JP5124037B2 - Brake device - Google Patents

Description

  The present invention relates to a brake device including a master cylinder that generates a brake fluid pressure by a driver's braking operation and an electrical fluid pressure generating unit that generates a brake fluid pressure by an electrically controllable actuator.

  A so-called BBW (brake-by-wire) is performed in which the braking operation of the driver is converted into an electric signal to operate the electric hydraulic pressure generating means, and the wheel cylinder is operated with the brake hydraulic pressure generated by the electric hydraulic pressure generating means. ) Type brake device is known from US Pat.

  By the way, in this kind of BBW type brake device, when the electric hydraulic pressure generating means fails, the brake hydraulic pressure generated by the master cylinder is directly transmitted to the wheel cylinder to brake the wheel, thereby fail-safe function. To come to show. Moreover, the master cylinder is a tandem type that supplies brake hydraulic pressure separately to the two hydraulic systems, and even if a leak occurs in one hydraulic system, one of the wheels can be braked by the other hydraulic system. It is like that.

  FIG. 7 shows the structure of a conventional electric hydraulic pressure generating means (motor cylinder 23). A rear piston 38A and a front piston urged in a backward direction by a pair of return springs 37A and 37B inside a cylinder body 36. The part piston 38B is slidably disposed, and a rear liquid chamber 39A is defined on the front surface of the rear piston 38A, and a front liquid chamber 39B is defined on the front surface of the front piston 38B.

  A rear reservoir chamber 38a is formed on the outer periphery of the rear piston 38A to prevent air from entering the rear liquid chamber 39A, and air is prevented from entering the front liquid chamber 39B on the outer periphery of the front piston 38B. A front reservoir chamber 38b is formed. The rear inlet port 40A of the rear liquid chamber 39A and the rear supply port 49A of the rear reservoir chamber 38a communicate with the master cylinder, and the rear outlet port 41A of the rear liquid chamber 39A communicates with the wheel cylinder. The front inlet port 40B of the front liquid chamber 39B and the front supply port 49B of the front reservoir chamber 38b communicate with the master cylinder, and the front outlet port 41B of the front liquid chamber 39B communicates with the wheel cylinder.

  A rear first cup seal C1 is provided forward (at the front end of the rear piston 38A so as to exhibit a sealing function during advance), and a rear second cup seal C2 is provided forward at the rear end of the rear piston 38A. A front first cup seal C3 is provided forward at the front end of the front piston 38B, and a front second cup seal C4 is provided rearward at the rear end of the front piston 38B (so as to exhibit a sealing function when moving backward). Is provided.

JP 2003-137084 A

  By the way, in the structure of the conventional motor cylinder 23, when the wheel cylinder is operated with the brake fluid pressure generated by the motor cylinder 23 and the master cylinder is generated, the front supply port 49B is connected to the master cylinder. When the first hydraulic system fails and the rear fluid chamber 39A of the motor cylinder 23 is released to the atmosphere, the brake fluid pressure generated in the master cylinder is changed to the front supply port 49B → the front reservoir chamber 38b → the front portion. There is a possibility that leakage will occur in the path from the second cup seal C4 to the rear liquid chamber 39A, and the second hydraulic system connected to the front liquid chamber 39B will also fail at the same time.

  The present invention has been made in view of the above circumstances, and in a BBW brake device having two hydraulic systems, it is an object to ensure the function of the other hydraulic system when one hydraulic system fails. To do.

