JP5389509B2 - Brake device - Google Patents

Description

The present invention is configured separately from the master cylinder that generates hydraulic pressure corresponding to the operation amount of the brake pedal, the brake operation amount detection means that detects the operation amount of the brake pedal, and the master cylinder, Brake force generating means for generating a braking force of a predetermined magnitude according to the brake operation amount detected by the brake operation amount detection means, and a depression for detecting the depression speed of the brake pedal from the time change rate of the stroke of the brake pedal and a speed detection means, the braking force generating means, hardly generate a braking force in the first region detected brake operation amount increases from zero, the second region is larger brake operation amount than the first region In the third region where the braking force is suddenly increased and the brake operation amount is larger than that in the second region, the braking force is increased as the brake operation amount increases. That relates to a brake system.

  The braking force is not generated as long as the driver depresses the brake pedal, but when the pedaling force reaches a predetermined value, the braking force is suddenly raised, and thereafter the braking force is increased as the pedaling force increases. In a brake device that performs power jump-in control, a device that changes the jump-in amount of the braking force in accordance with the vehicle speed is known from Patent Document 1 below.

JP-T-2001-509753

  By the way, for example, the driver depresses the brake pedal strongly at the time of a panic brake for avoiding a collision with an obstacle. At this time, if the amount of jump-in of the braking force is small, the driver can fully experience the generation of the braking force. Therefore, there is a possibility that the brake feeling may be lowered due to anxiety about whether the requested braking force is actually generated.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to enhance the brake feeling when the driver demands the generation of a large braking force and depresses the brake pedal strongly.

In order to achieve the above object, according to the first aspect of the present invention, a master cylinder that generates hydraulic pressure in response to an operation amount of the brake pedal, and a brake operation amount that detects the operation amount of the brake pedal. detection means, is configured separately and independently from the master cylinder, a braking force generating means for generating a braking force of a predetermined size in accordance with the amount of brake operation the brake operating amount detecting means detects, of the brake pedal Stepping speed detecting means for detecting the stepping speed from the time rate of change of the stroke of the brake pedal , wherein the braking force generating means generates almost no braking force in the first region where the detected brake operation amount increases from zero. In the second region where the brake operation amount is larger than that in the first region, the braking force is suddenly increased, and the brake operation amount is larger than that in the second region. Met brake system is increased in accordance with the braking force to increase the braking operation amount in range, the interlocking brake pedal, between the front end of the linked push rods and pistons of the master cylinder, to generate invalid stroke The stepping speed detecting means detects the stepping speed of the brake pedal when the stroke of the brake pedal is in the invalid stroke range, and the braking force generating means A brake device is proposed that increases the amount of braking force in the second region as the depressed speed increases .

Incidentally, in response to the braking force generating means of the slave cylinder 23 is the invention of the embodiment, hydraulic pressure sensor Sa of the embodiment corresponds to the brake operating amount detecting means of the present invention, depression speed sensor of the embodiment Sc Corresponds to the stepping speed detecting means of the present invention.

  According to the configuration of the first aspect, the braking force generation means generates almost no braking force in the first region where the brake operation amount increases from zero, and controls in the second region where the brake operation amount is larger than the first region. The power is suddenly increased, and in the third region where the brake operation amount is larger than that in the second region, the braking force is increased in accordance with the increase in the brake operation amount. The person can surely experience the generation of the braking force accompanying the depression of the brake pedal, and the brake feeling is improved. As the initial depression speed of the brake pedal is increased, the braking force generating means increases the amount of braking force that is started up in the second region. Therefore, during a panic brake that requires a large braking force, the driver must It becomes possible to experience the generation of the braking force more reliably, and the brake feeling is further improved.

Also, in conjunction with the brake pedal, and a gap for generating an ineffective stroke is formed between the piston front end and the master cylinder of linked push rods, depression speed detecting means ineffective stroke of the brake pedal the Since the stepping speed is detected when it is within the stroke range, it becomes possible to complete the detection of the stepping speed before entering the second region where the magnitude of the stepping force suddenly increases the braking force. It is possible to accurately control the power startup amount.

