Patent Application
20230373452
The present disclosure relates to a hydraulic pressure control unit capable of accurately estimating a stroke amount of an armature of an electromagnetic valve.
Conventionally, as a behavior control system for controlling behavior of a vehicle such as a motorcycle, there is a system using a hydraulic pressure control unit that controls a hydraulic pressure generated in a hydraulic fluid. In the hydraulic pressure control unit, the hydraulic pressure generated in the hydraulic fluid is controlled by operating an electromagnetic valve that is provided to a channel for the hydraulic fluid.
Here, in order to cause the electromagnetic valve, which opens/closes the channel, to function appropriately, a stroke amount of an armature as a movable section in the electromagnetic valve has to be optimized. Accordingly, in order to optimize the stroke amount of the armature, a technique of estimating the stroke amount of the armature has been proposed (for example, see JP2019172015A).
However, it is unclear whether the stroke amount of the armature of the electromagnetic valve can accurately be estimated by the conventional technique related to the hydraulic pressure control unit. In other words, a new proposal for a mechanism that estimates the stroke amount of the armature is desired.
The present invention has been made in view of the above-described problem as the background and therefore obtains a hydraulic pressure control unit capable of accurately estimating a stroke amount of an armature of an electromagnetic valve.
A hydraulic pressure control unit according to the present invention is a hydraulic pressure control unit used for a behavior control system of a vehicle, and includes: a hydraulic pressure control mechanism that includes a base body and components that include an electromagnetic valve assembled in the base body for controlling a hydraulic pressure generated in a hydraulic fluid for the behavior control system; and a controller that includes a control section controlling operation of the components. The electromagnetic valve includes a wire and an armature that moves in association with application of a current to the wire, and is a valve that is closed or a valve that is opened in an energized state where the current is applied to the wire. The controller includes an estimation section that estimates a stroke amount of the armature. The estimation section estimates the stroke amount on the basis of a reduced amount of a current value at a time when the current value is temporarily reduced in a process that the current value of the current flowing through the wire is increased toward a target current value at beginning of the application of the current to the wire.
In the hydraulic pressure control unit according to the present invention, the controller includes the estimation section that estimates the stroke amount of the armature of the electromagnetic valve. The estimation section estimates the stroke amount on the basis of the reduced amount of the current value at the time when the current value is temporarily reduced in the process that the current value of the current flowing through the wire is increased toward the target current value at beginning of application of the current to the wire of the electromagnetic valve. In this way, it is possible to appropriately estimate the stroke amount of the armature by focusing on a phenomenon that a counter-electromotive force is generated to the wire in association with movement of the armature. Therefore, it is possible to accurately estimate the stroke amount of the armature of the electromagnetic valve.
A description will hereinafter be made on a hydraulic pressure control unit according to the present invention with reference to the drawings.
A description will hereinafter be made on the hydraulic pressure control unit that is used for a brake system of a two-wheeled motorcycle (see a vehicle 100 in
A description will hereinafter be made on a case where one front-wheel brake mechanism and one rear-wheel brake mechanism are provided (see a front-wheel brake mechanism 12 and a rear-wheel brake mechanism 14 in
A configuration, operation, and the like, which will be described below, constitute merely one example, and the hydraulic pressure control unit according to the present invention is not limited to a case with such a configuration, such operation, and the like.
The same or similar description will appropriately be simplified or will not be made below. In the drawings, the same or similar members or portions will not be denoted by a reference sign or will be denoted by the same reference sign. A detailed structure will appropriately be illustrated in a simplified manner or will not be illustrated.
A description will be made on a configuration of the vehicle 100 according to an embodiment of the present invention with reference to
The vehicle 100 is a two-wheeled motorcycle that corresponds to an example of the vehicle according to the present invention. As illustrated in
As illustrated in
The first brake operation section 11 is provided to the handlebar 2 and is operated by the rider's hand. The first brake operation section 11 is a brake lever, for example. The second brake operation section 13 is provided to a lower portion of the trunk 1 and is operated by the rider's foot. The second brake operation section 13 is a brake pedal, for example. However, like a brake operation section of a scooter or the like, each of the first brake operation section 11 and the second brake operation section 13 may be a brake lever that is operated by the rider's hand.
