Brake device and vehicle

Abstract

This brake device for a vehicle comprises: a rear-wheel brake operator and a front-wheel brake operator; a first detection unit that detects an operation amount of the rear-wheel brake operator; a second detection unit that detects an operation amount of the front-wheel brake operator; an assisting mechanism that provides brake assistance for increasing the braking force of the vehicle; and a control unit that controls the assisting mechanism so as to execute the brake assistance for the vehicle when the operation amount of the rear-wheel brake operator as detected by the first detection unit has exceeded a first threshold. The first threshold is set in accordance with the operation amount of the front-wheel brake operator as detected by the second detection unit.

Description

Brake device and vehicle

[0001] The present invention relates to vehicle braking technology.

[0002] In recent years, efforts have been activated to provide access to sustainable transport systems that also take into consideration vulnerable people among road users. Towards achieving this goal, further improvements in traffic safety and convenience are being pursued through research and development related to driving support technology. Patent Document 1 describes that, in a braking device for a motorcycle having a front wheel braking mechanism and a rear wheel braking mechanism, when an assist condition is satisfied during operation of one of the front wheel braking mechanism and the rear wheel braking mechanism, the assist for the braking operation by each braking mechanism is controlled.

[0003] Japanese Unexamined Patent Publication No. 2001-180462

[0004] When the operation amount of a front brake operating member by a driver is relatively large, the driver performs the brake operation with the intention of increasing the braking force of the vehicle such as for emergency braking. In this case, in order to more effectively increase the braking force of the vehicle, it is desired to facilitate intervention of brake assist in accordance with the operation of the rear brake operating member.

[0005] Accordingly, an object of the present invention is to provide a technology capable of executing appropriate brake assist that conforms to the driver's intention. Further, it contributes to the development of sustainable transport systems in the long run.

[0006] In order to achieve the above object, a brake device according to one aspect of the present invention is a brake device for a vehicle, comprising: a rear brake operating member and a front brake operating member operated by a driver of the vehicle; a first detection unit that detects an operation amount of the rear brake operating member; a second detection unit that detects an operation amount of the front brake operating member; an assist mechanism that performs brake assist to increase the braking force of the vehicle; and a control unit that controls the assist mechanism so as to execute brake assist for the vehicle when the operation amount of the rear brake operating member detected by the first detection unit exceeds a first threshold value, wherein the first threshold value is set according to the operation amount of the front brake operating member detected by the second detection unit.

[0007] According to the present invention, for example, it is possible to provide a technology that can perform appropriate brake assist in accordance with the driver's intentions.

[0008] Other features and advantages of the present invention will become apparent from the following description with reference to the accompanying drawings. In the accompanying drawings, the same or similar components are given the same reference numeral.

[0009] The attached drawings are included in the specification and constitute part thereof, illustrating embodiments of the present invention and are used together with the description to explain the principles of the present invention.

[0010] Side view of a saddle-type vehicle according to the first embodiment Schematic diagram showing an example of the configuration of the brake system according to the first embodiment Control block diagram of the brake system according to the first embodiment Diagram showing an example of the time change of the front wheel assist amount and rear wheel assist amount Diagram showing an example of the time change of the front wheel assist amount and rear wheel assist amount Diagram showing an example of the time change of the front wheel assist amount and rear wheel assist amount Diagram showing an example of setting the pedal operation threshold Diagram showing an example of setting the pedal operation threshold Diagram showing an example of setting the pedal operation threshold Diagram showing an example of setting the pedal operation threshold Flowchart showing the control flow of brake assist in the brake system according to the first embodiment Flowchart showing the method of setting the first threshold in the second embodiment Diagram showing an example of setting the pedal operation threshold and lever operation threshold in the second embodiment Diagram showing an example of setting the pedal operation threshold and lever operation threshold in the second embodiment Diagram showing an example of setting the pedal operation threshold and lever operation threshold in the second embodiment

[0011] 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.

[0012] <First Embodiment> A first 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.

[0013] Vehicle 100 is equipped with a body frame 101 that forms its skeleton. The body frame 101 rotatably supports the front wheel steering section 102 at its front end and swingably supports the swing arm 115 at its rear end. The front wheel steering section 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 driver (rider) to control the acceleration of the vehicle 100. Near the right grip 105, a brake lever 106 (front wheel brake operator) that receives the driver's brake operation on the front wheel FW is rotatably provided. The swing arm 115 is swingably supported at its front end by the body frame 101 and supports the rear wheel RW at its rear end.

[0014] In the region between the front wheel FW and the rear wheel RW, an internal combustion engine 107 and a transmission 108, supported by the vehicle frame 101, are arranged. 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). Thus, this embodiment uses a chain drive mechanism, but 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. Behind the fuel tank 109 is a seat 110 where the driver sits. A brake pedal 119 (rear wheel brake operator) that receives the driver's brake operation on the rear wheel RW is rotatably provided on the right side of the vehicle 100. 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. In this case, the driving force may be transmitted directly from an electric motor mounted in the wheel to the wheel.

[0015] The front wheel 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 front wheel brake mechanism 111 is described. The front wheel 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 driver on the brake lever 106. In addition, the front fork 103 is provided with a wheel speed sensor 114 that detects the amount of rotation of the front wheel FW.

[0016] The rear wheel brake mechanism 116 is a mechanism that applies braking force to the rear wheel RW. In this embodiment, an example in which a disc brake is used as the rear wheel brake mechanism 116 is described. The rear wheel brake mechanism 116 comprises a brake rotor 117 that rotates coaxially and integrally with the rear wheel RW, and a brake caliper 118 having brake pads (not shown). The brake caliper 118 is supported by a swing arm 115 and clamps the brake rotor 117 with the brake pads, thereby braking the rear wheel RW which rotates integrally with the brake rotor 117. The clamping force of the brake caliper 118 (i.e., the braking force of the rear wheel RW) can be generated according to the amount of brake operation performed by the driver on the brake pedal 119. In addition, the swing arm 115 is provided with a wheel speed sensor 120 that detects the amount of rotation of the rear wheel RW.

[0017] [Configuration of Brake Device] Figure 2 is a schematic diagram showing an example of the configuration of a brake device 130 (brake system) that applies braking force to the front wheels FW and rear wheels RW in the vehicle 100 of this embodiment. The brake device 130 includes a front wheel brake mechanism 111 that applies braking force to the front wheels FW according to the amount of operation of the brake lever 106 by the driver, and a rear wheel brake mechanism 116 that applies braking force to the rear wheels RW according to the amount of operation of the brake pedal 119 by the driver.

