) generates a braking force larger than that of the front wheels (FL, FR).

  Thus, the inward yaw moment can also be generated by making the braking force of the rear wheels (RL, RR) higher than that of the front wheels (FL, FR). Thereby, the same effect as that of the sixth aspect can be obtained. Further, as in the invention described in claim 8, the control for increasing the braking force of the rear wheels (RL, RR) more than the front wheels (FL, FR) with respect to the invention described in claim 6. If this is done, a larger inward yaw moment can be generated, and the above effect can be obtained.

  In the invention according to claim 10, the electronic control unit (70) has a larger braking force difference between the rear wheels (RL, RR) and the front wheels (FL, FR) as at least one of the steering angle and the steering angular velocity increases. Thus, an electrical signal is output to the pressure generating means (50), and the pressure generated in the wheel cylinder (14, 15, 34, 35) is adjusted.

  Thus, the difference in braking force between the rear wheels (RL, RR) and the front wheels (FL, FR) can be increased according to at least one of the steering angle and the steering angular velocity.

  According to the eleventh aspect of the present invention, there are provided operation switches that are respectively provided on the left and right sides of the steering (82) and that output a detection signal indicating a steering assist request of the driver, and based on the detection signal of the operation switch, It is characterized by detecting a steering assist request.

  As described above, instead of the load sensor (80, 81) described in claim 1, it may be configured such that the driver's steering assistance request can be indicated by the operation switches provided on the left and right sides of the steering (82). it can.

  In the invention according to claim 12, the vehicle speed detecting means for inputting information relating to the vehicle speed to the electronic control device (70) is provided, and the electronic control device (70) uses the wheel based on the detection result of the vehicle speed detecting means. The braking force distribution generated in each wheel (FL, FR, RL, RR) is adjusted by correcting the pressure generated in the cylinder (14, 15, 34, 35).

  In this way, the distribution of braking force generated on each wheel (FL, FR, RL, RR) can be adjusted according to the vehicle speed. Accordingly, for example, when the vehicle is at a low speed, an inward yaw moment can be generated, and when the vehicle is traveling at a high speed, an outward yaw moment can be generated.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
FIG. 1 shows a block configuration of the braking force control apparatus 1 of the present embodiment. Hereinafter, with reference to FIG. 1, the braking force control apparatus 1 of this embodiment is demonstrated.

  As shown in FIG. 1, the braking force control device 1 includes a brake pedal 11, a booster device 12, an M / C 13, W / C 14, 15, 34, and 35, and a brake fluid pressure control actuator 50. And a brake ECU 70. FIG. 2 is a diagram showing a detailed structure of each part.

  As shown in FIG. 2, a brake pedal 11 as a brake operation member that is depressed by a driver when applying a braking force to the vehicle is connected to a booster 12 and a M / C 13 that serve as a brake fluid pressure generation source. When the driver depresses the brake pedal 11, the stepping force is boosted by the booster 12, and the master pistons 13a and 13b disposed in the M / C 13 are pressed. Thereby, the same M / C pressure is generated in the primary chamber 13c and the secondary chamber 13d defined by the master pistons 13a and 13b.

  The M / C 13 is provided with a master reservoir 13e having passages communicating with the primary chamber 13c and the secondary chamber 13d. The master reservoir 13e supplies brake fluid into the M / C 13 through the passage, or stores excess brake fluid in the M / C 13. Note that each passage is formed to have a diameter that is much smaller than the diameter of each main pipeline extending from the primary chamber 13c and the secondary chamber 13d. An orifice effect is exhibited when the brake fluid flows into the tank.

  The M / C pressure generated in the M / C 13 is transmitted to each of the W / Cs 14, 15, 34, 35 through the brake fluid pressure control actuator 50.

  The brake fluid pressure control actuator 50 includes a first piping system 50a and a second piping system 50b. The first piping system 50a controls the brake fluid pressure applied to the left front wheel FL and the right rear wheel RR, and the second piping system 50b controls the brake fluid pressure applied to the right front wheel FR and the left rear wheel RL. X piping is constituted by these two piping systems of the first and second piping systems 50a, 50b.

  Hereinafter, the first and second piping systems 50a and 50b will be described. However, since the first piping system 50a and the second piping system 50b have substantially the same configuration, the first piping system 50a will be described here. The description of the second piping system 50b is omitted with reference to the first piping system 50a.

  The first piping system 50a includes a pipeline A serving as a main pipeline that transmits the above-described M / C pressure to the W / C 14 provided in the left front wheel FL and the W / C 15 provided in the right rear wheel RR. ing. A W / C pressure can be generated in each of the W / Cs 14 and 15 through the pipe A.

  Further, the pipe line A is provided with a first differential pressure control valve 16 composed of an electromagnetic valve capable of controlling two positions in the communication / differential pressure state. The first differential pressure control valve 16 is in a communicating state in a normal brake state, and the valve position is in a differential pressure state when electric power is supplied to the solenoid coil. At the valve position of the differential pressure state in the first differential pressure control valve 16, the M from the W / C 14, 15 side is only when the brake fluid pressure on the W / C 14, 15 side becomes a predetermined level or higher than the M / C pressure. Brake fluid flow is allowed only to the / C13 side. For this reason, the W / C 14 and 15 side is always maintained so as not to be higher than the M / C 13 side by a predetermined pressure or more, and the respective pipelines are protected.

