A front-rear wheel linkage anti-lock brake control system and method for a two-wheeled vehicle

Abstract

The application discloses a front-rear wheel linkage anti-lock braking control system and method for a two-wheeled vehicle, which comprises a hydraulic circuit and an electronic control unit, and the hydraulic circuit is provided with a first main braking circuit, a second main braking circuit and a first linkage braking circuit; the second braking unit is provided with a first main braking cavity and a first linkage braking cavity which are independent of each other, the first main braking cavity is connected to the second main braking circuit, and the first linkage braking cavity is connected to the first linkage braking circuit; the first linkage braking circuit comprises a first linkage sub-circuit and a second linkage sub-circuit, the first linkage sub-circuit is provided with a first normally-open CBS electromagnetic valve, and both ends of the first normally-open CBS electromagnetic valve are connected to a first braking master cylinder and the first linkage braking cavity, respectively; and the second linkage sub-circuit is provided with a first normally-closed CBS electromagnetic valve, and both ends of the first normally-closed CBS electromagnetic valve are connected to the first linkage braking cavity and the first braking master cylinder, respectively. The application integrates ABS and CBS functions, has a compact structure, and can prevent oil from leaking between front braking and rear braking, thereby improving braking safety and driving experience of the two-wheeled vehicle.

Description

Technical Field

[0001] This invention belongs to the field of two-wheel braking technology, and particularly relates to an anti-lock braking control system and method for two-wheeled vehicles with front and rear wheel linkage. Background Technology

[0002] The braking system is a core component for the safe operation of two-wheeled vehicles such as motorcycles and electric bicycles. ABS (Antilock Braking System) and CBS (Combined Braking System) are two control devices within it. ABS prevents wheel lock-up and improves braking stability; CBS enables a single device to control the combined braking of the front and rear wheels, reducing operational difficulty.

[0003] Traditional two-wheeled vehicles either only have ABS installed, requiring both hands or feet to brake simultaneously on both front and rear wheels, lacking the ability to link front and rear wheel braking, thus affecting the braking experience and effectiveness; or they only have CBS installed, which lacks anti-lock braking function during emergency braking, making the vehicle prone to accidents such as loss of steering or fishtailing during emergency braking.

[0004] To address the integration issue between ABS and CBS, a Chinese invention patent application [Publication No.: CN121291656A] discloses a linkage, an integrated main control unit, an ABS braking system, and a braking control method. This solution designs a first cavity, a second cavity, and a second oil circuit inside the ABS main valve body, and includes a linkage comprising a piston assembly and a one-way seal. The working principle is as follows: when the driver operates the rear brake, the brake fluid output from the rear brake master cylinder drives the rear wheel brakes via the second oil circuit. Simultaneously, this hydraulic pressure pushes the piston to move, causing multiple small holes on the piston's sidewall to be blocked by the one-way seal, thereby cutting off the first oil circuit connected to the front brake master cylinder. The piston movement establishes hydraulic pressure within the first cavity, forcing the brake fluid towards the front wheel brakes, thus achieving linkage braking of the front wheels during rear brake operation.

[0005] The above-mentioned solution suffers from structural complexity and high processing costs. Furthermore, this solution relies on the hydraulic pressure of the second oil circuit to push the piston assembly to block the first oil circuit to achieve linkage. There is a problem of mutual oil leakage between the front and rear brakes. Simultaneous operation of the front and rear brakes will cause mutual interference. Specifically, during the linkage process, because the piston isolates the handbrake operating end from the first cavity, if the driver squeezes the handbrake, the handbrake lever will have an abnormal "locked" or "no free travel" feel. Conversely, if the handbrake is squeezed first and then the foot brake is pressed, the high pressure built up by the foot brake will also push the handbrake hydraulic circuit in the opposite direction through the piston, causing the handbrake lever to unexpectedly rebound on its own, affecting the driving experience. It also causes the front and rear braking systems to lose their ability to independently superimpose. Summary of the Invention

[0006] The purpose of this invention is to propose an anti-lock braking control system for two-wheeled vehicles that links the front and rear wheels, addressing the problems existing in the prior art.

[0007] Another objective of this invention is to propose an anti-lock braking control method for two-wheeled vehicles that links the front and rear wheels.

[0008] To achieve the above objectives, the present invention adopts the following technical solutions:

[0009] An anti-lock braking system for a two-wheeled vehicle with front and rear wheel linkage includes a hydraulic circuit and an electronic control unit. The hydraulic circuit includes a first main braking circuit, a second main braking circuit, and a first linkage braking circuit.

[0010] The first main braking circuit corresponds to the first master cylinder, the first braking unit, and the first wheel, and has a first normally open ABS solenoid valve and a first normally closed ABS solenoid valve that are controlled by the electronic control unit to perform main braking anti-lock control on the first wheel.

[0011] The second main braking circuit corresponds to the second master cylinder, the second braking unit, and the second wheel, and has a second normally open ABS solenoid valve and a second normally closed ABS solenoid valve that are controlled by the electronic control unit to perform main braking anti-lock control on the second wheel.

[0012] The second braking unit has a first main braking chamber and a first linkage braking chamber that are independent of each other. The first main braking chamber is hydraulically connected to the second main braking circuit, and the first linkage braking chamber is hydraulically connected to the first linkage braking circuit.

[0013] The first linkage braking circuit includes a first linkage sub-circuit and a second linkage sub-circuit;

[0014] The first linkage sub-circuit has a first normally open CBS solenoid valve electrically connected to the electronic control unit, and its two ends are hydraulically connected to the first master cylinder and the first linkage braking chamber respectively according to the brake fluid flow direction; the second linkage sub-circuit has a first normally closed CBS solenoid valve electrically connected to the electronic control unit, and its two ends are hydraulically connected to the first linkage braking chamber and the first master cylinder respectively according to the brake fluid flow direction, for use in linkage braking of the second wheel and linkage braking anti-lock control.