Each of the front-wheel brake mechanism 12 and the rear-wheel brake mechanism 14 includes: a master cylinder 21 in which a piston (not illustrated) is installed; a reservoir 22 that is attached to the master cylinder 21; a brake caliper 23 that is held by the trunk 1 and has a brake pad (not illustrated); a wheel cylinder 24 that is provided to the brake caliper 23; a primary channel 25 through which a brake fluid in the master cylinder 21 flows into the wheel cylinder 24; a secondary channel 26 through which the brake fluid in the wheel cylinder 24 is released; and a supply channel 27 through which the brake fluid in the master cylinder 21 is supplied to the secondary channel 26.
Each of the front-wheel brake mechanism 12 and the rear-wheel brake mechanism 14 is provided with an electromagnetic valve 31 for controlling a hydraulic pressure generated in the brake fluid as a hydraulic fluid. In an example illustrated in
The inlet valve 31a is provided to the primary channel 25. The secondary channel 26 bypasses a portion of the primary channel 25 between the wheel cylinder 24 side and the master cylinder 21 side of the inlet valve 31a. The secondary channel 26 is sequentially provided with the outlet valve 31b, an accumulator 32, and a pump 33 from an upstream side. The first valve 31c is provided between an end on the master cylinder 21 side of the primary channel 25 and a portion of the primary channel 25 to which a downstream end of the secondary channel 26 is connected. The supply channel 27 communicates between the master cylinder 21 and a portion of the secondary channel 26 on a suction side of the pump 33. The second valve 31d is provided to the supply channel 27.
The inlet valve 31a is the electromagnetic valve 31 that is opened in an unenergized state and is closed in an energized state, for example. The outlet valve 31b is the electromagnetic valve 31 that is closed in the unenergized state and opened in the energized state, for example. The first valve 31c is the electromagnetic valve 31 that is opened in the unenergized state and is closed in the energized state, for example. The second valve 31d is the electromagnetic valve 31 that is closed in the unenergized state and is opened in the energized state, for example.
The hydraulic pressure control unit 5 includes: a hydraulic pressure control mechanism 51 that includes a part of the front-wheel brake mechanism 12 and a part of the rear-wheel brake mechanism 14 described above; and a controller (ECU) 52 that controls operation of the hydraulic pressure control mechanism 51.
The hydraulic pressure control mechanism 51 includes: a base body 51a; and components that are assembled in the base body 51a and include the electromagnetic valves 31 for controlling the hydraulic pressure generated in the brake fluid as the hydraulic fluid in the brake system 10. The component means an element such as a part that is assembled in the base body 51a.
The base body 51a has a substantially rectangular-parallelepiped shape and is formed of a metal material, for example. In the base body 51a of the hydraulic pressure control mechanism 51, the primary channels 25, the secondary channels 26, and the supply channels 27 are formed, and the electromagnetic valves 31 (more specifically, the inlet valves 31a, the outlet valves 31b, the first valves 31c, and the second valves 31d), the accumulators 32, and the pumps 33 are assembled as the components therein. As will be described below, operation of each of these components is controlled by the controller 52 of the hydraulic pressure control unit 5. The base body 51a may be formed of one member or may be formed of plural members. In the case where the base body 51a is formed of plural members, the components may separately be provided in the plural members.
A description will hereinafter be made on a detailed configuration of the electromagnetic valve 31 that is provided to the hydraulic pressure control unit 5 with reference to
As illustrated in
The armature 312 corresponds to a movable section that can reciprocate relative to the case 311 in the case 311. The armature 312 has a substantially cylindrical shape, for example. The armature 312 is arranged in an internal space that is formed in the case 311, and can reciprocate along an axial direction of the armature 312. The tappet 313 is fixed to the armature 312 and can move integrally with the armature 312. For example, the tappet 313 is a solid rod member that has a circular cross-sectional shape, and is fitted and fixed to an inner circumferential section of the armature 312.
