Patent Publication Number: US-2023141000-A1

Title: Straddle vehicle

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority from JP Patent Application Serial No. 2021-183299 filed on Nov. 10, 2021; the entire content of which is incorporated herein by reference. 
     FIELD 
     The present disclosure relates to a straddle vehicle having a brake lamp. 
     BACKGROUND 
     The patent literature 1 (JP Patent Application Laid-Open No. 2020-91671) discloses a straddle vehicle having a brake lamp and a speed controller. A speed controller adjusts the speed of the straddle-type vehicle in response to adaptive cruise control. The speed controller reduces speed of the straddle vehicle by actuating the brakes. The straddle vehicle has a warning device that warns when the warning device recognizes a possibility of colliding with a following vehicle. A brake lamp is disclosed as one example of the warning devices. 
     SUMMARY 
     The patent literature 1 discloses that the brake lamp is automatically turned on when a possibility of colliding with a following vehicle is recognized. However, the patent literature 1 does not disclose that the brake lamp is automatically turned on when a possibility of collision with the following vehicle cannot be recognized. Therefore, for example, when the speed controller deceases a speed of the straddle vehicle in a situation where the following vehicle is far from the straddle vehicle, the brake lamp does not turn on. In other words, there is a possibility that turning on or not of the brake lamp is different between when a driver actuates the brake and when the speed controller actuates the brake. In particular, downsizing, low cost, or the like are strongly demanded in a straddle vehicle, it is desirable to achieve above functions with a simple circuit configuration. 
     The present disclosure relates a straddle vehicle that turns on a brake lamp when a brake is automatically actuated as when a brake is manually actuated. 
     According to the aspect of the present disclosure, a straddle vehicle having the following configuration is provided. That is, the straddle vehicle includes a brake lamp, a brake operation unit, a first switching unit, a second switching unit, and a brake controller. The brake lamp turns on by supply of a driving current. The brake operation unit receives a brake operation. The first switching unit that is switched a circuit state so that the driving current is supplied to the brake lamp while the brake operation is being performed. 
     The second switching unit is switched a circuit state between a closed state in which the driving current is supplied to the brake lamp regardless of the brake operation and an opened state in which the second switching unit is not electrically connected with the brake lamp. The brake controller that controls to actuates a brake and switches the second switching unit from the opened state to the closed state when a brake activation condition is met. 
     According to the present application, a straddle vehicle that turns on a brake lamp when a brake is automatically actuated as when a brake is manually actuated is provided. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         FIG.  1    is a side view of a motorcycle according to this embodiment. 
         FIG.  2    is a block diagram for performing a vehicle speed control. 
         FIG.  3    is a circuit diagram showing a switch from a circuit state in which a brake lamp is off due to no brake operation to a circuit state in which the brake lamp is on by ACC brake. 
         FIG.  4    is a circuit diagram showing a switch from a circuit state in which a brake lamp is on due to a brake operation to a circuit state in which the brake lamp is off by ESS. 
         FIG.  5    is a circuit diagram showing a switch from a circuit state in which a brake lamp is off to a circuit state in which the brake lamp is on by ACC brake. 
         FIG.  6    is a timing chart of a turning off check process and a turning on check process. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, this embodiment a motorcycle  1 , which is an example of a straddle vehicle will be described with reference to the drawings. 
     In descriptions below, the left-right direction of the motorcycle  1  is defined based on the view from a rider riding on the motorcycle  1 . Therefore, the front-rear direction coincides with a vehicle length direction, and the left-right direction coincides with a vehicle width direction. The vertical direction and the up-down direction coincide with a height direction. As shown in  FIG.  1   , the motorcycle  1  includes a vehicle body  10 , a front wheel  11 , and a rear wheel  12 . 