[0015] In the above-mentioned anti-lock braking control system for two-wheeled vehicles with front and rear wheel linkage, the first wheel is the front wheel, the second wheel is the rear wheel, the first main braking circuit corresponds to the front wheel and the front wheel's master cylinder and braking unit, and the second main braking circuit corresponds to the rear wheel and the rear wheel's master cylinder and braking unit.

[0016] Alternatively, the second wheel is the front wheel, the first wheel is the rear wheel, the second master brake circuit corresponds to the front wheel and the master cylinder and brake unit of the front wheel, and the first master brake circuit corresponds to the rear wheel and the master cylinder and brake unit of the rear wheel.

[0017] In the above-mentioned anti-lock braking control system for two-wheeled vehicles that links the front and rear wheels, the hydraulic circuit also includes a second linkage braking circuit.

[0018] The first braking unit has a second main braking chamber and a second linkage braking chamber that are independent of each other. The second main braking chamber is hydraulically connected to the first main braking circuit, and the second linkage braking chamber is hydraulically connected to the second linkage braking circuit.

[0019] The second linkage braking circuit is symmetrical in structure to the first linkage braking circuit. It includes a second normally open CBS solenoid valve and a second normally closed CBS solenoid valve electrically connected to the electronic control unit for linkage braking of the first wheel and linkage braking anti-lock control.

[0020] In the above-mentioned anti-lock braking control system for two-wheeled vehicles with front and rear wheel linkage, the braking unit with linkage braking chamber has two sets of pistons, one set of pistons is hydraulically connected to the corresponding main braking chamber, and the other set of pistons is hydraulically connected to the corresponding linkage braking chamber.

[0021] Each set of pistons includes one or more pistons, which are hydraulically driven by the main braking chamber or linkage braking chamber in hydraulic communication with it to contact the brake pads to brake the corresponding wheel.

[0022] In a single braking unit, the volume of the main braking chamber is larger than the volume of the linkage braking chamber, and the number of pistons corresponding to the main braking chamber is greater than the number of pistons corresponding to the linkage braking chamber.

[0023] In the above-mentioned anti-lock braking control system for front and rear wheels of two-wheeled vehicles, the braking unit with the linkage braking chamber is a six-piston braking unit. The main braking chamber includes two main braking sub-chambers, and the linkage braking chamber is located between the two main braking sub-chambers. The sum of the volumes of the two main braking sub-chambers is greater than the volume of the linkage braking chamber.

[0024] Each main braking chamber corresponds to two pistons, and the linkage braking chamber corresponds to two pistons, so that four pistons are responsible for the main braking and two pistons are responsible for the linkage auxiliary braking.

[0025] In the above-mentioned anti-lock braking control system for two-wheeled vehicles with front and rear wheel linkage, the first normally closed ABS solenoid valve and the first normally closed CBS solenoid valve are hydraulically connected to the first reservoir and hydraulically connected to the first master cylinder through the first return pump.

[0026] The second normally closed ABS solenoid valve is hydraulically connected to the second reservoir, either alone or together with the second normally closed CBS solenoid valve, and is hydraulically connected to the second brake master cylinder via the second return pump;

[0027] The first return pump and the second return pump are electrically connected to the motor, and the motor is electrically connected to the electronic control unit.

[0028] In the above-mentioned anti-lock braking system for two-wheeled vehicles that links the front and rear wheels, each CBS solenoid valve and each ABS solenoid valve are integrated on the same valve block base.

[0029] Each return pump has a check valve at both ends that allows hydraulic fluid to flow only from the braking unit to the master cylinder.

[0030] A two-wheeled vehicle, including the aforementioned anti-lock braking system that links the front and rear wheels of the two-wheeled vehicle.

[0031] An anti-lock braking control method based on the aforementioned anti-lock braking control system for front and rear wheels of a two-wheeled vehicle includes:

[0032] When the master cylinder is compressed, the wheel connected to it via the master brake circuit is braked by the master brake, and the wheel connected to it via the linkage brake circuit is braked by the linkage brake.

[0033] The electronic control unit receives vehicle status information in real time, including the rotational speed of both wheels, the vehicle reference speed, and the pressure build-up status of the two brake master cylinders;

[0034] Based on the vehicle status information, determine whether each wheel is in the first trigger state or the second trigger state;

[0035] For the wheel determined to be in the first trigger state, activate the pressure-holding anti-lock braking control for that wheel:

[0036] If the master cylinder fails to build up pressure, the normally open CBS solenoid valve in the linkage braking circuit is closed, while the other solenoid valves corresponding to the wheel remain normally open / normally closed. If the master cylinder fails to build up pressure, the wheel may become prone to locking due to linkage braking. Anti-lock braking is achieved by controlling the solenoid valves in the linkage braking circuit.

[0037] Otherwise, the normally open ABS solenoid valve in the main braking circuit is controlled to be closed, or the normally open CBS solenoid valve in the linkage braking circuit is controlled to be closed at the same time, while the other solenoid valves remain in the normally open / normally closed state; the wheel in the brake master cylinder under pressure build-up state tends to lock up. If the wheel can be linked, the solenoid valves of the main braking circuit and the linkage braking circuit can be controlled at the same time for anti-lock control; if the wheel cannot be linked, only the solenoid valve of the main braking circuit needs to be controlled for anti-lock control.