The hydraulic circuit figure at the time of normal of a BBW type brake device. FIG. 2 is a hydraulic circuit diagram at the time of abnormality corresponding to FIG. 1. 3 is an enlarged view of part 3 of FIG. The graph which shows the relationship between the depressing force of a brake pedal, and the deceleration of a vehicle body.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the tandem master cylinder 11 includes a secondary hydraulic pressure chamber 13A and a primary hydraulic pressure chamber 13B that output brake hydraulic pressure in accordance with a pedaling force applied by the driver to the brake pedal 12, and a secondary hydraulic pressure chamber 13B is provided. The hydraulic chamber 13A is connected to the wheel cylinders 16 and 17 of the disc brake devices 14 and 15 of, for example, the left front wheel and the right rear wheel via the fluid paths Pa, Pb, Pc, Pd, and Pe. For example, it is connected to the wheel cylinders 20 and 21 of the disc brake devices 18 and 19 for the right front wheel and the left rear wheel via the roads Qa, Qb, Qc, Qd and Qe.

  An on-off valve 22A, which is a normally open solenoid valve, is disposed between the liquid paths Pa, Pb, and an on-off valve 22B, which is a normally open solenoid valve, is disposed between the liquid paths Qa, Qb, and the liquid paths Pb, Qb and the liquid path A slave cylinder 23 is arranged between Pc and Qc. A stroke simulator 26 is connected to the fluid paths Ra and Rb branched from the fluid path Pa extending from the secondary fluid pressure chamber 13A via a reaction force permission valve 25 which is a normally closed electromagnetic valve. The stroke simulator 26 has a piston 29 urged by a simulator spring 28 slidably fitted to a cylinder 27, and a hydraulic chamber 30 formed on the side of the piston 29 opposite to the simulator spring 28 has a fluid path Rb. Communicate with. A check valve 24 that permits only the flow of brake fluid from the stroke simulator 26 side to the master cylinder 11 side is connected so as to bypass the reaction force permission valve 25.

  The actuator 51 of the slave cylinder 23 includes a drive bevel gear 53 provided on the rotating shaft of the electric motor 52, a driven bevel gear 54 that meshes with the drive bevel gear 53, and a ball screw mechanism 55 that is operated by the driven bevel gear 54. A sleeve 58 is rotatably supported on the actuator housing 56 via a pair of ball bearings 57, 57. An output shaft 59 is coaxially disposed on the inner periphery of the sleeve 58, and a driven bevel gear 54 is provided on the outer periphery thereof. Fixed.

  A secondary piston 38A and a primary piston 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 slave cylinder 23, and a secondary liquid is disposed in front of the secondary piston 38A. A pressure chamber 39A is defined, and a primary hydraulic chamber 39B is defined in front of the primary piston 38B. The front end of the output shaft 59 contacts the rear end of the secondary piston 38A. The secondary hydraulic chamber 39A communicates with the fluid paths Pb and Pc via the ports 40A and 41A, and the primary hydraulic chamber 39B communicates with the fluid paths Qb and Qc via the ports 40B and 41B.

  The fluid passage Pa is provided with a fluid pressure sensor Sa that detects the brake fluid pressure generated by the secondary fluid pressure chamber 13A of the master cylinder 11, and the fluid fluid Pc is brake fluid generated by the secondary fluid pressure chamber 39A of the slave cylinder 23. A hydraulic pressure sensor Sb that detects pressure is provided. Further, the brake pedal 12 is provided with a stepping speed sensor Sc that detects the stepping speed of the brake pedal 12 from the time change rate of the stroke. An electronic control unit (not shown) to which signals from the hydraulic pressure sensors Sa and Sb and the depression speed sensor Sc are input controls the operation of the on-off valves 22A and 22B, the reaction force permission valve 25, and the slave cylinder 23.

As apparent from FIG. 3, the rear end of the flop Sshuroddo 63 in an intermediate portion of the brake pedal 12 which is pivotally supported upper end in the fulcrum pin 61, in conjunction with the brake pedal 12, via a pivot pin 62 so as to link pivot Be supported. A reaction force spring 66 made of a coil spring is contracted between a spring seat 64 provided at the end of the push rod 63 on the brake pedal 12 side and the rear end of the secondary piston 67A of the master cylinder 11. The secondary piston 67A disposed behind the secondary hydraulic chamber 13A of the master cylinder 11 is urged rearward by the secondary return spring 68A, and the primary piston 67B disposed behind the primary hydraulic chamber 13B of the master cylinder 11 is the primary return spring. It is urged backward at 68B. When the brake pedal 12 is not operated, a gap α for generating an invalid stroke is formed between the front end of the push rod 63 extending forward from the brake pedal 12 and the rear end of the secondary piston 67A.