[0018] The front wheel brake mechanism 111 includes a hydraulic circuit 1a that supplies hydraulic pressure of brake fluid (working fluid) generated in accordance with the amount of operation of the brake lever 106 by the driver to the brake caliper 113. The brake caliper 113 uses the hydraulic pressure of the brake fluid supplied by the hydraulic circuit 1a to clamp the brake rotor 112 with brake pads (not shown), thereby generating braking force for the front wheel FW. In this embodiment, the hydraulic circuit 1a includes a master cylinder 2a. The master cylinder 2a converts the amount of operation of the brake lever 106 into hydraulic pressure of the brake fluid by supplying brake fluid stored in the reservoir 3a to the flow path FP 1a in accordance with the amount of operation of the brake lever 106. The hydraulic pressure of the brake fluid generated in the master cylinder 2a is transmitted to the brake caliper 113, causing the brake rotor 112 to be clamped by the brake pads of the brake caliper 113, generating braking force for the front wheel FW. The amount of operation of the brake lever 106 may be directly detected by a lever operation amount sensor 4a (second detection unit) such as a potentiometer. Alternatively, it may be detected using information correlated with the amount of operation of the brake lever 106, such as the brake fluid pressure in the flow path FP3 detected by the hydraulic pressure sensor 8a (which may be understood as the master cylinder pressure, which is substantially the pressure of the brake fluid in the master cylinder 2a) or the brake fluid pressure in the flow path FP2 detected by the hydraulic pressure sensor 9a (which may be understood as the brake caliper pressure, which is substantially the pressure of the brake fluid in the brake caliper 113). In this case, either the hydraulic pressure sensor 8a or the hydraulic pressure sensor 9a, or both, constitute the second detection unit.

[0019] The rear wheel brake mechanism 116 includes a hydraulic circuit 1b that supplies hydraulic pressure of brake fluid (working fluid) generated in accordance with the amount of operation of the brake pedal 119 by the driver to the brake caliper 118. The brake caliper 118 uses the hydraulic pressure of the brake fluid supplied by the hydraulic circuit 1b to clamp the brake rotor 117 with brake pads (not shown), thereby generating braking force for the rear wheel RW. In this embodiment, the hydraulic circuit 1b may include a master cylinder 2b. The master cylinder 2b converts the amount of operation of the brake pedal 119 into hydraulic pressure of the brake fluid by supplying brake fluid stored in the reservoir 3b to the flow path FP 1b in accordance with the amount of operation of the brake pedal 119. The hydraulic pressure of the brake fluid generated in the master cylinder 2b is transmitted to the brake caliper 118, causing the brake rotor 117 to be clamped by the brake pads of the brake caliper 118, generating braking force for the rear wheel RW. The amount of operation of the brake pedal 119 may be directly detected by a pedal operation amount sensor 4b (first detection unit) such as a potentiometer. Alternatively, it may be detected using information correlated with the amount of operation of the brake pedal 119, such as the brake fluid pressure in the flow path FP3 detected by the hydraulic pressure sensor 8b (which may be understood as the master cylinder pressure, which is substantially the pressure of the brake fluid in the master cylinder 2a) or the brake fluid pressure in the flow path FP2 detected by the hydraulic pressure sensor 9b (which may be understood as the brake caliper pressure, which is substantially the pressure of the brake fluid in the brake caliper 118). In this case, either the hydraulic pressure sensor 8b or the hydraulic pressure sensor 9b, or both, constitute the first detection unit.

[0020] Furthermore, in the brake device 130 of this embodiment, brake assist is performed when an emergency brake operation to suddenly stop the vehicle 100 is input by the driver to the brake lever 106 and / or brake pedal 119. The brake assist includes pressurization assist, which increases the braking force of the vehicle 100 (front wheels FW, rear wheels RW) by increasing the hydraulic pressure of the brake fluid applied to the brake calipers 113 and 118. To perform such brake 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 assist mechanism 6. The assist mechanism 6 may include a front wheel assist mechanism 6a that performs brake assist for the front wheels FW and a rear wheel assist mechanism 6b that performs brake assist for the rear wheels RW. The front wheel assist mechanism 6a may be configured as part of the front wheel brake mechanism 111, and the rear wheel assist mechanism 6b may be configured as part of the rear wheel brake mechanism 116. The following describes an example in which the front wheel assist mechanism 6a and the rear wheel assist mechanism 6b are each composed of a recirculating hydraulic modulator, but the system is not limited to this, and the assist mechanism 6 may be composed of other mechanisms such as brake-by-wire.

[0021] The front wheel assist mechanism 6a of the front wheel brake mechanism 111 includes a plurality of solenoid valves 10 to 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 are normally closed solenoid valves. The brake fluid flow path FP1a branches into flow path FP2 and flow path FP3 at branching point b1. Flow path FP2 is connected to the brake caliper 113.

[0022] Solenoid valves 10 and 12 are installed in the flow path FP2 to open and close the flow path FP2. Solenoid valve 12 is positioned on the brake caliper 113 side of the flow path FP1a than solenoid valve 10. Solenoid valve 11 is installed in the flow path FP3 to open and close the flow path FP3.

[0023] Flow path FP3 branches into flow path FP4 and flow path FP5 at branching point b2. Flow path FP4 connects branching point b2 with the portion of flow path FP2 between solenoid valve 10 and solenoid valve 12. A pump 14 driven by motor 15 is provided in flow path FP4. The output port of pump 14 is located on the flow path FP2 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 out by pump 14 in the direction of branching point b2 → flow path FP4 → flow path FP2. Meanwhile, flow path FP5 connects the portion of flow path FP2 between solenoid valve 12 and brake caliper 113 with branching point b2 via solenoid valve 13 and check valve 16.

[0024] The solenoid valve 13 is installed in the flow path FP5 and opens and closes the flow path FP5. Between the solenoid valve 13 and the branching point b2 in the flow path FP5, 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 is in communication 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 fluid path FP3 is provided with a hydraulic pressure sensor 8 that detects the hydraulic pressure of the brake fluid in the fluid path FP3 between the branching point b1 and the solenoid valve 11. The hydraulic pressure sensor 8 may be understood as a sensor that detects the master cylinder pressure, which is the pressure of the brake fluid in the master cylinder 2a. The fluid path FP2 is provided with a hydraulic pressure sensor 9 that detects the hydraulic pressure of the brake fluid in the fluid path FP2 between the solenoid valve 12 and the brake caliper 113. The hydraulic pressure sensor 9 may be understood as a sensor that detects the brake caliper pressure, which is the pressure of the brake fluid in the brake caliper 113.

[0026] In the front wheel assist mechanism 6a configured in this way, the main passage FP1a and the main passage FP2 are configured to supply brake fluid from the master cylinder 2a to the brake caliper 113. The secondary passage FP4 and the main passage FP5 are configured to return the brake fluid from the brake caliper 113 to the main passage (passage FP2). The main passage FP3 is configured to supply brake fluid from the main passage (passage FP1a) to the secondary passages (passages FP4 and FP5). The control unit 7 drives the multiple solenoid valves 10 to 13 and the motor 15 (pump 14) in the front wheel assist mechanism 6a to control the flow of brake fluid in the main passage, secondary passage and supply passage, thereby enabling brake assist to increase the braking force of the front wheel FW.

[0027] The rear wheel assist mechanism 6b of the rear wheel brake mechanism 116 has the same configuration as the front wheel assist mechanism 6a of the front wheel brake mechanism 111. However, in the above description of the front wheel assist mechanism 6a, the master cylinder 2a, brake caliper 113, and flow path FP1a are replaced by the master cylinder 2b, brake caliper 118, and flow path FP1b, respectively. The control unit 7 can drive a plurality of solenoid valves 10 to 13 and a motor 15 (pump 14) in the rear wheel assist mechanism 6a to control the flow of brake fluid in the main flow path, sub-flow path, and supply flow path, thereby performing (intervening in) brake assist to increase the braking force of the rear wheel RW.