[0038] For the wheel determined to be in the second trigger state, activate the decompression anti-lock braking control for that wheel:

[0039] If the master cylinder does not build up pressure, the normally open CBS solenoid valve in the linkage braking circuit is closed, the normally closed CBS solenoid valve is open, and the solenoid valve in the master braking circuit does not operate.

[0040] Otherwise, the normally open ABS solenoid valve in its main braking circuit is closed and the normally closed ABS solenoid valve is open, or the normally open CBS solenoid valve in its linkage braking circuit is closed and the normally closed CBS solenoid valve is open.

[0041] During the decompression process, the oil in the corresponding chamber enters the corresponding reservoir and is pumped back to the corresponding master cylinder by the corresponding return pump when the motor is driven.

[0042] In the above-mentioned anti-lock braking control method, the front and rear wheels are determined to be in the first or second trigger state by means of the following method:

[0043] Calculate the deceleration of the corresponding wheel based on the wheel speed change trend of each wheel;

[0044] Calculate the wheel slip ratio of each wheel based on its current wheel speed and the vehicle's reference speed.

[0045] When the deceleration is greater than the first preset deceleration threshold, or the wheel slip ratio is greater than the first preset slip ratio threshold, the corresponding wheel is determined to be in the first trigger state.

[0046] When the deceleration is greater than the second preset deceleration threshold, or the wheel slip ratio is greater than the second preset slip ratio threshold, the corresponding wheel is determined to be in the second trigger state.

[0047] The second preset deceleration threshold is greater than the first preset deceleration threshold;

[0048] The second preset slip ratio threshold is greater than the first preset slip ratio threshold.

[0049] The advantages of this invention are: it solves the problem that traditional two-wheeled vehicles such as motorcycles do not have both front and rear linkage braking and anti-lock braking functions, shortens the braking distance triggered by a single brake, and improves the braking safety of two-wheeled vehicles.

[0050] This solution optimizes the hydraulic circuit structure, replaces the braking unit with a structure featuring two independent braking chambers, and incorporates a small number of solenoid valves within the optimized hydraulic passages. By connecting to the existing ABS ECU and employing appropriate control strategies, it achieves the integration of ABS and CBS functions while effectively preventing hydraulic fluid leakage between the front and rear brake circuits. This ensures that the front and rear brake operations are independent and do not interfere with each other, providing complete and independent front and rear braking functions, maintaining a good braking experience, and offering advantages such as compact structure and low cost.

[0051] This solution can independently control the anti-lock braking of the main brake wheel and the linkage brake wheel according to the operating status of the master cylinder and the tendency of wheel lock-up. It not only ensures the rapid response and efficient braking of the linkage brake, but also realizes independent anti-lock braking of the main brake wheel and the linkage brake wheel, further ensuring the stability and safety of braking. Attached Figure Description

[0052] Figure 1 This is a schematic diagram of the hydraulic control principle of the anti-lock braking system of the present invention;

[0053] Figure 2 This is a schematic diagram of the cavity layout of the second braking unit in Embodiment 1 of the present invention;

[0054] Figure 3 This is a schematic diagram of the oil flow direction during the pre-braking phase in Embodiment 1 of the present invention;

[0055] Figure 4 This is a flowchart of the anti-lock braking control method in Embodiment 1 of the present invention;

[0056] Figure 5 This is a graph showing the changing trends of various parameters during dual braking on a low-friction surface before rear linkage in Embodiment 2 of the present invention;

[0057] Figure 6 This is a schematic diagram of the bidirectional linkage hydraulic control principle in Embodiment 3 of the present invention.

[0058] Reference numerals: 1. First main brake circuit; 2. Second main brake circuit; 3. First linkage brake circuit; 4. First master cylinder; 5. First brake unit; 6. First normally open ABS solenoid valve; 7. First normally closed ABS solenoid valve; 8. Second master cylinder; 9. Second brake unit; 10. Second wheel; 11. Second normally open ABS solenoid valve; 12. Second normally closed ABS solenoid valve; 13. First main brake chamber; 14. First linkage brake chamber; 15. First linkage sub-circuit; 16. Second linkage sub-circuit; 17. First normally open CBS solenoid valve; 18. First normally closed CBS solenoid valve; 19. Second linkage brake circuit; 20. Second main brake chamber; 21. Second linkage brake chamber; 22. Second normally open CBS solenoid valve; 23. Second normally closed CBS solenoid valve; 24. First return pump; 25. Check valve; 26. First reservoir; 27. Motor; 28. Second return pump; 29. ​​Second reservoir; 30. Detailed Implementation

[0059] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0060] Example 1

[0061] This embodiment describes a scenario where the front brake is linked to the rear wheel in a hydraulic braking system. Specifically, when the driver operates the front brake control device to build up pressure in the front brake master cylinder, the system simultaneously applies main braking to the front wheels and linked braking to the rear wheels. This front brake control device can be an electronic parking brake or a mechanical parking brake; this embodiment is not limited to either.

[0062] Specifically, such as Figure 1 As shown, the anti-lock braking system provided in this embodiment includes a hydraulic control unit (HCU) and an electronic control unit (ECU). The HCU includes a valve block base, a solenoid valve mounted on the valve block base, and an oil passage machined inside the valve block base.

[0063] The oil passage includes a first main braking circuit 1, a second main braking circuit 2, and a first linkage braking circuit 3.