  The pipe A branches into two pipes A1 and A2 downstream of the first differential pressure control valve 16 on the W / C 14 and 15 side. One of the two pipes A1 and A2 is provided with a first pressure increase control valve 17 for controlling the increase of the brake fluid pressure to the W / C 14, and the other is an increase of the brake fluid pressure to the W / C 15. A second pressure increase control valve 18 is provided for controlling the pressure.

  The first and second pressure increase control valves 17 and 18 are configured as electromagnetic valves as two-position valves that can control the communication / blocking state. When the first and second pressure-increasing control valves 17 and 18 are controlled to communicate, the M / C pressure or the brake fluid pressure due to the discharge of brake fluid from a pump 19 described later is set to W / C 14 and 15. Can be added to.

  Note that, during normal braking by the operation of the brake pedal 11 performed by the driver, the first differential pressure control valve 16 and the first and second pressure increase control valves 17 and 18 are always controlled to be in a communication state.

  The first differential pressure control valve 16 and the first and second pressure increase control valves 17 and 18 are provided with safety valves 16a, 17a and 18a, respectively, in parallel. The safety valve 16a of the first differential pressure control valve 16 reduces the M / C pressure to W / C14 when the driver depresses the brake pedal 11 when the valve position of the first differential pressure control valve 16 is in the differential pressure state. , 15 so as to be able to transmit. The safety valves 17a and 18a of the pressure increase control valves 17 and 18 are returned to the brake pedal 11 by the driver, particularly when the pressure increase control valves 17 and 18 are controlled to be shut off during ABS control. In some cases, the W / C pressure of the left front wheel FL and the right rear wheel RR is provided so as to be able to be reduced corresponding to this return operation.

  In the pipeline A, the first and second pressure increase control valves 17 and 18 and the pipeline B serving as a pressure-reducing pipeline connecting the pressure regulating reservoir 20 between the W / Cs 14 and 15 are controlled in communication / blocking states. As a two-position valve that can be formed, a first pressure reduction control valve 21 and a second pressure reduction control valve 22 each comprising an electromagnetic valve are provided. The first and second pressure reduction control valves 21 and 22 are always cut off during normal braking.

  A conduit C serving as a reflux conduit is disposed so as to connect the pressure regulating reservoir 20 and the conduit A serving as the main conduit. This pipe C is provided with a self-priming pump 19 driven by a motor 60 so as to suck and discharge brake fluid from the pressure regulating reservoir 20 toward the M / C 13 side or the W / C 14, 15 side. Yes.

  A safety valve 19 a is provided on the discharge port side of the pump 19 so that high-pressure brake fluid is not applied to the pump 19. A fixed capacity damper 23 is disposed on the discharge side of the pump 19 in the pipe C in order to reduce the pulsation of the brake fluid discharged by the pump 19.

  And the pipe line D used as an auxiliary pipe line is provided so that the pressure regulation reservoir 20 and M / C3 may be connected. Brake fluid is sucked from the M / C 13 by the pump 19 through this pipeline D and discharged to the pipeline A, so that the brake fluid is supplied to the W / C 14, 15 side during TCS control or ABS control. In addition, the W / C pressure of the target wheel can be increased.

  The pressure regulating reservoir 20 is connected to the pipeline D and receives the brake fluid from the M / C 3 side, and receives the brake fluid that is connected to the pipelines B and C and escapes from the W / Cs 14 and 15. In addition, a reservoir hole 20b for supplying brake fluid to the suction side of the pump 19 is provided and communicates with the reservoir chamber 20c. A ball valve 20d is disposed inside the reservoir hole 20a. The ball valve 20d is provided with a rod 20f having a predetermined stroke for moving the ball valve 20d up and down separately from the ball valve 20d.

  Also, in the reservoir chamber 20c, there are a piston 20g interlocking with the rod 20f, and a spring 20h that generates a force for pressing the piston 20g toward the ball valve 20d to push out the brake fluid in the reservoir chamber 20c. Is provided.

  The pressure regulating reservoir 20 configured as described above is configured such that when a predetermined amount of brake fluid is stored, the ball valve 20d is seated on the valve seat 20e and the brake fluid does not flow into the pressure regulating reservoir 20. . For this reason, more brake fluid than the suction capacity of the pump 19 does not flow into the reservoir chamber 20c, and no high pressure is applied to the suction side of the pump 19.

  On the other hand, as described above, the second piping system 50b has substantially the same configuration as the first piping system 50a. That is, the first differential pressure control valve 16 corresponds to the second differential pressure control valve 36. The first and second pressure increase control valves 17 and 18 correspond to the third and fourth pressure increase control valves 37 and 38, respectively, and the first and second pressure increase control valves 21 and 22 correspond to the third and fourth values, respectively. This corresponds to the pressure reduction control valves 41 and 42. The pressure regulation reservoir 20 corresponds to the pressure regulation reservoir 40. The pump 19 corresponds to the pump 39. The damper 23 corresponds to the damper 43. Further, the pipeline A, the pipeline B, the pipeline C, and the pipeline D correspond to the pipeline E, the pipeline F, the pipeline G, and the pipeline H, respectively. As described above, the hydraulic piping structure in the braking force control apparatus 1 is configured.