     The vehicle body  10  includes a plurality of the vehicle body frames serving as a framework of the motorcycle  1 . Various components constituting the motorcycle  1  are attached to these body frames. An engine  13  is provided in vicinity of a center in the vehicle length direction of the vehicle body  10 . The engine  13  is a drive source for driving the motorcycle  1 . The engine  13  of this embodiment is a gasoline engine. Instead of or in addition to the gasoline engine, another driving source, for example, an electric motor for traveling may be provided. Power generated by the engine  13  is transmitted to the rear wheel  12  via a drive chain. This makes it possible to drive the motorcycle  1 . The drive source may be omitted and power may be generated by pedaling of the rider. 
     The front wheel  11  is rotatably attached to the vehicle body  10  via an axle. A front brake device  14  is attached to the front wheel  11 . The front brake device  14  includes a front brake disc  14   a  and a front brake caliper  14   b.  The front brake disc  14   a  rotates integrally with the front wheel  11 . The front brake caliper  14   b  is attached not to the front wheel  11  side but to the vehicle body  10  side, so that even if the front brake disc  14   a  rotates, the front brake caliper  14   b  does not rotate. The front brake caliper  14   b  can switch between a state in which the brake pad is pressed against the front brake disc  14   a  and a state in which the brake pad is separated from the front brake disc  14   a.  A braking force is generated by pressing the brake pad against the front brake disc  14   a.    
     The rear wheel  12  is rotatably attached to the vehicle body  10  via an axle. A rear brake device  15  is attached to the rear wheel  12 . The rear brake device  15  includes a rear brake disc  15   a  and a rear brake caliper  15   b.  The rear brake disc  15   a  rotates integrally with the rear wheel  12 . The rear brake caliper  15   b  is attached not to the rear wheel  12  side but to the vehicle body  10  side, so that even if the rear brake disc  15   a  rotates, the rear brake caliper  15   b  does not rotate. The rear brake caliper  15   b  can switch between a state in which the brake pad is pressed against the rear brake disc  15   a  and a state in which the brake pad is separated from the rear brake disc  15   a.  A braking force is generated by pressing the brake pad against the rear brake disc  15   a.    
     A front fork  16  is attached to the vehicle body frame. A pair of left and right front forks  16  are provided so as to sandwich the front wheel  11  in a front view. A handle unit  17  is provided near the upper end of the front fork  16 . The handle unit  17  includes a steering handle  17   a,  a brake lever  17   b,  and various switches. 
     The steering handle  17   a  is a bar handle type and an operating tool that is gripped by the rider for steering. When the rider rotates the steering handle  17   a  about a steering shaft, the front fork  16  and the front wheel  11  rotate. This makes it possible to turn to change a travel direction of the motorcycle  1 . The motorcycle  1  is a lean vehicle in which the vehicle body  10  is tilted toward the turning center with respect to a road surface when turning. 
     The brake lever  17   b  is an operation tool for actuating the front brake device  14 . The brake lever  17   b  is a brake operation unit. The rider performs a brake operation by gripping the brake lever  17   b.  The rider performs the brake operation to the brake lever  17   b,  and therefore a brake fluid is supplied to the front brake caliper  14   b  via a brake hose. A braking force is generated by pressing the brake pad against the front brake disc  14   a.    
     A fuel tank  20  is provided behind the handle unit  17  and above the engine  13 . The fuel tank  20  stores fuel to be supplied to the engine  13 . A seat  21  on which the rider sits is provided behind the fuel tank  20 . Steps  18  are provided on the left side and the right side of the vehicle body  10 , respectively. The rider straddles the seat  21  and places his/her feet on the left and right steps  18 . In this way, the rider sits across the seat  21 , so the motorcycle  1  is a straddle vehicle. 
     A brake pedal  19  is arranged in front of the step  18  on the right side. The brake pedal  19  is a brake operation unit. The rider performs a brake operation by treading the brake pedal  19  with the foot. The rider performs the brake operation to the brake pedal  19 , and therefore a brake fluid is supplied to the rear brake caliper  15   b  via a brake hose. A braking force is generated by pressing the brake pad against the rear brake disc  15   a.    
     The brake configuration described above is an example and may differ from this embodiment. For example, the braking device is not limited to disc brakes and may be drum brakes. The brake caliper may be actuated by wires instead of the brake fluid. The brake pedal  19  may be omitted and both the front and rear brakes may be actuated by the brake lever  17   b.    
