Patent Application
20250010939
This disclosure relates to a vehicle brake system capable of suppressing a cost increase.
Conventionally, a vehicle such as a motorcycle is provided with a hydraulic pressure control unit for controlling a braking force that is generated on a wheel. In a vehicle brake system that includes the hydraulic pressure control unit, a master chamber of a master cylinder or the like and a wheel cylinder communicate with each other via the hydraulic pressure control unit. Then, when operation of a component, such as a valve, that is provided to the hydraulic pressure control unit is controlled, a pressure of a brake fluid in the wheel cylinder is controlled (for example, see JP-A-2018-8674).
By the way, there is a case where one of a master chamber for a front wheel and a master chamber for a rear wheel communicates with both of a wheel cylinder for the front wheel and a wheel cylinder for the rear wheel. For example, there is a case where, in the motorcycle, the plural wheel cylinders for the front wheel exist, the master cylinder for the front wheel communicates with a part of the wheel cylinders for the front wheel, and the master cylinder for the rear wheel communicates with both of a part of the other wheel cylinders for the front wheel and the wheel cylinder for the rear wheel. It is considered to provide the hydraulic pressure control unit to such a vehicle, so as to be able to separately control a braking force generated on the front wheel and a braking force generated on the rear wheel. However, in such a case, cost is possibly increased due to an increase in the number of components in the hydraulic pressure control unit, or the like.
The present invention has been made with the above-described problem as the background and therefore obtains a vehicle brake system capable of suppressing a cost increase.
A vehicle brake system according to the present invention is a vehicle brake system that includes: a hydraulic pressure control unit that controls a braking force generated to a vehicle; a first master chamber that is a master chamber for a front wheel and at least communicates with a wheel cylinder of the front wheel of the vehicle; and a second master chamber that is a master chamber for a rear wheel and at least communicates with a wheel cylinder of the rear wheel of the vehicle. The hydraulic pressure control unit controls a braking force that is generated on one wheel of the front wheel and the rear wheel, the first master chamber and the second master chamber are connected to the hydraulic pressure control unit, and, of the first master chamber and the second master chamber, the master chamber for the other of the front wheel and the rear wheel is connected to the wheel cylinder of the other wheel without the hydraulic pressure control unit being interposed therebetween.
The vehicle brake system according to the present invention is the vehicle brake system that includes: the hydraulic pressure control unit that controls the braking force generated to the vehicle; the first master chamber that is the master chamber for the front wheel and at least communicates with the wheel cylinder of the front wheel of the vehicle; and the second master chamber that is the master chamber for the rear wheel and at least communicates with the wheel cylinder of the rear wheel of the vehicle. The hydraulic pressure control unit controls the braking force that is generated on the one wheel of the front wheel and the rear wheel, the first master chamber and the second master chamber are connected to the hydraulic pressure control unit, and, of the first master chamber and the second master chamber, the master chamber for the other of the front wheel and the rear wheel is connected to the wheel cylinder of the other wheel without the hydraulic pressure control unit being interposed therebetween. In this way, compared to a case where the braking force generated on the front wheel and the braking force generated on the rear wheel can separately be controlled, it is possible to suppress an increase in the number of components of the hydraulic pressure control unit, and the like. Therefore, it is possible to suppress a cost increase.
A description will hereinafter be made on a vehicle brake system according to the present invention with reference to the drawings.
A description will hereinafter be made on the vehicle brake system that is mounted to a two-wheeled motorcycle (see a vehicle 1 in
A configuration, operation, and the like, which will be described below, merely constitute one example. The vehicle brake system according to the present invention is not limited to a case with such a configuration, such operation, and the like.
The same or similar description will appropriately be simplified or will not be made below. In the drawings, the same or similar members or portions will not be denoted by a reference sign or will be denoted by the same reference sign. A detailed structure will appropriately be illustrated in a simplified manner or will not be illustrated.
A description will be made on a configuration of the vehicle 1 according to an embodiment of the present invention with reference to
The vehicle 1 is a two-wheeled motorcycle that corresponds to an example of the vehicle according to the present invention. As illustrated in
The front-wheel rotational frequency sensor 4 is a wheel rotational frequency sensor that detects a rotational frequency of the front wheel 2 (for example, a rotational frequency of the front wheel 2 per unit time [rpm], a travel distance of the front wheel 2 per unit time [km/h], or the like), and outputs a detection result. The front-wheel rotational frequency sensor 4 may detect another physical quantity that can substantially be converted to the rotational frequency of the front wheel 2. The front-wheel rotational frequency sensor 4 is provided to the front wheel 2.
The rear-wheel rotational frequency sensor 5 is a wheel rotational frequency sensor that detects a rotational frequency of the rear wheel 3 (for example, the rotational frequency of the rear wheel 3 per unit time [rpm], a travel distance of the rear wheel 3 per unit time [km/h], or the like), and outputs a detection result. The rear-wheel rotational frequency sensor 5 may detect another physical quantity that can substantially be converted to the rotational frequency of the rear wheel 3. The rear-wheel rotational frequency sensor 5 is provided to the rear wheel 3.