[0028] [Control Block Diagram of Brake System] Figure 3 is a control block diagram of the brake system 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 (front wheel assist mechanism 6a, rear wheel assist mechanism 6b) 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 detection result of the lever operation amount sensor 4a (amount of operation of the brake lever 106) and the detection result of the pedal operation amount sensor 4b (amount of operation of the brake pedal 119) are input to the interface unit 73 via a signal processing circuit (not shown). The detection results of hydraulic pressure sensors 8-9 and wheel speed sensors 114, 120 may also be input to the interface unit 73. Based on these detection results, the processing unit 71 controls the driving of the solenoid valves 10-13 and motor 15 of the assist mechanism 6 (front wheel assist mechanism 6a, rear wheel assist mechanism 6b) 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.

[0029] The following describes an example of brake assist control by the brake device 130 of this embodiment. In the brake device 130 of this embodiment, brake assist is performed (intervened) when the amount of brake lever 106 detected by at least one of the lever operation amount sensor 4a, hydraulic pressure sensor 8, or hydraulic pressure sensor 9 exceeds the lever operation threshold (second threshold), and / or when the amount of brake pedal 119 detected by at least one of the pedal operation amount sensor 4a, hydraulic pressure sensor 8, or hydraulic pressure sensor 9 exceeds the pedal operation threshold (first threshold). In the following, the amount of brake assist for the front wheel FW generated by the front wheel assist mechanism 6a may be referred to as the "front wheel assist amount," and the amount of brake assist for the rear wheel RW generated by the rear wheel assist mechanism 6b may be referred to as the "rear wheel assist amount."

[0030] Figure 4A shows the amount of front wheel assist FA after the amount of brake lever 106 is operated to reach the lever operation threshold. １ and rear wheel assist amount RA １ This shows an example of the time change. When the amount of brake lever 106 operated by at least one of the lever operation amount sensor 4a, hydraulic pressure sensor 8, or hydraulic pressure sensor 9 exceeds the lever operation threshold, the control unit 7 starts brake assist on the rear wheel RW using the rear wheel assist mechanism 6b, and after a predetermined period of time has elapsed thereafter, starts brake assist on the front wheel FW using the front wheel assist mechanism 6a. For example, as shown in Figure 4A, the control unit 7 controls the rear wheel assist amount RA １ The rear wheel assist mechanism 6b performs brake assist on the rear wheel RW to rapidly (instantaneously) increase the front wheel assist amount FA to a predetermined value. Then, after a predetermined time T has elapsed, the control unit 7 adjusts the front wheel assist amount FA １ The front wheel assist mechanism 6b performs brake assist on the front wheel FW so that the amount of front wheel assist FA is gradually increased and maintained at a predetermined value. １ This reduces the sudden increase in braking force of the front wheels (FW) which causes the vehicle to tilt forward (i.e., changes in pitching).

[0031] Furthermore, Figure 4B shows the amount of front wheel assist FA after the amount of operation of the brake pedal 119 reaches the pedal operation threshold. ２ and rear wheel assist amount RA ２ This shows an example of the time change. When the amount of operation of the brake pedal 119 detected by at least one of the pedal operation amount sensor 4b, hydraulic pressure sensor 8, or hydraulic pressure sensor 9 exceeds the pedal operation threshold, the control unit 7 performs brake assist only on the front wheel FW using the front wheel assist mechanism 6a. For example, as shown in Figure 4B, the control unit 7 sets the front wheel assist amount FA ２the brake assist for the front wheels FW by the front wheel assist mechanism 6b is executed so as to be gradually increased and maintained at a predetermined value, and the brake assist for the rear wheels RW by the rear wheel assist mechanism 6a is not executed. Such control can reduce a driver's discomfort caused by excessive braking force generated on the rear wheels RW. Note that brake assist for the rear wheels RW may be executed within a range that does not cause significant discomfort to the driver.

[0032] FIG. 5 illustrates the front wheel assist amount FA when the operation amount of the brake pedal 119 exceeds the pedal operation threshold and the operation amount of the brake pedal 119 exceeds the pedal operation threshold total of an example. Here, the brake assist control when the operation amount of the brake lever 106 exceeds the lever operation threshold and the brake assist control when the operation amount of the brake pedal 119 exceeds the pedal operation threshold can be executed separately. That is, the assist amount generated when the operation amount of the brake lever 106 exceeds the lever operation threshold and the assist amount generated when the operation amount of the brake pedal 119 exceeds the pedal operation threshold are added together. The front wheel assist amount FA total can be the sum of the front wheel assist amount FA shown in FIG. 4A １ and the front wheel assist amount FA shown in FIG. 4B ２ .

[0033] By the way, when the operation amount of the brake lever 106 by the driver is relatively large, there is a high possibility that the driver is performing the brake operation with the intention of increasing the braking force of the vehicle 100 such as for emergency braking. In this case, in order to increase the braking force of the vehicle 100 more effectively, it is desirable to make it easier to intervene (execute) brake assist in accordance with the operation amount of the brake pedal 119. Therefore, in the brake device 130 of the present embodiment, the pedal operation threshold (first threshold) is set according to the operation amount of the brake lever 106 detected by at least any one of the lever operation amount sensor 4a, the hydraulic pressure sensor 8, or the hydraulic pressure sensor 9.

[0034] FIGS. 6 to 9 show the pedal operation threshold TH ＰThe following are examples of settings. In Figures 6 to 9, the horizontal axis represents the front wheel deceleration based on the amount of operation of the brake lever 106 detected by at least one of the lever operation amount sensor 4a, hydraulic pressure sensor 8, or hydraulic pressure sensor 9, and the vertical axis represents the rear wheel deceleration based on the amount of operation of the brake pedal 119 detected by at least one of the pedal operation sensor 4b, hydraulic pressure sensor 8, or hydraulic pressure sensor 9. Figures 6 to 9 also show the ideal braking force distribution curve BFD between the front wheel FW and the rear wheel RW of the vehicle 100, as well as the lock limit lines (front wheel lock limit line FL, rear wheel lock limit line RL) for the front wheel FW and the rear wheel RW, respectively. The ideal braking force distribution curve BFD, the front wheel lock limit line FL, and the rear wheel lock limit line RL can be determined using known calculation methods. Note that in Figures 6 to 9, the horizontal axis may be understood as the braking force of the front wheel FW, and the vertical axis may be understood as the braking force of the rear wheel RW.

[0035] Furthermore, the amount of operation of the brake lever 106 and the brake pedal 119 and the deceleration are in a proportional relationship, depending on the characteristics of the master cylinder 2a and the brake caliper 113. Therefore, the pedal operation threshold TH Ｐ This is the vehicle deceleration, and the amount of operation of the brake lever 106 and the brake pedal 119 is equal to the pedal operation threshold TH. Ｐ Brake assist is activated when the vehicle's deceleration exceeds a certain value.