     A brake lamp  22  is arranged at the rear part of the motorcycle  1 . When the rider or a brake controller  32 , which will be described later, actuate the brake, the brake lamps  22  are turned on. The light source of the brake lamp  22  may be a light bulb using a filament or may be an LED. 
     A radar device  23  for detecting forward is arranged at the front end or near thereof of the motorcycle  1 . The radar device  23  detects distance and to one or more objects in front and speed of the objects by transmitting detection waves forward and acquiring reflected waves reflected by the objects. The detection waves transmitted by the radar device  23  are electromagnetic waves, specifically infrared rays, millimeter waves, or microwaves. The motorcycle  1  notifies the rider of information about the detected objects and controls the speed of the motorcycle  1  based on the detection result of the radar device  23 . 
     Next, a vehicle speed control of the motorcycle  1  will be described with reference to  FIG.  2   . 
     As shown in  FIG.  2   , the motorcycle  1  includes an engine controller  31 , a brake controller, and various sensors. Each device can transmit and receive data by CAN communication, for example. Instead of the CAN communication, data may be transmitted and received by connecting each device with an individual signal line. The sensors are the radar device  23  and the vehicle speed sensor  33 , for example. The vehicle speed sensor  33  is a sensor that detects the vehicle speed based on the number of rotations of the front wheel  11 , for example. 
     The engine controller  31  includes an arithmetic unit such as a CPU, and a storage device such as a RAM and a storage. The engine controller  31  performs various controls related to the engine  13  by executing a program stored in the storage device by the arithmetic unit. Specifically, the engine controller  31  controls ignition timing, valve opening/closing timing, fuel injection amount, or the like. For example, the engine controller  31  can accelerate the motorcycle  1  by increasing the fuel injection amount. 
     The brake controller  32  includes an arithmetic unit such as a CPU, and a storage device such as a RAM and a storage. The brake controller  32  performs various controls related to the break by executing a program stored in the storage device by the arithmetic unit. Specifically, the brake controller  32  controls the brake actuator  34  to actuate the brake when the brake controller  32  determines that a brake activation condition is met. The brake actuator  34  is a pump in this embodiment and is a device for feeding brake fluid to at least one of the front brake device  14  and the rear brake device  15 . The brake actuator  34  may be a device that generates a mechanical pressing force. 
     The brake activation condition is a condition for actuating the brake by the brake controller  32 . For example, when a command to reduce the vehicle speed is received from the engine controller  31 , the brake activation condition is met. The brake activation condition may include a condition that a distance from a preceding vehicle is equal to or less than a threshold. 
     The motorcycle  1  can perform adaptive cruise control (ACC control). The adaptive cruise control is control in which the distance from the preceding vehicle keeps constant by accelerating or decelerating the motorcycle  1  within a predetermined vehicle speed range. Specifically, the radar device  23  calculates the acceleration for maintaining the distance between the motorcycle  1  and the preceding object based on the distance to the preceding object and the speed of the preceding object. In the following explanation, a wording “acceleration” includes not only acceleration, but also deceleration. The radar device  23  requests the calculated acceleration from the brake controller  32 . The brake controller  32  calculates braking force and engine torque for achieving the acceleration requested by the radar device  23 . The brake controller  32  calculates torque engine brake torque instead of the engine torque when the motorcycle  1  is decelerating. The brake controller  32  controls pressure of the brake fluid by using the pump described above so that the calculated brake force is generated. Further, the brake controller  32  requests the calculated engine torque or engine brake torque from the engine controller  31 . The engine controller  31  controls the engine  13  so that the engine torque or the engine brake torque requested by the brake controller  32  is archived. The adaptive cruise control is performed as described above. 