The hydraulic pressure control unit 6 is a unit that has a function of controlling a braking force generated to the vehicle 1. For example, the hydraulic pressure control unit 6 includes components (for example, a control valve and a pump) that are provided on an oil channel connecting a master cylinder and a wheel cylinder and that control a pressure of a brake fluid in the wheel cylinder. When operation of the components in the hydraulic pressure control unit 6 is controlled, the braking force generated on the wheel is controlled. A detailed description on the vehicle brake system 10 that includes the hydraulic pressure control unit 6 will be made below.
The controller 7 controls operation of the hydraulic pressure control unit 6. For example, the controller 7 is partially or entirely constructed of a microcomputer, a microprocessor unit, or the like. In addition, the controller 7 may partially or entirely be constructed of one whose firmware and the like can be updated, or may partially or entirely be a program module or the like that is executed by a command from a CPU or the like, for example. The controller 7 may be provided as one unit or may be divided into plural units, for example. In the example illustrated in
Here, a detailed description will be made on the vehicle brake system 10 of the vehicle 1 with reference to
The vehicle brake system 10 also includes the hydraulic pressure control unit 6, and the front-wheel brake mechanism 12 and the rear-wheel brake mechanism 14 are partially included in the hydraulic pressure control unit 6. The hydraulic pressure control unit 6 is a unit that has a function of controlling the braking force applied to the front wheel 2 by the front-wheel brake mechanism 12 and the braking force applied to the front wheel 2 by the rear-wheel brake mechanism 14. Just as described, the hydraulic pressure control unit 6 controls the braking force that is generated on the front wheel 2 as one wheel of the front wheel 2 and the rear wheel 3.
A description will hereinafter be made on an example in which, of the front wheel 2 and the rear wheel 3, the hydraulic pressure control unit 6 controls the braking force generated on the front wheel 2. However, as will be described below, of the front wheel 2 and the rear wheel 3, the hydraulic pressure control unit 6 may control the braking force generated on the rear wheel 3. In this case, the front-wheel brake mechanism 12 brakes both of the front wheel 2 and the rear wheel 3, and the rear-wheel brake mechanism 14 brakes only the rear wheel 3 of the front wheel 2 and the rear wheel 3.
The first brake operation section 11 is provided to a handlebar of the vehicle 1 and is operated by the rider's hand, for example. The first brake operation section 11 is a brake lever, for example. The second brake operation section 13 is provided to a lower portion of a trunk of the vehicle 1 and is operated by the rider's foot, for example. The second brake operation section 13 is a brake pedal, for example. However, like a brake operation section of the scooter or the like, each of the first brake operation section 11 and the second brake operation section 13 may be the brake lever that is operated by the rider's hand.
A first master cylinder 21a is attached to the first brake operation section 11. A first reservoir 22a is attached to the first master cylinder 21a. A second master cylinder 21b is attached to the second brake operation section 13. A second reservoir 22b is attached to the second master cylinder 21b.
The front wheel 2 is provided with a brake caliper 23 that is held by the trunk of the vehicle 1 and has a brake pad (not illustrated). The brake caliper 23 is provided with wheel cylinders 24a, 24b, 24c as wheel cylinders 24 of the front wheel 2. Of the wheel cylinders 24a, 24b, 24c, the wheel cylinders 24a, 24c will also be referred to as first wheel cylinders 24a, 24c. Of the wheel cylinders 24a, 24b, 24c, the wheel cylinder 24b will also be referred to as a second wheel cylinder 24b.
The wheel cylinders 24a, 24b, 24c of the front wheel 2 are aligned in this order at spaced intervals in a circumferential direction of the front wheel 2, for example. Thus, the second wheel cylinder 24b is arranged between the first wheel cylinders 24a, 24c. Thus, the second wheel cylinder 24b is arranged between the first wheel cylinders 24a, 24c. However, a positional relationship among the first wheel cylinders and the second wheel cylinder is not limited to this example. In addition, the number of the first wheel cylinders and the number of the second wheel cylinder are not limited to this example. For example, the number of the first wheel cylinders may be one, three, or more. The number of the second wheel cylinders may be two or more. The number of the first wheel cylinders may be larger than, may be the same as, or may be smaller than the number of the second wheel cylinders.
The rear wheel 3 is provided with a brake caliper 25 that is held by the trunk of the vehicle 1 and has a brake pad (not illustrated). The brake caliper 25 is provided with a wheel cylinder 26 of the rear wheel 3.
The first master cylinder 21a corresponds to an example of a first master chamber as a master chamber for the front wheel 2 that communicates with at least the wheel cylinders 24 of the front wheel 2. The second master cylinder 21b corresponds to an example of a second master chamber as a master chamber for the rear wheel 3 that communicates with at least the wheel cylinder 26 of the rear wheel 3. The first master cylinder 21a and the second master cylinder 21b are connected to the hydraulic pressure control unit 6. The hydraulic pressure control unit 6 is connected to the first wheel cylinders 24a, 24c and the second wheel cylinder 24b as the wheel cylinders 24 of the front wheel 2.