  The brake ECU 70 corresponds to an electronic control unit, and is constituted by a well-known microcomputer having a CPU, ROM, RAM, I / O, and the like, and performs processing such as various calculations according to a program stored in the ROM. Execute.

  Based on the electrical signal from the brake ECU 70, the control valves 16-18, 21, 22, 36-38, 41, 42 and the pumps 19, 39 in the brake fluid pressure control actuator 50 configured as described above are provided. Voltage application control to the motor 60 for driving is executed. Thereby, control of the W / C pressure generated in each W / C 14, 15, 34, 35 is performed.

  For example, when a control voltage is applied from the brake ECU 70 to the motor 60 and the solenoid for driving the solenoid valve, the brake fluid pressure control actuator 50 applies a brake within the brake fluid pressure control actuator 50 according to the applied voltage. The piping route is set. The brake fluid pressure corresponding to the set brake pipe path is generated in the W / Cs 14, 15, 34, and 35 so that the braking force generated in each wheel can be controlled.

  Further, detection signals from the load sensors 80 and 81 are input to the braking force control device 1. The load sensors 80 and 81 correspond to load detecting means, and are provided on the left and right sides of the steering 82, and are used for fixing the annular wheel portion 82a and the wheel portion 82a to the boss portion 83 in the steering 82. It is provided in the boundary part with the T-shaped support part 82b. When the driver applies a load to the steering wheel 82, for example, when a force is applied to the steering wheel 82 in the vehicle forward direction so as to protrude the steering wheel 82, the boundary between the wheel part 82a and the support part 82b is This is the part that undergoes the most stress deformation. For this reason, the load sensors 80 and 81 are composed of, for example, gauge resistances, and the brake ECU 70 transmits a detection signal corresponding to a change in resistance value of the gauge resistance due to stress deformation to the brake ECU 70 so that the driver applies a load to the steering 82. It is possible to detect the addition. When the detection signals of the load sensors 80 and 81 are very small, for example, the detection signal after amplification by an amplifier or the like may be transmitted to the brake ECU 70.

  As described above, the braking force control apparatus 1 of the present embodiment is configured. Next, the steering assist function by the braking force distribution adjustment by the braking force control device 1 will be described.

  The steering assist function is to make the steering 82 easily cut off by applying a braking force to a specific wheel by the braking force control device 1, that is, assisting the steering 82 by the driver.

  FIG. 3 illustrates a mechanism for facilitating turning off of the steering 82, and shows an example in which the steering 82 is easily cut off by adjusting the distribution of braking force between the left and right wheels. In FIG. 3, the arrow attached to the side of each wheel indicates the magnitude of the braking force, and the longer the arrow, the greater the braking force.

  As shown in FIG. 3, when the vehicle turns, when the vehicle turns, for example, when turning left, the left wheels FL and RL generate greater braking force than the right wheels RL and RR that are turning outer wheels. I will let you. In this way, an inward yaw moment is generated due to a difference in braking force between the left and right wheels, and the inward yaw moment acts as a force to assist the operation of the steering 82. As a result, the steering 82 appears to have become lighter. Therefore, the steering 82 is easily cut.

  In this way, an inward yaw moment can be generated by the difference in braking force between the left and right wheels. Accordingly, here, processing is performed in which an inward yaw moment is generated by generating a braking force difference between the left and right wheels. Note that FIG. 3 illustrates an example of a situation in which braking force is generated on both sides of the left and right wheels. However, if the turning inner wheel side has a larger braking force than the turning outer wheel side, the inner yaw moment It is not always necessary to generate a braking force on the turning outer wheel side. That is, the braking force may be generated only on the turning inner wheel side.

  Steering assistance using such a mechanism is a steering assistance function by adjusting the braking force distribution of the braking force control apparatus 1 of the present embodiment. FIG. 4 shows a flowchart of a specific steering assist process performed by the braking force control apparatus 1. The operation assisting process shown in this figure is executed by the brake ECU 70 in the braking force control apparatus 1, and is executed at predetermined calculation cycles in accordance with a program stored in advance in a ROM or the like in the brake ECU 70.

  First, in step 100, a force applied to the handle portion (steering 82) is input. This process is performed based on the detection signals of the load sensors 80 and 81 described above. Thus, the left force of the steering 82 is obtained from the detection signal of the left load sensor 80, and the right force of the steering 82 is obtained from the detection signal of the right load sensor 81.

  Subsequently, in Step 110, the total StrForce-value (= left force + right force) of the left and right forces of the steering 82 obtained in Step 100 is obtained.

  In step 120, the target left-right braking force difference is obtained from the total StrForce-value of the left and right forces of the steering 82 obtained in step 110. The target right / left braking force difference here means a braking force difference to be generated in the left and right wheels. This target right / left braking force difference is obtained from, for example, a map showing the relationship between the total StrForce-value of the left and right forces of the steering 82 and the target left / right braking force difference. Specifically, these relationships are proportional to each other as shown in FIG. 5, for example, and if the right force is greater than the left force, the driver wants to turn to the left. Steering intention display, when the left part force is greater than the right part force, it is assumed that the driver wants to turn to the right and the steering intention display is made. The target left-right braking force difference is determined according to the magnitude of the total force StrForce-value.

