Brake system

Abstract

This technology provides appropriate brake assist in response to the rider's braking input. [Solution] The vehicle's braking system includes an assist mechanism that provides brake assist to increase the braking force of the vehicle, a behavior detection unit that detects the pitching behavior of the vehicle, and a control unit that controls the brake assist by the assist mechanism according to the pitching behavior detected by the behavior detection unit.

Description

Technical Field

[0001] The present invention relates to a braking technology for controlling a brake assist mechanism that increases the braking force of a vehicle.

Background Art

[0002] In recent years, initiatives to provide access to sustainable transportation systems that also consider people in vulnerable positions among traffic participants have become increasingly active. To achieve this, efforts are being focused on research and development that further improve traffic safety and convenience through research and development related to driving assistance technologies.

[0003] Patent Document 1 describes a brake system that controls the braking force of a saddle-ride type vehicle using a braking mechanism (a so-called reflux modulator) including a main flow passage that distributes brake fluid in a master cylinder to wheel cylinders, a sub flow passage that releases brake fluid from the wheel cylinders, and a supply flow passage that supplies brake fluid from the master cylinder to the sub flow passage. In this brake system, when it is determined that a rider is performing a brake operation based on a detected value of master cylinder pressure, a driving assistance mode (so-called brake assist) that amplifies the braking force of the saddle-ride type vehicle is executed. Further, when the detected value of the master cylinder pressure becomes lower than a reference pressure, it is determined that the brake operation has been released, and the driving assistance mode is terminated.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a recirculating modulator equipped with a main channel, a secondary channel, and a supply channel, situations may arise where the brake operation performed by the rider does not match the detected master cylinder pressure. For example, during pressurized assist, brake fluid from the master cylinder flows into the secondary channel via the supply channel, which may cause the detected master cylinder pressure to be lower than the value corresponding to the brake operation. Also, during anti-lock braking system (ABS) operation, brake fluid flows into the master cylinder, which may cause the detected master cylinder pressure to be higher than the value corresponding to the brake operation. Therefore, if brake assist is controlled using the detected master cylinder pressure as the rider's brake operation, the brake assist may not be properly performed in accordance with the rider's intentions.

[0006] Therefore, the present invention aims to provide a technology that enables appropriate brake assist in accordance with the rider's actual brake operation, thereby contributing to the development of sustainable transportation systems. [Means for solving the problem]

[0007] To achieve the above objective, a brake device as one aspect of the present invention is a brake device for a vehicle, characterized by comprising: an assist mechanism that provides brake assist to increase the braking force of the vehicle; a behavior detection unit that detects the pitching behavior of the vehicle; and a control unit that controls the brake assist by the assist mechanism in accordance with the pitching behavior detected by the behavior detection unit. [Effects of the Invention]

[0008] According to the present invention, for example, it is possible to provide a technology that can perform appropriate brake assist in accordance with the rider's intentions. [Brief explanation of the drawing]

[0009] [Figure 1] Side view of a saddle-type vehicle in one embodiment [Figure 2]A schematic diagram showing an example of the configuration of a brake device in one embodiment. [Figure 3] This figure shows the normal operating state of the assist mechanism in one embodiment. [Figure 4] This figure shows the operating status of the assist mechanism during pressurized assist in one embodiment. [Figure 5] This figure shows the operating status of the assist mechanism during ABS depressurization in one embodiment. [Figure 6] Control block diagram of a brake system in one embodiment [Figure 7] A diagram to explain the pitching behavior of a vehicle. [Figure 8] Flowchart showing the control flow of a brake system in one embodiment [Figure 9] Flowchart showing the control flow of a brake system in one embodiment [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described below with reference to the drawings. The present invention is not limited to the following embodiments, and includes changes and modifications to the configuration within the scope of the spirit of the invention. Furthermore, not all combinations of features described in these embodiments are essential to the present invention. The same reference numeral is used for identical components, and their descriptions are omitted.

[0011] An embodiment of the present invention will now be described. Figure 1 is a side view of the saddle-type vehicle 100 (hereinafter sometimes simply referred to as vehicle 100) of this embodiment. Vehicle 100 is a motorcycle equipped with one front wheel FW and one rear wheel RW. The present invention is not limited to saddle-type vehicles, but can also be applied to other types of vehicles such as four-wheeled vehicles.

[0012] Vehicle 100 is equipped with a body frame 101 that forms its skeleton. A front wheel steering unit 102 is rotatably attached to the front end of the body frame 101 via a front suspension 122. The front suspension 122 is a mechanism that supports the front wheel steering unit 102 (front wheel FW) so that it can swing up and down, and can be configured as an electronically controlled suspension capable of electronically controlling damping force, for example. The front suspension 122 is equipped with a front stroke sensor 123 that detects the stroke amount and / or stroke speed of the front suspension as an indicator of the suspension state of vehicle 100. The front wheel steering unit 102 includes a pair of left and right front forks 103 that support the front wheel FW, and a steering handle 104 attached to the upper part of the pair of front forks 103. The right grip 105 of the steering handle 104 is an accelerator grip that allows the rider to control the acceleration of vehicle 100. A brake lever 106 (front wheel brake operator) is rotatably mounted near the right grip 105, which receives the rider's brake operation on the front wheel FW.

[0013] A swingarm 115 is rotatably attached to the rear end of the vehicle frame 101. The swingarm 115 is rotatably supported at its front end by the vehicle frame 101 and supports the rear wheel RW at its rear end. A rear suspension 124 is provided between the vehicle frame 101 and the swingarm 115. The rear suspension 124 is a mechanism that supports the swingarm 115 (rear wheel RW) so that it can swing up and down, and can be configured as an electronically controlled suspension capable of electronically controlling damping force, for example. Near the rear suspension 124, a rear stroke sensor 125 is provided to detect the stroke amount and / or stroke speed of the rear suspension as an indicator of the suspension state of the vehicle 100.