  To achieve the above object, according to the first aspect of the present invention, a master cylinder that generates brake fluid pressure by a driver's braking operation, and an actuator that communicates with the master cylinder and is electrically controllable. A hydraulic fluid pressure generating means having a rear fluid chamber and a front fluid chamber for generating a brake fluid pressure, and a plurality of wheels for communicating with the rear fluid chamber and the front fluid chamber to generate a braking force for braking the wheel. A brake device that operates a wheel cylinder with a brake hydraulic pressure generated by a master cylinder when the electric hydraulic pressure generating means fails, wherein the electric hydraulic pressure generating means is advanced by an actuator to move the rear liquid Rear piston and front piston that generate brake fluid pressure in the chamber and front fluid chamber, respectively, and formed in the rear fluid chamber and connected to the master cylinder A rear inlet port connected to the wheel cylinder, a rear outlet port connected to the wheel cylinder, a rear supply port formed adjacent to the rear inlet port and connected to the master cylinder, and a front liquid chamber formed to connect to the master cylinder A front outlet port connected to the front inlet port and the wheel cylinder, a front supply port formed adjacent to the rear of the front inlet port and connected to the master cylinder, and disposed forwardly at the front end of the rear piston Rear first cup seal, rear second cup seal disposed forward at the rear end of the rear piston, front first cup seal disposed forward at the front end of the front piston, and rear end of the front piston A rear second cup seal disposed in a rearward direction, and the communication between the master cylinder and the wheel cylinder is communicated with the rear piston. And the front piston moves forward to close the rear inlet port and the front inlet port, thereby blocking the master cylinder, the rear inlet port, and the front inlet port. A shut-off valve disposed between the two is configured as a normally open solenoid valve, and the front second cup seal prevents the brake fluid from flowing out from the rear fluid chamber to the master cylinder side, and a front portion of the front piston. A front third cup seal that is disposed forward and adjacent to the front of the second cup seal and prevents the brake fluid supplied from the master cylinder to the front inlet port or the front supply port from flowing into the rear fluid chamber. A brake device characterized in that is provided is proposed.

  The motor cylinder 23 according to the embodiment corresponds to the electrical hydraulic pressure generating means of the present invention.

  According to the configuration of the first aspect, when the wheel cylinder is operated with the brake hydraulic pressure generated by the master cylinder due to the failure of the electric hydraulic pressure generating means, the second fluid chamber connected to the rear fluid chamber of the electric hydraulic pressure generating means is provided. When the first hydraulic system fails and the atmosphere is released, braking is performed with the brake hydraulic pressure of the second hydraulic system transmitted from the master cylinder to the wheel cylinder through the front hydraulic chamber of the electrical hydraulic pressure generating means. Is called. At this time, since the front third cup seal facing forward is disposed between the front supply port communicating with the master cylinder and the rear liquid chamber opened to the atmosphere due to failure, the brake hydraulic pressure generated by the master cylinder is reduced. Leakage from the front supply port through the rear liquid chamber is prevented by the front third cup seal, and braking by the second hydraulic system connected to the front liquid chamber of the electric hydraulic pressure generating means is ensured. it can.

Hydraulic circuit diagram for normal operation of vehicle brake device according to reference example Hydraulic circuit diagram at the time of abnormality corresponding to FIG. 1 is an enlarged view of the main part of FIG. Hydraulic circuit diagram at normal time of vehicle brake device according to embodiment Hydraulic circuit diagram at the time of abnormality corresponding to FIG. 4 is an enlarged view of the main part of FIG. Cross section of conventional motor cylinder

  Hereinafter, reference examples and embodiments of the present invention will be described with reference to the accompanying drawings.

  FIGS. 1 to 3 show a reference example of the present invention, FIG. 1 is a hydraulic circuit diagram in a normal state of a vehicle brake device, FIG. 2 is a hydraulic circuit diagram in an abnormal state corresponding to FIG. FIG. 2 is an enlarged view of a main part of FIG. 1.

  As shown in FIG. 1, the tandem master cylinder 11 includes two fluid chambers 13A and 13B that output brake fluid pressure in accordance with the pedaling force of the driver stepping on the brake pedal 12, and one fluid chamber 13A is provided. Is connected to the wheel cylinders 16 and 17 of the disc brake devices 14 and 15 of the left front wheel and the right rear wheel via the liquid paths Pa, Pb, Pc, Pd and Pe, and the other liquid chamber 13B is connected to the liquid path Qa. , Qb, Qc, Qd, Qe, for example, are connected to the wheel cylinders 20, 21 of the disc brake devices 18, 19 of the right front wheel and the left rear wheel.

  A shutoff valve 22A, which is a normally open solenoid valve, is disposed between the fluid paths Pa, Pb, and a shutoff valve 22B, which is a normally open solenoid valve, is disposed between the fluid paths Qa, Qb, and the fluid paths Pb, Qb and the fluid path. The motor cylinder 23 is disposed between Pc and Qc, and the ABS device 24 is disposed between the liquid paths Pc and Qc and the liquid paths Pd and Pe; Qd and Qe.