  Thereafter, in step 130, an electrical signal is output to the brake fluid pressure control actuator 50 so as to achieve the target left-right braking force difference. As a result, a braking force is generated or adjusted by the brake fluid pressure control actuator 50, and a braking force that causes a target left-right braking force difference is generated on the left and right wheels.

  For example, in a situation where the braking force is not originally generated, such as when the brake pedal 11 is not depressed by the driver, the braking force of the target left-right braking force difference is generated on the turning inner wheel side. No braking force is generated on the turning outer wheel side. In addition, when the braking force is already generated, such as when the brake pedal 11 is depressed by the driver, this time is obtained for the braking force already generated. The value obtained by adding the difference between the target left and right braking force is set as the braking force on the inner turning wheel side, and the braking force already generated on the turning outer wheel side is left as it is. Of course, even in such a situation where the braking force has already been generated, the target left-right braking force difference does not have to be added to the turning inner wheel side as it is, for example, it is generated. The braking force between the turning inner wheel and the turning outer wheel can also be adjusted so that the braking force difference obtained this time can be obtained without changing the total value of the braking force.

  Specifically, when the turning inner wheel is a left wheel, W / C pressure is generated for W / C 14 of the left front wheel FL and W / C 35 of the left rear wheel RL in the brake fluid pressure control actuator 50. To be able to. In this case, the first and second differential pressure control valves 16 and 36 are set in a differential pressure state, the second and third pressure increase control valves 18 and 37 are shut off based on an electrical signal from the brake ECU 70, and the motor Pumps 19 and 39 are driven when 60 is turned on. As a result, the brake fluid in the M / C 13 is sucked into the pumps 19 and 39 and then discharged toward the W / C 14 and 35, and the W / C 14 and 35 are pressurized so that the left front wheel FL A braking force is generated on the left rear wheel RL.

  The operation when the W / C pressure on the turning inner wheel side is increased in this manner is the same when the braking force is already generated and when it is not generated.

  According to the braking force control device 1 of the present embodiment described above, the driver's steering assist is detected by detecting the load applied by the driver to the steering 82 by the load sensors 80 and 81 provided at the left and right positions of the steering 82. The request can be detected. Then, in response to the driver's steering assistance request, the brake hydraulic pressure control actuator 50 is driven, so that a larger braking force is applied to the turning inner wheel side than to the turning outer wheel side, thereby generating an inward yaw moment. .

  For this reason, when the driver operates the steering 82 to turn the vehicle, the inward yaw moment acts as a force assisting the operation of the steering 82, and as a result, the steering 82 is easily turned off as if the steering 82 has become lighter. . As a result, the steering operation can be performed easily as intended by the driver, and the exercise performance can be improved. Therefore, it is possible to improve the exercise performance without a complicated power transmission mechanism. Further, since the improvement of the motion performance as described above can be realized by using the brake fluid pressure control actuator 50 that performs the ABS control or the like that is becoming common in recent years, the existing equipment can be effectively used.

  Although only the case where the inward yaw moment is generated in accordance with the driver's steering assistance request has been described here, the magnitude of the generated yaw moment may be corrected according to the vehicle speed. In other words, when the vehicle is at a low speed, the driver generally wants the steering 82 to be easily cut off, but the vehicle behavior becomes unstable if the steering 82 is cut off too much in a lane change or the like during high-speed driving. It can be.

  Accordingly, the W / C pressure generated in each of the turning inner wheel and the turning outer wheel is corrected according to the vehicle speed. For example, as shown in FIG. 6, the turning inner wheel side turns until the vehicle speed reaches 50 km / h, for example. By setting it so that a larger braking force is generated than on the outer ring side, an inward yaw moment is generated. On the other hand, for a higher speed, the turning outer wheel side has a larger braking force than the turning inner wheel side. By generating, an outward yaw moment may be generated so that the steering 82 is difficult to turn.

  Then, by increasing the inward yaw moment as the vehicle speed becomes slower and increasing the outward yaw moment as the vehicle speed becomes faster, it becomes possible to set the ease of turning of the steering 82 corresponding to the vehicle speed.

  In such a case, it is necessary to input information regarding the vehicle speed to the brake ECU 70. However, since a wheel speed sensor is originally provided for performing ABS control or the like, this is used as a vehicle speed detection means. Can be used. Of course, other vehicle speed detection means such as a vehicle speed sensor may be employed.

(Second Embodiment)
A second embodiment of the present invention will be described. In the first embodiment, the inner turning yaw moment is generated by setting the braking inner wheel side to have a larger braking force than the turning outer wheel side. However, in the present embodiment, the rear wheel RL, By using a larger braking force on the RR side, an inward yaw moment is generated, and the steering 82 is easily cut off. Note that the configuration of the braking force control apparatus of the present embodiment is almost the same as the configuration shown in FIGS. 1 and 2, and only the processing executed by the brake ECU 70 is different. Therefore, only the differences will be described. To do.

  FIG. 7 illustrates a mechanism for facilitating turning off of the steering 82, and shows an example in which the steering 82 is easily cut off by adjusting the distribution of braking force between the front and rear wheels. In FIG. 7, the arrow attached to the side of each wheel indicates the magnitude of the braking force, and the longer the arrow, the greater the braking force.