[0014] In the region between the front wheel FW and the rear wheel RW, an internal combustion engine 107 and a transmission 108 are arranged, supported by the vehicle frame 101. The output of the internal combustion engine 107 is transmitted to the rear wheel RW via the transmission 108 and a chain drive mechanism (not shown). Although this embodiment uses a chain drive mechanism, a shaft drive mechanism or a belt drive mechanism may also be used. A fuel tank 109 is located above the internal combustion engine 107. A seat 110 on which the rider sits is located behind the fuel tank 109. In this embodiment, the vehicle 100 is a vehicle driven by an internal combustion engine 107, but is not limited to that, and may be an electric vehicle driven by an electric motor.

[0015] The brake mechanism 111 is a mechanism that applies braking force to the front wheel FW. In this embodiment, an example in which a disc brake is used as the brake mechanism 111 is described. The brake mechanism 111 comprises a brake rotor 112 that rotates coaxially and integrally with the front wheel FW, and a brake caliper 113 having brake pads (not shown). The brake caliper 113 is supported by the front fork 103 and clamps the brake rotor 112 with the brake pads, thereby braking the front wheel FW which rotates integrally with the brake rotor 112. The clamping force of the brake caliper 113 (i.e., the braking force of the front wheel FW) can be generated according to the amount of brake operation by the rider on the brake lever 106. In addition, the front fork 103 is provided with a front wheel speed sensor 114 that detects the amount of rotation of the front wheel FW.

[0016] The brake mechanism 116 is a mechanism that applies a braking force to the rear wheel RW. In the present embodiment, an example in which a disc brake is used as the brake mechanism 116 will be described. The brake mechanism 116 includes a brake rotor 117 that rotates coaxially and integrally with the rear wheel RW, and a brake caliper 118 having a brake pad (not shown). The brake caliper 118 is supported by the swing arm 115, clamps the brake rotor 117 with the brake pad, and brakes the rear wheel RW that rotates integrally with the brake rotor 117. On the right side portion of the vehicle 100, a brake pedal 119 (rear wheel brake operating element) that receives a rider's braking operation for the rear wheel RW is rotatably provided, and the clamping force of the brake caliper 118 (that is, the braking force of the rear wheel RW) can be generated in accordance with the amount of the rider's braking operation on the brake pedal 119. Further, the swing arm 115 is provided with a rear wheel speed sensor 120 that detects the amount of rotation of the rear wheel RW.

[0017] The vehicle 100 of the present embodiment is provided with an inertial sensor 121. The inertial sensor 121 includes, for example, an inertial measurement unit (IMU; Internal Measurement Unit), and detects acceleration and angular velocity generated in the vehicle 100 (vehicle body). Specifically, the inertial sensor 121 detects the acceleration of the vehicle 100 in each of the front-rear direction, the vehicle width direction, and the up-down direction, and detects the angular velocity of the vehicle 100 in each of the roll direction, the pitch direction, and the yaw direction. Here, in the present embodiment, an example using the inertial sensor 121 will be described, but sensors for detecting acceleration and / or angular velocity in each direction may be provided individually. Further, sensors for detecting the speed of the vehicle 100 in each of the front-rear direction, the vehicle width direction, and the up-down direction may be provided, or sensors for detecting the angle of the vehicle 100 in each of the roll direction, the pitch direction, and the yaw direction may be provided.

[0018] [Configuration of Brake Apparatus] Figure 2 is a schematic diagram showing a configuration example of a brake device 130 (brake system) for a front wheel FW. The brake device 130 for the front wheel FW includes a hydraulic circuit 1 that supplies the hydraulic pressure of brake fluid (working fluid) generated according to the rider's brake operation amount on a brake lever 106 to a brake caliper 113 of a brake mechanism 111. The brake caliper 113 clamps a brake rotor 112 with brake pads (not shown) by the hydraulic pressure of the brake fluid supplied by the hydraulic circuit 1, and generates a braking force for the front wheel FW. Here, the brake device 130 for the front wheel FW will be described below, but the brake device 130 can be applied not only to the front wheel FW but also to a rear wheel RW. When the brake device 130 is applied to the rear wheel RW, the brake device 130 (hydraulic circuit 1) supplies the hydraulic pressure of brake fluid (working fluid) generated according to the rider's brake operation amount on a brake pedal 119 to a brake caliper 118 of a brake mechanism 116.

[0019] The hydraulic circuit 1 includes a master cylinder 2. The master cylinder 2 converts the operation amount of the brake lever 106 into the hydraulic pressure of the brake fluid by supplying the brake fluid stored in a reservoir 3 to a flow path 1a according to the operation amount of the brake lever 106. As the hydraulic pressure of the brake fluid generated in the master cylinder 2 is transmitted to the brake caliper 113, the brake rotor 112 is clamped by the brake pads of the brake caliper 113, and the braking force of the front wheel FW is generated.

[0020] In the brake device 130 of this embodiment, when an emergency brake operation to suddenly stop the vehicle 100 is input to the brake lever 106 by the rider, pressurization assist is performed to increase the braking force of the front wheel FW by increasing the hydraulic pressure of the brake fluid supplied to the brake caliper 113. In addition, when the anti-lock braking system (ABS) is in operation, depressurization assist may be performed to decrease the braking force of the front wheel FW by decreasing the hydraulic pressure of the brake fluid supplied to the brake caliper 113. In order to perform such brake assists as pressurization assist and depressurization assist, the brake device 130 of this embodiment is provided with an assist mechanism 6 that performs brake assist and a control unit 7 that controls the brake assist by the assist mechanism 6. In the following, an example in which the assist mechanism 6 is configured by a recirculating hydraulic modulator will be described, but it is not limited to this, and the assist mechanism 6 may be configured by other mechanisms such as brake-by-wire.

[0021] The assist mechanism 6 (hydraulic modulator) includes a plurality of solenoid valves 10-13 and a motor 15 whose drive is controlled by the control unit 7. Solenoid valves 10 and 12 are normally open solenoid valves, while solenoid valves 11 and 13 may be normally closed solenoid valves. The brake fluid flow path 1a branches into flow path 1b and flow path 1c at branching point b1. Flow path 1b is connected to the brake caliper 113.

