KR101776311B1

KR101776311B1 - Dead stroke compensation method of disk brake

Info

Publication number: KR101776311B1
Application number: KR1020110064179A
Authority: KR
Inventors: 조성현
Original assignee: 현대자동차주식회사
Priority date: 2011-06-30
Filing date: 2011-06-30
Publication date: 2017-09-07
Also published as: KR20130003114A

Abstract

[0001] The present invention relates to a brake drag reducing structure for a disc brake and a method for compensating for an invalid stroke, and more particularly, to a disc brake for reducing the brake drag phenomenon and improving the fuel economy of the vehicle, It is possible to eliminate the invalid stroke generated by the braking force, thereby improving the initial response and braking feeling when the braking force is generated.

Description

DISCHARGE COMPRESSION METHOD OF DISK BRAKE [0002]

[0001] The present invention relates to a brake drag reducing structure for a disc brake and, more particularly, to a disc brake reducing method for a disc brake by reducing the brake drag phenomenon by increasing the amount of roll back of the piston seal upon brake release, The brake drag reduction structure of the disc brake and the invalid stroke compensation method which can eliminate the deterioration of the braking feeling by allowing the invalid stroke to be eliminated.

Generally, as shown in FIG. 1, when a brake pedal is depressed by a driver, a pressure is applied to the master cylinder, so that the hydraulic pressure is pushed into the caliper housing 1 and the piston 2 It is pushed out.

The brake pad 4 engaged with the piston 2 via the back plate 3 moves forward to the disk 5 and generates a braking force as it makes frictional contact with the side surface of the disk 5 .

When the braking of the vehicle is ended and the driver releases the pressing force applied to the brake pedal, the hydraulic pressure that has been pushed into the caliper housing 1 is released, and the piston 2 moves in a direction away from the disk 5 At the same time, the braking force is released as the brake pad 4 moves away from the disk 5 and moves back to its original position.

2, a piston seal 6 for holding the airtightness between the caliper housing 1 and the piston 2 is mounted on the disk brake, The outer circumferential surface of which is seated in the seal groove 7 formed in the caliper housing 1 and the inner circumferential surface thereof is in close contact with the outer surface of the piston 2. [

The piston seal 6 is resiliently deformed (in a state shown by a dotted line) so that the piston seal 6 moves together with the piston 2 when the piston 2 moves toward the disk 5 (In a state shown by a solid line) to return the piston 2 to its original position (the right direction of the arrow M1).

Here, the amount of elastic deformation of the piston seal 6 at the time of braking force generation and braking force release is called a rollback, and the amount of rollback RB1 has a great influence on the brake drag phenomenon.

That is, if the rollback amount RB1 of the piston seal 6 is not sufficient in the disc brake, the brake pad 4 is not sufficiently released from the disc 5 when the braking force is released, resulting in an excessive brake drag phenomenon, There is a problem that the fuel efficiency of the engine becomes poor.

Conversely, if the amount of rollback RB1 of the piston seal 6 is large, the brake drag phenomenon does not occur when the braking force is released.

However, as the amount of rollback increases, the invalid stroke is increased at the initial operation of the brake pedal. This causes a problem that the initial responsiveness is deteriorated and the feeling of deterioration is deteriorated.

As described above, the technique for reducing the brake drag and the technique for eliminating the invalid stroke are technologies that are contradictory to each other, and conventional disc brakes can not satisfy both of the above-described techniques.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and it is an object of the present invention to provide a brake control apparatus and brake control method for a brake control apparatus capable of reducing a brake drag phenomenon by increasing the amount of rollback of a piston seal upon release of braking force, The present invention has been made in view of the above problems, and it is an object of the present invention to provide a brake drag reduction structure and a stroke compensation method for an invalid disc brake which can eliminate the deterioration of the braking feeling.

In order to achieve the above and other objects, there is provided a brake drag reduction structure for a disc brake in which, when a braking force is released, a shape of a piston seal mounted on a seal groove of a caliper housing is restored to reduce a brake drag phenomenon, Is formed such that the width between the front surface and the rear surface facing the disc is larger than the width of the seal seating surface on which the outer peripheral surface of the piston seal is seated.