  As shown in FIG. 7, when the vehicle turns, a larger braking force is generated on the rear wheels RL and RR than on the front wheels FL and FR. In this way, an inward yaw moment is generated due to a difference in braking force between the front and rear wheels. Therefore, as in the case of FIG. 3 shown in the first embodiment, the inward yaw moment causes the steering 82 to operate. It acts as an assisting force, and as a result, the steering 82 is easily cut as if the steering 82 is lightened.

  In this way, an inward yaw moment can be generated by the difference in braking force between the front and rear wheels. In addition, here, the situation where the braking force is generated in both the front and rear wheels is described as an example. However, if the rear wheels RL and RR have a larger braking force than the front wheels FL and FR, the inward rotation will occur. A yaw moment can be generated, and it is not always necessary to generate a braking force on the front wheels FL and FR. That is, the braking force may be generated only in the rear wheels RL and RR.

  FIG. 8 shows a flowchart of a specific steering assist process performed by the braking force control apparatus 1 of the present embodiment. The operation assisting process shown in this figure is executed by the brake ECU 70 in the braking force control apparatus 1, and is executed at predetermined calculation cycles in accordance with a program stored in advance in a ROM or the like in the brake ECU 70.

  First, in steps 200 and 210, processing similar to that in steps 100 and 110 shown in FIG. 4 is executed. Accordingly, the total StrForce-value of the forces of the left part and the right part of the steering 82 is obtained.

  Then, at step 220, the target front-rear braking force difference is obtained from the total StrForce-value of the left and right forces of the steering 82 obtained at step 210. The target front / rear braking force difference here means a braking force difference to be generated on the front and rear wheels. This target front / rear braking force difference is obtained, for example, from a map showing the relationship between the total Str-force-value of the left and right forces of the steering 82 and the target front / rear braking force difference. Specifically, for example, these relationships are proportional to each other as shown in FIG. 9, and when the right force is greater than the left force, the driver wants to turn to the left. Steering intention display, when the left part force is greater than the right part force, it is assumed that the driver wants to turn to the right and the steering intention display is made. The target front-rear braking force difference is determined according to the magnitude of the total force StrForce-value.

  Thereafter, in step 230, processing similar to that in step 130 shown in FIG. 4 is executed. As a result, an electrical signal is output to the brake hydraulic pressure control actuator 50 so that the difference between the target front and rear braking forces is generated, and the braking force is generated or adjusted by the brake hydraulic pressure control actuator 50, so A braking force that causes a difference is generated in the front and rear wheels.

  As for the control mode of each part of the brake fluid pressure control actuator 50 when the braking force is generated for the front and rear wheels in this way, the target wheel whose W / C pressure is to be increased is the left rear wheel RL and the right rear wheel. The only difference is the wheel RR, and the rest is the same, and is omitted here.

  As described above, the inward yaw moment can also be generated by increasing the braking force of the rear wheels RL and RR rather than the front wheels FL and FR. In this case as well, the same as in the first embodiment. The effect of can be obtained.

(Third embodiment)
A third embodiment of the present invention will be described. FIG. 10 is a block diagram showing a schematic configuration of the braking force control apparatus 1 according to the present embodiment. As shown in this figure, the braking force control apparatus 1 of the present embodiment is provided with a steering sensor 84 instead of the load sensors 80 and 81 with respect to the first embodiment. This is the same as in the first embodiment.

  The steering sensor 84 outputs a detection signal corresponding to the steering angle and transmits the detection signal to the brake ECU 70. The brake ECU 70 obtains the steering angle based on the detection signal from the steering sensor 84 and obtains the steering angular velocity by differentiating the steering angle with respect to time.

  For example, the steering angle is zero when the vehicle is in a straight traveling state, a negative value when the driver performs an operation to rotate the steering 82 to the left, and a positive value when the driver performs an operation to rotate the vehicle to the right. The steering angular velocity is expressed as positive when the steering 82 is accelerated in the left rotation direction and negative when the steering 82 is accelerated in the right rotation direction.

  In FIG. 11, the flowchart of the specific steering assistance process which the braking force control apparatus 1 of this embodiment performs is shown. The operation assisting process shown in this figure is executed by the brake ECU 70 in the braking force control apparatus 1, and is executed at predetermined calculation cycles in accordance with a program stored in advance in a ROM or the like in the brake ECU 70.

  First, at step 300, the steering angle is input. This process is performed based on the detection signal of the steering sensor 84 described above. The steering angle is obtained from this detection signal, and the steering angular velocity is obtained.

  Subsequently, in step 310, the parameter Str-value corresponding to the steering angle and the steering angular velocity is obtained by substituting the steering angle and the steering angular velocity into a function having the steering angle and the steering angular velocity as variables. For example, in this embodiment, the following equation is used as the function. In the following equation, K1 and K2 are constants determined according to the vehicle type.

(Equation 1)
Str-value = K1 × steering angle + K2 × steering angular velocity In step 320, the target left-right braking force difference is obtained from the parameter Str-value obtained in step 310. The target left / right braking force difference here is the same as the target left / right braking force difference described in the first embodiment. The target left / right braking force difference is obtained from, for example, a map showing the relationship between the parameter Str-value and the target left / right braking force difference. Specifically, these relationships are proportional to each other as shown in FIG. 12, for example, and when the parameter Str-value is large, a steering intention display indicating that the driver wants to turn further to the left, and the parameter Str-value. Is small, it is assumed that the driver wants to turn to the right, and the target left-right braking force difference is determined according to the magnitude of the parameter Str-value.