[0036] In the example in Figure 6, the pedal operation threshold TH Ｐ The pedal operation threshold TH is set to decrease as the amount of front wheel deceleration based on the amount of brake lever 106 operated detected by the lever operation amount sensor 4a increases. Ｐ The rate of change (i.e., the slope) can be determined using experiments, simulations, etc. (the same applies to the examples in Figures 7 to 9 described later).

[0037] In the example in Figure 7, the pedal operation threshold TH ＰThe pedal operation threshold TH is set to decrease as the amount of front wheel deceleration based on the amount of brake lever operation detected by the lever operation amount sensor 4a increases, after the front wheel deceleration based on the amount of brake lever operation detected by the lever operation amount sensor 4a reaches a first predetermined amount A1. In this case, until the front wheel deceleration based on the amount of brake lever operation detected by the brake lever 106 reaches the first predetermined amount A1, the pedal operation threshold TH Ｐ This can be set to a constant value. The first predetermined quantity A1 can be determined using experiments, simulations, etc. (the same applies to the example in Figure 9, which will be described later).

[0038] In the example in Figure 8, the pedal operation threshold TH Ｐ The pedal operation threshold TH is set to decrease as the amount of front wheel deceleration based on the amount of brake lever operation detected by the lever operation amount sensor 4a increases, until the front wheel deceleration based on the amount of brake lever operation reaches a second predetermined amount A2. Ｐ The pedal operation threshold TH is set to be greater than the ideal braking force distribution curve BFD until the front wheel deceleration based on the amount of operation of the brake lever 106 detected by the lever operation amount sensor 4a reaches the second predetermined amount A2. In this case, after the front wheel deceleration based on the amount of operation of the brake lever 106 reaches the second predetermined amount A2, the pedal operation threshold TH Ｐ This can be set to a constant value (for example, zero). The second predetermined quantity A2 can be determined using experiments or simulations (the same applies to the example in Figure 9, which will be discussed later).

[0039] In the example in Figure 9, the pedal operation threshold TH Ｐ The pedal operation threshold TH is set to a constant value until the front wheel deceleration based on the amount of operation of the brake lever 106 detected by the lever operation amount sensor 4a reaches a first predetermined amount A1, and after the front wheel deceleration based on the amount of operation of the brake lever 106 reaches the first predetermined amount A1, it is set to decrease as the amount of front wheel deceleration based on the amount of operation of the brake lever increases. Then, after the front wheel deceleration based on the amount of operation of the brake lever 106 detected by the lever operation amount sensor 4a reaches a second predetermined amount A2, the pedal operation threshold TH Ｐ The pedal operation threshold TH is set to a constant value (for example, zero). ＰThis is set so that the front wheel deceleration, based on the amount of brake lever 106 operated by the lever operation amount sensor 4a, is greater than the ideal braking force distribution curve BFD until it reaches a second predetermined amount A2. Note that the second predetermined amount A2 is a value greater than the first predetermined amount A1.

[0040] Here, as described above, the control unit 7 performs brake assist when the front wheel deceleration based on the amount of operation of the brake lever 106 detected by the lever operation amount sensor 4a exceeds the lever operation threshold (second threshold), and / or when the front wheel deceleration based on the amount of operation of the brake pedal 119 detected by the pedal operation amount sensor 4a exceeds the pedal operation threshold (first threshold). In this case, the control unit 7 can control the assist mechanism 6 (front wheel assist mechanism 6a, rear wheel assist mechanism 6b) for each of the front wheel FW and rear wheel RW so that the amount of brake assist is aligned with the lock limit lines (front wheel lock limit line FL, rear wheel lock limit line RL). This enables stable and effective braking of the vehicle 100.

[0041] [Control Flow of Brake Assist] Below, an example of the control flow of the brake assist in the brake device 130 of this embodiment will be described. Figure 10 is a flowchart of the control flow of the brake assist. The control flow in Figure 10 is executed by the control unit 7. Furthermore, the control flow in Figure 10 is executed repeatedly. That is, once the flowchart in Figure 10 is completed, the flowchart in Figure 10 may be started again.

[0042] In step S101, the control unit 7 determines that the front wheel deceleration based on the amount of brake lever 106 operated by the lever operation amount sensor 4a (hereinafter sometimes referred to as lever operation amount) is the lever operation threshold TH Ｌ Determine whether it exceeds the lever operation threshold TH. The front wheel deceleration based on the lever operation amount is determined by the lever operation threshold TH. Ｌ If it exceeds this, proceed to step S102, and the front wheel deceleration based on the lever operation amount is determined by the lever operation threshold TH. Ｌ If it does not exceed that value, proceed to step S107.

[0043] In step S102, the control unit 7 determines that the rear wheel deceleration based on the amount of brake pedal 119 operated by the pedal operation amount sensor 4b (hereinafter sometimes referred to as pedal operation amount) is the pedal operation threshold TH Ｐ Determine whether it exceeds the pedal operation threshold TH. The rear wheel deceleration based on the pedal operation amount is determined by the pedal operation threshold TH. Ｐ If it exceeds this, proceed to step S103, and the rear wheel deceleration based on the pedal operation amount is the pedal operation threshold TH Ｐ If it does not exceed that value, proceed to step S106.

[0044] In step S103, the control unit 7 calculates a provisional assist amount corresponding to the lever operation amount detected by the lever operation amount sensor 4a for both the front wheel FW and the rear wheel RW. The provisional assist amount may be calculated using information showing the relationship between the lever operation amount and the assist amount. This information may be acquired in advance for both the front wheel FW and the rear wheel RW through experiments, simulations, etc. Also, in step S104, the control unit 7 calculates a provisional assist amount corresponding to the pedal operation amount detected by the pedal operation amount sensor 4b for both the front wheel FW and the rear wheel RW. The provisional assist amount may be calculated using information showing the relationship between the pedal operation amount and the assist amount. This information may be acquired in advance for both the front wheel FW and the rear wheel RW through experiments, simulations, etc.

[0045] In step S105, the control unit 7 determines the front wheel assist amount and the rear wheel assist amount based on the provisional assist amount calculated in step S103. Specifically, the control unit 7 determines the front wheel assist amount by adding the provisional assist amount of the front wheel FW calculated in step S103 to the provisional assist amount of the front wheel FW calculated in step S103. Similarly, the control unit 7 determines the rear wheel assist amount by adding the provisional assist amount of the rear wheel RW calculated in step S103 to the provisional assist amount of the rear wheel RW calculated in step S103.

[0046] Next, in step S109, the control unit 7 performs brake assist (intervenes) to increase or maintain the brake assist amount based on the front wheel assist amount and rear wheel assist amount determined in step S105. Specifically, the control unit 7 controls the front wheel brake mechanism 111 so that the front wheel assist amount determined in step S105 is generated, and controls the rear wheel brake mechanism 116 so that the rear wheel assist amount determined in step S105 is generated. In step S110, the control unit 7 determines whether or not the rider's brake operation has been released (release determination). If the brake operation has been released, the process proceeds to step S111, where the control unit 7 reduces the brake assist amount. On the other hand, if the brake operation has not been released, the flowchart ends.