The front surface of the seal groove may include a braking surface that is bent toward the piston at the front end of the seal seating surface to restrict the movement of the piston seal while preventing deformation of the piston seal when the braking force is generated; And an inclined surface inclined from the end of the braking surface toward the disc.

The depth of the inclined surface is preferably formed to have a dimension of 65% to 75% with respect to the entire depth of the seal groove. The angle? 1 formed by the braking surface and the inclined surface is in a range of 145 ° to 150 °, .

The present invention also provides a method of compensating for an invalid stroke of a piston when the piston moves toward the disc at the time of braking force generation, comprising: determining a driver's will to brake; The braking oil pressure is generated before the driver depresses the brake pedal to determine the braking intention, and the piston is moved toward the disk until the invalid stroke is minimized.

Here, it is determined that there is a driver's will to brake when the Excel pedal sensor is OFF (OFF).

According to an embodiment of the present invention, the time point at which the invalid stroke is minimized is determined by the stroke difference of the piston. The difference in stroke of the piston is a difference between a backward movement stroke (S1) of the piston when brake drag occurs when the braking force is released and a backward movement stroke (S2) of the piston when no brake drag occurs.

According to another embodiment of the present invention, the point at which the invalid stroke is minimized is determined by the difference in braking hydraulic pressure for moving the piston when the braking force is generated. The difference between the braking hydraulic pressures is a difference between the braking hydraulic pressure P1 required to move the piston toward the disc when the brake drag occurs and the braking hydraulic pressure P2 required when the brake drag does not occur.

According to the present invention, it is possible to reduce the brake drag phenomenon, improve the fuel economy of the vehicle, and eliminate the invalid stroke caused by the increased amount of rollback by achieving an increase in the rollback amount when the braking force is released from the disc brake, It is possible to improve the property and improve the feeling of feeling.

1 is a view for explaining the structure of a disc brake,
FIG. 2 is a view for explaining the seal groove of the conventional structure in FIG. 1,
3 is a view for explaining a brake drag reduction structure according to the present invention,
4 is a view for explaining an invalid stroke compensation method according to the present invention.

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

3, a piston seal 6 for sealing the airtightness between the caliper housing 1 and the piston 2 is mounted on the disc brake. The piston seal 6 has an outer circumferential surface which is engaged with the caliper housing 1 1 and the inner circumferential surface thereof is in close contact with the outer surface of the piston 2.

The piston seal 6 is resiliently deformed (in a state shown by a dotted line) to be in a state of being moved together (left direction of the arrow M1) when the piston 2 moves toward the disk 5 (see FIG. 1) The piston 2 is restored to the original position (rightward direction of the arrow M1) while being elastically restored when the braking force is released (in a state shown by a solid line).

Here, the amount of elastic deformation of the piston seal 6 at the time of braking force generation and braking force release is called a rollback, and the amount of rollback RB2 has a great influence on the brake drag phenomenon.

The embodiment according to the present invention can increase the rollback amount RB2 of the piston seal 6 when the braking force is released by changing the shape of the seal groove 10 and thereby reduce the brake drag phenomenon .

The seal groove 10 according to the present invention formed in the caliper housing 1 in the structure of the disc brake is designed such that the width D1 between the front face 11 and the rear face 12, Is larger than the width (D2) of the seal seating surface (13) on which the outer peripheral surface of the seat (6) is seated.

The front surface 11 of the seal groove 10 is formed in the front end of the seal seating surface 13 so as to restrict the movement of the piston seal 6 while preventing the piston seal 6 from being deformed when a braking force is generated. And a sloped surface 11b inclined from the end of the braking surface 11a toward the disc 5. The braking surface 11a is formed by bending the piston 2 from the braking surface 11a.

The seal groove 10 is formed such that the width D1 between the front face 11 and the rear face 12 is larger than the width D2 of the seal seating face 13 by the inclined face 11b It becomes a structure.