Here, the hydraulic pressure control unit 6 is provided with: a first channel 27 that communicates between the first master cylinder 21a and each of the first wheel cylinders 24a, 24c; and a second channel 28 that communicates between the second master cylinder 21b and the second wheel cylinder 24b. Thus, the first master cylinder 21a is connected to the first wheel cylinders 24a, 24c of the wheel cylinders 24 of the front wheel 2 via the hydraulic pressure control unit 6. Meanwhile, the second master cylinder 21b is connected to the second wheel cylinder 24b of the wheel cylinders 24 of the front wheel 2 via the hydraulic pressure control unit 6.
Of the first master cylinder 21a and the second master cylinder 21b, the second master cylinder 21b, which corresponds to the master chamber for the rear wheel 3, is connected to the wheel cylinder 26 of the rear wheel 3 without the hydraulic pressure control unit 6 being interposed therebetween. More specifically, the second master cylinder 21b is connected to the wheel cylinder 26 of the rear wheel 3 without at least a base body 6a, which will be described below, of the hydraulic pressure control unit 6 being interposed therebetween. In the example illustrated in
The front-wheel brake mechanism 12 includes the first brake operation section 11, the first master cylinder 21a, the first reservoir 22a, the brake caliper 23 of the front wheel 2, the first wheel cylinders 24a, 24c of the wheel cylinders 24 of the front wheel 2, and the first channel 27. The first channel 27 includes a first primary channel 27a and a first secondary channel 27b.
The first primary channel 27a communicates between the first master cylinder 21a and each of the first wheel cylinders 24a, 24c. The first primary channel 27a is provided with a first inlet valve 31a. The first secondary channel 27b releases the brake fluid in each of the first wheel cylinders 24a, 24c to an intermediate portion P1 of the first primary channel 27a. The first secondary channel 27b bypasses a portion of the first primary channel 27a between the first wheel cylinders 24a, 24c side and the first master cylinder 21a side of the first inlet valve 31a. The first secondary channel 27b is sequentially provided with a first outlet valve 32a, a first accumulator 33a, and a first pump 34a from an upstream side.
The rear-wheel brake mechanism 14 includes the second brake operation section 13, the second master cylinder 21b, the second reservoir 22b, the brake caliper 23 of the front wheel 2, the second wheel cylinder 24b of the wheel cylinders 24 of the front wheel 2, the brake caliper 25 of the rear wheel 3, the wheel cylinder 26 of the rear wheel 3, and the second channel 28. The second channel 28 includes a second primary channel 28a and a second secondary channel 28b.
The second primary channel 28a communicates between the second master cylinder 21b and the second wheel cylinder 24b. The second primary channel 28a is provided with a second inlet valve 31b. The second secondary channel 28b releases the brake fluid in the second wheel cylinder 24b to an intermediate portion P2 of the second primary channel 28a. The second secondary channel 28b bypasses a portion of the second primary channel 28a between the second wheel cylinder 24b side and the second master cylinder 21b side of the second inlet valve 31b. The second secondary channel 28b is sequentially provided with a second outlet valve 32b, a second accumulator 33b, and a second pump 34b from the upstream side.
The first inlet valve 31a and the second inlet valve 31b are electromagnetic valves, each of which is opened in an unenergized state and closed in an energized state, for example. The first outlet valve 32a and the second outlet valve 32b are electromagnetic valves, each of which is closed in the unenergized state and opened in the energized state, for example.
The hydraulic pressure control unit 6 is provided with a common drive source 35 that drives both of the first pump 34a and the second pump 34b. The drive source 35 is an electric motor, for example. Operation of the drive source 35 is controlled by the controller 7.
The hydraulic pressure control unit 6 is provided with a first master cylinder pressure sensor 36a and a second master cylinder pressure sensor 36b. However, the hydraulic pressure control unit 6 may not be provided with the first master cylinder pressure sensor 36a and the second master cylinder pressure sensor 36b.
The first master cylinder pressure sensor 36a detects a first master cylinder pressure that is a pressure of the brake fluid in the first master cylinder 21a, and outputs a detection result. The first master cylinder pressure sensor 36a may detect another physical quantity that can substantially be converted to the first master cylinder pressure.
The second master cylinder pressure sensor 36b detects a second master cylinder pressure that is a pressure of the brake fluid in the second master cylinder 21b, and outputs a detection result. The second master cylinder pressure sensor 36b may detect another physical quantity that can substantially be converted to the second master cylinder pressure.
The hydraulic pressure control unit 6 includes: components such as the first inlet valve 31a, the first outlet valve 32a, the first accumulator 33a, the first pump 34a, the second inlet valve 31b, the second outlet valve 32b, the second accumulator 33b, the second pump 34b, and the drive source 35 used to control the pressure of the brake fluid; and the base body 6a that is provided with those components and is formed with channels constituting the first channel 27 and the second channel 28 therein.