The wire 314 is fixed to the case 311, and generates a magnetic field when being applied with a current. For example, the wire 314 is provided in a manner to surround the internal space of the case 311 along a circumferential direction of the armature 312. The core 315 is an iron core that is magnetized by the magnetic field generated by the wire 314, and has a substantially cylindrical shape, for example. In the internal space of the case 311, the core 315 is coaxially arranged with the armature 312, and the tappet 313 is inserted through an inner circumferential section of the core 315. When the core 315 is magnetized, a magnetic force in a direction to approach the core 315 acts on the armature 312. In this way, the armature 312 moves in association with application of the current to the wire 314.
The spring 316 urges the armature 312 in a direction away from the core 315. For example, in the internal space of the case 311, the spring 316 is provided in a manner to be held between an inner circumferential section of the case 311 and an end surface of the armature 312 on the core 315 side.
The first channel 317 and the second channel 318 are formed in the case 311 and each form a part of the primary channel 25, the secondary channel 26, or the supply channel 27 provided with the electromagnetic valve 31. In addition, in the case 311, the first channel 317 and the second channel 318 are mutually connected via a space where a tip of the tappet 313 is accommodated.
In the electromagnetic valve 31 (more specifically, the inlet valve 31a and the first valve 31c) that is closed in the energized state, in a state where the current is not applied to the wire 314 (that is, the unenergized state), as indicated by a solid line in
Meanwhile, in a state where the current is applied to the wire 314 (that is, in the energized state), the armature 312 is attracted to the core 315 side with the tappet 313 by the magnetic force generated between the magnetized core 315 and the armature 312, and is held at a position indicated by a two-dot chain line in
In the electromagnetic valve 31 that is opened in the energized state (more specifically, the outlet valve 31b and the second valve 31d), in the unenergized state, as indicated by the two-dot chain line in
As illustrated in
A description will hereinafter be made on a detailed configuration of the current sensor 41 that is provided to the hydraulic pressure control unit 5 with reference to
As illustrated in
The shunt resistor 411 is connected in series to the wire 314 of the electromagnetic valve 31 that is connected to a power supply 7 such as a secondary battery. Electric power is supplied from the power supply 7 to the wire 314 of the electromagnetic valve 31. The operational amplifier 412 is connected in parallel with the shunt resistor 411 and amplifies a difference in voltage generated at both ends of the shunt resistor 411 to output. The current sensor 41 detects the current value of the current flowing through the wire 314 of the electromagnetic valve 31 on the basis of a resistance value of the shunt resistor 411 and an output value of the operational amplifier 412.
As illustrated in
The controller 52 in the hydraulic pressure control unit 5 controls the operation of the above-described components that are assembled in the base body 51a of the hydraulic pressure control mechanism 51. For example, the controller 52 is partially or entirely constructed of a microcomputer, a microprocessor unit, or the like. In addition, the controller 52 may partially or entirely be constructed of one whose firmware and the like can be updated, or may partially or entirely be a program module or the like that is executed by a command from a CPU or the like, for example. The controller 52 may be provided as one unit or may be divided into plural units, for example. Furthermore, the controller 52 may be attached to the base body 51a or may be attached to a member other than the base body 51a.
The acquisition section 52a acquires information from each of the sensors provided in the hydraulic pressure control unit 5 and outputs the information to the control section 52b and the estimation section 52c. For example, the acquisition section 52a acquires information from each of the current sensors 41 and the temperature sensors 42, 43.
The control section 52b controls the operation of each of the above-described components that are assembled in the base body 51a of the hydraulic pressure control mechanism 51. In this way, the control section 52b can control the braking force to be applied to the front wheel 3 by the front-wheel brake mechanism 12 and the braking force to be applied to the rear wheel 4 by the rear-wheel brake mechanism 14. As will be described below, the control section 52b can also control operation of the notification device 6.