The rear surface 12 of the seal groove 10 is formed in a shape bent at a right angle from the rear end of the seal seating surface 13 toward the piston 2, The braking surface (11a) has a structure parallel to the rear surface (12).

When the seal groove 10 is formed as described above, the amount of rollback RB2, which is the amount of elastic deformation of the piston seal 6, is significantly increased compared to the conventional structure described above with reference to FIG.

That is, when the braking force is generated, the piston seal 6 elastically deforms to correspond to the inclined surface 11b of the seal groove 10, so that the embodiment of the present invention is configured such that the rollback amount RB2 of the piston seal 6 is increased And the rollback amount is increased by RB3 as compared with the conventional rollback amount RB1.

Therefore, the structure according to the present invention increases the rollback amount RB2 of the piston seal 6 by the increased rollback amount RB3 in the disc brake, so that the braking force is released from the disc 5 to the brake pad 4 Is sufficiently lowered, thereby reducing or eliminating the brake drag phenomenon. As a result, there is an advantage that the fuel efficiency of the vehicle is greatly improved.

In the present invention, the depth T1 of the inclined surface 11b is formed to have a dimension of 65% to 75% with respect to the entire depth T2 of the seal groove 10.

If the depth T1 of the inclined surface 11b is less than 65% of the total depth T2 of the seal groove 10, the depth T1 of the inclined surface 11b is reduced, The depth of the first electrode 11a is increased.

In this case, the deformation of the piston seal 6 can be further prevented and the movement of the piston seal 6 can be further restricted by the depth of the braking surface 11a, which is increased when the braking force is generated, The elastic deformation is further restrained, thereby adversely affecting the increase of the rollback amount.

If the depth T1 of the inclined surface 11b is larger than the total depth T2 of the seal groove 10 by a dimension greater than 75%, the depth of the braking surface 11a is reduced, The depth Tl of the light-shielding film is increased.

In this case, the amount of rollback can be further increased, but conversely, the piston seal 6 is excessively deformed and excessively moved by the braking oil pressure, thereby causing a situation in which the piston seal 6 does not perform its own role properly do.

Therefore, in order to prevent an appropriate deformation of the piston seal 6 and to increase the amount of movement restriction and the amount of rollback when the braking force is generated, the depth T1 of the inclined surface 11b is set to the entire depth T2 of the seal groove 10 Is preferably formed so as to have a dimension of 65% to 75%.

The present invention is characterized in that the angle? 1 between the braking surface 11a and the inclined surface 11b is between 145 degrees and 155 degrees.

If the angle? 1 is less than 145 degrees (°), the amount of rollback can be further increased. However, excessive bending and excessive movement of the piston seal 6 due to the braking hydraulic pressure may occur, (6) does not perform its own role properly.

When the angle? 1 is formed at an angle larger than 155 degrees (?), Deformation of the piston seal 6 is further prevented and the movement of the piston seal 6 is further restricted when the braking force is generated. The elastic deformation of the piston seal 6 is further restrained, thereby adversely affecting the increase of the rollback amount.

Therefore, in order to prevent proper deformation of the piston seal 6 and increase the amount of movement restriction and the amount of rollback when the braking force is generated, the angle? 1 formed by the braking surface 11a and the inclined surface 11b is 145 degrees ) To 155 degrees ([deg.]).

On the other hand, according to the structure of the present invention, when the amount of rollback is increased in order to reduce the brake drag, ineffective stroke occurs when braking force is generated.

The invalid stroke refers to a phenomenon in which when the driver depresses the brake pedal, the brake pedal 3 does not directly contact the disk 5 and the brake pedal is turned off like a sponge phenomenon during a certain stroke interval, Corresponds to a moving section that does not affect the generation of the braking force in the section moving toward the engine 5, and increases to an invalid stroke by an increased amount of the rollback.

Therefore, the embodiment according to the present invention is characterized in that it is possible to eliminate the occurrence of invalid strokes together with the structure for increasing the amount of rollback, thereby improving the initial response and eliminating deterioration of the damping feeling.