     The brake controller  32  can also perform ABS control. ABS stands for Anti-lock Braking System. The ABS control is control that prevents locking of the front wheel  11  and the rear wheel  12  when the brake is actuated. The brake controller  32  estimates slip conditions of the front wheel  11  and the rear wheel  12  based on information input from wheel sensors or the like. The brake controller  32  actuates the brake actuator  34  depending on the slip conditions of the front wheel  11  and the rear wheel  12  to pressurize or depressurize the brake fluid, thereby preventing the front wheel  11  and the rear wheel  12  from locking and to brake the motorcycle  1 . 
     The brake controller  32  can also perform ESS. ESS stands for Emergency Stop Signal. Specifically, when the rider actuates heavy brake, the brake controller  32  turns on the brake lamp  22  to notify the following vehicle of the matter. 
     Next, a circuit configuration for turning on and off the brake lamp  22  will be described with reference to from  FIG.  3    to  FIG.  5   . In  FIG.  3    to  FIG.  5   , thick lines indicate current flowing portions. ACC brake is a brake actuated in the adaptive cruise control. 
     As shown in  FIG.  3   , a battery  41 , a first input unit  42 , a second input unit  43 , a first switching unit  44 , and a relay assembly  45  are provided. The relay assembly  45  includes a second switching unit  45   a  and a third switching unit  45   b.  The second switching unit  45   a  and the third switching unit  45   b  are relays that switch the opened/closed state of the circuit according to the current signal. 
     The battery  41  stores electric power generated using the power of the engine  13  of the motorcycle  1 . The electrical components of the motorcycle  1  are electrically connected to the battery  41  and actuated by the electric power of the battery  41 . The battery  41  is electrically connected to the first input unit  42  and the second input unit  43 . 
     A circuit for supplying driving current to the brake lamps  22  is connected to each of the first input unit  42  and the second input unit  43 . The driving current is a current for turning on the brake lamp  22 . By electrically connecting the battery  41  and the brake lamp  22 , the driving current is supplied from the battery  41  to the brake lamp  22  to turn on the brake lamp  22 . 
     A circuit connected to the first input unit  42  is connected to the brake lamp  22  through the second switching unit  45   a.  Therefore, when the second switching unit  45   a  is in the closed state, the driving current is supplied to the brake lamp  22  and the brake lamp  22  is turned on. When the second switching unit  45   a  is in the opened state, the second switching unit  45   a  and the brake lamp  22  are not electrically connected and the driving current is not supplied to the brake lamp  22  via the second switching unit  45   a.    
     The opened/closed state of the second switching unit  45   a  is controlled by the brake controller  32 . The brake controller  32  includes a first switch  32   a.  The brake controller  32  can switch the opened/closed state of the first switch  32   a.  The first switch  32   a  is connected to the second input unit  43  via a coil of the second switching unit  45   a.  Therefore, the brake controller  32  can switch the opened/closed states of the second switching unit  45   a  by switching the opened/closed states of the first switch  32   a.    
       FIG.  3    shows that the second switching unit  45   a  is switched from the opened state to the closed state and the driving current is supplied to the brake lamp  22  by switching the first switch  32   a  from the opened state to the closed state by the brake controller  32 . In other words, the brake lamp  22  can be turned on by the control of the brake controller  32  regardless of the brake operation to the brake operation unit. 
     When the brake controller  32  determines that the brake activation condition is met, the brake controller  32  actuates the brake by the brake actuator  34  and switches the first switch  32   a  to the closed state to turn on the brake lamp  22 . Since the second switching unit  45   a  is a relay, it is possible to switch between supply and non-supply of the driving current without performing control system communication. The second switching unit  45   a  is not limited to a relay, and may be a switching element that receives a signal of the control system and switches between opened/closed states. 
     A condition for switching the first switch  32   a  to the closed state may be added. For example, in addition to meet the brake activation condition, a condition in which deceleration exceeds a first threshold may be added. As a result, the brake lamp  22  is not turned on when the deceleration is low, and the brake lamp  22  is turned on when the deceleration is high. 