  A stroke simulator 26 is connected to the liquid paths Ra and Rb branched from the liquid path Qa via a reaction force permission valve 25 which is a normally closed solenoid valve. The stroke simulator 26 is a cylinder 27 in which a piston 29 urged by a spring 28 is slidably fitted, and a liquid chamber 30 formed on the side opposite to the spring 28 of the piston 29 communicates with a liquid path Rb. .

  The actuator 31 of the motor cylinder 23 includes a drive bevel gear 33 provided on the output shaft of the electric motor 32, a driven bevel gear 34 that meshes with the drive bevel gear 33, and a ball screw mechanism 35 that is operated by the driven bevel gear 34. A pair of pistons 38A and 38B urged in a backward direction by a pair of return springs 37A and 37B are slidably disposed in a cylinder body 36 of the motor cylinder 23, and a rear liquid chamber is provided in front of the rear piston 38A. 39A is defined, and a front liquid chamber 39B is defined on the front surface of the front piston 38B.

  As apparent from FIGS. 1 and 3, the rear liquid chamber 39A communicates with the liquid paths Pb and Pc via the rear inlet port 40A and the rear outlet port 41A, respectively, and the rear supply port 49A, the liquid path Rc, and the liquid. It communicates with the reservoir 50 via the path Re. The front liquid chamber 39B communicates with the liquid paths Qb and Qc through the front inlet port 40B and the front outlet port 41B, respectively, and the reservoir 50 through the front supply port 49B, the liquid path Rd, and the liquid path Re. Communicate with.

  A rear first cup seal C1 is provided forward (at the front end of the rear piston 38A so as to exhibit a sealing function during advance), and a rear second cup seal C2 is provided forward at the rear end of the rear piston 38A. A front first cup seal C3 is provided forward at the front end of the front piston 38B, and a front second cup seal C4 is provided rearward at the rear end of the front piston 38B (so as to exhibit a sealing function when moving backward). Is provided.

  A rear reservoir chamber 38a sandwiched between the rear first and second cup seals C1 and C2 is formed at an intermediate portion of the rear piston 38A, and a rear supply port 49A communicates with the rear reservoir chamber 38a. A front reservoir chamber 38b sandwiched between the front first and second cup seals C3 and C4 is formed at an intermediate portion of the front piston 38B, and a front supply port 49B communicates with the front reservoir chamber 38b. To do.

  The rear liquid chamber 39A is sandwiched between the front-facing rear first cup seal C1 and the rear-facing front second cup seal C4 to ensure liquid tightness, and the rear piston 38A leaks backward from the rear reservoir chamber 38a. Is blocked by a forward facing rear second cup seal C2.

  When the motor cylinder 23 is not operated, the rear first cup seal C1 of the rear piston 38A is positioned immediately behind the rear inlet port 40A. When the rear piston 38A is slightly advanced, the rear first cup seal C1 is moved to the rear inlet port 40A. And brake fluid pressure is generated in the first fluid chamber 39A. When the motor cylinder 23 is not operated, the front first cup seal C3 of the front piston 38B is located immediately after the front inlet port 40B, and when the front piston 38B slightly advances, the front first cup seal C3 is moved forward. Passes through the front inlet port 40B, and brake fluid pressure is generated in the front fluid chamber 39B.

  Thus, when the electric motor 32 is driven in one direction, the rear and front pistons 38A and 38B move forward via the drive bevel gear 33, the driven bevel gear 34 and the ball screw mechanism 35, and the rear and front connected to the liquid passages Pb and Qb. The brake fluid pressure is generated in the rear and front fluid chambers 39A and 39B at the moment when the part inlet ports 40A and 40B are closed, and the brake fluid pressure is supplied to the fluid passages Pc and Pc via the rear and front outlet ports 41A and 41B. Qc can be output.

  As shown in FIG. 1, the structure of the ABS device 24 is well known, and the system of the left front wheel and right rear wheel disc brake devices 14, 15 and the system of the right front wheel and left rear wheel disc brake devices 18, 19 are shown. Are provided with the same structure. As a representative example, the system of the disc brake devices 14 and 15 for the left front wheel and the right rear wheel will be described. Between the liquid passage Pc and the liquid passages Pd and Pe, in-valves 42 and 42 made up of a pair of normally open solenoid valves are arranged. In addition, out valves 44 and 44, which are normally closed electromagnetic valves, are disposed between the fluid paths Pd and Pe on the downstream side of the in valves 42 and 42 and the reservoir 43. A hydraulic pump 47 sandwiched between a pair of check valves 45 and 46 is disposed between the reservoir 43 and the fluid path Pc. The hydraulic pump 47 is driven by an electric motor 48.