[0022] Solenoid valves 10 and 12 are installed in the flow path 1b and open and close the flow path 1b. Solenoid valve 12 is positioned on the brake caliper 113 side of the flow path 1b than solenoid valve 10. Solenoid valve 11 is installed in the flow path 1c and opens and closes the flow path 1c.

[0023] Flow path 1c branches into flow path 1d and flow path 1e at branching point b2. Flow path 1d connects branching point b2 with the portion of flow path 1b between solenoid valve 10 and solenoid valve 12. A pump 14 driven by motor 15 is provided in flow path 1d. The output port of pump 14 is located on the flow path 1b side, and the input port of pump 14 is located on the branching point b2 side. When motor 15 is driven, brake fluid is sent by pump 14 in the direction of branching point b2 → flow path 1d → flow path 1b. Meanwhile, flow path 1e connects branching point b2 with the portion of flow path 1b between solenoid valve 12 and brake caliper 113.

[0024] The solenoid valve 13 is installed in the flow path 1e and opens and closes the flow path 1e. Between the solenoid valve 13 and the branching point b2 in the flow path 1e, a check valve 16 and a storage section 17 are provided. The check valve 16 is configured to allow the flow of brake fluid from the solenoid valve 13 toward the pump 14, while restricting the flow of brake fluid in the reverse direction. The storage section 17 communicates with the solenoid valve 13 and the check valve 16 and is configured to store brake fluid. In this embodiment, the storage section 17 is an accumulator.

[0025] The flow path 1c is provided with a hydraulic pressure sensor 8 that detects the hydraulic pressure of the brake fluid in the flow path 1c between the branching point b1 and the solenoid valve 11. The hydraulic pressure sensor 8 is a sensor that detects the master cylinder pressure, which is the pressure of the brake fluid in the master cylinder 2. Hereinafter, the hydraulic pressure sensor 8 will be referred to as the "M / C pressure sensor 8," and the master cylinder pressure detected by the M / C pressure sensor 8 will be referred to as the "M / C detected value." In this embodiment, the M / C pressure sensor 8 is used as an operation detection unit that detects an operation index value that fluctuates according to the amount of brake operation by the rider (amount of operation of the brake lever 106), and the M / C detected value can be used as the detected value of the operation index value obtained by the operation detection unit.

[0026] Furthermore, the flow path 1b is equipped with a hydraulic pressure sensor 9 that detects the hydraulic pressure of the brake fluid in the flow path 1b between the solenoid valve 12 and the brake caliper 113. The hydraulic pressure sensor 9 is a sensor that detects the brake caliper pressure, which is the pressure of the brake fluid in the brake caliper 113. Hereafter, the hydraulic pressure sensor 9 will be referred to as the "CAL pressure sensor 9," and the brake caliper pressure detected by the CAL pressure sensor 9 will be referred to as the "CAL detected value."

[0027] In the assist mechanism 6 (hydraulic modulator) configured in this way, the main flow path is formed by flow path 1a and flow path 1b for supplying brake fluid from the master cylinder 2 to the brake caliper 113. In addition, the secondary flow path is formed by flow path 1d and flow path 1e for returning (returning) brake fluid from the brake caliper 113 to the main flow path (flow path 1b). Flow path 1c is formed by a supply flow path for supplying brake fluid from the main flow path (flow path 1a) to the secondary flow paths (flow paths 1d and 1e). The flow of brake fluid in these main flow path, secondary flow path, and supply flow path is controlled by driving a plurality of solenoid valves 10 to 13 and a motor 15 (pump 14).

[0028] For example, in the assist mechanism 6 under normal conditions (when brake assist is not being performed), as shown by the dashed arrow A1 in Figure 3, only the main passages (passages 1a and 1b) are connected, and brake fluid corresponding to the amount of operation of the brake lever 106 is supplied from the master cylinder 2 to the brake caliper 113 via the main passages. On the other hand, in the assist mechanism 6 when pressurizing assist is being performed as brake assist, as shown by the dashed arrow A2 in Figure 4, the supply passage (passage 1c) is further connected, and brake fluid is supplied from the master cylinder 2 to the brake caliper 113 via the supply passage. In this operating state, the solenoid valve 10 can be opened and closed as appropriate for pressurizing adjustment.

[0029] In the assist mechanism 6, when the brake caliper pressure is decreasing during ABS operation, the sub-flow channels (flow channels 1d and 1e) are connected, as shown by the dashed arrow A3 in Figure 5, and brake fluid is returned from the brake caliper 113 to the master cylinder 2 through the sub-flow channels. In the assist mechanism 6, when the brake caliper pressure is being maintained during ABS operation, the motor 15 is stopped and the solenoid valve 13 is closed compared to the state in Figure 5. In the assist mechanism 6, when the brake caliper pressure is being increased during ABS operation, the motor 15 is stopped, the solenoid valve 13 is closed and the solenoid valve 12 is opened compared to the state in Figure 5.

[0030] [Control block diagram of the braking system] Figure 6 is a control block diagram of the brake device 130. The control unit 7 includes a processing unit 71, a storage unit 72 such as RAM or ROM, and an interface unit 73 that relays the transmission and reception of signals to and from external devices. The processing unit 71 is a processor, such as a CPU, and controls the assist mechanism 6 by executing a program stored in the storage unit 72. The storage unit 72 stores various data in addition to the program executed by the processing unit 71. The interface unit 73 receives the detection results of the M / C pressure sensor 8, CAL pressure sensor 9, wheel speed sensors (front wheel speed sensor 114, rear wheel speed sensor 120), inertia sensor 121, and stroke sensors (front stroke sensor 123, rear stroke sensor 125) via a signal processing circuit (not shown). Based on these detection results, the processing unit 71 controls the driving of each solenoid valve 10-13 and the motor 15 by a drive circuit (not shown). The control unit 7 (processing unit 71) may be configured by an ECU (Electronic Control Unit) mounted on the vehicle 100.