  Thereafter, the process proceeds to step 330, and an electrical signal is output to the brake hydraulic pressure control actuator 50 so that the target left-right braking force difference obtained in step 320 is obtained. As a result, in the same manner as in the first embodiment, the braking force is generated or adjusted by the brake fluid pressure control actuator 50, and the braking force that causes the target left-right braking force difference is generated on the left and right wheels. Become.

  As described above, it is possible to obtain the target left-right braking force difference according to the steering angle and the steering angular velocity, and to generate the inward yaw moment based on this difference. As described above, it is considered that the steering angle and the steering angular velocity represent the driver's steering assistance request, and it is possible to generate the inward yaw moment according to these. Thereby, the effect similar to 1st Embodiment can be acquired.

(Fourth embodiment)
In the third embodiment, the inner yaw moment is generated by setting the braking inner wheel side to have a larger braking force than the turning outer wheel side. However, in this embodiment as well, the front wheel is the same as the second embodiment. An inward yaw moment is generated by using a larger braking force on the rear wheel side than on the rear side so that the steering 82 can be easily turned off.

  FIG. 13 shows a flowchart of a specific steering assist process performed by the braking force control apparatus 1 of the present embodiment. The operation assisting process shown in this figure is executed by the brake ECU 70 in the braking force control apparatus 1, and is executed at predetermined calculation cycles in accordance with a program stored in advance in a ROM or the like in the brake ECU 70.

  First, in steps 400 and 410, processing similar to that in steps 300 and 310 shown in FIG. 11 is executed. Thereby, the magnitude of the parameter Str-value is obtained.

  Subsequently, in step 420, a target front-rear braking force difference of the parameter Str-value obtained in step 410 is obtained. The target front / rear braking force difference here is the same as the target front / rear braking force difference described in the second embodiment. This target front-rear braking force difference is obtained from, for example, a map showing the relationship between the magnitude of the parameter Str-value and the target front-rear braking force difference. Specifically, these relationships are proportional to each other as shown in FIG. 14, for example, and when the parameter Str-value is large, a steering intention display indicating that the driver wants to turn further to the left, and the parameter Str-value. In the case of small, it is assumed that the driver wants to turn to the right, and the target front / rear braking force difference is determined according to the magnitude of the parameter Str-value.

  Thereafter, in step 430, processing similar to that in step 130 shown in FIG. 4 is executed. As a result, an electrical signal is output to the brake hydraulic pressure control actuator 50 so that the difference between the target front and rear braking forces is generated, and the braking force is generated or adjusted by the brake hydraulic pressure control actuator 50, so that the target front and rear braking force is obtained. A braking force that causes a difference is generated in the front and rear wheels.

  As described above, it is possible to generate the inward yaw moment also by increasing the braking force of the rear wheels RL and RR rather than the front wheels FL and FR. In this case as well, the same effect as that of the third embodiment is achieved. Can be obtained.

(Other embodiments)
In the first and second embodiments, the load sensors 80 and 82 can detect the driver's steering assistance request, but this is merely an example, and the driver's steering assistance request can be detected by other means. It is also possible to do so. For example, instead of the load sensors 80 and 81, a steering assist request display switch may be provided at the left and right positions of the support portion 82b in the steering 82, and the driver may make a steering assist request by operating this switch. it can.

  In the first to fourth embodiments, the inward yaw moment is generated based on either the braking force difference between the left and right wheels or the braking force difference between the front and rear wheels, but it is also possible to combine them. It is. In this case, the front wheel of the turning inner wheel generates a larger braking force than the front wheel of the turning outer wheel, the rear wheel of the turning inner wheel generates a larger braking force than the rear wheel of the turning outer wheel, and more than the front wheel of the turning inner wheel. A large braking force is generated on the rear wheel of the turning inner wheel, and a larger braking force is generated on the rear wheel of the turning outer wheel than the front wheel of the turning outer wheel.

  In the third and fourth embodiments, the steering assistance request is detected from both the steering angle and the steering angular velocity. However, one of these may be used.

  Furthermore, in the above embodiment, when the brake pedal 11 corresponding to the brake operating member is operated, the wheel cylinders 14, 15, 34, 35 are connected via the brake fluid pressure control actuator 50 corresponding to the M / C 13 and the pressure generating means. The hydraulic braking force control device 1 to which the brake fluid pressure is applied has been described, but it may be an electric type. In this case, by driving the motor, pressure is applied to the wheel cylinder, so the motor corresponds to the pressure generating means.

  Note that the steps shown in each figure correspond to means for executing various processes.