     A circuit connected to the second input unit  43  is connected to the brake lamp  22  through the third switching unit  45   b  and the first switching unit  44 . Therefore, when the third switching unit  45   b  and the first switching unit  44  are closed state, the driving current is supplied to the brake lamp  22  and the brake lamp  22  is turned on. When at least one of the third switching unit  45   b  and the first switching unit  44  is in the opened state, the driving current is not supplied to the brake lamp  22  via the first input unit  42 . Since a circuit from the first input unit  42  to the brake lamp  22  and a circuit from the second input unit  43  to the brake lamp  22  are independent, the driving current can be supplied via either one of them and the brake lamp  22  is turned on. 
     The opened/closed states of the third switching unit  45   b  is controlled by the brake controller  32 , like the second switching unit  45   a.  The brake controller  32  includes a second switch  32   b.  The brake controller  32  can switch the opened/closed state of the second switch  32   b.  The second switch  32   a  is connected to the second input unit  43  via a coil of the third switching unit  45   b.  Therefore, the brake controller  32  can switch the opened/closed states of the third switching unit  45   b  by switching the opened/closed states of the second switch  32   b.    
     The first switching unit  44  is switched between the opened/closed state depending on whether or not the brake operation is performed to the brake operation unit. Specifically, the first switching unit  44  includes two switches arranged in parallel. Each switch actuates in conjunction with the brake lever  17   b  and the brake pedal  19 . That is, one switch of the first switching unit  44  is closed state while the brake operation is performed to the brake lever  17   b.  The other switch of the first switching unit  44  is closed state while the brake operation is performed to the brake pedal  19 . In other words, the first switching unit  44  is closed state while the brake operation is performed to at least one of the brake operation units. 
     Therefore, the brake lamp  22  is turned on by the brake operation to the brake operation units while the brake controller  32  controls the third switching unit  45   b  to be the closed state. While the brake controller  32  controls the third switching unit  45   b  to be the opened state, the brake lamp  22  is turned off regardless of the operation of the brake operation units. 
       FIG.  4    shows that the third switching unit  45   b  is switched from the closed state to the opened state and the supply of the driving current to the brake lamp  22  is stopped by switching the second switch  32   b  from the opened state to the closed state by the brake controller  32 . In other words, the brake lamp  22  can be turned off by the control of the brake controller  32  even while the brake operation is being performed to the brake operation units. 
     When the brake controller  32  determines that the turning off condition is met, the brake controller  32  turns off the brake lamp  22  by switching the third switching unit  45   b  to the open state. In this embodiment, the turning off condition about the ESS described above is set. In other words, the brake controller  32  blinks the brake lamp  22  by continuously switching the state of the third switching unit  45   b  when the brake controller  32  determines that the rider actuates heavy brake. That is, the turning off condition is that the deceleration of the motorcycle  1  exceeds the second threshold. The second threshold is a value greater than the first threshold described above. Other turning off condition may be set. 
     The brake controller  32  includes a detection switch  32   c.  The detection switch  32   c  is electrically connected between the second switching unit  45   a  and the brake lamp  22 , and electrically connected between the first switching unit  44  and the brake lamp  22 . Therefore, in a situation where the driving current is supplied to the brake lamp  22 , the current is also supplied to the detection switch  32   c.  The brake controller  32  can detect whether or not the driving current is supplied to the brake lamp  22  based on the current detection result by the detection switch  32   c.    
     As described above, the brake lamp  22  is turned on by supplying the driving current via the first input unit  42  or the second input unit  43 . Therefore, as shown in  FIG.  5   , even if the brake controller  32  makes the third switching unit  45   b  be the opened state, the brake lamp  22  is turned on by switching the second switching unit  45   a  to the closed state by the brake controller  32 . In other words, in this embodiment, when the process of turning on the brake lamp  22  and the process of turning off the brake lamp  22  are performed at the same time, the brake lamp  22  is turned on. 
     Next, a method for checking a turning off function of the brake lamp  22  by the ESS and a turning on function of the brake lamp  22  by the ACC of the brake controller  32  will be described. In the following description, processes of checking turning off function will be referred to as turning off check process, and processes of checking the turning on function will be referred to as turning on check process. 