The control section 52b controls the operation of each of the above components according to a travel state of the vehicle 100, for example. In a normal time (that is, when anti-lock brake control, automated brake control, or the like, which will be described below, is not executed), the control section 52b opens the inlet valve 31a and closes the outlet valve 31b. When the first brake operation section 11 is operated in such a state, in the front-wheel brake mechanism 12, the piston (not illustrated) in the master cylinder 21 is pressed to increase a hydraulic pressure of the brake fluid in the wheel cylinder 24, the brake pad (not illustrated) of the brake caliper 23 is then pressed against a rotor 3a of the front wheel 3, and the braking force is thereby generated on the front wheel 3. Meanwhile, when the second brake operation section 13 is operated, in the rear-wheel brake mechanism 14, the piston (not illustrated) in the master cylinder 21 is pressed to increase the hydraulic pressure of the brake fluid in the wheel cylinder 24, the brake pad (not illustrated) of the brake caliper 23 is then pressed against a rotor 4a of the rear wheel 4, and the braking force is thereby generated on the rear wheel 4.
The anti-lock brake control is control that is executed when the wheel (more specifically, the front wheel 3 or the rear wheel 4) is locked or possibly locked and that reduces the braking force applied to the wheel without relying on a brake operation by the rider, for example. For example, in a state where the anti-lock brake control is executed, the control section 52b closes the inlet valve 31a, opens the outlet valve 31b, opens the first valve 31c, and closes the second valve 31d. When the pump 33 is driven by the control section 52b in such a state, the hydraulic pressure of the brake fluid in the wheel cylinder 24 is reduced, and the braking force that is applied to the wheel is thereby reduced.
The automated brake control is control that is executed when it is necessary to stabilize a posture of the vehicle 100 during turning or the like of the vehicle 100 and that causes generation of the braking force to be applied to the wheel (more specifically, the front wheel 3 or the rear wheel 4) without relying on the brake operation by the rider, for example. For example, when the automated brake control is executed, the control section 52b opens the inlet valve 31a, closes the outlet valve 31b, closes the first valve 31c, and opens the second valve 31d. When the pump 33 is driven by the control section 52b in such a state, the hydraulic pressure of the brake fluid in the wheel cylinder 24 is increased, and the braking force that brakes the wheel is thereby generated.
The estimation section 52c estimates a stroke amount Δx (see
In the example illustrated in
In this embodiment, by devising the processing for estimating the stroke amount Δx of the armature 312 that is executed by the controller 52, the stroke amount Δx is accurately estimated. A detailed description on such processing for estimating the stroke amount Δx of the armature 312 will be made below.
A description will herein be made on operation of the hydraulic pressure control unit 5 according to the embodiment of the present invention with reference to
In this embodiment, the estimation section 52c estimates the stroke amount Δx of the armature 312 on the basis of behavior of the current value of the current flowing through the wire 314 at beginning of the application of the current to the wire 314 of the electromagnetic valve 31. A description will hereinafter be made on the behavior of the current value of the current flowing through the wire 314 at beginning of the application of the current to the wire 314 with reference to
When the current starts being applied to the wire 314 of the electromagnetic valve 31, the current value i of the current flowing through the wire 314 starts being increased toward a target current value isw. Then, after reaching the target current value isw, the current value i is maintained at the target current value isw. In the present specification, time at which the current starts being applied to the wire 314 of the electromagnetic valve 31 means a period from time at which the current value i starts being increased in association with the application of the current to the wire 314 to time at which the current value i reaches the target current value isw.