It is the figure which showed the block configuration of the braking force control apparatus in 1st Embodiment of this invention. It is the figure which showed the detailed structure of each part of the static power control apparatus shown in FIG. It is the schematic diagram which showed the mechanism which steering becomes easy to cut. It is a flowchart of the steering assistance process which the braking force control apparatus shown in FIG. 1 performs. It is the map which showed the relationship between total StrForce-value of the force of each of the left part of steering, and the right part, and a target right-and-left braking force difference. It is the map which showed the relationship between the vehicle speed and the W / C pressure generated in each turning inner wheel and turning outer wheel. It is the schematic diagram which showed the mechanism which steering becomes easy to cut. It is a flowchart of the steering assistance process which the braking force control apparatus in 2nd Embodiment of this invention performs. It is the map which showed the relationship between the total Str-force-value of each force of the left part of steering, and the right part, and a target front-and-back braking force difference. It is the figure which showed the block configuration of the braking force control apparatus in 3rd Embodiment of this invention. It is a flowchart of the steering assistance process which the braking force control apparatus shown in FIG. 10 performs. It is the map which showed the relationship between parameter Str-value and a target right-and-left braking force difference. It is a flowchart of the steering assistance process which the braking force control apparatus in 4th Embodiment of this invention performs. It is the map which showed the relationship between parameter Str-value and a target right-and-left braking force difference.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Brake pedal, 13 ... M / C, 16, 36 ... Differential pressure control valve, 17, 18, 37, 38 ... Pressure increase control valve, 21, 22, 41, 42 ... Pressure reduction control valve, 50 ... Brake fluid pressure Actuator for control, 50a, 50b ... 1st, 2nd piping system, 70 ... Brake ECU, 80, 81 ... Load sensor, 82 ... Steering, 82a ... Wheel part, 82b ... Support part, 84 ... Steering sensor.

Claims (12)