[0047] In step S102, the rear wheel deceleration based on the pedal operation amount is set to the pedal operation threshold TH Ｐ In step S106, which proceeds if the threshold is not exceeded, the control unit 7 determines the front wheel assist amount and the rear wheel assist amount based on the lever operation amount detected by the lever operation amount sensor 4a. Specifically, the control unit 7 can determine the front wheel assist amount and the rear wheel assist amount using information showing the relationship between the lever operation amount and the assist amount. This information can be acquired in advance for each of the front wheels FW and rear wheels RW through experiments, simulations, etc.

[0048] Next, in step S109, the control unit 7 performs brake assist (intervenes) to increase or maintain the brake assist amount based on the front wheel assist amount and rear wheel assist amount determined in step S106. Specifically, the control unit 7 controls the front wheel brake mechanism 111 so that the front wheel assist amount determined in step S106 is generated, and controls the rear wheel brake mechanism 116 so that the rear wheel assist amount determined in step S106 is generated. In step S110, the control unit 7 determines whether or not the rider's brake operation has been released (release determination). If the brake operation has been released, the process proceeds to step S111, where the control unit 7 reduces the brake assist amount. On the other hand, if the brake operation has not been released, the flowchart ends.

[0049] In step S101, the front wheel deceleration based on the lever operation amount is determined by the lever operation threshold TH Ｌ If the pedal operation amount is not exceeded, the control unit 7 proceeds to step S107, in which the control unit 7 determines that the rear wheel deceleration based on the pedal operation amount is equal to the pedal operation threshold TH Ｐ Determine whether it exceeds the pedal operation threshold TH. The rear wheel deceleration based on the pedal operation amount is determined by the pedal operation threshold TH. Ｐ If it does not exceed the threshold, the process proceeds to step S110, and the control unit 7 terminates without performing brake assist. Meanwhile, the rear wheel deceleration based on the pedal operation amount exceeds the pedal operation threshold TH Ｐ If it exceeds this value, proceed to step S108.

[0050] In step S108, the control unit 7 determines the front wheel assist amount and the rear wheel assist amount based on the pedal operation amount detected by the pedal operation amount sensor 4b. Specifically, the control unit 7 can determine the front wheel assist amount and the rear wheel assist amount using information showing the relationship between the pedal operation amount and the assist amount. This information can be acquired in advance for each of the front wheels FW and rear wheels RW through experiments, simulations, etc.

[0051] As mentioned above, in this embodiment, when only the amount of operation of the brake pedal 119 reaches the pedal operation threshold, the rear wheel assist mechanism 6a does not perform brake assist on the rear wheel RW. In this case, the amount of rear wheel assist determined in step S108 becomes 0. However, the present invention is not limited thereto.

[0052] Next, in step S109, the control unit 7 performs brake assist (intervenes) to increase or maintain the brake assist amount based on the front wheel assist amount and rear wheel assist amount determined in step S108. Specifically, the control unit 7 controls the front wheel brake mechanism 111 so that the front wheel assist amount determined in step S108 is generated, and controls the rear wheel brake mechanism 116 so that the rear wheel assist amount determined in step S108 is generated. Also, in step S110, the control unit 7 determines whether or not the rider's brake operation has been released (release determination). If the brake operation has been released, the process proceeds to step S111, where the control unit 7 reduces the brake assist amount. On the other hand, if the brake operation has not been released, the flowchart ends.

[0053] <Second Embodiment> A second embodiment of the present invention will now be described. This embodiment basically follows the first embodiment, and except for the matters mentioned below, it can be described in accordance with the first embodiment. In this embodiment, the configuration of the vehicle 100 and the brake device 130 is the same, but the method of setting the first threshold is different. Therefore, the method of setting the first threshold in this embodiment will be described below.

[0054] Figure 11 is a flowchart showing the method for setting the first threshold in the second embodiment. The flowchart in Figure 11 can be executed by the control unit 7. Specifically, the flowchart in Figure 11 is executed by the processing unit 71 and the storage unit 72. Furthermore, the flowchart in Figure 11 can be executed repeatedly.

[0055] In step S201, the memory unit 72 records the distribution of front wheel deceleration based on the amount of brake lever 106 operated by the rider within a predetermined period and rear wheel deceleration based on the brake pedal 119. The predetermined period here may refer only to a predetermined time after the ignition is turned on, or the recorded results may be updated each time a predetermined amount of time has elapsed while riding.

[0056] In step S202, the processing unit 71 determines whether the recorded results of the distribution of front wheel deceleration based on the amount of brake lever 106 operated by the rider within a predetermined period by the storage unit 72 and the rear wheel deceleration based on the brake pedal 119 fall within the vicinity of the ideal braking force distribution curve BFD (i.e., whether the front and rear braking force distribution is appropriate). The values ​​that fall within the vicinity of the ideal braking force distribution curve BFD may be set as appropriate.

[0057] In step S202, if it is determined that the distribution of front wheel deceleration based on the amount of operation of the brake lever 106 by the rider within a predetermined period and rear wheel deceleration based on the amount of operation of the brake pedal 119 falls near the ideal braking force distribution curve BFD (the front and rear braking force distribution is appropriate), the process proceeds to step S203. In step S203, the processing unit 71 sets the pedal operation threshold TH based on the threshold data for when the front and rear braking force distribution is appropriate, which has been stored in the storage unit 72 in advance. Ｐ The lever operation threshold TH is set based on the threshold data for the appropriate front and rear braking force distribution that has been stored in the storage unit 72 in advance. Ｌ Set it.

[0058] If, in step S202, it is determined that the distribution of the front wheel deceleration based on the amount of operation of the brake lever 106 by the rider within a predetermined period and the rear wheel deceleration based on the amount of operation of the brake pedal 119 does not fall near the ideal braking force distribution curve BFD (i.e., the front and rear braking force distribution is not appropriate), the process proceeds to step S205.

[0059] In step S205, the processing unit 71 determines whether the front wheel deceleration based on the amount of operation of the brake lever 106 is excessive compared to the front-to-rear braking force distribution. If it is determined in step S205 that the front wheel deceleration based on the amount of operation of the brake lever 106 is excessive, the process proceeds to step S206.

[0060] In step S206, the processing unit 71 determines the pedal operation threshold TH based on the threshold data when the front and rear braking force distribution is appropriate. Ｐ and lever operation threshold TH Ｌ To make the pedal operation threshold TH lower Ｐ and lever operation threshold TH Ｌ In addition to setting the lever operation threshold TH Ｌ The amount of decrease is the pedal operation threshold TH Ｐ The amount of reduction is set to be greater than the amount of reduction. Also, if it is determined in step S205 that the distribution of the rear wheel deceleration degree based on the amount of operation of the brake pedal 119 is excessive, the process proceeds to step S207.