[0031] In the brake system 130 configured as described above, conventionally, the master cylinder pressure was detected by the M / C pressure sensor 8 as the amount of brake operation by the rider, and the brake assist by the assist mechanism 6 was controlled based solely on the master cylinder pressure (M / C detected value) detected by the M / C pressure sensor 8. However, in the assist mechanism 6, which is composed of a recirculating hydraulic modulator or the like, situations may arise where the amount of brake operation by the rider and the M / C detected value do not match. For example, when pressurizing assist is performed, the brake fluid from the master cylinder 2 flows into the sub-channel (channel 1d) via the supply channel (channel 1c), which may cause the M / C detected value to be lower than the value corresponding to the amount of brake operation by the rider. Also, when depressurizing assist is performed while ABS is operating, the brake fluid recirculates to the main channel (channel 1a) via the sub-channels (channels 1d, 1e), which may cause the M / C detected value to be higher than the value corresponding to the amount of brake operation by the rider. Therefore, if the brake assist by the assist mechanism 6 is controlled using only the M / C detected value, the brake assist may not be performed appropriately in accordance with the rider's intentions.

[0032] Therefore, in the brake device 130 of this embodiment, the pitching behavior of the vehicle 100 is detected, and the brake assist by the assist mechanism 6 is controlled according to the detection result (pitching behavior). For example, if the vehicle 100 pitches downward forward as shown in Figure 7(a), it is highly likely that the rider intentionally performed an emergency brake operation to stop the vehicle 100 suddenly, increasing the deceleration of the vehicle 100. In this case, the brake device 130 (control unit 7) performs brake assist to increase the amount of brake assist. On the other hand, if the vehicle 100 pitches upward forward as shown in Figure 7(b) while brake assist is being performed, it is highly likely that the rider intentionally reduced (loosened) the amount of brake operation, decreasing the deceleration of the vehicle 100. In this case, the brake device 130 (control unit 7) reduces the amount of brake assist. In other words, by controlling the brake assist according to the pitching behavior of the vehicle 100, brake assist can be appropriately performed in accordance with the rider's intentions.

[0033] Here, the pitching behavior of the vehicle 100 refers to the rotation of the vehicle 100 in the pitch direction. In this embodiment, at least one of the inertial sensor 121, front stroke sensor 123, and rear stroke sensor 125 may be used as a behavior detection unit for detecting the pitching behavior of the vehicle 100. In this embodiment, reducing the amount of brake assist may include releasing the brake assist (i.e., setting the assist amount to zero).

[0034] [Brake assist control flow] The following describes an example of the control flow of the brake assist in the brake device 130 of this embodiment. Figures 8 to 9 are flowcharts of the control flow of the brake device 130 in this embodiment. The control flow in Figures 8 to 9 can be executed by the control unit 7 (for example, the processing unit 71).

[0035] In step S101, the control unit 7 determines whether the M / C detection value detected by the M / C pressure sensor 8 is equal to or greater than a threshold. The threshold used in step S101 can be pre-set to a value that allows the rider to determine whether or not a brake operation (for example, operation of the brake lever 106) has been performed. If the M / C detection value is less than the threshold, the control unit 7 determines that no brake operation has been performed by the rider and proceeds to step S108, and does not intervene (execute) brake assist by the assist mechanism 6. On the other hand, if the M / C detection value is equal to or greater than the threshold, the control unit 7 determines that a brake operation has been performed by the rider and proceeds to step S102.

[0036] In step S102, the control unit 7 determines whether the M / C pressure sensor 8 has detected an increase rate of the M / C detection value that is greater than a predetermined value. As described above, in this embodiment, the M / C pressure sensor 8 is used as an operation detection unit that detects an operation index value that fluctuates according to the amount of brake operation by the rider, and the M / C detection value is used as the operation index value. In other words, the change (increase rate) of the M / C detection value detected by the M / C pressure sensor 8 is used as the change (increase rate) of the operation index value detected by the operation detection unit. Furthermore, the predetermined value used in step S102 can be set in advance using experiments, simulations, etc., to a value (increase rate) that allows the rider to determine whether or not they have intentionally performed an emergency brake operation.

[0037] If no increase in the M / C detection value greater than a predetermined value is detected, the control unit 7 determines that no emergency braking operation has been performed by the rider and proceeds to step S108, and does not intervene (execute) brake assist by the assist mechanism 6. On the other hand, if an increase in the M / C detection value greater than a predetermined value is detected, the control unit 7 determines that there is a possibility that an emergency braking operation has been performed by the rider and proceeds to step S103.

[0038] In step S103, the control unit 7 determines whether or not a first pitching behavior of the vehicle 100 has been detected. The first pitching behavior is a behavior in which the amount of pitching of the vehicle 100 becomes greater than a predetermined amount. The first pitching behavior may be understood as a behavior in which the vehicle 100 pitches downwards and forwards, as shown in Figure 7(a). Furthermore, the predetermined amount used in this step S103 can be set in advance using experiments, simulations, etc., to a pitching amount that allows the rider to determine whether or not they have intentionally performed an emergency braking operation.

[0039] If the first pitching behavior of the vehicle 100 is not detected, the control unit 7 determines that no emergency braking operation has been performed by the rider, even if an increase rate of the M / C detection value greater than a predetermined value is detected in step S102, and proceeds to step S108, and does not intervene (execute) brake assist by the assist mechanism 6. On the other hand, if the first pitching behavior of the vehicle 100 is detected, the control unit 7 determines that there is a possibility that an emergency braking operation has been performed by the rider, and proceeds to step S104.

[0040] As mentioned above, in this embodiment, at least one of the inertial sensor 121, front stroke sensor 123, and rear stroke sensor 125 can be used as the behavior detection unit for detecting the pitching behavior of the vehicle 100. For example, the control unit 7 can determine that it has detected a first pitching behavior of the vehicle 100 when the inertial sensor 121 detects that the vehicle 100 has pitched forward and downward by a rotation amount greater than a predetermined amount. The control unit 7 may also determine that it has detected a first pitching behavior of the vehicle 100 when the front stroke sensor 123 detects that the front suspension 122 has compressed by a stroke amount greater than a predetermined amount as the suspension state of the vehicle 100. The control unit 7 may also determine that it has detected a first pitching behavior of the vehicle 100 when the rear stroke sensor 125 detects that the rear suspension 124 has extended by a stroke amount greater than a predetermined amount as the suspension state of the vehicle 100.