     The turning off check process and the turning on check process are automatically performed when electrical system is started. The starting time of the electrical system is timing when electric power is supplied to the electrical components of the motorcycle  1 . The motorcycle  1  of this embodiment performs a turning off check process and the turning on check process at the timing when the power-off state is switched to the ignition-on state. When an ignition power supply and an accessory power supply are separated, the turning off check process and the turning on check process may be performed at the timing when being switched to the accessory-on state. 
     It is supposed that the rider checks results of the turning off check process and the turning on check process. Therefore, an example in which the rider checks will be described below. However, a person other than the rider, for example, a maintenance worker may check it. 
     The rider switches to the ignition-on state while performing the brake operation (time T 1 ). Since the rider is performing the brake operation, the brake lamp  22  is turned on by switching to the ignition-on state. 
     Next, the brake controller  32  repeats the process of turning off the brake lamp  22  by switching the third switching unit  45   b  to the opened state (from time T 2  to time T 3 ). As a result, the brake lamp  22  blinks. The rider can confirm that the turning off function is normal by confirming that the brake lamp  22  is turned off. Furthermore, the rider can also confirm that a blinking function is normal by confirming that the brake lamp  22  blinks. 
     The motorcycle  1  may determine that the turning off function and the blinking function are normal instead of the rider. The brake controller  32  can detect whether or not the brake lamp  22  is turned on or off because the brake controller  32  includes the detection switch  32   c.  when the brake controller  32  detects that the brake lamp  22  is switched between a turning on and a turning off from time T 2  to time T 3 , the brake controller  32  determines that the turning off function and the blinking function are normal. 
     Next, the brake controller  32  switches the second switching unit  45   a  from the opened state to the closed state to turn on the brake lamp  22  in a situation where the third switching unit  45   b  is kept opened state to turn off the brake lamp  22  (time T 4 ). As described above, the brake lamp  22  is turned on when both the process of turning off the brake lamp  22  and the process of turning on the brake lamp  22  are performed by the brake controller  32 . The rider can confirm that the turning on function is normal by confirming that the brake lamp  22  blinks, is turned off, and is turned on. 
     The motorcycle  1  may determine that the turning on function is normal instead of the rider. When the brake controller  32  detects that the brake lamp  22  is switched from off to on at time T 4 , the brake controller  32  determines that the turning on function is normal. 
     Next, the brake controller  32  switched the second switching unit  45   a  back to the opened state and the third switching unit  45   b  back to the closed state. Thus, in this embodiment, the turning off check process and the turning on check process can be performed in a series of processes. 
     In this embodiment, the turning on check process is performed in a situation where the brake controller  32  turns off the brake lamp  22 . Therefore, even if the rider is performing the brake operation, the turning on check process can be performed without any problem since the brake lamp  22  is turned off. 
     The turning off check process and the turning on check process may be performed separately. The motorcycle  1  perform only one of the turning off check process and the turning on check process. The motorcycle  1  may perform the turning off check process or the turning on check process in response to an indication of the rider instead of the timing of the ignition-on. Alternatively, the turning off check process and the turning on check process may be performed only when the ignition is switched to on while the rider is performing the brake operation. 
     As described above, the motorcycle  1  of this embodiment includes the brake lamp  22 , the brake operation unit, the first switching unit  44 , the second switching unit  45   a,  and the brake controller  32 . The brake lever  17   b  and the brake pedal  19  correspond to the brake operation unit. The brake lamp  22  turns on by supplying the driving current. The brake operation unit receives the brake operation. The first switching unit  44  is switched the circuit state so that the driving current is supplied to the brake lamp  22  while the brake operation is being performed. The second switching unit  45   a  is switched the circuit state between the closed state in which the driving current is supplied to the brake lamp  22  regardless of the brake operation and the opened state in which the second switching unit  45   a  is not electrically connected with the brake lamp  22 . The brake controller  32  controls to actuate the brake and switches the second switching unit  45   a  from the opened state to the closed state when the brake activation condition is met. 
     Accordingly, when the brake controller  32  actuates the brake, the brake lamp  22  can be turned on in the same manner as when the rider performs the brake operation. The circuit configuration can be simplified because two electrical systems for turning on the brake lamp  22  can be achieved simply by switching the circuit state. 