  An electronic control unit (not shown) that controls the operation of the shutoff valves 22A and 22B, the reaction force permission valve 25, the motor cylinder 23, and the ABS device 24 includes a hydraulic pressure sensor Sa that detects the brake hydraulic pressure generated by the master cylinder 11. The hydraulic pressure sensor Sb for detecting the brake hydraulic pressure transmitted to the disc brake devices 18 and 19 and the wheel speed sensor Sc for detecting the wheel speed of each wheel are connected.

  Next, the operation of the reference example of the present invention having the above configuration will be described.

  When the system functions normally, the shutoff valves 22A and 22B made of normally open solenoid valves are demagnetized and opened, and the reaction force permission valve 25 made of normally closed solenoid valves is excited and opened. In this state, when the hydraulic pressure sensor Sa provided in the liquid path Qa detects the depression of the brake pedal 12 by the driver, the actuator 31 of the motor cylinder 23 is operated, and the rear and front pistons 38A and 38B move forward. Brake fluid pressure is generated in the rear and front fluid chambers 39A and 39B. The brake fluid pressure is transmitted to the wheel cylinders 16, 17, 20, and 21 of the disc brake devices 14, 15, 18, and 19 via the in-valves 42 that are opened by the ABS device 24, and brakes each wheel.

  When the rear part of the motor cylinder 23 and the front pistons 38A and 38B are slightly advanced, the rear part and the front inlet ports 40A and 40B are closed, and the fluid passages Pb and Qb communicate with the rear part and the front liquid chambers 39A and 39B. As a result, the brake fluid pressure generated by the master cylinder 11 is not transmitted to the disc brake devices 14, 15, 18, 19. At this time, the brake fluid pressure generated in the other fluid chamber 13B of the master cylinder 11 is transmitted to the fluid chamber 30 of the stroke simulator 26 via the opened reaction force permitting valve 25, and the piston 29 resists the spring 28. Thus, the stroke of the brake pedal 12 can be allowed and a pseudo pedal reaction force can be generated to eliminate the driver's uncomfortable feeling.

  Then, the brake fluid pressure by the motor cylinder 23 detected by the fluid pressure sensor Sb provided in the fluid passage Qc has a magnitude corresponding to the brake fluid pressure by the master cylinder 11 detected by the fluid pressure sensor Sa provided in the fluid passage Qa. As described above, by controlling the operation of the actuator 31 of the motor cylinder 23, it is possible to cause the disc brake devices 14, 15, 18, 19 to generate a braking force corresponding to the pedaling force input to the brake pedal 12 by the driver.

  During the braking described above, when it is detected that the slip ratio of any wheel has increased due to the output of the wheel speed sensor Sc..., The shutoff valve 22A comprising a normally open solenoid valve is detected. 22B is excited to close the valve and the motor cylinder 23 is maintained in the operating state, and the ABS device 24 is operated in this state to prevent the wheels from being locked.

  That is, when a predetermined wheel tends to be locked, the in-valve 42 connected to the wheel cylinder of the disc brake device of the wheel is closed and the out-valve 44 is opened with the transmission of the brake fluid pressure from the motor cylinder 23 blocked. The wheel does not lock by performing a pressure reducing action to release the brake fluid pressure of the wheel cylinder to the reservoir 43 and a holding action to close the out valve 44 and hold the brake fluid pressure of the wheel cylinder. So as to reduce the braking force.

  As a result, when the wheel speed recovers and the slip ratio decreases, the braking force of the wheel is increased by opening the in-valve 42 and increasing the brake fluid pressure of the wheel cylinder. When the wheel becomes locked again by this pressure increasing action, the pressure reduction, holding, and pressure increasing are executed again, and the maximum braking force can be generated while suppressing the wheel lock by repeating the operation. In the meantime, the brake fluid that has flowed into the reservoir 43 is returned to the upstream fluid paths Pc and Qc by the hydraulic pump 47.