The base body 6a may be formed of one member or may be formed of plural members. In addition, in the case where the base body 6a is formed of the plural members, the components may separately be provided to the different members.
The controller 7 controls operation of the above components of the hydraulic pressure control unit 6. As a result, the braking force generated on the front wheel 2 and the braking force generated on the rear wheel 3 are controlled.
During normal time (that is, when the braking force that corresponds to a brake operation by the rider is set to be generated on the wheel), the controller 7 opens the first inlet valve 31a and the second inlet valve 31b and closes the first outlet valve 32a and the second outlet valve 32b. When the first brake operation section 11 is operated in such a state, in the front-wheel brake mechanism 12, a piston (not illustrated) in the first master cylinder 21a is pressed to increase the pressure of the brake fluid in each of the first wheel cylinders 24a, 24c of the front wheel 2, the brake pad (not illustrated) of the brake caliper 23 of the front wheel 2 is then pressed against a rotor 2a of the front wheel 2, and the braking force is thereby generated on the front wheel 2.
Meanwhile, when the second brake operation section 13 is operated, in the rear-wheel brake mechanism 14, a piston (not illustrated) in the second master cylinder 21b is pressed to increase the pressure of the brake fluid in the wheel cylinder 26 of the rear wheel 3, the brake pad (not illustrated) of the brake caliper 25 of the rear wheel 3 is then pressed against a rotor 3a of the rear wheel 3, and the braking force is thereby generated on the rear wheel 3. In addition, when the second brake operation section 13 is operated, in the rear-wheel brake mechanism 14, the piston (not illustrated) in the second master cylinder 21b is pressed to increase the pressure of the brake fluid in the second wheel cylinder 24b of the front wheel 2, too, the brake pad (not illustrated) of the brake caliper 23 of the front wheel 2 is then pressed against the rotor 2a of the front wheel 2, and the braking force is also thereby generated on the front wheel 2.
A detailed description will hereinafter be made on the functional configuration of the controller 7 with reference to
The acquisition section 71 acquires information from each of the devices in the vehicle 1, and outputs the acquired information to the execution section 72. For example, the acquisition section 71 acquires the information from the front-wheel rotational frequency sensor 4, the rear-wheel rotational frequency sensor 5, the first master cylinder pressure sensor 36a, and the second master cylinder pressure sensor 36b. In the present specification, the acquisition of the information can include extraction, generation, and the like of the information.
The execution section 72 controls the operation of each of the components of the hydraulic pressure control unit 6. For example, the execution section 72 controls the operation of the first inlet valve 31a, the first outlet valve 32a, the second inlet valve 31b, the second outlet valve 32b, and the drive source 35.
As described above, during the normal time, the execution section 72 controls the operation of each of the components in the hydraulic pressure control unit 6 such that the braking force corresponding to the brake operation by the rider is generated on the wheel. Meanwhile, in a particular case, the execution section 72 executes anti-lock brake control. In the anti-lock brake control, the braking force of the wheel is adjusted to such a braking force with which locking of the wheel can be avoided. The operation of the vehicle brake system 10 in the anti-lock brake control will be described below.
A description will be made on the operation of the vehicle brake system 10 according to the embodiment of the present invention with reference to
As described above, the execution section 72 of the controller 7 can execute the anti-lock brake control. A description will hereinafter be made on processing that is related to the anti-lock brake control executed by the controller 7 with reference to a flowchart in
When the control flow illustrated in
For example, the execution section 72 acquires a speed of the vehicle 1 on the basis of the detection results of the front-wheel rotational frequency sensor 4 and the rear-wheel rotational frequency sensor 5. Then, in the case where a slip rate of the front wheel 2 exceeds a target slip rate, the execution section 72 determines the front wheel 2 slips or possibly slips. That is, this case corresponds to a case where the slip or the possible slip of the front wheel 2 is detected. The slip rate is an index that indicates a degree of slippage of the wheel on a road surface, and is a value that is acquired by dividing a difference between the vehicle speed and the wheel rotational frequency by the vehicle speed.
If it is determined that the slip or the possible slip of the front wheel 2 is not detected (step S102/NO), step S102 is repeated. On the other hand, if it is determined that the slip or the possible slip of the front wheel 2 is detected (step S102/YES), the processing proceeds to step S103. In step S103, the execution section 72 executes the anti-lock brake control.
In the anti-lock brake control, depressurization control is executed. In the depressurization control, the pressure of the brake fluid in the wheel cylinder 24 of the front wheel 2 is reduced by controlling the operation of each of the components of the hydraulic pressure control unit 6. As a result, the braking force of the front wheel 2 is adjusted to such a braking force with which locking thereof can be avoided. In detail, in the anti-lock brake control, the depressurization control, hydraulic pressure keeping control for keeping the pressure of the brake fluid in the wheel cylinder 24 of the front wheel 2, and pressurization control for increasing the pressure of the brake fluid in the wheel cylinder 24 of the front wheel 2 are repeatedly executed in this order. A detailed description on the depressurization control in the anti-lock brake control will be made below.