In the example indicated by a solid line in
Here, when the current starts being applied to the wire 314, the core 315 is magnetized, and the magnetic force in the direction to approach the core 315 acts on the armature 312. Consequently, the armature 312 is attracted to and moves toward the core 315 side with the tappet 313. At this time, in the magnetic field generated by the wire 314, the armature 312 moves relative to the magnetic field. As a result, a counter-electromotive force is generated to the wire 314 in a manner to weaken magnetic flux generated by the wire 314. Thus, in a process in which the current value i of the current flowing through the wire 314 is increased toward the target current value isw, the current value i exhibits behavior of being temporarily reduced. For example, in the example indicated by the solid line in
In this embodiment, the estimation section 52c estimates the stroke amount Δx of the armature 312 on the basis of a reduced amount Δi of the current value i at the time when the current value i is temporarily reduced in the process in which the current value i of the current flowing through the wire 314 is increased toward the target current value isw at the beginning of the application of the current to the wire 314 of the electromagnetic valve 31. For example, the reduced amount Δi in the example indicated by the solid line in
Here, in the case where the current value i from a reduction start time point of the current value i (for example, the time point t2 in the example indicated by the solid line in
Compared to the example indicated by the solid line, an example indicated by a broken line in
The control flow illustrated in
When the control flow illustrated in
For example, the estimation section 52c determines whether the current starts being applied to the wire 314 on the basis of the detection value of the current sensor 41. As described above, when the current starts being applied to the wire 314, the current value i of the current flowing through the wire 314 starts being increased toward the target current value isw. Accordingly, the estimation section 52c can determine whether the current starts being applied to the wire 314 on the basis of the behavior of the current value i of the current flowing through the wire 314 (for example, whether the current value i is increased to exceed a specified value).
If it is determined YES in step S102, in step S103, the estimation section 52c determines whether the current value i of the current flowing through the wire 314 of the electromagnetic valve 31 stops being increased. If it is determined that the current value i of the current flowing through the wire 314 stops being increased (step S103/YES), the processing proceeds to step S104. On the other hand, if it is determined that the current value i of the current flowing through the wire 314 does not stop being increased (step S103/NO), the determination processing in step S103 is repeated.
For example, the estimation section 52c determines whether the current value i of the current flowing through the wire 314 stops being increased on the basis of the detection value of the current sensor 41. As described above, after being increased to the target current value isw, the current value i of the current flowing through the wire 314 is maintained at the target current value isw. Accordingly, the estimation section 52c can determine whether the current value i of the current flowing through the wire 314 stops being increased on the basis of the behavior of the current value i of the current flowing through the wire 314 (for example, whether a fluctuation width of the current value i becomes equal to or smaller than a specified value).
If it is determined YES in step S103, in step S104, the estimation section 52c estimates the stroke amount Δx of the armature 312. More specifically, as described above, the estimation section 52c estimates the stroke amount Δx of the armature 312 on the basis of the reduced amount Δi of the current value i at the time when the current value i is temporarily reduced in the process in which the current value i of the current flowing through the wire 314 is increased toward the target current value isw at the beginning of the application of the current to the wire 314 of the electromagnetic valve 31. For example, after step S102 and until it is determined YES in step S103, the acquisition section 52a keeps acquiring the current value i at each of the time points, and the estimation section 52c can identify the reduced amount Δi on the basis of history of the obtained current value i.
Here, from a perspective of improving estimation accuracy of the stroke amount Δx of the armature 312, the estimation section 52c preferably estimates the stroke amount Δx on the basis of another parameter in addition to the reduced amount Δi of the current value i.
For example, the estimation section 52c estimates the stroke amount Δx on the basis of viscosity index information that is information as an index of viscosity evaluation of the brake fluid as the hydraulic fluid in addition to the reduced amount Δi of the current value i. The viscosity index information includes temperature information of the brake fluid (that is, information on the temperature of the brake fluid), for example. There is a relationship that the viscosity of the brake fluid is increased with the reduction in the temperature of the brake fluid. Thus, the temperature of the brake fluid is the index for evaluating the viscosity of the brake fluid. The acquisition section 52a can acquire the temperature information of the brake fluid from the temperature sensors 42, 43, for example. Here, the temperature information of the brake fluid may be information that directly indicates the temperature of the brake fluid, or may be information that indicates another physical quantity that can substantially be converted to the temperature of the brake fluid.