[0064] The first master brake circuit 1 corresponds to the front wheel, which is the first wheel 6, and its first master brake cylinder 4 and first brake unit 5. At this time... Figure 1The wheel on the left is the front wheel, and the wheel on the right is the rear wheel. The braking unit used in this paper preferably employs a brake wheel cylinder; the specific structure of the brake wheel cylinder can use a common structure and will not be elaborated here. The first master brake cylinder 4 is driven by the driver through the front brake operating device, and its outlet is hydraulically connected to the first master brake circuit 1. The first master brake circuit 1 is sequentially equipped with a first normally open ABS solenoid valve 7 and a first normally closed ABS solenoid valve 8. The two ends of the first normally open ABS solenoid valve 7 are hydraulically connected to the brake chambers of the first master brake cylinder 4 and the first brake unit 5, respectively. One end of the first normally closed ABS solenoid valve 8 is hydraulically connected to the oil line between the brake chamber of the first brake unit 5 and the first normally open ABS solenoid valve 7, and the other end is hydraulically connected to the first reservoir 27. The first master brake circuit 1 also includes a first return pump 25. The inlet of the first return pump 25 is connected to the oil line node between the first normally closed ABS solenoid valve 8 and the first reservoir 27 via a one-way valve 26, and the outlet is connected to the oil line node between the first normally open ABS solenoid valve 7 and the first master brake cylinder 4 via a one-way valve 26. The first normally open ABS solenoid valve 7, the first normally closed ABS solenoid valve 8, and the motor 28 that drives the first return pump 25 are all electrically connected to the ECU.

[0065] The second master brake circuit 2 corresponds to the rear wheel, which serves as the second wheel 11, and its second master brake cylinder 9 and second brake unit 10. The second master brake cylinder 9 is driven by the driver through a rear brake operating device, which can be a handbrake or a foot brake. Similarly, it can be electronic or mechanical, and this embodiment does not impose any specific limitations on this.

[0066] like Figure 2 As shown, unlike conventional braking units, the second braking unit 10 has a dual-chamber structure with an independent first main braking chamber 14 and a first linkage braking chamber 15. Specifically, the second braking unit 10 is a six-piston braking unit, which internally has two main braking chambers and a first linkage braking chamber 15 located between the two main braking chambers. The sum of the volumes of the two main braking chambers is greater than the volume of the first linkage braking chamber 15. Alternatively, the volumes of each chamber are approximately equal, so that the volume of the first linkage braking chamber 15 is approximately half that of the first main braking chamber 14. Each main braking chamber corresponds to two pistons, for a total of four pistons performing the main braking function; the first linkage braking chamber 15 corresponds to two pistons and performs the linkage auxiliary braking function. The first main braking chamber 14 of the second braking unit 10 is hydraulically connected to the second main braking circuit 2. The second main braking circuit 2 is also equipped with a second normally open ABS solenoid valve 12, a second normally closed ABS solenoid valve 13, and a second return pump 29, which are similar in structure to those of the first main braking circuit 1, for implementing independent anti-lock braking control of the rear wheels.

[0067] The core of this embodiment lies in the optimization of the oil passage and the addition of a first linkage braking circuit 3. The first linkage braking circuit 3 is used to guide the hydraulic fluid generated by the front braking operation to the rear wheel. It includes a first linkage sub-circuit 16 and a second linkage sub-circuit 17 connected in parallel.

[0068] Specifically, such as Figure 1 As shown, the first linkage sub-circuit 16 is equipped with a first normally open CBS solenoid valve 18. The two ends of the first normally open CBS solenoid valve 18 are hydraulically connected to the outlet of the first brake master cylinder 4 (i.e., the front brake master cylinder side) and the first linkage brake chamber 15 of the second brake unit 10, respectively. The second linkage sub-circuit 17 is equipped with a first return pump 25 and a first normally closed CBS solenoid valve 19 hydraulically connected in sequence. The first return pump 25 preferably reuses the existing first return pump and motor unit in the HCU. The end of the first normally closed CBS solenoid valve 19 away from the first normally closed CBS solenoid valve 19 (i.e., the outlet end) is hydraulically connected to the first brake master cylinder 4, specifically connected to the node between the first normally open CBS solenoid valve 18 and the first brake master cylinder 4 on the first linkage sub-circuit 16. The end of the first normally closed CBS solenoid valve 19 away from the first return pump 25 (i.e., the inlet end) is hydraulically connected to the first linkage brake chamber 15 of the second brake unit 10. The oil passage between the first normally closed CBS solenoid valve 19 and the first return pump 25 is also connected to the first reservoir 27 for storing oil during depressurization. Both the first normally open CBS solenoid valve 18 and the first normally closed CBS solenoid valve 19 are integrated into the valve block base of the HCU, sharing the same valve block base with the aforementioned ABS solenoid valves, and achieving the above connection through internally optimized oil passages.

[0069] like Figure 4 As shown, during vehicle operation, the ECU receives vehicle status information in real time, including front wheel speed, rear wheel speed, vehicle reference speed, and pressure sensor signals or brake operation device switch signals (BLS) used to detect whether the first brake master cylinder 4 and the second brake master cylinder 9 are in a pressure build-up state.

[0070] When the driver operates only the front brake, the first master cylinder 4 is compressed, and its output high-pressure hydraulic fluid is divided into two paths: Figure 3 As indicated by the red arrows, the first path enters the brake chamber of the first front wheel braking unit 5 via the first normally open ABS solenoid valve 7 in the first master brake circuit 1, pushing the corresponding piston to generate front wheel braking force; the second path enters the first linkage brake chamber 15 of the second rear wheel braking unit 10 via the first normally open CBS solenoid valve 18 in the first linkage brake circuit 3, pushing the two pistons corresponding to the first linkage brake chamber 15 to generate rear wheel auxiliary braking force, thus realizing combined braking of the front wheel master brake and the rear wheel auxiliary brake under front braking operation. At this time, if the ECU does not detect any wheel lock-up tendency, each solenoid valve maintains its initial normally open or normally closed state, and the system maintains normal braking.