After step S103, in step S104, the execution section 72 determines whether a termination condition of the anti-lock brake control is satisfied. The termination condition of the anti-lock brake control only needs to be a condition capable of determining that locking of the front wheel 2 is avoided, and any of the various conditions can be used.
If it is determined that the termination condition of the anti-lock brake control is not satisfied (step S104/NO), the processing returns to step S103. On the other hand, if it is determined that the termination condition of the anti-lock brake control is satisfied (step S104/YES), the processing proceeds to step S105. In step S105, the execution section 72 terminates the anti-lock brake control, and the processing returns to step S102.
As described above, in the anti-lock brake control, the controller 7 executes the depressurization control for reducing the pressure of the brake fluid in the wheel cylinder 24 of the front wheel 2. In the vehicle brake system 10, in the case where the slip or the possible slip of the front wheel 2 is detected, the controller 7 executes, as the depressurization control, at least one of first wheel cylinder depressurization control and second wheel cylinder depressurization control.
As illustrated in
As described above, the first wheel cylinder depressurization control is the depressurization control to bring the first inlet valve 31a into the closed state and brings the first outlet valve 32a into the open state. The first wheel cylinder depressurization control is executed in conjunction with driving of the drive source 35. Initiation timing of driving of the drive source 35 may be before, may match, or may be after timing of bringing the first inlet valve 31a into the closed state and bringing the first outlet valve 32a into the open state.
As illustrated in
As described above, the second wheel cylinder depressurization control is the depressurization control to bring the second inlet valve 31b into the closed state and bring the second outlet valve 32b into the open state. The second wheel cylinder depressurization control is executed in conjunction with driving of the drive source 35. The initiation timing of driving of the drive source 35 may be before, may match, or may be after timing of bringing the second inlet valve 31b into the closed state and bringing the second outlet valve 32b into the open state.
As illustrated in
The controller 7 can determine whether to execute the first wheel cylinder depressurization control and the second wheel cylinder depressurization control by various methods. A description will hereinafter be made on various examples related to the determination on whether to execute the first wheel cylinder depressurization control and the second wheel cylinder depressurization control.
In the case where the slip or the possible slip of the front wheel 2 is detected, the controller 7 may execute, in conjunction with driving of the drive source 35, both of the first wheel cylinder depressurization control and the second wheel cylinder depressurization control not on the basis of the operation states of the first brake operation section 11 and the second brake operation section 13.
Here, the controller 7 can acquire the operation state of the first brake operation section 11 by using the detection result of the first master cylinder pressure sensor 36a, and can acquire the operation state of the second brake operation section 13 by using the detection result of the second master cylinder pressure sensor 36b. For example, the operation state of each of the brake operation sections can include a state such as a magnitude of an operation amount of the respective brake operation section, in addition to whether the respective brake operation section is operated.
However, in the case where the first master cylinder pressure sensor 36a and the second master cylinder pressure sensor 36b are not provided, or the like, the controller 7 may not be able to acquire the operation states of the first brake operation section 11 and the second brake operation section 13. In such a case, it is difficult to determine the brake operation of which of the brake operation sections causes the slip or the possible slip of the front wheel 2. Thus, when both of the first wheel cylinder depressurization control and the second wheel cylinder depressurization control are executed, locking of the front wheel 2 can appropriately be avoided.
In addition, the controller 7 may determine whether to execute the first wheel cylinder depressurization control and the second wheel cylinder depressurization control on the basis of the operation states of the first brake operation section 11 and the second brake operation section 13.
More specifically, in the case where the brake operation using the first brake operation section 11 is prioritized over the brake operation using the second brake operation section 13, the controller 7 may permit the first wheel cylinder depressurization control and prohibit the second wheel cylinder depressurization control. For example, in the case where the brake operation using the second brake operation section 13 is not performed, and only the brake operation using the first brake operation section 11 is performed, the controller 7 may permit the first wheel cylinder depressurization control and prohibit the second wheel cylinder depressurization control. In addition, for example, in the case where the operation amount of the first brake operation section 11 is larger than the operation amount of the second brake operation section 13, the controller 7 may permit the first wheel cylinder depressurization control and prohibit the second wheel cylinder depressurization control.
On the other hand, in the case where the brake operation using the second brake operation section 13 is prioritized over the brake operation using the first brake operation section 11, the controller 7 may permit the second wheel cylinder depressurization control and prohibit the first wheel cylinder depressurization control. For example, in the case where the brake operation using the first brake operation section 11 is not performed, and only the brake operation using the second brake operation section 13 is performed, the controller 7 may permit the second wheel cylinder depressurization control and prohibit the first wheel cylinder depressurization control. In addition, for example, in the case where the operation amount of the second brake operation section 13 is larger than the operation amount of the first brake operation section 11, the controller 7 may permit the second wheel cylinder depressurization control and prohibit the first wheel cylinder depressurization control.