[0061] In step S207, the processing unit 71 determines the pedal operation threshold TH when the front and rear braking force distribution is appropriate. Ｐ and lever operation threshold TH Ｌ To make the pedal operation threshold TH lower Ｐ and lever operation threshold TH Ｌ In addition to setting the lever operation threshold TH Ｐ The amount of decrease is the pedal operation threshold TH Ｌ Set it so that it is greater than the amount of decrease. After completing the control in either step S206 or step S207, proceed to S101 in Figure 10.

[0062] Figure 12 shows the pedal operation threshold TH in the second embodiment. Ｐ and lever operation threshold TH Ｌ An example of the settings is shown. The solid line represents the range ARa. １ This indicates the case where the distribution of front wheel deceleration based on the amount of brake lever 106 operated by the rider within a predetermined period and rear wheel deceleration based on the amount of brake pedal 119 operated falls near the ideal braking force distribution curve BFD (the front and rear braking force distribution is appropriate). The dashed line indicates the range ARa. ２This indicates a case where the distribution of front wheel deceleration based on the amount of brake lever 106 operated by the rider within a predetermined period and rear wheel deceleration based on the amount of brake pedal 119 operated does not fall within the vicinity of the ideal braking force distribution curve BFD (the front and rear braking force distribution is not appropriate). In the example in Figure 12, the case where the front and rear braking force distribution is appropriate (range ARa １ ) Compared to when the front and rear braking force distribution is not appropriate (range ARa ２ ) is better, pedal operation threshold TH Ｐ and lever operation threshold TH Ｌ All of these are set to be low. Also, in the example in Figure 12, the rear wheel deceleration based on the amount of brake pedal 119 is excessive, so the lever operation threshold TH is lower compared to when the front and rear braking force distribution is appropriate. Ｌ The amount of decrease is the pedal operation threshold TH Ｐ It is set to be greater than the amount of decrease.

[0063] Figure 13 shows the pedal operation threshold TH in the second embodiment. Ｐ and lever operation threshold TH Ｌ The following shows an example of the settings. The solid line represents the range ARb. １ This indicates the case where the distribution of front wheel deceleration based on the amount of brake lever 106 operated by the rider within a predetermined period and rear wheel deceleration based on the amount of brake pedal 119 operated falls within the vicinity of the ideal braking force distribution curve BFD (i.e., the front and rear braking force distribution is appropriate). The dashed line represents the range ARb. ２ This indicates a case where the distribution of front wheel deceleration based on the amount of brake lever 106 operated by the rider within a predetermined period and rear wheel deceleration based on the amount of brake pedal 119 operated does not fall within the vicinity of the ideal braking force distribution curve BFD (the front and rear braking force distribution is not appropriate). In the example in Figure 13, the case where the rear braking force distribution is appropriate (range ARb) is shown. １ ) Compared to when the front and rear braking force distribution is not appropriate (range ARb ２ ) is better, pedal operation threshold TH Ｐ and lever operation threshold TH Ｌ All of these are set to be low. Also, in the example in Figure 13, the front wheel deceleration based on the amount of brake lever 106 is excessive, so the pedal operation threshold TH is lower compared to when the front and rear braking force distribution is appropriate. Ｐ The amount of decrease is the lever operation threshold THＬ It is set to be greater than the amount of decrease.

[0064] Furthermore, Figure 14 shows the pedal operation threshold TH set in Figures 12 to 13. Ｐ and lever operation threshold TH Ｌ This shows an example of a setting that applies correction based on rider input. In the example in Figure 14, the pedal operation threshold TH when the front and rear braking force distribution is judged to be appropriate in Figure 12 is shown. Ｐ and lever operation threshold TH Ｌ Regarding this, the rider inputted an instruction to increase the frequency of brake assist intervention, which caused the pedal operation threshold TH Ｐ and lever operation threshold TH Ｌ The pedal operation threshold TH is being corrected to be lower. Ｐ and lever operation threshold TH Ｌ The ratio should preferably be the same as the ratio set in Figure 12. In this embodiment, the rider operates the HMI (Human Machine Interface), such as a meter (not shown), a voice recognition system, and various switches, and the result of the operation is input via the interface unit 73. The rider's input is the pedal operation threshold TH Ｐ and lever operation threshold TH Ｌ Even if the range ARc is changed continuously, １ ~ARC ３ As shown, by selecting a predetermined correction level (e.g., high, medium, low), the pedal operation threshold TH Ｐ and lever operation threshold TH Ｌ The value may be corrected to a value corresponding to the correction level. Also, in the example in Figure 14, the pedal operation threshold TH Ｐ and lever operation threshold TH Ｌ This is to set the pedal operation threshold TH low based on user input. Ｐ and lever operation threshold TH Ｌ It may be possible to allow for a higher level of correction.

[0065] Further, the correction in Fig. 14 may be performed based on driving environment information acquired from driving environment detection means such as a camera, radar, and IMU. The driving environment information may include images acquired by a camera, detection information of surrounding objects by radar, road surface friction coefficient information by a road surface friction coefficient determination sensor, vehicle body behavior information such as the bank angle of the vehicle body acquired by an IMU, and the like. These pieces of information are acquired via the interface 73, and based on the information, the control unit 7 determines whether the driving environment is, for example, an urban area or a winding road. When the control unit 7 determines that the driving environment is an urban area, the pedal operation threshold TH Ｐ and the lever operation threshold TH Ｌ are corrected to be lower, and when it is determined that the driving environment is a winding road, the pedal operation threshold TH Ｐ and the lever operation threshold TH Ｌ are corrected to be higher. Further, regarding a specific correction amount, the correction may be made to a predetermined value in accordance with each piece of driving environment information, or the rider's input tendency for each piece of driving environment information may be learned and the correction may be made to a value calculated from the learning result.

[0066] <Third Embodiment> A third embodiment according to the present invention will be described. This embodiment basically inherits the first to second embodiments, and may follow the first to second embodiments except for matters mentioned below.

[0067] In the third embodiment, the control unit 7 learns, as a reference operation amount, the average operation amount of the brake lever 106 and the average operation amount of the brake pedal 119 during normal traveling in which the rider's brake assist is not intervened. As the reference operation amount (learning information) decreases, the control unit 7 decreases the pedal operation threshold TH Ｐ and the lever operation threshold TH Ｌ and increases the pedal operation threshold TH Ｐ and the lever operation threshold TH Ｌ as the reference operation amount increases. For example, the reference operation amount may be updated at regular intervals; the operation amount may be learned with a period from when the ignition is turned on to when the ignition is turned off as one cycle, and the reference operation amount may be set based on the learning in the previous cycle when the ignition is turned on next time.

[0068] As described above, in the brake device 130 of this embodiment, the pedal operation threshold is set according to the front wheel deceleration based on the amount of operation of the brake lever 106 detected by the lever operation amount sensor 4a. This makes it easier to intervene (execute) brake assist according to the rear wheel deceleration based on the amount of operation of the brake pedal 119 when there is a high possibility that the driver is performing a brake operation with the intention of increasing the braking force of the vehicle 100, such as in emergency braking, thereby increasing the braking force of the vehicle 100 more effectively. In other words, it is possible to perform appropriate brake assist in line with the driver's intention to brake.