[0071] If the ECU determines that the rear wheels are likely to lock up during combined braking, it will perform the following controls based on the degree of lockup and the pressure build-up status of the second master cylinder 9:

[0072] When the rear wheel deceleration or slip ratio reaches the threshold corresponding to the first trigger state (deceleration reaches the first preset deceleration threshold, or slip ratio reaches the first preset slip ratio threshold), the pressure holding mode is entered. Since the second master cylinder 9 is in an unpressurized state at this time (the driver only applies the front brake), the ECU only controls the first normally open CBS solenoid valve 18 in the first linkage braking circuit 3 to close, cutting off the fluid inlet passage from the first master cylinder 4 to the rear wheel first linkage braking chamber 15, thus maintaining the pressure within the rear wheel first linkage braking chamber 15. The first normally closed CBS solenoid valve 19, as well as all ABS valves, maintain their initial normally open or normally closed state, and the front wheel main brakes are unaffected.

[0073] When the rear wheel lock-up tendency intensifies and reaches the threshold corresponding to the second trigger state (deceleration reaches the second preset deceleration threshold, or slip ratio reaches the second preset slip ratio threshold), the active decompression mode is entered. While keeping the first normally open CBS solenoid valve 18 closed, the ECU controls the first normally closed CBS solenoid valve 19 to open, and hydraulic oil is sent to the first reservoir 27. When the return pump is driven by the motor 28, the hydraulic oil in the first reservoir 27 is pumped back to the first brake master cylinder 4. During this process, the ABS valves in the second master brake circuit 2 do not need to operate because the rear brake master cylinder is not activated, and the front wheels do not tend to lock up, so they also do not need to operate.

[0074] Similarly, when the front wheels lock up independently, if the driver only operates the front brake master cylinder and the front wheels show a tendency to lock up, the ECU controls the system according to the degree of lockup: When the first trigger state is reached, the first normally open ABS solenoid valve 7 in the first master brake circuit 1 is closed, cutting off the fluid inlet passage from the first brake master cylinder 4 to the brake chamber of the first front wheel brake unit 5, thus maintaining the front wheel braking force. The remaining solenoid valves in the oil passage remain initially normally open or normally closed. When the second trigger state is reached, while maintaining the first normally open ABS solenoid valve 7 closed, the first normally closed ABS solenoid valve 8 is opened, and hydraulic oil is sent to the first reservoir 27, achieving active decompression of the front wheels. During this process, the CBS solenoid valves in the first linkage brake circuit 3 maintain their original state, and the rear wheel linkage braking is not disturbed.

[0075] If the driver operates both the front and rear brakes simultaneously, the rear wheels will be simultaneously subjected to both main braking and linkage braking, while the front wheels will be primarily braked. The main braking circuit for the rear wheels is independent of the linkage braking circuit 3 after the front linkage. During linkage braking, the rear main braking can still be operated normally. Similarly, if the rear brake is operated first, the front brake can also be operated normally, with no abnormal feel between the front and rear brakes, and the front and rear braking actions do not interfere with each other. If the front wheels show a tendency to lock up, the ECU will control the first normally open ABS solenoid valve 7 and the first normally closed ABS solenoid valve 8 to switch states for independent anti-lock braking control of the front wheels, while the linkage braking of the rear wheels continues. If the rear wheels show a tendency to lock up, in addition to the pressure reduction action of the first linkage braking circuit 3, the ECU also simultaneously controls the second normally open ABS solenoid valve 12 in the second main braking circuit 2 to close and the second normally closed ABS solenoid valve 13 to open. That is, in this scheme, both normal independent braking of the front and rear wheels and normal independent anti-lock braking control of the front and rear wheels can be achieved.

[0076] This embodiment employs a second braking unit 10 with an independent first linkage braking chamber 15 and a first main braking chamber 14. A first linkage sub-circuit 16 containing a first normally open CBS solenoid valve 18 and a second linkage sub-circuit 17 containing a first return pump 25 and a first normally closed CBS solenoid valve 19 are constructed between the first master cylinder 4 and the first linkage braking chamber 15. The second master cylinder 9 is connected to the first main braking chamber 14. While achieving linkage braking, the hydraulic circuits of the front and rear master cylinders are isolated from each other, solving the problem of mutual oil leakage between the front and rear brakes during linkage braking, and ensuring that the operation feel of the front and rear brakes is independent and does not interfere with each other. Meanwhile, the structure of this solution allows the first linkage braking circuit 3 to have an independent pressure reduction path that does not depend on the operating state of the second master cylinder 9 or the lock-up state of the first wheel 6. When the rear wheel shows signs of locking, it can independently control the opening and closing of the first normally open CBS solenoid valve 18 and the first normally closed CBS solenoid valve 19, as well as the operation of the first return pump 25, based on the degree of rear wheel lock-up and the inactive state of the second master cylinder 9. This maintains and reduces the pressure of the hydraulic fluid in the first linkage braking chamber 15 of the rear wheel, thereby achieving anti-lock braking control of the rear wheels without interfering with the main braking of the front wheels. Furthermore, this solution only requires optimizing the oil passages inside the ABSHCU and adding a few CBS solenoid valves to achieve a balance between linkage braking, independent anti-lock braking, and no oil leakage. The structure is compact and the cost is controllable.

[0077] Example 2

[0078] This embodiment provides a scenario where the rear brake is linked to the front brake. That is, the driver operates the rear brake operating device to put the rear brake master cylinder into a pressure build-up state, and the system performs linkage braking on the front wheels while realizing the main braking of the rear wheels.