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

  When the system functions normally, the on-off valves 22A and 22B made of normally open solenoid valves are excited and closed, and the reaction force permission valve 25 made of normally closed solenoid valves is excited and opened. In this state, when the driver depresses the brake pedal 12, the master cylinder 11 operates, and when the hydraulic pressure sensor Sa provided in the liquid passage Qa detects an increase in the brake hydraulic pressure, the actuator 51 of the slave cylinder 23 operates. That is, when the electric motor 52 is driven in one direction, the output shaft 59 advances through the drive bevel gear 53, the driven bevel gear 54, and the ball screw mechanism 55, so that the secondary piston 38A and the primary piston 38B pressed against the output shaft 59. Will move forward. Since the on-off valves 22A and 22B are closed, the brake fluid pressure is generated in the secondary fluid pressure chamber 39A and the primary fluid pressure chamber 39B immediately after both pistons 38A and 38B start moving forward. It is transmitted to the wheel cylinders 16, 17; 20, 21 of the brake devices 14, 15; 18, 19 to brake each wheel.

  At this time, the brake hydraulic pressure generated in the secondary hydraulic pressure chamber 13A of the master cylinder 11 is transmitted to the hydraulic pressure chamber 30 of the stroke simulator 26 via the opened reaction force permission valve 25, and the piston 29 is transferred to the simulator spring 28. By moving it against, 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.

  And the brake fluid pressure by the slave cylinder 23 detected by the fluid pressure sensor Sb provided in the fluid passage Pc becomes a magnitude according to the brake fluid pressure by the master cylinder 11 detected by the fluid pressure sensor Sa provided in the fluid passage Pa. In other words, by controlling the operation of the actuator 51 of the slave cylinder 23 so as to have a magnitude corresponding to the pedaling force input to the brake pedal 12 by the driver, the driver can respond to the pedaling force input to the brake pedal 12. The braking force can be generated in the disc brake devices 14, 15;

  Now, at the initial depression of the brake pedal 12, the brake fluid pressure generated by the slave cylinder 23 is so-called jump-in control. As shown in FIG. 4, when the pedaling force of the brake pedal 12, that is, the brake fluid pressure detected by the fluid pressure sensor Sa provided in the fluid passage Pa is gradually increased from zero, the region A, the region B, and the region C are divided. In the region A, the deceleration of the vehicle body (that is, the brake fluid pressure generated by the slave cylinder 23) is maintained at substantially zero. When the pedal force increases and enters the region B, the brake fluid pressure generated by the slave cylinder 23 suddenly rises. When the pedal force further increases and enters the region C, the brake fluid pressure generated by the slave cylinder 23 is proportional to the pedal force. And increase on the line L passing through the origin.

  At this time, the jump-in amount in the region B changes from GI1 to GI4 according to the depression speed of the brake pedal 12 detected by the depression speed sensor Sc. That is, when the depression speed of the brake pedal 12 is less than the first threshold value, the jump-in amount is GI1, and after the completion of the jump-in, the brake hydraulic pressure generated by the slave cylinder 23 increases in proportion to the depression force. When the depressing speed of the brake pedal 12 is equal to or higher than the first threshold value and lower than the second threshold value, the jump-in amount is GI2, and even after the jump-in is finished, the brake fluid pressure does not increase and the line L It increases along the line L after crossing.

  When the stepping speed of the brake pedal 12 is equal to or higher than the second threshold value and lower than the third threshold value, the jump-in amount is GI3. It increases along the line L after crossing. When the depressing speed of the brake pedal 12 is equal to or higher than the third threshold value and lower than the fourth threshold value, the jump-in amount is GI4. After the jump-in is finished, the brake fluid pressure does not increase and the line L It increases along the line L after crossing.

  Therefore, as shown in FIG. 4, a plurality of tables having different jump-in amounts GI1 to GI4 are prepared in advance, and a corresponding table is selected according to the depression speed of the brake pedal 12, and the table according to the pedaling force is selected. The deceleration, that is, the target brake hydraulic pressure to be generated in the slave cylinder 23 can be searched.

  As described above, almost no braking force is generated in the first region A where the pedaling force of the brake pedal 12 increases from zero, and the braking force is suddenly jumped in in the second region B where the pedaling force is larger than the first region A. Therefore, the driver can surely experience the generation of the braking force accompanying the depression of the brake pedal 12, and the brake feeling is improved. Furthermore, since the jumping-in amount of the braking force in the second region B is increased as the initial depression speed of the brake pedal 12 is increased, the driver is required to perform a panic brake that requires a large braking force. It becomes possible to experience the generation of the braking force more reliably, and the brake feeling is further improved.

  By the way, in this embodiment, since the depression speed is detected from the stroke of the brake pedal 12 by the depression speed sensor Sc, assuming that the brake pedal 12 is directly connected to the master cylinder 11, the depression speed sensor Sc is When twelve stepping speeds are detected, the treading force has already entered the second region B, and there is a possibility that accurate jump-in control cannot be performed.