[0041] In this embodiment, the determination of the rate of increase of the M / C detected value in step S102 and the determination of the first pitching behavior in step S103 were used in conjunction to determine whether the rider intentionally performed an emergency braking operation, but this is not the only method. For example, the determination of whether the rider intentionally performed an emergency braking operation could be made using only the detection of the first pitching behavior in step S103. In this case, steps S101 to S102 could be omitted.

[0042] In step S104, the control unit 7 determines whether the suspension of the vehicle 100 has changed at a stroke speed greater than a predetermined value. The suspension stroke speed can be detected as the suspension state of the vehicle 100 by at least one of the front stroke sensor 123 and the rear stroke sensor 125, which are behavior detection units. For example, the control unit 7 determines whether the front stroke sensor 123 has detected that the front suspension 122 has compressed at a stroke speed greater than a predetermined value, and / or whether the rear stroke sensor 125 has detected that the rear suspension 124 has compressed at a stroke speed greater than a predetermined value. The predetermined value used in step S104 can be set in advance using experiments, simulations, etc., to a stroke speed value that allows the rider to determine whether or not they have intentionally performed an emergency braking operation.

[0043] If the suspension of vehicle 100 is not changing at a stroke speed greater than a predetermined value, the control unit 7 determines that the rider has not performed an emergency braking operation and proceeds to step S108, and does not intervene (execute) brake assist by the assist mechanism 6. On the other hand, if the suspension of vehicle 100 changes at a stroke speed greater than a predetermined value, the control unit 7 determines that the rider has performed an emergency braking operation and proceeds to step S105.

[0044] In this embodiment, the determination of the rate of increase of the M / C detected value in step S102, the detection of the first pitching behavior in step S103, and the determination of the stroke speed in step S104 were used in combination to determine whether the rider intentionally performed an emergency braking operation, but this is not the only method. For example, the determination of the stroke speed in step S104 alone may be used to determine whether the rider intentionally performed an emergency braking operation. In this case, steps S101 to S103 can be omitted.

[0045] In step S105, the control unit 7 determines, based on the detection result of the inertial sensor 121, whether the roll angle (bank angle) of the vehicle 100 is smaller than an angle threshold. For example, the roll angle of the vehicle 100 can be obtained by integrating the angular velocity in the roll direction detected by the inertial sensor 121. If the roll angle of the vehicle 100 is large, applying brake assist (pressure assist) in addition to emergency braking by the rider may cause the vehicle 100's posture to become unstable. Therefore, the angle threshold can be set in advance using experiments or simulations to a value (e.g., a limit value) that allows the vehicle 100's posture to be stabilized even when brake assist is applied in addition to emergency braking. If the roll angle of the vehicle 100 is greater than the angle threshold, the process proceeds to step S108, and the control unit 7 does not intervene (execute) brake assist by the assist mechanism 6. On the other hand, if the roll angle of the vehicle 100 is less than or equal to the angle threshold, the process proceeds to step S106.

[0046] In step S106, the control unit 7 initiates brake assist intervention based on the M / C detection value. Then, in step S107, the control unit 7 determines the brake assist gain (assist gain) according to the vehicle speed (vehicle speed 100) at the time of brake assist intervention. The assist gain may be understood as the amplification factor of the pressure. The vehicle speed can be obtained based on the detection results of the wheel speed sensors 114 and 120. For example, the control unit 7 may have information in the storage unit 72 that shows the relationship between the vehicle speed and the assist gain, and can determine the assist gain from the vehicle speed based on this information.

[0047] Moving on to Figure 9, in step S109, the control unit 7 changes the distribution of braking force (brake assist) between the front and rear of the vehicle, i.e., the distribution of braking force (brake assist) between the front wheels FW and the rear wheels RW, according to the pitch angle of the vehicle 100. The pitch angle of the vehicle can be obtained by integrating the angular velocity in the pitch direction detected by the inertial sensor 121. For example, as the pitch angle, with the direction in which the vehicle 100 is tilted forward being the positive direction, increases, the control unit 7 changes the distribution of braking force between the front wheels FW and the rear wheels RW so that the braking force of the rear wheels RW becomes greater than that of the front wheels FW. As an example, if the pitch angle in the positive direction increases due to emergency braking, the brake assist is activated in the rear wheel RW brake device 130 (assist mechanism 6), but not in the front wheel FW brake device 130 (assist mechanism 6). This stabilizes the attitude of the vehicle 100 in the pitch direction.

[0048] In step S110, the control unit 7 increases or maintains the amount of brake assist according to the elapsed time since the start of brake assist intervention in step S106. For example, the control unit 7 increases the amount of brake assist at a predetermined rate until a predetermined time has elapsed since the start of brake assist intervention, and then maintains the amount of brake assist at a constant level after the predetermined time has elapsed.

[0049] In step S111, the control unit 7 determines whether the M / C pressure sensor 8 has detected a decrease in the M / C detected value that is greater than a predetermined value. In this embodiment, the change in the M / C detected value detected by the M / C pressure sensor 8 is used as the change in the operation index value detected by the operation detection unit (decrease rate). The predetermined value used in step S111 can be set in advance using experiments, simulations, etc., to a value (decrease rate) that allows the rider to determine whether or not they intentionally reduced the amount of brake operation.

[0050] If no decrease in the M / C detection value greater than a predetermined value is detected, the control unit 7 determines that the rider has not intentionally reduced the amount of brake operation and proceeds to step S115, continuing the brake assist by the assist mechanism 6. On the other hand, if a decrease in the M / C detection value greater than a predetermined value is detected, the control unit 7 determines that the rider may have intentionally reduced the amount of brake operation and proceeds to step S112.

[0051] In step S112, the control unit 7 determines whether or not a second pitching behavior of the vehicle 100 has been detected. The second pitching behavior is a behavior in which the amount of pitching of the vehicle 100 becomes greater than a predetermined amount. The second pitching behavior may also be understood as a behavior in which the vehicle 100 pitches forward and upward, as shown in Figure 7(b). Furthermore, the predetermined amount used in this step S112 can be set in advance using experiments, simulations, etc., to a pitching amount that allows the rider to determine whether or not they have intentionally reduced the amount of brake operation.