In the case where whether to execute the first wheel cylinder depressurization control and the second wheel cylinder depressurization control is determined as described above, and the front wheel 2 slips or possibly slips due to the brake operation using the first brake operation section 11, locking of the front wheel 2 can be avoided only by the first wheel cylinder depressurization control. Meanwhile, in the case where the front wheel 2 slips or possibly slips due to the brake operation using the second brake operation section 13, locking of the front wheel 2 can be avoided only by the second wheel cylinder depressurization control. In this way, unnecessary execution of both of the first wheel cylinder depressurization control and the second wheel cylinder depressurization control is suppressed, and thus worsening of the rider's comfort, which is caused by vibration generated to the brake operation section due to the depressurization control, or the like, is suppressed.
The controller 7 may determine whether to execute the first wheel cylinder depressurization control and the second wheel cylinder depressurization control on the basis of the information other than the operation states of the first brake operation section 11 and the second brake operation section 13. For example, the controller 7 may determine whether to execute the first wheel cylinder depressurization control and the second wheel cylinder depressurization control on the basis of a comparison result between the braking force (more specifically, an estimated value) applied to the front wheel 2 by the first wheel cylinders 24a, 24c and the braking force (more specifically, an estimated value) applied to the front wheel 2 by the second wheel cylinder 24b. In this case, for example, in the case where the braking force applied to the front wheel 2 by the first wheel cylinders 24a, 24c is larger than the braking force applied to the front wheel 2 by the second wheel cylinder 24b, the controller 7 may permit the first wheel cylinder depressurization control and prohibit the second wheel cylinder depressurization control. On the other hand, in the case where the braking force applied to the front wheel 2 by the second wheel cylinder 24b is larger than the braking force applied to the front wheel 2 by the first wheel cylinders 24a, 24c, the controller 7 may permit the second wheel cylinder depressurization control and prohibit the first wheel cylinder depressurization control.
In addition, the controller 7 may determine the execution of which one of the first wheel cylinder depressurization control and the second wheel cylinder depressurization control is prioritized on the basis of a magnitude relationship between the number of the first wheel cylinders 24a, 24c and the number of the second wheel cylinder 24b. In the above example, the number of the first wheel cylinders 24a, 24c is two, and the number of the second wheel cylinder 24b is one. Thus, the number of the first wheel cylinders 24a, 24c is larger than the number of the second wheel cylinder 24b.
Just as described, in the case where the number of the first wheel cylinders 24a, 24c is larger than the number of the second wheel cylinder 24b, the controller 7 may prioritize the execution of the first wheel cylinder depressurization control over the execution of the second wheel cylinder depressurization control. For example, in the case where the slip or the possible slip of the front wheel 2 is detected, the controller 7 first executes the first wheel cylinder depressurization control. Then, only when it is difficult to avoid locking of the front wheel 2 only by the first wheel cylinder depressurization control, the controller 7 executes the second wheel cylinder depressurization control in addition to the first wheel cylinder depressurization control.
Here, as the number of the wheel cylinders is increased, a magnitude of the braking force that can be generated is increased. Accordingly, when the determination is made on the execution of which one of the first wheel cylinder depressurization control and the second wheel cylinder depressurization control is prioritized, such a situation can arise where locking of the front wheel 2 can be avoided by only one of the first wheel cylinder depressurization control and the second wheel cylinder depressurization control. As a result, the unnecessary execution of both of the first wheel cylinder depressurization control and the second wheel cylinder depressurization control is suppressed, and thus worsening of the rider's comfort, which is caused by the vibration generated to the brake operation section due to the depressurization control, or the like, is suppressed.
As the example of the case where the execution of the first wheel cylinder depressurization control is prioritized over the execution of the second wheel cylinder depressurization control, the above description has been made on the example in which the controller 7 executes the first wheel cylinder depressurization control earlier than the second wheel cylinder depressurization control. However, the control in which the execution of the first wheel cylinder depressurization control is prioritized over the execution of the second wheel cylinder depressurization control is not limited to this example. For example, in the case where the execution of the first wheel cylinder depressurization control is prioritized over the execution of the second wheel cylinder depressurization control, the controller 7 may increase a reduced amount of the pressure of the brake fluid in each of the first wheel cylinders 24a, 24c by the first wheel cylinder depressurization control to be larger than a reduced amount of the pressure of the brake fluid in the second wheel cylinder 24b by the second wheel cylinder depressurization control.
Here, unlike the above example, in the case where the number of the second wheel cylinders is larger than the number of the first wheel cylinders, the controller 7 may prioritize the execution of the second wheel cylinder depressurization control over the execution of the first wheel cylinder depressurization control.