  However, according to the present embodiment, when the driver steps on the brake pedal 12, as shown in FIG. 3, the push rod 63 moves forward while compressing the reaction force spring 66, but the push rod 63 and the secondary piston 67A. Therefore, the pedaling force applied by the driver to the brake pedal 12 is transmitted from the brake pedal 12 to the secondary piston 67A via the reaction spring 66 without passing through the push rod 63.

  As a result, the rise of the brake fluid pressure generated by the master cylinder 11 is delayed by the amount of the reaction force spring 66 being compressed, and the detection of the depression speed of the brake pedal 12 is completed before the depression force enters the second region B. As a result, the jump-in control can be started immediately when the pedal force enters the second region B.

  Furthermore, by setting the set load of the reaction force spring 66 smaller than the set load of the secondary return spring 68A and the primary return spring 68B, the reaction force at the start of the brake pedal 12 can be reduced. The pedal feeling of the brake pedal 12 can be enhanced.

  When the slave 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 slave cylinder 23.

  That is, when the power supply fails, as shown in FIG. 2, the on-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 turned on. Close the valve. In this state, the brake hydraulic pressure generated in the secondary hydraulic pressure chamber 13A and the primary hydraulic pressure chamber 13B of the master cylinder 11 is not absorbed by the stroke simulator 26, and the secondary hydraulic pressure chamber 39A and the primary hydraulic pressure of the slave cylinder 23 are absorbed. Passing through the chamber 39B, the wheel cylinders 16, 17; 20, 21 of the disc brake devices 14, 15; 18, 19 of each wheel can be operated to generate a braking force without any trouble.

  When the driver depresses the brake pedal 12 and the brake fluid sent from the secondary hydraulic chamber 13A of the master cylinder 11 is absorbed by the stroke simulator 26, the power failure occurs, and the reaction force permission valve comprising a normally closed solenoid valve. 25 automatically closes and the brake fluid is trapped in the hydraulic chamber 30 of the stroke simulator 26. However, the brake fluid passes through the check valve 24 and is returned to the master cylinder 11 side, so that the brake fluid is insufficient. Thus, it is possible to prevent the position of the brake pedal 12 from changing.

  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, in the embodiment, the brake operation is detected from the depression force of the brake pedal 12, that is, the brake fluid pressure generated by the master cylinder 11, but this is detected by a strain gauge or the like provided between the brake pedal 12 and the master cylinder 11. can do. It is also possible to detect the brake operation from the operation stroke of the brake pedal 12.

  In the embodiment, the braking force generating means is constituted by the slave cylinder 23 for generating the brake fluid pressure. However, the braking force generating means of the present invention is a driving force of the electric motor and the brake caliper is not driven by the brake fluid pressure. The brake pad may be directly driven.

11 master cylinder 12 brake pedal 23 slave cylinder (braking force generating means)
63 push rod
Piston A of 67A master cylinder 1st area B 2nd area C 3rd area Sa Hydraulic pressure sensor (brake operation amount detection means)
Sc Depression speed sensor (Depression speed detection means)
α Clearance for generating invalid stroke

Claims (1)

A master cylinder (11) that generates hydraulic pressure corresponding to the operation amount of the brake pedal (12), a brake operation amount detection means (Sa) that detects the operation amount of the brake pedal (12), and the master cylinder ( consists 11) separately and independently, said braking force generating means for braking operation amount detecting means (Sa) based on the braking operation amount detected by generating a braking force of a predetermined magnitude (23), the brake pedal And a stepping speed detecting means (Sc) for detecting the stepping speed of (12) from the time change rate of the stroke of the brake pedal (12), and the braking force generating means (23) has a detected brake operation amount of zero. In the first region (A) that increases from the first region (A), almost no braking force is generated, and in the second region (B) where the brake operation amount is larger than that in the first region (A), the braking force is suddenly increased. Met brake system increases the third region (C) in the braking force is large brake operation amount than the second region (B) according to the increase in the brake operation amount,
A gap (α) for generating an invalid stroke is formed between the front end of the push rod (63) linked and connected to the brake pedal (12) and the piston (67A) of the master cylinder (11). The stepping speed detecting means (Sc) detects the stepping speed of the brake pedal (12) when the stroke of the brake pedal (12) is in the invalid stroke range, and the braking force generating means (23) The braking device is characterized in that as the detected depressing speed is larger, the amount of braking force rise in the second region (B) is increased.

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