Here, compared to the example indicated by the solid line, in the example indicated by the broken line in
As described above, there is a tendency that the reduced amount Δi of the current value i is reduced with the reduction in the temperature of the brake fluid. That is, there is a tendency that the reduced amount Δi of the current value i is reduced with an increase in the viscosity of the brake fluid. Just as described, the reduced amount Δi of the current value i varies in association with a change in the viscosity of the brake fluid. Accordingly, the estimation section 52c can improve the estimation accuracy of the stroke amount Δx by estimating the stroke amount Δx (for example, estimating a smaller value as the stroke amount Δx as the temperature of the brake fluid is reduced) by taking not only the reduced amount Δi but also the viscosity index information into consideration.
Although the above description has been made on the example in which the temperature information of the brake fluid is used as the viscosity index information, the estimation section 52c may use the viscosity index information other than the temperature information of the brake fluid. For example, the estimation section 52c may use, as the viscosity index information, the number of days elapsed since a date when the brake fluid is most recently replaced, or information on deceleration that is generated to the vehicle 100 during actuation of the anti-lock brake control, or the like.
Alternatively, for example, the estimation section 52c estimates the stroke amount Δx on the basis of the target current value isw in addition to the reduced amount Δi of the current value i.
Here, compared to the example indicated by the solid line, in the example indicated by the one-dot chain line in
As described above, there is a tendency that the reduced amount Δi of the current value i is increased with the reduction in the target current value isw. Just as described, the reduced amount Δi of the current value i varies in association with a change in the target current value isw. Accordingly, the estimation section 52c can improve the estimation accuracy of the stroke amount Δx by estimating the stroke amount Δx (for example, estimating a larger value as the stroke amount Δx as the target current value isw is reduced) by taking not only the reduced amount Δi but also the target current value isw into consideration.
The above description has sequentially been made on the example in which the viscosity index information of the brake fluid is used in addition to the reduced amount Δi of the current value i for the estimation of the stroke amount Δx and the example in which the target current value isw is used in addition to the reduced amount Δi of the current value i therefor. However, from a perspective of effectively improving the estimation accuracy of the stroke amount Δx of the armature 312, the estimation section 52c preferably estimates the stroke amount Δx on the basis of both of the viscosity index information of the brake fluid and the target current value isw in addition to the reduced amount Δi of the current value i. A mathematical formula, a map, or the like that specifies the relationship between the stroke amount Δx and each of the parameters (for example, the reduced amount Δi, the temperature of the brake fluid, and the target current value isw) and that is used to estimate the stroke amount Δx may be determined on the basis of a theoretical formula or may be determined on the basis of an experimental result.
Next, in step S105, the control section 52b determines whether the stroke amount Δx is smaller than a reference stroke amount. If it is determined that the stroke amount Δx is smaller than the reference stroke amount (step S105/YES), the processing proceeds to step S106, and the control section 52b increases the target current value isw to be higher than the current value. Accordingly, in the process of repeating the control flow illustrated in
The reference stroke amount in step S105 is set to a value with which it is possible to determine whether the stroke amount Δx is large enough to allow the electromagnetic valve 31 to function appropriately. In other words, if it is determined that the stroke amount Δx is equal to or larger than the reference stroke amount (that is, if it is determined NO in step S105), it is possible to determine that the stroke amount Δx is large enough to allow the electromagnetic valve 31 to function appropriately.
On the other hand, if it is determined that the stroke amount Δx is smaller than the reference stroke amount (that is, if it is determined YES in step S105), it is possible to determine that the stroke amount Δx is insufficient to such extent that the electromagnetic valve 31 does not function appropriately. In such a case, the control section 52b increases the target current value isw to be higher than the current value. In this way, the stroke amount Δx can be increased. Thus, it is possible to eliminate shortage of the stroke amount Δx and allow the electromagnetic valve 31 to function appropriately.