[0079] This embodiment is similar to Embodiment 1, except that the linkage direction is interchanged. The first wheel 6 is the rear wheel, its first brake master cylinder 4 is the rear brake master cylinder, and its first brake unit 5 is the rear wheel brake unit; the second wheel 11 is the front wheel, its second brake master cylinder 9 is the front brake master cylinder, and its second brake unit 10 is the front wheel brake unit.

[0080] At this time, the second braking unit 10, which has an independent first main braking chamber 14 and a first linkage braking chamber 15, is the front wheel braking unit. This front wheel braking unit also adopts a six-piston structure, with the first main braking chamber 14 (four pistons) hydraulically connected to the second main braking circuit 2 (front main braking circuit), and the first linkage braking chamber 15 (two pistons) hydraulically connected to the first linkage braking circuit 3.

[0081] In the first linkage braking circuit 3, the first normally open CBS solenoid valve 18 on the first linkage sub-circuit 16 is hydraulically connected at both ends to the rear brake master cylinder and the first linkage braking chamber 15 of the front wheel brake unit, respectively. In the second linkage sub-circuit 17, the end of the first return pump 25 away from the first normally closed CBS solenoid valve 19 is hydraulically connected to the rear brake master cylinder, and the end of the first normally closed CBS solenoid valve 19 away from the first return pump 25 is hydraulically connected to the first linkage braking chamber 15 of the front wheel brake unit.

[0082] When the driver operates only the rear brake operating device, the hydraulic fluid output from the rear brake master cylinder drives the rear wheel main brake through the first main brake circuit 1 on the one hand, and drives the front wheel first linkage brake chamber 15 through the first linkage brake circuit 3 to generate auxiliary braking on the other hand.

[0083] If the front wheels show signs of locking up, the ECU, based on the front wheel speed signal and the inactive state of the second brake master cylinder 9, controls the first normally open CBS solenoid valve 18 in the first linkage brake circuit 3 to close, the first normally closed CBS solenoid valve 19 to open, and the first return pump 25 to operate. This actively pumps the hydraulic fluid in the first linkage brake chamber 15 of the front wheels back to the rear brake master cylinder side, thereby independently completing the anti-lock decompression control of the front wheels. The specific control logic is similar to that in Embodiment 1 and will not be repeated here.

[0084] Figure 5 The curves of each parameter changing with time under dual braking conditions on a low-friction road surface in the scenario before the linkage is presented. The horizontal axis represents the time process, and the vertical axis represents the speed or pressure change. The values ​​increase gradually from the origin outwards, and the curves of each parameter change synchronously with the braking sequence.

[0085] The black line at the top of the diagram is the brake signal line. During braking, the signal changes instantly and remains constant, indicating the start and end times of braking.

[0086] The two black curves at the bottom represent the reference vehicle speed. As you can see, they gradually decrease from the start of braking, indicating the vehicle's deceleration state.

[0087] The pink and blue curves that overlap with the two reference vehicle speed curves are the front wheel speed and rear wheel speed curves, respectively. It can be seen that the two wheel speeds decrease synchronously with the vehicle speed, reflecting the characteristics of wheel slip change.

[0088] The green curve represents the pressure signal of the front wheel linkage braking, the red curve overlapping with the green curve represents the pressure signal of the front wheel main braking, and the blue curve at the bottom represents the pressure signal of the rear wheels. These curves rapidly build up pressure upon triggering the braking signal, exhibiting a stepped dynamic change of pressure holding and depressurization, reflecting the ABS intervention and adjustment process.

[0089] As shown in the figure, during the entire braking process, there were no abnormal fluctuations or abrupt changes in the front and rear brake pressures, nor were there any sudden changes in wheel speed or wheel lock-up. This indicates that under the dual-brake operation with the rear brake linked to the front brake, the front and rear brake circuits operate independently without interference, there is no pressure fluctuation between them, and the front and rear brakes can independently and normally build up pressure, with their braking effects being cumulative. The brake pressure timing is regular, with no abnormal pressure reverse impact, confirming that the brake lever does not rebound or lock up, indicating no abnormal feel. Simultaneously, the ABS anti-lock braking system's adjustment logic response is also quite accurate, and the entire braking process is smooth, effectively verifying the reliability of this control system.

[0090] Example 3

[0091] like Figure 6 As shown, this embodiment provides a two-way linkage scenario, that is, two sets of opposing linkage braking circuits are set up in the HCU at the same time, so that the other wheel can be linked to brake regardless of whether the driver operates the front brake master cylinder or the rear brake master cylinder.

[0092] Based on Embodiment 1, this embodiment further includes a second linkage braking circuit 20 with the same structure as the first linkage braking circuit 3. Both braking units employ structures with independent main braking chambers and linkage braking chambers. In this embodiment, the first wheel 6 is the front wheel, and the first master cylinder 4 and the first braking unit 5 are the front wheel master cylinder and front wheel braking unit, respectively. The second wheel 11 is the rear wheel, and the second master cylinder 9 and the second braking unit 10 are the rear wheel master cylinder and rear wheel braking unit, respectively.

[0093] Specifically, both the first braking unit 5 and the second braking unit 10 are six-piston dual-chamber calipers. The second main braking chamber 21 of the first braking unit 5 is hydraulically connected to the first main braking circuit 1, and the first main braking chamber 14 of the second braking unit 10 is hydraulically connected to the second main braking circuit 2.

[0094] The first linkage braking circuit 3 is the same as in Embodiment 1, used to transmit the pressure of the first master cylinder 4 to the first linkage braking chamber 15 of the second braking unit 10. The second linkage braking circuit 20 is arranged oppositely: its two ends of the second normally open CBS solenoid valve 23 are hydraulically connected to the second master cylinder 9 and the second linkage braking chamber 22 of the first braking unit 5, respectively; the end of the second return pump 29 in its linkage sub-circuit away from the second normally closed CBS solenoid valve 24 is hydraulically connected to the second master cylinder 9, and the end of the second normally closed CBS solenoid valve 24 away from the second return pump 29 is hydraulically connected to the second linkage braking chamber 22 of the first braking unit 5.