The above description has been made on the example in which the hydraulic pressure control unit 6 controls the braking force generated on the front wheel 2, which is the one wheel of the front wheel 2 and the rear wheel 3. However, of the front wheel 2 and the rear wheel 3, the hydraulic pressure control unit 6 may control the braking force generated on the rear wheel 3. In this case, the plural wheel cylinders 26 are provided to the rear wheel 3. Similar to the above example, the first master cylinder 21a and the second master cylinder 21b are connected to the hydraulic pressure control unit 6. The hydraulic control unit 6 is connected to the plural wheel cylinders 26 of the rear wheel 3. Then, of the first master cylinder 21a and the second master cylinder 21b, the first master cylinder 21a that corresponds to the master chamber for the front wheel 2 is connected to the wheel cylinders 24 of the front wheel 2 without the hydraulic pressure control unit 6 being interposed therebetween. For this reason, the front-wheel brake mechanism 12, which includes the first master cylinder 21a, brakes both of the front wheel 2 and the rear wheel 3, and the rear-wheel brake mechanism 14, which includes the second master cylinder 21b, only brakes the rear wheel 3 of the front wheel 2 and the rear wheel 3.
The above description has been made on the exemplary configurations of the first channel 27 and the second channel 28 of the hydraulic pressure control unit 6 with reference to
A description will be made on effects of the vehicle brake system 10 according to the embodiment of the present invention.
The vehicle brake system 10 includes: the hydraulic pressure control unit 6 that controls the braking force generated to the vehicle 1; the first master cylinder 21a that corresponds to the first master chamber as the master chamber for the front wheel 2 and at least communicates with the wheel cylinders 24 of the front wheel 2 of the vehicle 1; and the second master cylinder 21b that corresponds to the second master chamber as the master chamber for the rear wheel 3 and at least communicates with the wheel cylinder 26 of the rear wheel 3 of the vehicle 1. In the vehicle brake system 10, the hydraulic pressure control unit 6 controls the braking force generated on the front wheel 2, which is the one wheel of the front wheel 2 and the rear wheel 3, the first master cylinder 21a and the second master cylinder 21b are connected to the hydraulic pressure control unit 6, and, of the first master cylinder 21a and the second master cylinder 21b, the second master cylinder 21b, which corresponds to the master chamber for the rear wheel 3 as the other of the front wheel 2 and the rear wheel 3, is connected to the wheel cylinder 26 of the rear wheel 3 as the other wheel without the hydraulic pressure control unit 6 being interposed therebetween.
In this way, compared to the case where the braking force generated on the front wheel 2 and the braking force generated on the rear wheel 3 can separately be controlled, it is possible to suppress the increase in the number of the components of the hydraulic pressure control unit 6, and the like. For example, in the case where the braking force generated on the front wheel 2 and the braking force generated on the rear wheel 3 can separately be controlled, the hydraulic pressure control unit 6 is provided with the components for reducing the pressure of the brake fluid in the wheel cylinder 26 of the rear wheel 3, which is the other vehicle described above. On the other hand, such components are unnecessary in this embodiment. Therefore, it is possible to suppress a cost increase.
However, as described above, the one wheel described above may be the rear wheel 3, and the other wheel described above may be the front wheel 2. Also, in such a case, the same effect as above is exerted.
Preferably, in the vehicle brake system 10, the hydraulic pressure control unit 6 is connected to the first wheel cylinders 24a, 24c and the second wheel cylinder 24b as the wheel cylinders 24 of the front wheel 2 corresponding to the one wheel, and the hydraulic pressure control unit 6 is provided with: the first channel 27 that communicates between the first master cylinder 21a corresponding to the first master chamber and each of the first wheel cylinders 24a, 24c; the first pump 34a that is provided to the first channel 27; the second channel 28 that communicates between the second master cylinder 21b corresponding to the second master chamber and the second wheel cylinder 24b; the second pump 34b that is provided to the second channel 28; and the common drive source 35, the operation of which is controlled by the controller 7, and that drives both of the first pump 34a and the second pump 34b. Accordingly, by driving the common drive source 35, the brake fluid can be delivered by each of the pumps in both of the first channel 27 and the second channel 28. Therefore, it is possible to control the pressure of the brake fluid in each of the first wheel cylinders 24a, 24c and the second wheel cylinder 24b by using the common drive source 35.
Preferably, in the vehicle brake system 10, the first channel 27 includes: the first primary channel 27a that communicates between the first master cylinder 21a as the first master chamber and each of the first wheel cylinders 24a, 24c and is provided with the first inlet valve 31a; and the first secondary channel 27b, through which the brake fluid in each of the first wheel cylinders 24a, 24c is released to the intermediate portion P1 of the first primary channel 27a, and that is provided with the first outlet valve 32a, and the second channel 28 includes: the second primary channel 28a that communicates between the second master cylinder 21b corresponding to the second master chamber and the second wheel cylinder 24b and is provided with the second inlet valve 31b; and the second secondary channel 28b, through which the brake fluid in the second wheel cylinder 24b is released to the intermediate portion P2 of the second primary channel 28a, and that is provided with the second outlet valve 32b. In this way, it is possible to execute the depressurization control, which reduces the pressure of the brake fluid, for both of the first wheel cylinders 24a, 24c and the second wheel cylinder 24b.