  While the above-described ABS control is executed, the shutoff valves 22A and 22B are maintained in the closed state, so that the hydraulic pressure change due to the operation of the ABS device 24 becomes a kickback, and the master cylinder 11 transfers to the brake pedal 12. It can be prevented from being transmitted.

  When the motor cylinder 23 becomes inoperable due to a power failure or the like, braking is performed by the brake fluid pressure generated by the master cylinder 11 instead of the brake fluid pressure generated by the motor cylinder 23.

  When the power supply fails, as shown in FIG. 2, the shut-off valves 22A and 22B made of normally open solenoid valves are automatically opened, and the reaction force permission valve 25 made of normally closed solenoid valves is automatically closed. The in-valve 42 made up of a normally-open electromagnetic valve is automatically opened, and the out-valve 44 made up of a normally-closed electromagnetic valve is automatically closed. In this state, the brake fluid pressure generated in the fluid chambers 13A and 13B of the master cylinder 11 is not absorbed by the stroke simulator 26, but the shut-off valves 22A and 22B, the rear part of the motor cylinder 23, and the front fluid chambers 39A and 39B. And the wheel cylinders 16, 17, 20, and 21 of the disc brake devices 14, 15, 18, and 19 of the respective wheels are operated through the in-valves 42, so that the braking force can be generated without any trouble.

  At the time of the abnormality described above, the left side of one of the liquid chambers 13A of the master cylinder 11 passes through the liquid path Pa, the shutoff valve 22A, the liquid path Pb, the rear liquid chamber 39A of the motor cylinder 23, the liquid path Pc, and the liquid paths Pd and Pe. When the first hydraulic system connected to the wheel cylinders 16 and 17 of the disc brake devices 14 and 15 of the front wheel and the right rear wheel fails and the brake fluid leaks, the fluid path from the other fluid chamber 13B of the master cylinder 11 Qa, shutoff valve 22B, liquid path Qb, front cylinder chamber 39B of motor cylinder 23, liquid path Qc and liquid cylinders Qd, Qe, wheel cylinders 20, right and left rear wheel disc cylinders 18, 19 The second hydraulic system connected to 21 can be operated to generate a braking force on at least two of the four wheels, thereby enabling fail-safety.

  At this time, in the conventional example shown in FIG. 7, since the front supply port 49B is connected to the master cylinder 11 instead of the reservoir 50, the first hydraulic system fails and the rear liquid chamber 39A of the motor cylinder 23 When the air is released, the brake fluid pressure generated in the fluid chamber 13B of the master cylinder 11 leaks through the path of the front supply port 49B → the front reservoir chamber 38b → the front second cup seal C4 → the rear fluid chamber 39A. Therefore, the second hydraulic system connected to the front liquid chamber 39B may also be lost at the same time.

  However, in the reference example shown in FIG. 3, since the front supply port 49B is connected to the reservoir 50, even if the first hydraulic system fails and the rear liquid chamber 39A of the motor cylinder 23 is released to the atmosphere. The brake fluid pressure generated in the fluid chamber 13B of the master cylinder 11 is not transmitted to the front supply port 49B. Therefore, the brake fluid pressure is not applied to the front reservoir chamber 38b → the front second cup seal C4 → the rear fluid chamber 39A. It is possible to prevent the second hydraulic system connected to the front liquid chamber 39B from failing at the same time without leaking along the path.

  4 to 6 show an embodiment of the present invention. FIG. 4 is a hydraulic circuit diagram when the vehicle brake device is normal. FIG. 5 is a hydraulic circuit diagram when an abnormality corresponding to FIG. 6 is an enlarged view of a main part of FIG.

  In the reference example, the rear and front supply ports 49A and 49B of the motor cylinder 23 are connected to the reservoir 50. However, in the embodiment, the rear and front supply ports 49A and 49B are similar to the conventional example shown in FIG. The master cylinder 11 is connected to a pair of liquid chambers 13A and 13B. Instead, a front-facing front third cup seal C5 facing the rear end of the front reserve chamber 38b is disposed immediately before the front second cup seal C4 of the front piston 38B.