[0052] If the second pitching behavior of the vehicle 100 is not detected, the control unit 7 determines that the rider has not intentionally reduced the amount of brake operation, even if a decrease rate of the M / C detection value greater than a predetermined value is detected in step S111, and proceeds to step S115, continuing the brake assist by the assist mechanism 6. On the other hand, if the second pitching behavior of the vehicle 100 is detected, the control unit 7 determines that the rider may have intentionally reduced the amount of brake operation and proceeds to step S113.

[0053] As mentioned above, in this embodiment, at least one of the inertial sensor 121, front stroke sensor 123, and rear stroke sensor 125 can be used as the behavior detection unit for detecting the pitching behavior of the vehicle 100. For example, the control unit 7 can determine that it has detected a second pitching behavior of the vehicle 100 when the inertial sensor 121 detects that the vehicle 100 has pitched forward and upward by a rotation amount greater than a predetermined amount. The control unit 7 may also determine that it has detected a second pitching behavior of the vehicle 100 when the front stroke sensor 123 detects that the front suspension 122 has extended by a stroke amount greater than a predetermined amount as the suspension state of the vehicle 100. The control unit 7 may also determine that it has detected a second pitching behavior of the vehicle 100 when the rear stroke sensor 125 detects that the rear suspension 124 has compressed by a stroke amount greater than a predetermined amount as the suspension state of the vehicle 100.

[0054] In this embodiment, the determination of the decrease rate of the M / C detection value in step S111 and the determination of the second pitching behavior in step S112 were used in conjunction to determine whether the rider intentionally reduced the amount of brake operation, but this is not the only method. For example, the determination of whether the rider intentionally reduced the amount of brake operation could be made using only the detection of the second pitching behavior in step S112. In this case, step S111 could be omitted.

[0055] In step S113, the control unit 7 determines whether the suspension of the vehicle 100 has changed at a stroke speed greater than a predetermined value. The suspension stroke speed can be detected as the suspension state of the vehicle 100 by at least one of the front stroke sensor 123 and the rear stroke sensor 125, which act as behavior detection units. For example, the control unit 7 determines whether the front stroke sensor 123 has detected that the front suspension 122 has compressed at a stroke speed greater than a predetermined value, and / or whether the rear stroke sensor 125 has detected that the rear suspension 124 has compressed at a stroke speed greater than a predetermined value. Furthermore, the predetermined value used in step S104 can be set in advance using experiments, simulations, etc., to a stroke speed value that allows the rider to determine whether or not they have intentionally reduced the amount of brake operation.

[0056] If the suspension of vehicle 100 is not changing at a stroke speed greater than a predetermined value, the control unit 7 determines that the rider has not intentionally reduced the amount of brake operation and proceeds to step S115, continuing the brake assist by the assist mechanism 6. On the other hand, if the suspension of vehicle 100 changes at a stroke speed greater than a predetermined value, the control unit 7 determines that the rider has intentionally reduced the amount of brake operation and proceeds to step S114, reducing the amount of brake assist provided by the assist mechanism 6. Note that reducing the amount of brake assist may include releasing the brake assist (i.e., setting the assist amount to zero).

[0057] In this embodiment, the determination of the rate of increase of the M / C detected value in step S111, the detection of the first pitching behavior in step S112, and the determination of the stroke speed in step S113 were used in combination to determine whether the rider intentionally performed an emergency braking operation, but this is not the only method. For example, the determination of the stroke speed in step S113 alone may be used to determine whether the rider intentionally performed an emergency braking operation. In this case, steps S111 to S112 can be omitted.

[0058] Here, the control unit 7 may release the brake assist by the assist mechanism 6 if it determines that the vehicle 100 has stopped. For example, the determination conditions for determining that the vehicle 100 has stopped include a first condition relating to the suspension state of the vehicle 100 and a second condition relating to the rider's brake operation. Then, if the control unit 7 satisfies both the first and second conditions, it determines that the vehicle 100 has stopped and releases the brake assist by the assist mechanism 6.

[0059] The first condition regarding the suspension state of vehicle 100 may include the condition that the front stroke sensor 123 detects that the stroke speed of the front suspension 122 has fallen below a predetermined value when the front suspension 122 is extending, and / or the condition that the front stroke sensor 123 detects that the stroke speed of the rear suspension 124 has fallen below a predetermined value when the rear suspension 124 is compressing. The predetermined value here is set in advance using experiments, simulations, etc., to a stroke speed value that allows for the determination of whether or not vehicle 100 has stopped.

[0060] A second condition regarding the rider's brake operation may include the condition that the M / C detection value detected by the M / C pressure sensor 8 is less than a threshold. The threshold here may be the same as the threshold used in step S101 above, and can be pre-set to a value that allows for the determination of whether or not the rider's brake operation has been released. If the M / C detection value detected by the M / C pressure sensor 8 is less than the threshold, the control unit 7 can determine that the rider's brake operation has been released.

[0061] As described above, the brake device 130 of this embodiment detects the pitching behavior of the vehicle 100 and controls the brake assist by the assist mechanism 6 according to the detection result. This makes it possible for the assist mechanism 6 (recirculating hydraulic modulator) to appropriately provide brake assist in accordance with the rider's intentions, even when the amount of brake operation by the rider and the M / C detection value do not match.

[0062] <Summary of Embodiments> (Item 1) A brake system (e.g., 130) of a vehicle (e.g., 100), An assist mechanism (e.g., 6) that provides brake assist to increase the braking force of the vehicle, The vehicle includes a behavior detection unit (for example, 121, 123, 125) that detects the pitching behavior of the vehicle, A control unit (e.g., 7) controls the brake assist by the assist mechanism in accordance with the pitching behavior detected by the behavior detection unit, A braking device characterized by being equipped with the following features. According to this section, by using the pitching behavior associated with vehicle deceleration as a criterion for determining whether the rider intentionally performed a braking operation, it becomes possible to appropriately provide brake assist in accordance with the rider's actual braking operation, even if the detected value as the amount of braking operation by the driver does not match the rider's intention.