[0095] The two sets of linkage braking circuits share the valve block base of the HCU, and a compact layout is achieved through internal oil passage optimization.

[0096] The control method in this embodiment is essentially a superposition of the control logic of Embodiment 1 and Embodiment 2.

[0097] When the driver operates only the front brake master cylinder, the first linkage braking circuit 3 is activated, applying the main brake to the front wheels and the linkage brake to the rear wheels. If the rear wheels show a tendency to lock up, the ECU, based on the rear wheel status and the information that the rear brake master cylinder is not operated, controls the first normally open CBS solenoid valve 18, the first normally closed CBS solenoid valve 19, and the first return pump 25 in the first linkage braking circuit 3 to independently depressurize the first linkage braking chamber 15 of the rear wheels.

[0098] When the driver operates only the rear brake master cylinder, the second linkage braking circuit 20 is activated, applying the main brake to the rear wheels and the linkage brake to the front wheels. If the front wheels show a tendency to lock up, the ECU controls the corresponding CBS solenoid valve and the second return pump 29 in the second linkage braking circuit 20 to independently depressurize the second linkage braking chamber 22 of the front wheels.

[0099] When the driver operates the front and rear master cylinders simultaneously, the system is equivalent to two independent braking circuits for the front and rear wheels working in parallel. The braking of the front wheels includes the main braking of the first master cylinder 4 and the linkage braking of the second master cylinder 9. The braking of the rear wheels includes the main braking of the second master cylinder 9 and the linkage braking of the first master cylinder 4. The ECU independently controls the ABS solenoid valve and CBS solenoid valve of the corresponding wheel according to the lock-up state of the two wheels to achieve independent anti-lock braking adjustment of the front and rear wheels.

[0100] Example 4

[0101] This embodiment provides a vehicle that includes the HCU-integrated CBS anti-lock braking system described in any of the above embodiments. The vehicle can be a motorcycle, electric motorcycle, electric bicycle, or other two-wheeled vehicle. Due to the braking system provided by this invention, the vehicle can achieve combined braking of the front and rear wheels during braking, reducing the driver's operational difficulty. Furthermore, when any wheel shows a tendency to lock up, regardless of whether the corresponding master cylinder is operated by the driver, and regardless of whether the wheel is locking up due to the main brake or the combined braking, the system can actively implement independent anti-lock control, significantly improving the vehicle's driving stability and safety during emergency braking and on low-friction surfaces. In addition, because the hydraulic circuits of the front and rear master cylinders are isolated from each other, there is no oil leakage between the front and rear brakes during combined braking, and the front and rear brake operation feels independent and do not interfere with each other, maintaining a good driving experience while achieving combined braking and independent anti-lock effects. Moreover, the CBS function is integrated into the HCU, and each CBS solenoid valve is directly integrated into the ABS valve block substrate, resulting in a simple and compact braking system structure with advantages such as limited space occupation and high assembly efficiency.

[0102] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A two-wheeled vehicle anti-lock braking system that links the front and rear wheels, characterized in that, It includes a hydraulic circuit and an electronic control unit. The hydraulic circuit includes a first main braking circuit (1), a second main braking circuit (2), and a first linkage braking circuit (3). The first master brake circuit (1) corresponds to the first master brake cylinder (4), the first brake unit (5), and the first wheel (6), and has a first normally open ABS solenoid valve (7) and a first normally closed ABS solenoid valve (8) controlled by the electronic control unit to perform master brake anti-lock control on the first wheel (6). The second master brake circuit (2) corresponds to the second master brake cylinder (9), the second brake unit (10), and the second wheel (11), and has a second normally open ABS solenoid valve (12) and a second normally closed ABS solenoid valve (13) controlled by the electronic control unit to perform master brake anti-lock control on the second wheel (11). The second braking unit (10) has a first main braking chamber (14) and a first linkage braking chamber (15) that are independent of each other. The first main braking chamber (14) is hydraulically connected to the second main braking circuit (2), and the first linkage braking chamber (15) is hydraulically connected to the first linkage braking circuit (3). The first linkage braking circuit (3) includes a first linkage sub-circuit (16) and a second linkage sub-circuit (17). The first linkage sub-circuit (16) has a first normally open CBS solenoid valve (18) electrically connected to the electronic control unit, and is hydraulically connected to the first master cylinder (4) and the first linkage brake chamber (15) respectively according to the direction of brake fluid flow; the second linkage sub-circuit (17) has a first normally closed CBS solenoid valve (19) electrically connected to the electronic control unit, and is hydraulically connected to the first linkage brake chamber (15) and the first master cylinder (4) respectively according to the direction of brake fluid flow, for use in linkage braking of the second wheel (11) and linkage braking anti-lock control.

2. The anti-lock braking control system for two-wheeled vehicles with front and rear wheel linkage according to claim 1, characterized in that, The first wheel (6) is the front wheel, the second wheel (11) is the rear wheel, the first main braking circuit (1) corresponds to the front wheel and the master cylinder and braking unit of the front wheel, and the second main braking circuit (2) corresponds to the rear wheel and the master cylinder and braking unit of the rear wheel. Alternatively, the second wheel (11) is the front wheel, the first wheel (6) is the rear wheel, the second master brake circuit (2) corresponds to the front wheel and the master brake cylinder and brake unit of the front wheel, and the first master brake circuit (1) corresponds to the rear wheel and the master brake cylinder and brake unit of the rear wheel.