As described above, from a perspective of avoiding the shortage of the stroke amount Δx, the control section 52b preferably controls the target current value isw on the basis of an estimation result of the stroke amount Δx. More specifically, in the above example, the control section 52b increases the target current value isw in the case where the current stroke amount Δx is smaller than the reference stroke amount. However, the control section 52b may increase the target current value isw in the case where it is predicted that the stroke amount Δx possibly falls below the reference stroke amount in the future.
For example, the control section 52b can predict whether the stroke amount Δx possibly falls below the reference stroke amount in the future on the basis of a temperature such as the current temperature of the brake fluid or an ambient temperature. For example, in the case where the current temperature of the brake fluid is high to some extent, it is assumed that the temperature of the brake fluid is significantly reduced in the future. Accordingly, even when the current stroke amount Δx is equal to or larger than the reference stroke amount, there is a case where the control section 52b predicts that the stroke amount Δx possibly falls below the reference stroke amount in the future. In such a case, it is possible to avoid the shortage of the stroke amount Δx in advance by increasing the target current value isw in advance.
If it is determined NO in step S105, or in step S107 following step S106, the control section 52b controls the notification operation on the basis of the estimation result of the stroke amount Δx, and then the control flow illustrated in
The notification operation is operation to notify the rider of various types of information. For example, the notification operation is performed by the notification device 6 and may be operation to show the information or operation to output sound. Here, in the case where the notification operation continues for a set time, the control flow illustrated in
In step S107, for example, if it is determined that the stroke amount Δx is smaller than the reference stroke amount (that is, if it is determined YES in step S105), the control section 52b causes the notification device 6 to perform the notification operation that notifies of the shortage of the stroke amount Δx to such extent that the electromagnetic valve 31 no longer functions appropriately. On the other hand, if it is determined that the stroke amount Δx is equal to or larger than the reference stroke amount (that is, if it is determined NO in step S105), the control section 52b stops the notification operation by the notification device 6. However, if it is determined NO in step S105, the control section 52b may cause the notification device 6 to perform the notification operation so as to notify that the stroke amount Δx is large enough to allow the electromagnetic valve 31 to function appropriately.
The notification operation may be performed by a device other than the notification device 6. For example, the notification operation may be performed by a display device (for example, a transmissive display arranged over the rider's line of sight) that is provided to a helmet worn on the rider's head. Alternatively, for example, the notification operation may be performed by a sound output device that is provided to the helmet worn on the rider's head. Further alternatively, for example, the notification operation may be operation to generate vibration by a vibration generator that is provided to the vehicle 100 or is attached to the rider. For example, the notification operation may be operation to instantaneously decelerate the vehicle 100. The instantaneous deceleration may occur by reducing output of the drive source, may occur by generating the braking force by the hydraulic pressure control unit 5, or may occur by changing a gear ratio of a transmission mechanism of the vehicle 100.
The above description has been made on the example of the processing procedure related to the estimation of the stroke amount Δx with reference to
A description will be made on effects of the hydraulic pressure control unit 5 according to the embodiment of the present invention.
In the hydraulic pressure control unit 5, the estimation section 52c estimates the stroke amount Δx of the armature 312 on the basis of the reduced amount Δi of the current value i at the time when the current value i is temporarily reduced in the process in which the current value i of the current flowing through the wire 314 is increased toward the target current value isw at the beginning of the application of the current to the wire 314 of the electromagnetic valve 31. In this way, it is possible to appropriately estimate the stroke amount Δx of the armature 312 by focusing on the phenomenon that the counter-electromotive force is generated to the wire 314 in association with the movement of the armature 312. Thus, it is possible to accurately estimate the stroke amount Δx of the armature 312 of the electromagnetic valve 31. Furthermore, it is also possible to estimate the stroke amount Δx without using a sensor that directly detects the stroke amount Δx of the armature 312.