Preferably, in the vehicle brake system 10, in the case where the slip or the possible slip of the front wheel 2 as the one wheel described above is detected, the controller 7 executes, in conjunction with driving of the drive source 35, at least one of the first wheel cylinder depressurization control for bringing the first inlet valve 31a into the closed state and bringing the first outlet valve 32a into the open state and the second wheel cylinder depressurization control for bringing the second inlet valve 31b into the closed state and bringing the second outlet valve 32b into the open state. In this way, it is possible to reduce the pressure of the brake fluid in each of the wheel cylinders 24 of the front wheel 2. Therefore, it is possible to reduce the braking force generated on the front wheel 2 and thus can avoid locking of the front wheel 2.
Preferably, the vehicle brake system 10 includes: the first brake operation section 11 that is attached to the first master cylinder 21a corresponding to the first master chamber; and the second brake operation section 13 that is attached to the second master cylinder 21b corresponding to the second master chamber, and the controller 7 executes, in conjunction with driving of the drive source 35, both of the first wheel cylinder depressurization control and the second wheel cylinder depressurization control not on the basis of the operation states of the first brake operation section 11 and the second brake operation section 13 in the case where the slip or the possible slip of the front wheel 2 as the one wheel described above is detected. In this way, also, in the case where the first master cylinder pressure sensor 36a and the second master cylinder pressure sensor 36b are not provided, or the like, it is possible to appropriately avoid locking of the front wheel 2.
Preferably, the vehicle brake system 10 includes: the first brake operation section 11 that is attached to the first master cylinder 21a corresponding to the first master chamber; and the second brake operation section 13 that is attached to the second master cylinder 21b corresponding to the second master chamber, and the controller 7 determines whether to execute the first wheel cylinder depressurization control and the second wheel cylinder depressurization control on the basis of the operation states of the first brake operation section 11 and the second brake operation section 13. As a result, the unnecessary execution of both of the first wheel cylinder depressurization control and the second wheel cylinder depressurization control is suppressed, and thus worsening of the rider's comfort, which is caused by the vibration generated to the brake operation section due to the depressurization control, or the like, is suppressed.
Preferably, in the vehicle brake system 10, in the case where the brake operation using the first brake operation section 11 is prioritized over the brake operation using the second brake operation section 13, the controller 7 permits the first wheel cylinder depressurization control and prohibits the second wheel cylinder depressurization control, and in the case where the brake operation using the second brake operation section 13 is prioritized over the brake operation using the first brake operation section 11, the controller 7 permits the second wheel cylinder depressurization control and prohibits the first wheel cylinder depressurization control. In this way, the unnecessary execution of both of the first wheel cylinder depressurization control and the second wheel cylinder depressurization control is further appropriately suppressed, and thus worsening of the rider's comfort, which is caused by the vibration generated to the brake operation section due to the depressurization control, or the like, is further appropriately suppressed.
Preferably, in the vehicle brake system 10, the controller 7 determines the execution of which one of the first wheel cylinder depressurization control and the second wheel cylinder depressurization control is prioritized on the basis of the magnitude relationship between the number of the first wheel cylinders 24a, 24c and the number of the second wheel cylinder 24b. As a result, such a situation can arise where locking of the front wheel 2 can be avoided by only one of the first wheel cylinder depressurization control and the second wheel cylinder depressurization control. Therefore, the unnecessary execution of both of the first wheel cylinder depressurization control and the second wheel cylinder depressurization control is suppressed, and thus worsening of the rider's comfort, which is caused by the vibration generated to the brake operation section due to the depressurization control, or the like, is suppressed.
Preferably, in the vehicle brake system 10, the vehicle 1 is the motorcycle. In this way, it is possible to suppress the cost increase of the vehicle brake system 10 that is mounted to the motorcycle. Furthermore, in the motorcycle compared to a four-wheeled automobile and the like, a mounting space for the hydraulic pressure control unit 6 is limited. Accordingly, a degree of freedom in arrangement of the hydraulic pressure control unit 6 is improved by simplifying the configuration of the hydraulic pressure control unit 6 and thus downsizing the hydraulic pressure control unit 6.
Preferably, in the case where the vehicle 1 is the motorcycle, the one wheel described above is the front wheel 2. In the motorcycle, the braking force generated on the front wheel 2 is basically larger than the braking force generated on the rear wheel 3. Thus, necessity of avoiding locking of the front wheel 2 is high. Therefore, when the hydraulic pressure control unit 6 controls the braking force generated on the front wheel 2, behavior of the motorcycle can be stabilized.
The present invention is not limited to the embodiment that has been described. For example, only a part of the embodiment may be implemented.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-187318 | Nov 2021 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2022/060337 | 10/27/2022 | WO |