[0069] <Summary of Embodiments> (Item 1) A brake device for a vehicle, comprising: a rear wheel brake lever and a front wheel brake lever; a first detection unit for detecting the amount of operation of the rear wheel brake lever; a second detection unit for detecting the amount of operation of the front wheel brake lever; an assist mechanism for performing brake assist to increase the braking force of the vehicle; and a control unit for controlling the assist mechanism to perform brake assist for the vehicle when the amount of operation of the rear wheel brake lever detected by the first detection unit exceeds a first threshold, wherein the first threshold is set according to the amount of operation of the front wheel brake lever detected by the second detection unit. According to this item, in cases where there is a high possibility that the driver is performing brake operation with the intention of increasing the braking force of the vehicle, such as in emergency braking, it is possible to intervene (execute) brake assist according to the amount of operation of the rear wheel brake lever, thereby increasing the braking force of the vehicle more effectively. In other words, it is possible to perform appropriate brake assist in accordance with the driver's intention to brake.

[0070] (Item 2) The brake device according to Item 1, characterized in that the first threshold is set to decrease as the amount of operation of the front wheel brake lever detected by the second detection unit increases. According to this item, the larger the amount of operation of the front wheel brake lever, the easier it is to intervene (execute) brake assist corresponding to the amount of operation of the rear wheel brake lever, thereby increasing the braking force of the vehicle more effectively.

[0071] (Item 3) The brake device according to Item 1, characterized in that the first threshold is set to decrease as the amount of operation of the front wheel brake lever detected by the second detection unit increases after the amount of operation of the front wheel brake lever reaches a first predetermined amount. According to this item, the larger the amount of operation of the front wheel brake lever, the easier it is to intervene (execute) brake assist corresponding to the amount of operation of the rear wheel brake lever, thereby increasing the braking force of the vehicle more effectively. In addition, when the amount of operation of the front wheel brake lever is relatively small, it is possible to reduce excessive intervention of brake assist corresponding to the amount of operation of the rear wheel brake lever.

[0072] (Item 4) The brake device according to Item 3, characterized in that the first threshold is set to a constant value until the amount of operation of the front wheel brake lever detected by the second detection unit reaches the first predetermined amount. According to this item, when the amount of operation of the front wheel brake lever is relatively small, it is possible to reduce excessive intervention of brake assist in accordance with the amount of operation of the rear wheel brake lever.

[0073] (Item 5) The brake device according to any one of Items 1 to 4, characterized in that the first threshold is set to decrease as the amount of operation of the front wheel brake lever detected by the second detection unit increases, until the amount of operation of the front wheel brake lever reaches a second predetermined amount. According to this item, the larger the amount of operation of the front wheel brake lever, the easier it is to intervene (execute) brake assist corresponding to the amount of operation of the rear wheel brake lever, thereby increasing the braking force of the vehicle more effectively. Furthermore, when the amount of operation of the front wheel brake lever is relatively large, it is possible to further intervene (execute) brake assist corresponding to the amount of operation of the rear wheel brake lever.

[0074] (Item 6) The brake device according to Item 5, characterized in that the first threshold is set to a constant value after the amount of operation of the front wheel brake lever detected by the second detection unit reaches the second predetermined amount. According to this item, when the amount of operation of the front wheel brake lever is relatively large, it is possible to further intervene (execute) brake assist corresponding to the amount of operation of the rear wheel brake lever.

[0075] (Item 7) The brake device according to Item 5 or 6, characterized in that the first threshold is set to be greater than the ideal braking force distribution curve between the front and rear wheels of the vehicle until the amount of operation of the front wheel brake lever detected by the second detection unit reaches a second predetermined amount. According to this item, it is possible to intervene with brake assist early when the braking force distribution between the front and rear wheels is not appropriate, and to prevent excessive brake assist intervention when the braking force distribution is appropriate.

[0076] (Item 8) The brake device according to any one of Items 1 to 7, characterized in that the control unit controls the assist mechanism for each of the front and rear wheels of the vehicle so that the amount of brake assist is in line with the lock limit line. According to this item, the vehicle can be braked stably and effectively.

[0077] (Item 9) The brake device according to any one of Items 1 to 8, wherein the assist mechanism includes a front wheel assist mechanism that provides brake assist to the front wheels of the vehicle and a rear wheel assist mechanism that provides brake assist to the rear wheels of the vehicle, and the control unit controls the assist mechanism to perform the brake assist when the amount of operation of the rear wheel brake lever detected by the first detection unit exceeds the first threshold, and / or when the amount of operation of the front wheel brake lever detected by the second detection unit exceeds the second threshold. According to this item, brake assist can be performed appropriately based on the amount of operation of the front wheel brake lever and / or the amount of operation of the rear wheel brake lever.

[0078] (Item 10) The brake device according to Item 9, characterized in that the control unit starts the brake assist on the rear wheel using the rear wheel assist mechanism when the amount of operation of the front wheel brake lever detected by the second detection unit exceeds the second threshold, and then starts the brake assist on the front wheel using the front wheel assist mechanism after a predetermined period of time has elapsed. According to this item, it is possible to reduce the sudden application of braking force to the front wheel by the brake assist on the front wheel, which causes the vehicle body to tilt forward (i.e., changes in pitching).

[0079] (Item 11) The brake device according to Item 9 or 10, characterized in that when the amount of operation of the rear wheel brake lever detected by the first detection unit exceeds the first threshold, the control unit performs the brake assist only on the front wheel using the front wheel assist mechanism. According to this item, it is possible to reduce the driver's discomfort caused by excessive braking force on the rear wheel.

[0080] (Item 12) The brake device according to any one of Items 1 to 11, characterized in that the vehicle is a saddle-type vehicle. According to this item, in a saddle-type vehicle, appropriate brake assist can be performed in accordance with the driver's intention to operate the brakes.

[0081] (Item 13) The brake device according to any one of items 1 to 12, characterized in that the control unit records the distribution between the amount of operation of the rear brake lever detected by the first detection unit and the amount of operation of the front brake lever detected by the second detection unit, and sets the first threshold according to the record. According to this item, by making it possible to set a rear brake assist intervention threshold according to the rider's braking tendencies, it becomes possible to perform appropriate brake assist intervention for each rider.

[0082] (Item 14) The brake device according to Item 13, characterized in that the control unit controls the assist mechanism to execute the brake assist when the amount of operation of the front wheel brake operator detected by the second detection unit exceeds a second threshold, and further sets the second threshold according to the record. According to this item, by making it possible to set a front wheel brake assist intervention threshold according to the rider's brake operation tendency, it becomes possible to perform brake assist intervention that is more suitable to the operation preferences of each rider.

[0083] (Item 15) The brake device according to Item 13, characterized in that the vehicle has a setting input unit that accepts setting input from the occupant, and the control unit can correct the set first threshold in accordance with the setting input. According to this item, by making it possible to correct the rear wheel brake assist intervention threshold in accordance with the rider's setting input, it becomes possible to perform appropriate brake assist according to the driving conditions and the rider's preferences.