Preferably, in the hydraulic pressure control unit 5, the estimation section 52c estimates the stroke amount Δx on the basis of the target current value isw in addition to the reduced amount Δi of the current value i. In this way, it is possible to appropriately estimate the stroke amount Δx of the armature 312 by focusing on the relationship between the target current value isw and the reduced amount Δi. Thus, it is possible to improve the estimation accuracy of the stroke amount Δx of the armature 312 of the electromagnetic valve 31.
Preferably, in the hydraulic pressure control unit 5, the estimation section 52c estimates the stroke amount Δx on the basis of the viscosity index information that is the information as the index of the viscosity evaluation of the hydraulic fluid (in the above example, the brake fluid) in addition to the reduced amount Δi of the current value i. In this way, it is possible to further appropriately estimate the stroke amount Δx of the armature 312 by focusing on the relationship between the viscosity of the brake fluid and the reduced amount Δi. Thus, it is possible to improve the estimation accuracy of the stroke amount Δx of the armature 312 of the electromagnetic valve 31.
Preferably, in the hydraulic pressure control unit 5, the viscosity index information includes the temperature information of the hydraulic fluid (in the above example, the brake fluid). In this way, it is possible to appropriately estimate the stroke amount Δx of the armature 312 by focusing on the relationship between the viscosity of the brake fluid and the reduced amount Δi. Thus, it is possible to appropriately improve the estimation accuracy of the stroke amount Δx of the armature 312 of the electromagnetic valve 31.
Preferably, in the hydraulic pressure control unit 5, the control section 52b controls the target current value isw on the basis of the estimation result of the stroke amount Δx. In this way, in the case where the stroke amount Δx is insufficient or possibly becomes insufficient in the future to such extent that the electromagnetic valve 31 no longer functions appropriately, it is possible to avoid the shortage of the stroke amount Δx and cause the electromagnetic valve 31 to function appropriately.
Preferably, in the hydraulic pressure control unit 5, the control section 52b increases the target current value isw in the case where the stroke amount Δx is smaller than the reference stroke amount. In this way, in the case where the stroke amount Δx is insufficient to such extent that the electromagnetic valve 31 no longer functions appropriately, it is possible to eliminate the shortage of the stroke amount Δx and cause the electromagnetic valve 31 to function appropriately.
Preferably, in the hydraulic pressure control unit 5, the control section 52b increases the target current value isw in the case where it is predicted that the stroke amount Δx possibly falls below the reference stroke amount in the future. In this way, in the case where the stroke amount Δx possibly becomes insufficient in the future to such extent that the electromagnetic valve 31 no longer functions appropriately, it is possible to avoid the shortage of the stroke amount Δx in advance and cause the electromagnetic valve 31 to function appropriately.
Preferably, in the hydraulic pressure control unit 5, the control section 52b controls the notification operation on the basis of the estimation result of the stroke amount Δx. In this way, it is possible to notify the rider of the information on the estimation result of the stroke amount Δx. Thus, the rider can understand whether the electromagnetic valve 31 is in the appropriately functioning state. Therefore, safety is improved.
Preferably, in the hydraulic pressure control unit 5, the estimation section 52c determines that the current value i is temporarily reduced in the case where the current value i at the time point after the lapse of the reference time from the reduction start time point of the current value i is lower than the current value i at the reduction start time point by the reference value or greater. In this way, it is possible to distinguish whether the current value i is temporarily reduced due to the generation of the counter-electromotive force to the wire 314 or the detection value of the current sensor 41 is only instantaneously and slightly reduced by the noise component. Thus, it is possible to appropriately estimate the stroke amount Δx by focusing on the phenomenon that the counter-electromotive force is generated to the wire 314 in association with the movement of the armature 312.
The present invention is not limited to the embodiment that has been described. For example, only a part of the embodiment may be implemented.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-001172 | Jan 2021 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2021/061815 | 12/16/2021 | WO |