[0063] (Item 2) The system further includes an operation detection unit (e.g., 8) that detects an operation index value that fluctuates according to the amount of brake operation performed by the driver, The brake device according to item 1, characterized in that the control unit further controls the brake assist by the assist mechanism in response to the change in the operation index value detected by the operation detection unit. According to this section, by combining changes in the operational indicator value with the pitching behavior associated with vehicle deceleration, it becomes possible to provide brake assist more appropriately in line with the rider's actual braking operation.

[0064] (Item 3) The brake device according to item 2, characterized in that the control unit performs the brake assist by the assist mechanism when the operation detection unit detects an increase rate of the operation index value that is greater than a predetermined value, and the behavior detection unit detects a first pitching behavior in which the amount of pitching of the vehicle is greater than a predetermined amount. According to this item, by using the rate of increase in the operational indicator value in conjunction with the pitching behavior accompanying the vehicle's deceleration, it is possible to determine whether the rider intentionally performed an emergency braking operation, thereby enabling brake assist to be more appropriate to the rider's actual braking operation.

[0065] (Item 4) The brake device according to item 3, characterized in that the first pitching behavior is a behavior in which the vehicle pitches forward and downward. According to this feature, by detecting the vehicle's forward-downward pitching behavior, it is possible to accurately determine whether the rider intentionally increased the brake application amount for emergency braking, or whether there is a discrepancy between the detected brake application amount and the rider's actual operation.

[0066] (Item 5) The brake device according to any one of items 2 to 4, characterized in that the control unit reduces the amount of brake assist when, during the execution of the brake assist by the assist mechanism, the operation detection unit detects a decrease rate of the operation index value that is greater than a predetermined value, and the behavior detection unit detects a second pitching behavior in which the amount of pitching of the vehicle is greater than a predetermined amount. According to this item, by using the rate of decrease in the operational indicator value and the vehicle's pitching behavior in conjunction, it is possible to determine whether the rider intentionally reduced the amount of brake operation or whether there is a discrepancy between the detected brake operation amount and the rider's operation. This makes it possible to provide brake assist more appropriately in line with the rider's actual brake operation.

[0067] (Item 6) The braking device according to item 5, characterized in that the second pitching behavior is a behavior in which the vehicle pitches forward and upward. According to this item, by detecting the vehicle's forward-upward pitching motion, it is possible to accurately determine whether the pitching motion was caused by the rider releasing the brakes or by the activation of the anti-lock braking system.

[0068] (Item 7) The brake device according to any one of items 2 to 6, characterized in that the behavior detection unit detects the pitching behavior by detecting the suspension state of the vehicle. According to this section, the pitching behavior of a vehicle used for brake assist control can be detected using the vehicle's suspension state.

[0069] (Item 8) The brake device according to item 7, characterized in that the control unit performs the brake assist by the assist mechanism when the behavior detection unit detects that the front suspension of the vehicle has been compressed by a stroke amount greater than a predetermined amount while an operation index value greater than a predetermined value is input, as the suspension state. According to this feature, based on the front suspension stroke, it is possible to determine whether the rider intentionally increased the brake application for emergency braking, or whether there is a discrepancy between the detected brake application and the rider's operation, making it possible to provide brake assist more appropriately in line with the rider's actual braking operation.

[0070] (Item 9) The brake device according to item 7 or 8, characterized in that the control unit performs the brake assist by the assist mechanism when the behavior detection unit detects that the rear suspension of the vehicle has extended by a stroke amount greater than a predetermined amount while an operation index value greater than a predetermined value is input, as the suspension state. According to this feature, based on the rear suspension stroke, it is possible to determine whether the rider intentionally increased the brake application amount for emergency braking, or whether there is a discrepancy between the detected brake application amount and the rider's operation, making it possible to provide brake assist more appropriately in line with the rider's actual braking operation.

[0071] (Item 10) The brake device according to any one of items 7 to 9, characterized in that the control unit reduces the amount of brake assist when the behavior detection unit detects that the front suspension of the vehicle has extended by a stroke amount greater than a predetermined amount as the suspension state while the brake assist is being performed by the assist mechanism. According to this feature, based on the front suspension stroke, it is possible to determine whether the rider intentionally reduced the amount of brake operation or whether there is a discrepancy between the detected brake operation amount and the rider's operation, making it possible to provide brake assist more appropriately in line with the rider's actual braking operation.

[0072] (Item 11) The brake device according to any one of items 7 to 10, characterized in that the control unit reduces the amount of brake assist when the behavior detection unit detects that the rear suspension of the vehicle has been compressed by a predetermined amount or more as the suspension state while the brake assist is being performed by the assist mechanism. According to this feature, based on the rear suspension stroke, it is possible to determine whether the rider intentionally reduced the amount of brake operation, or whether there is a discrepancy between the detected brake operation amount and the rider's operation, making it possible to provide brake assist more appropriately in line with the rider's actual braking operation.

[0073] (Item 12) The brake device according to any one of items 7 to 11, characterized in that the control unit performs brake assist when the behavior detection unit detects that the suspension of the vehicle has changed at a stroke speed greater than a predetermined value as the suspension state. According to this feature, based on the suspension stroke speed of the vehicle, it is possible to determine whether the rider intentionally increased the brake application amount for emergency braking, or whether there is a discrepancy between the detected brake application amount and the rider's operation, making it possible to provide brake assistance more appropriately in line with the rider's actual braking operation.

[0074] (Item 13) The brake device according to any one of items 7 to 12, characterized in that the control unit reduces the amount of brake assist when the behavior detection unit detects that the suspension of the vehicle has changed to a stroke speed greater than a predetermined value, as the suspension state, while the brake assist is being performed by the assist mechanism. According to this feature, based on the suspension stroke speed of the vehicle, it is possible to determine whether the rider intentionally reduced the amount of brake operation, whether there is a discrepancy between the detected brake operation amount and the rider's operation, or whether it is due to an external disturbance (such as uneven road surface), making it possible to provide brake assist more appropriately in line with the rider's intentions.