A brake operating member (11) operated by a driver;
A wheel cylinder (14, 15, 34, 35) provided for each of a plurality of wheels (FL, FR, RL, RR);
When the brake operating member (11) is operated, pressure generating means (50) for generating a pressure corresponding to the operation amount in the wheel cylinder (14, 15, 34, 35);
An electronic control device (70) for instructing the wheel cylinder (14, 15, 34, 35) to generate a desired wheel cylinder pressure by outputting an electric signal to the pressure generating means (50). )When,
Load detecting means (80, 81) that are provided on both the left and right sides of the steering (82) and detect a load that is applied to the steering (82) and that protrudes in the vehicle forward direction,
The electronic control unit (70) obtains the load applied to the left side of the steering (82) and the load applied to the right side based on detection signals of the load detection means (80, 81). The steering assist request by the driver is detected at
When the load applied to the left side of the steering (82) is larger than the load applied to the right side, an electric signal is output to the pressure generating means (50), and the wheel cylinder (14 , 15, 34, 35) corresponding to the left wheel (FL, RL), by generating a pressure higher than that corresponding to the right wheel (FR, RR), the left wheel (FL, RL) with respect to the right wheel (FR, RR) is generated,
When the load applied to the right side of the steering (82) is larger than the load applied to the left side, an electric signal is output to the pressure generating means (50), and the wheel cylinder (14 , 15, 34, 35) corresponding to the right wheel (FR, RR), by generating a pressure higher than that corresponding to the left wheel (FL, RL), the right wheel (FR, A braking force control device characterized in that a braking force larger than that of the left wheel (FL, RL) is generated with respect to (RR). The electronic control unit (70) has a larger braking force difference between the right wheel (FR, RR) and the left wheel (FL, RL) as the load difference between the left and right of the steering (82) is larger. Thus, an electric signal is output to the pressure generating means (50) to adjust the pressure generated in the wheel cylinder (14, 15, 34, 35). Item 4. The braking force control device according to Item 1. The electronic control unit (70) is configured such that the load applied to the left side of the steering (82) is larger than the load applied to the right side, or the right side of the steering (82). When the load is larger than the load applied to the left side, an electric signal is output to the pressure generating means (50), and the rear wheels (14, 15, 34, 35) of the wheel cylinders (14, 15, 34, 35) are output. RL, RR) is applied to the rear wheels (RL, RR) from the front wheels (FL, FR) by generating a higher pressure than that corresponding to the front wheels (FL, FR). The braking force control device according to claim 1 or 2, wherein a large braking force is generated. A brake operating member (11) operated by a driver;
A wheel cylinder (14, 15, 34, 35) provided for each of a plurality of wheels (FL, FR, RL, RR);
When the brake operating member (11) is operated, pressure generating means (50) for generating a pressure corresponding to the operation amount in the wheel cylinder (14, 15, 34, 35);
An electronic control device (70) for instructing the wheel cylinder (14, 15, 34, 35) to generate a desired wheel cylinder pressure by outputting an electric signal to the pressure generating means (50). )When,
Load detecting means (80, 81) that are provided on both the left and right sides of the steering (82) and detect a load that is applied to the steering (82) and that protrudes in the vehicle forward direction,
The electronic control unit (70) obtains the load applied to the left side of the steering (82) and the load applied to the right side based on detection signals of the load detection means (80, 81). The steering assistance request by the driver is detected,
The load applied to the left side of the steering (82) is greater than the load applied to the right side, or the load applied to the right side of the steering (82) is applied to the left side. If it is larger than that, an electric signal is output to the pressure generating means (50), and the wheel cylinder (14, 15, 34, 35) corresponding to the rear wheel (RL, RR) On the other hand, by generating a higher pressure than that corresponding to the front wheels (FL, FR), a larger braking force than the front wheels (FL, FR) is generated on the rear wheels (RL, RR). A braking force control device characterized by that. In the electronic control unit (70), the greater the difference between the loads on the left and right of the steering (82), the greater the braking force difference between the rear wheels (RL, RR) and the front wheels (FL, FR). Thus, an electrical signal is output to the pressure generating means (50) to adjust the pressure generated in the wheel cylinder (14, 15, 34, 35). 5. A braking force control device according to 4. A brake operating member (11) operated by a driver;
A wheel cylinder (14, 15, 34, 35) provided for each of a plurality of wheels (FL, FR, RL, RR);
When the brake operating member (11) is operated, pressure generating means (50) for generating a pressure corresponding to the operation amount in the wheel cylinder (14, 15, 34, 35);
An electronic control device (70) for instructing the wheel cylinder (14, 15, 34, 35) to generate a desired wheel cylinder pressure by outputting an electric signal to the pressure generating means (50). )When,
Steering angle detection means (84) for detecting the angle of the steering (82) by the operation of the driver,
The electronic control unit (70) is adapted to detect a steering assist request of the driver based on a detection signal of the steering angle detection means (84).
An electric signal is output based on at least one of a steering angle and a steering angular velocity obtained from the detection signal of the steering angle detection means (84), and corresponds to the turning inner wheel of the wheel cylinders (14, 15, 34, 35). The braking force control is characterized in that a higher braking force is generated on the inner turning wheel than on the turning outer wheel by generating a higher pressure than that corresponding to the turning outer wheel. apparatus. The electronic control unit (70) causes the pressure generating means (50) to generate a braking force on the turning inner wheel that is larger than that of the turning outer wheel as at least one of the steering angle and the steering angular velocity increases. The braking force control device according to claim 6, wherein an electric signal is output to adjust the pressure generated in the wheel cylinder (14, 15, 34, 35). The electronic control unit (70) outputs an electric signal based on at least one of a steering angle and a steering angular velocity obtained from a detection signal of the steering angle detection means (84), and the wheel cylinders (14, 15, 34, 35) of the rear wheels (RL, RR) corresponding to the rear wheels (RL, RR) by generating a pressure higher than that corresponding to the front wheels (FL, FR). The braking force control device according to claim 6 or 7, wherein a braking force larger than that of the front wheels (FL, FR) is generated. A brake operating member (11) operated by a driver;
A wheel cylinder (14, 15, 34, 35) provided for each of a plurality of wheels (FL, FR, RL, RR);
When the brake operating member (11) is operated, pressure generating means (50) for generating a pressure corresponding to the operation amount in the wheel cylinder (14, 15, 34, 35);
An electronic control device (70) for instructing the wheel cylinder (14, 15, 34, 35) to generate a desired wheel cylinder pressure by outputting an electric signal to the pressure generating means (50). )When,
Steering angle detection means (84) for detecting the angle of the steering (82) by the operation of the driver,
The electronic control unit (70) is adapted to detect a steering assist request of the driver based on a detection signal of the steering angle detection means (84).
An electric signal is output based on at least one of a steering angle and a steering angular velocity obtained from a detection signal of the steering angle detection means (84), and a rear wheel (RL, out of the wheel cylinders (14, 15, 34, 35) is output. RR) is larger than the front wheels (FL, FR) with respect to the rear wheels (RL, RR) by generating a higher pressure than that corresponding to the front wheels (FL, FR). A braking force control device characterized by generating a braking force. The electronic control unit (70) increases the braking force difference between the rear wheels (RL, RR) and the front wheels (FL, FR) as the at least one of the steering angle and the steering angular velocity increases. The electric signal is output to the pressure generating means (50), and the pressure generated in the wheel cylinder (14, 15, 34, 35) is adjusted. The braking force control apparatus described. A brake operating member (11) operated by a driver;
A wheel cylinder (14, 15, 34, 35) provided for each of a plurality of wheels (FL, FR, RL, RR);
When the brake operating member (11) is operated, pressure generating means (50) for generating a pressure corresponding to the operation amount in the wheel cylinder (14, 15, 34, 35);
An electronic control device (70) for instructing the wheel cylinder (14, 15, 34, 35) to generate a desired wheel cylinder pressure by outputting an electric signal to the pressure generating means (50). )When,
An operation switch that is provided on each of the left and right sides of the steering (82) and outputs a detection signal indicating a steering assist request of the driver;
The electronic control unit (70) can detect whether the operation switches provided on the left side and the right side of the steering (82) are operated based on a detection signal of the operation switch,
When the operation switch provided on the left side of the steering (82) is operated, an electric signal is output to the pressure generating means (50), and the wheel cylinder (14, 15, 34, 35) is output. Of the left wheel (FL, RL), the pressure corresponding to the left wheel (FL, RL) by generating a pressure higher than that corresponding to the right wheel (FR, RR). Generate a large braking force on the wheels (FR, RR)
When the operation switch provided on the right side of the steering (82) is operated, an electric signal is output to the pressure generating means (50), and the wheel cylinder (14, 15, 34, 35) is output. For the right wheel (FR, RR), the pressure corresponding to the right wheel (FR, RR) is higher than the one corresponding to the left wheel (FL, RL) by generating pressure to the right wheel (FR, RR). A braking force control device characterized in that a large braking force is generated on the left wheel (FL, RL). Vehicle speed detection means for inputting information relating to vehicle speed to the electronic control device (70);
The electronic control unit (70) corrects the pressure generated in the wheel cylinder (14, 15, 34, 35) based on the detection result of the vehicle speed detection means, thereby correcting each wheel (FL, FR, RL). , RR) is adjusted in braking force control device according to any one of claims 1 to 11.

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