3. The anti-lock braking control system for two-wheeled vehicles with front and rear wheel linkage according to claim 1, characterized in that, The hydraulic circuit also includes a second linkage braking circuit (20). The first braking unit (5) has a second main braking chamber (21) and a second linkage braking chamber (22) that are independent of each other. The second main braking chamber (21) is hydraulically connected to the first main braking circuit (1), and the second linkage braking chamber (22) is hydraulically connected to the second linkage braking circuit (20). The second linkage braking circuit (20) is symmetrical in structure to the first linkage braking circuit (3). It includes a second normally open CBS solenoid valve (23) and a second normally closed CBS solenoid valve (24) electrically connected to the electronic control unit, for linkage braking of the first wheel (6) and linkage braking anti-lock control.

4. The anti-lock braking control system for two-wheeled vehicles with front and rear wheel linkage according to any one of claims 1 to 3, characterized in that, The braking unit with a linkage braking chamber has two sets of pistons. One set of pistons is hydraulically connected to the corresponding main braking chamber, and the other set of pistons is hydraulically connected to the corresponding linkage braking chamber. Each set of pistons includes one or more pistons, which are hydraulically driven by the main braking chamber or linkage braking chamber in hydraulic communication with it to contact the brake pads to brake the corresponding wheel. In a single braking unit, the volume of the main braking chamber is larger than the volume of the linkage braking chamber, and the number of pistons corresponding to the main braking chamber is greater than the number of pistons corresponding to the linkage braking chamber.

5. The anti-lock braking control system for two-wheeled vehicles with front and rear wheel linkage according to claim 4, characterized in that, The braking unit with the linkage braking chamber is a six-piston braking unit. The main braking chamber includes two main braking sub-chambers, and the linkage braking chamber is located between the two main braking sub-chambers. The sum of the volumes of the two main braking sub-chambers is greater than the volume of the linkage braking chamber. Each main braking chamber corresponds to two pistons, and the linkage braking chamber corresponds to two pistons, so that four pistons are responsible for the main braking and two pistons are responsible for the linkage auxiliary braking.

6. The anti-lock braking control system for two-wheeled vehicles with front and rear wheel linkage according to any one of claims 1 to 3, characterized in that, The first normally closed ABS solenoid valve (8) and the first normally closed CBS solenoid valve (19) are hydraulically connected to the first reservoir (27) and hydraulically connected to the first brake master cylinder (4) through the first return pump (25); The second normally closed ABS solenoid valve (13) is hydraulically connected to the second reservoir (30) alone or together with the second normally closed CBS solenoid valve (24), and is hydraulically connected to the second brake master cylinder (9) via the second return pump (29). The first return pump (25) and the second return pump (29) are electrically connected to the motor (28), and the motor (28) is electrically connected to the electronic control unit.

7. The anti-lock braking control system for two-wheeled vehicles with front and rear wheel linkage according to claim 1, characterized in that, Each CBS solenoid valve and each ABS solenoid valve are integrated and mounted on the same valve block base. Each return pump has a check valve (26) at both ends that allows hydraulic fluid to flow only from the braking unit to the master cylinder.

8. A two-wheeled vehicle, characterized in that, The anti-lock braking system for two-wheeled vehicles with front and rear wheel linkage, as described in any one of claims 1 to 7, is included.

9. An anti-lock braking control method based on the anti-lock braking control system for two-wheeled vehicles with front and rear wheel linkage as described in any one of claims 1 to 7, characterized in that, include: When the master cylinder is compressed, the wheel connected to it via the master brake circuit is braked by the master brake, and the wheel connected to it via the linkage brake circuit is braked by the linkage brake. The electronic control unit receives vehicle status information in real time, including the rotational speed of both wheels, the vehicle reference speed, and the pressure build-up status of the two brake master cylinders; Based on the vehicle status information, determine whether each wheel is in the first trigger state or the second trigger state; For the wheel determined to be in the first trigger state, activate the pressure-holding anti-lock braking control for that wheel: If the master cylinder of the brake is not under pressure, the normally open CBS solenoid valve in the linkage braking circuit is closed, and the other solenoid valves remain in the normally open / normally closed state. Otherwise, the normally open ABS solenoid valve in its main braking circuit is closed, or the normally open CBS solenoid valve in its linkage braking circuit is closed at the same time, while the other solenoid valves remain in the normally open / normally closed state. For the wheel determined to be in the second trigger state, activate the decompression anti-lock braking control for that wheel: If the master cylinder does not build up pressure, the normally open CBS solenoid valve in the linkage braking circuit is closed, the normally closed CBS solenoid valve is open, and the solenoid valve in the master braking circuit does not operate. Otherwise, the normally open ABS solenoid valve in its main braking circuit is closed and the normally closed ABS solenoid valve is open, or the normally open CBS solenoid valve in its linkage braking circuit is closed and the normally closed CBS solenoid valve is open.

10. The anti-lock braking control method according to claim 9, characterized in that, The following method is used to determine whether the front and rear wheels are in the first or second trigger state: Calculate the deceleration of the corresponding wheel based on the wheel speed change trend of each wheel; Calculate the wheel slip ratio of each wheel based on its current wheel speed and the vehicle's reference speed. When the deceleration is greater than the first preset deceleration threshold, or the wheel slip ratio is greater than the first preset slip ratio threshold, the corresponding wheel is determined to be in the first trigger state. When the deceleration is greater than the second preset deceleration threshold, or the wheel slip ratio is greater than the second preset slip ratio threshold, the corresponding wheel is determined to be in the second trigger state. The second preset deceleration threshold is greater than the first preset deceleration threshold; The second preset slip ratio threshold is greater than the first preset slip ratio threshold.

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