[0084] (Item 16) The brake device according to Item 15, characterized in that the control unit controls the assist mechanism to execute the brake assist when the amount of operation of the front wheel brake lever detected by the second detection unit exceeds a second threshold, and corrects the second threshold based on the first threshold corrected according to the setting input. According to this item, by correcting the second threshold in accordance with the correction of the first threshold, it becomes possible to maintain an appropriate ratio between the first threshold and the second threshold.

[0085] (Item 17) The brake device according to Item 13, characterized in that the vehicle has a means for detecting the driving environment, and the control unit corrects the first threshold based on the driving environment information obtained from the means for detecting the driving environment. According to this item, by making it possible to set a rear wheel brake assist intervention threshold according to the rider's braking operation tendencies, it becomes possible to perform appropriate brake assist intervention for each rider.

[0086] (Item 18) The brake device according to Item 17, characterized in that the control unit controls the assist mechanism to execute the brake assist when the amount of operation of the front wheel brake operator detected by the second detection unit exceeds a second threshold, and corrects the second threshold based on the driving environment information obtained from the driving environment detection means. According to this item, by making it possible to set a front wheel brake assist intervention threshold according to the rider's brake operation tendency, it becomes possible to execute appropriate brake assist intervention for each rider.

[0087] (Item 19) The brake device according to any one of Items 1 to 18, characterized in that the control unit acquires learning information on the amount of operation of at least the front wheel brake lever and sets the first threshold based on the learning information. According to this item, by learning the amount of brake operation during normal riding of the rider, the brake assist can be set to intervene early for riders who tend not to apply the brakes strongly, and to intervene at an appropriate timing for riders who can apply the brakes sufficiently.

[0088] (Item 20) A vehicle having a braking system as described in any one of Items 1 to 19. According to this item, a vehicle is provided that has a braking system capable of performing appropriate brake assist in accordance with the driver's intention to brake.

[0089] The invention is not limited to the embodiments described above, and various modifications and changes are possible within the scope of the gist of the invention.

[0090] This application claims priority based on Japanese Patent Application No. 2025-047225, filed on 21 March 2025, and all of its contents are incorporated herein by reference.

[0091] 106: Brake lever (front brake control), 119: Brake pedal (rear brake control), 130: Brake device, 4a: Lever operation amount sensor (second detection unit), 4b: Pedal operation amount sensor (first detection unit), 6: Assist mechanism, 6a: Front wheel assist mechanism, 6b: Rear wheel assist mechanism, 7: Control unit

Claims

1. A brake system for a vehicle, comprising: a rear wheel brake lever and a front wheel brake lever; a first detection unit for detecting the amount of operation of the rear wheel brake lever; a second detection unit for detecting the amount of operation of the front wheel brake lever; an assist mechanism for performing brake assist to increase the braking force of the vehicle; and a control unit for controlling the assist mechanism to perform brake assist for the vehicle when the amount of operation of the rear wheel brake lever detected by the first detection unit exceeds a first threshold, wherein the first threshold is set according to the amount of operation of the front wheel brake lever detected by the second detection unit.

2. The brake device according to claim 1, characterized in that the first threshold is set to decrease as the amount of operation of the front wheel brake lever detected by the second detection unit increases.

3. The brake device according to claim 1 or 2, characterized in that the first threshold is set such that, after the amount of operation of the front wheel brake lever detected by the second detection unit reaches a first predetermined amount, the threshold decreases as the amount of operation of the front wheel brake lever increases.

4. The brake device according to claim 3, characterized in that the first threshold is set to a constant value until the amount of operation of the front wheel brake lever detected by the second detection unit reaches a first predetermined amount.

5. The brake device according to any one of claims 1 to 4, characterized in that the first threshold is set to decrease as the amount of operation of the front wheel brake lever detected by the second detection unit increases, until the amount of operation of the front wheel brake lever detected by the second detection unit reaches a second predetermined amount.

6. The brake device according to claim 5, characterized in that the first threshold is set to a constant value after the amount of operation of the front wheel brake lever detected by the second detection unit reaches the second predetermined amount.

7. The brake device according to claim 5 or 6, characterized in that the first threshold is set to be greater than the ideal braking force distribution curve between the front and rear wheels of the vehicle until the amount of operation of the front wheel brake lever detected by the second detection unit reaches a second predetermined amount.

8. The brake device according to any one of claims 1 to 7, characterized in that the control unit controls the assist mechanism for each of the front and rear wheels of the vehicle so that the amount of brake assist is in line with the lock limit line.

9. The brake device according to any one of claims 1 to 8, wherein the assist mechanism includes a front wheel assist mechanism that provides brake assist to the front wheels of the vehicle and a rear wheel assist mechanism that provides brake assist to the rear wheels of the vehicle, and the control unit controls the assist mechanism to perform the brake assist when the amount of operation of the rear wheel brake operator detected by the first detection unit exceeds the first threshold and / or when the amount of operation of the front wheel brake operator detected by the second detection unit exceeds the second threshold.

10. The brake device according to claim 9, characterized in that the control unit starts the brake assist for the rear wheel using the rear wheel assist mechanism when the amount of operation of the front wheel brake lever detected by the second detection unit exceeds the second threshold, and then starts the brake assist for the front wheel using the front wheel assist mechanism after a predetermined period of time has elapsed thereafter.

11. The brake device according to claim 9 or 10, characterized in that when the amount of operation of the rear wheel brake lever detected by the first detection unit exceeds the first threshold, the control unit performs the brake assist only on the front wheel using the front wheel assist mechanism.

12. The brake device according to any one of claims 1 to 11, characterized in that the vehicle is a saddle-type vehicle.

13. The brake device according to any one of claims 1 to 12, characterized in that the control unit records the distribution between the amount of operation of the rear wheel brake lever detected by the first detection unit and the amount of operation of the front wheel brake lever detected by the second detection unit, and sets the first threshold according to the record.

14. The brake device according to claim 13, characterized in that the control unit controls the assist mechanism to execute the brake assist when the amount of operation of the front wheel brake lever detected by the second detection unit exceeds a second threshold, and further sets the second threshold according to the record.

15. The brake device according to claim 13, characterized in that the vehicle has a setting input unit that receives setting input from an occupant, and the control unit can correct the set first threshold in accordance with the setting input.

16. The brake device according to claim 15, characterized in that the control unit controls the assist mechanism to execute the brake assist when the amount of operation of the front wheel brake lever detected by the second detection unit exceeds a second threshold, and corrects the second threshold based on the first threshold corrected according to the setting input.

17. The brake device according to claim 13, wherein the vehicle has a means for detecting the driving environment, and the control unit corrects the first threshold value based on the driving environment information obtained from the means for detecting the driving environment.

18. The brake device according to claim 17, characterized in that the control unit controls the assist mechanism to execute the brake assist when the amount of operation of the front wheel brake operator detected by the second detection unit exceeds a second threshold, and corrects the second threshold based on the driving environment information obtained from the driving environment detection means.

19. The brake device according to any one of claims 1 to 18, characterized in that the control unit acquires learning information of the amount of operation of at least the front wheel brake lever and sets the first threshold based on the learning information.

20. A vehicle having the brake device according to any one of claims 1 to 19.

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