  Therefore, at the time of abnormality, the left side of one of the liquid chambers 13A of the master cylinder 11 is left via the liquid path Pa, the shutoff valve 22A, the liquid path Pb, the rear liquid chamber 39A of the motor cylinder 23, the liquid path Pc, and the liquid paths Pd and Pe. When the first hydraulic system connected to the wheel cylinders 16 and 17 of the disc brake devices 14 and 15 of the front wheel and the right rear wheel fails and the brake fluid leaks, the fluid path from the other fluid chamber 13B of the master cylinder 11 Even if the brake fluid pressure is transmitted to the front fluid chamber 39B and the front reserve chamber 28b of the motor cylinder 23 via Qa, the shutoff valve 22B, and the fluid path Qb, the front reserve chamber 28b remains in the front third cup seal C5. Since the communication with the rear liquid chamber 39A opened to the atmosphere by the air is blocked, the brake fluid pressure in the front liquid chamber 39B is prevented from leaking through the rear liquid chamber 39A. Second hydraulic lines leading to 39B are not able to failure at the same time.

  The embodiments of the present invention have been described above, but various design changes can be made without departing from the scope of the present invention.

  For example, although the brake device of the embodiment includes the ABS device 24, the present invention can also be applied to a brake device that does not have the ABS device 24.

11 Master cylinder 16 Wheel cylinder 17 Wheel cylinder 20 Wheel cylinder 21 Wheel cylinder 22A Shut-off valve 22B Shut-off valve 23 Motor cylinder (electrical fluid pressure generating means)
31 Actuator 38A Rear piston 38B Front piston 39A Rear fluid chamber 39B Front fluid chamber 40A Rear inlet port 40B Front inlet port 41A Rear outlet port 41B Front outlet port 49A Rear supply port 49B Front supply port C1 Rear first cup Seal C2 Rear second cup seal C3 Front first cup seal C4 Front second cup seal C5 Front third cup seal

Claims (1)

A master cylinder (11) that generates a brake fluid pressure by a driver's braking operation;
Electrical hydraulic pressure generating means (39A) having a rear fluid chamber (39A) and a front fluid chamber (39B) communicating with the master cylinder (11) and generating brake fluid pressure by an electrically controllable actuator (31) 23)
A plurality of wheel cylinders (16, 17, 20, 21) that generate braking force to brake the wheels in communication with the rear liquid chamber (39A) and the front liquid chamber (39B), respectively.
A brake device for operating a wheel cylinder (16, 17, 20, 21) with a brake hydraulic pressure generated by a master cylinder (11) when an electric hydraulic pressure generating means (23) fails.
The electrical hydraulic pressure generating means (23)
A rear piston (38A) and a front piston (38B) which are advanced by an actuator (31) to generate brake fluid pressure in the rear liquid chamber (39A) and the front liquid chamber (39B), respectively;
A rear inlet port (40A) formed in the rear liquid chamber (39A) and connected to the master cylinder (11) and a rear outlet port (41A) connected to the wheel cylinders (16, 17);
A rear supply port (49A) formed adjacent to the rear of the rear inlet port (40A) and connected to the master cylinder (11);
A front inlet port (40B) connected to the master cylinder (11) formed in the front liquid chamber (39B) and a front outlet port (41B) connected to the wheel cylinders (20, 21);
A front supply port (49B) formed adjacent to the rear of the front inlet port (40B) and connected to the master cylinder (11);
A rear first cup seal (C1) disposed forwardly at the front end of the rear piston (38A);
A rear second cup seal (C2) disposed forward at the rear end of the rear piston (38A);
A front first cup seal (C3) disposed forward at the front end of the front piston (38B);
A front second cup seal (C4) disposed rearward at the rear end of the front piston (38B);
With
The rear piston (38A) and the front piston (38B) advance through the communication between the master cylinder (11) and the wheel cylinder (16, 17, 20, 21), respectively, and the rear inlet port (40A) and In what is configured to block by closing the front inlet port (40B),
A shut-off valve (22A, 22B) disposed between the master cylinder (11) and the rear inlet port (40A) and the front inlet port (40B) is a normally open solenoid valve, and the front portion The second cup seal (C4) prevents the brake fluid from flowing out from the rear fluid chamber (39A) to the master cylinder (11), and the front second cup seal (C4) of the front piston (38B) Brake fluid supplied from the master cylinder (11) to the front inlet port (40B) or the front supply port (49B) is prevented from flowing into the rear fluid chamber (39A). A brake device characterized in that a front third cup seal (C5) is provided.

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