     The second switching unit  45   a  of the motorcycle  1  of this embodiment is a relay. The brake controller  32  switches the circuit state of the second switching unit  45   a  by supplying the current to the second switching unit  45   a.    
     Accordingly, the second switching unit  45   a  can be switched without performing the control system communication. 
     The motorcycle  1  of this embodiment performs the adaptive cruise control that is a control for automatically adjusting the distance between the motorcycle  1  and the preceding vehicle. The brake activation condition that is determined by the brake controller  32  includes the condition in which the distance between the motorcycle  1  and the preceding vehicle is equal to or less than the threshold in the adaptive cruise control. 
     Accordingly, the brake lamp  22  can be turned on during actuating the brake by adaptive cruise control. 
     In the motorcycle  1  of this embodiment, the brake controller  32  performs the turning on check process in which the brake controller  32  switches the second switching unit  45   a  from the opened state to the closed state in order to check whether the function of turning on the brake lamp  22  by the brake controller  32  is normal or not. 
     Accordingly, turning on the brake lamp  22  by the brake controller  32  can be checked. 
     In the motorcycle  1  of this embodiment, the brake controller  32  automatically performs the turning on check process when the electrical system is started. 
     This allows for easily checking the function of turning on because the user needs not to instruct the turning on check process. 
     The motorcycle  1  of this embodiment includes the third switching unit  45   b.  The third switching unit  45   b  is switched the circuit state between the closed state in which the driving current is supplied to the brake lamp  22  by the brake operation and the opened state in which the driving current is not supplied to the brake lamp  22  even if the brake operation is performed. When the brake controller  32  determines that the turning off condition is met, the brake controller  32  turns off the brake lamp  22  by switching the third switching unit  45   b  from the closed state to the opened state. 
     Accordingly, the brake lamp  22  can be turned off by the process of the brake controller  32  even while performing the brake operation. 
     In the motorcycle  1  of this embodiment, the brake controller  32  performs the turning off check process in which the brake controller  32  switches the third switching unit  45   b  from the closed state to the opened state in order to check whether the function of turning off the brake lamp  22  by the brake controller  32  is normal or not. 
     Accordingly, turning off the brake lamp  22  by the brake controller  32  can be checked. 
     The motorcycle  1  of this embodiment includes the third switching unit  45   b.  The brake controller  32  performs the turning off check process and the turning on check process. 
     Accordingly, both of the process of turning on the brake lamp  22  by the brake controller  32  and the process of turning off the brake lamp  22  by the brake contro 11 er 32  can be checked 
     In the motorcycle  1  of this embodiment, after the brake controller  32  switches the third switching unit  45   b  to the opened state during the brake operation is performed, and the brake controller  32  switches the second switching unit  45   a  from the opened state to the closed state while maintaining the opened state of the third switching unit  45   b.    
     As a result, both of the process of turning on the brake lamp  22  and the process of turning off the brake lamp  22  can be checked that these processes are normal if it is confirmed that the brake lamp  22  is switched in the order of turning on, turning off, and turning on. In other words, two functions can be checked simply by performing a series of processes. 
     Although a preferred embodiment of the present invention has been described above, the configuration above can be modified, for example, as follows. 
     The circuit diagram shown in the drawings is an example and may be a different circuit configuration. For example, the function of turning off the brake lamp  22  may be omitted by omitting the third switching unit  45   b.    
     Although the second switching unit  45   a  and the third switching unit  45   b  are provided in one relay assembly  45  in the above embodiment, they may be provided separately. 
     In the above embodiment, the radar device  23  is used as an example of a forward detection device, but a sonar device or a camera may be used. 
     In the above embodiment, the motorcycle  1  was described as an example of the straddle vehicle, but straddle vehicles other than the motorcycle  1 , such as a straddle vehicle having two front wheels and one rear wheel or a straddle vehicle having one front wheel and two rear wheels can be applied the configuration of this embodiment.