[0075] (Item 14) The system further includes an operation detection unit (e.g., 8) that detects an operation index value that fluctuates according to the amount of brake operation performed by the driver, The brake device according to any one of items 7 to 13, characterized in that, while the brake assist by the assist mechanism is being performed, the behavior detection unit detects that the stroke speed of the front suspension when the front suspension of the vehicle extends falls below a predetermined value as the suspension state, and the operation index value detected by the operation detection unit is less than a threshold value, the control unit releases the brake assist by the assist mechanism. According to this item, by using the rate of decrease in the operational indicator value in conjunction with the state of the vehicle's front suspension, the accuracy of determining whether the rider intentionally reduced the amount of brake operation to release the brakes, or whether there is a discrepancy between the detected brake operation amount and the rider's operation, will be improved, making it possible to provide brake assist more appropriately in line with the rider's actual brake operation.

[0076] (Item 15) The system further includes an operation detection unit (e.g., 8) that detects an operation index value that fluctuates according to the amount of brake operation performed by the driver, The brake device according to any one of items 7 to 14, characterized in that, while the brake assist by the assist mechanism is being performed, the behavior detection unit detects that the stroke speed of the rear suspension when the rear suspension of the vehicle is compressed falls below a predetermined value as the suspension state, and the operation index value detected by the operation detection unit is less than a threshold value, the control unit releases the brake assist by the assist mechanism. According to this item, by using the rate of decrease in the operational indicator value in conjunction with the change in the state of the vehicle's rear suspension, the accuracy of determining whether the rider intentionally reduced the amount of brake operation to release the brakes will be improved, making it possible to provide brake assist more appropriately in line with the rider's actual braking operation.

[0077] The present invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the invention. [Explanation of Symbols]

[0078] 6: Assist mechanism (hydraulic modulator), 7: Control unit, 8: Hydraulic sensor (M / C pressure sensor), 9: Hydraulic sensor (CAL pressure sensor), 10-13: Solenoid valve, 14: Pump, 15: Motor, 121: Inertia sensor, 123: Front stroke sensor, 125: Rear stroke sensor, 130: Brake device

Claims

1. A vehicle brake system, An assist mechanism that provides brake assist to increase the braking force of the vehicle, A behavior detection unit for detecting the pitching behavior of the vehicle, A control unit controls the brake assist by the assist mechanism in accordance with the pitching behavior detected by the behavior detection unit, A braking device characterized by being equipped with the following features.

2. It further includes an operation detection unit that detects an operation index value that fluctuates according to the amount of brake operation performed by the driver, The brake device according to claim 1, characterized in that the control unit further controls the brake assist by the assist mechanism in response to the change in the operation index value detected by the operation detection unit.

3. The brake device according to claim 2, characterized in that the control unit performs the brake assist by the assist mechanism when the operation detection unit detects an increase rate of the operation index value that is greater than a predetermined value, and the behavior detection unit detects a first pitching behavior in which the amount of pitching of the vehicle is greater than a predetermined amount.

4. The brake device according to claim 3, characterized in that the first pitching behavior is a behavior in which the vehicle pitches forward and downward.

5. The brake device according to claim 2, characterized in that the control unit reduces the amount of brake assist when, during the execution of the brake assist by the assist mechanism, the operation detection unit detects a decrease rate of the operation index value that is greater than a predetermined value, and the behavior detection unit detects a second pitching behavior in which the amount of pitching of the vehicle is greater than a predetermined amount.

6. The brake device according to claim 5, characterized in that the second pitching behavior is a behavior in which the vehicle pitches forward and upward.

7. The brake device according to claim 2, characterized in that the behavior detection unit detects the pitching behavior by detecting the suspension state of the vehicle.

8. The brake device according to claim 7, characterized in that the control unit performs the brake assist by the assist mechanism when the behavior detection unit detects that the front suspension of the vehicle has been compressed by a stroke amount greater than a predetermined amount while an operation index value greater than a predetermined value has been input, as the suspension state.

9. The brake device according to claim 7, characterized in that the control unit performs the brake assist by the assist mechanism when the behavior detection unit detects that the rear suspension of the vehicle has extended by a stroke amount greater than a predetermined amount while an operation index value greater than a predetermined value has been input, as the suspension state.

10. The brake device according to claim 7, characterized in that the control unit reduces the amount of brake assist when the behavior detection unit detects that the front suspension of the vehicle has extended by a stroke amount greater than a predetermined amount while the brake assist is being performed by the assist mechanism.

11. The brake device according to claim 7, characterized in that the control unit reduces the amount of brake assist when the behavior detection unit detects that the rear suspension of the vehicle has been compressed by a predetermined amount or more as the suspension state while the brake assist is being performed by the assist mechanism.

12. The brake device according to claim 7, characterized in that the control unit performs brake assist when the behavior detection unit detects that the suspension of the vehicle has changed at a stroke speed greater than a predetermined value as the suspension state.

13. The brake device according to claim 7, characterized in that the control unit reduces the amount of brake assist when the behavior detection unit detects that the suspension of the vehicle has changed to a stroke speed greater than a predetermined value while the brake assist is being performed by the assist mechanism, as the suspension state.

14. It further includes an operation detection unit that detects an operation index value that fluctuates according to the amount of brake operation performed by the driver, The brake device according to claim 7, wherein the control unit, while the brake assist by the assist mechanism is being performed, the behavior detection unit detects that the stroke speed of the front suspension when the front suspension of the vehicle extends falls below a predetermined value as the suspension state, and the operation index value detected by the operation detection unit is less than a threshold value, and the control unit releases the brake assist by the assist mechanism.

15. It further includes an operation detection unit that detects an operation index value that fluctuates according to the amount of brake operation performed by the driver, The brake device according to claim 7, wherein the control unit, while the brake assist by the assist mechanism is being performed, the behavior detection unit detects that the stroke speed of the rear suspension when the rear suspension of the vehicle is compressed falls below a predetermined value as the suspension state, and the operation index value detected by the operation detection unit is less than a threshold value, and the control unit releases the brake assist by the assist mechanism.

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