That is, as shown in FIG. 4, the method of compensating for the invalid stroke of the disc brake according to the present invention includes the steps of: determining a driver's braking intent; and generating a braking hydraulic pressure before the driver depresses the brake pedal And moving the piston (2) toward the disk (5) to a point where the piston (2) is at a minimum.

Here, it is determined that there is a driver's braking intention at the time of turning off the Excel pedal sensor (OFF), and the main subject of the judgment is the electronic hydraulic control unit (HECU) provided in the brake system.

When the accelerator pedal sensor is turned off during the running of the vehicle, the electronic-hydraulic control unit HECU judges that the driver has a braking intention and drives the pump PUMP provided in the brake system.

Then, before the driver depresses the brake pedal, the braking hydraulic pressure is generated in advance by the driving of the pump, and the braking hydraulic pressure generated by the driving of the pump is supplied to the caliper housing 1, The hydraulic pressure generated by the operation of the brake pedal is supplied to the caliper housing 1 to generate a complete braking force.

Here, the time point at which the invalid stroke is minimum is determined by the stroke difference of the piston 2, and the stroke difference of the piston 2 is determined by the backward movement stroke S1 of the piston when the brake drag occurs when the braking force is released, And the retraction movement stroke (S2) of the piston when no brake drag occurs.

Therefore, when the excel pedal sensor is turned off during the running of the vehicle, the electronic-hydraulic control unit HECU determines that the driver has a braking intention and drives the pump PUMP provided in the brake system. At this time, Is equal to the difference (S2-S1) of the backward movement stroke of the piston (2).

The oil pressure thus generated is supplied to the caliper housing 1 in advance before the driver depresses the brake pedal. The piston 2 is moved toward the disk 5 until the point at which the invalid stroke is minimized by the braking hydraulic pressure supplied in advance .

Further, the point at which the invalid stroke is minimum may be determined by the difference in braking oil pressure that moves the piston 2 when the braking force is generated, and the difference in braking oil pressure is the difference between the braking oil pressure and the braking oil pressure, Is the difference between the braking hydraulic pressure P1 that is required to move to the disk 5 and the braking hydraulic pressure P2 that is required when no brake drag occurs.

Therefore, when the excel pedal sensor is turned off during the running of the vehicle, the electronic-hydraulic control unit HECU determines that the driver has a braking intention and drives the pump PUMP provided in the brake system. At this time, The braking hydraulic pressure generated by the braking hydraulic pressure P2 becomes equal to the difference between the braking hydraulic pressure P2-P1.

Therefore, according to the embodiment of the present invention, it is possible to previously supply the braking hydraulic pressure as much as the invalid stroke before the driver depresses the brake pedal, thereby moving the piston toward the disk. As a result, It is possible to eliminate the invalid stroke, thereby making it possible to eliminate the problem that the initial response is improved and the damping sensation is deteriorated when the braking force is generated.

1 - Caliper housing 2 - Piston
5 - Disc 6 - Piston seal
10 - Seal groove 11 - Front surface
11a - Braking surface 11b - Slope surface
12 - Rear face 13 - Seal seating face

Claims

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A method of compensating for an invalid stroke of a piston when the piston moves toward the disc at the time of braking force generation,
Determining a driver's braking intent;
The braking oil pressure is generated before the driver depresses the brake pedal to determine the braking intent, thereby moving the piston 2 toward the disk 5 until the invalid stroke is minimized
Wherein the disc brake has a plurality of discs.

7. The method according to claim 6, further comprising the step of determining that there is a driver's will to brake when the Excel pedal sensor is turned off
Wherein the disc brake is a disc brake.

[7] The method of claim 6, wherein a time point at which the invalid stroke becomes minimum is determined by a stroke difference of the piston (2);
The stroke difference of the piston 2 is the difference between the backward movement stroke S1 of the piston when the braking drag occurs and the backward movement stroke S2 of the piston when no brake drag occurs
Wherein the disc brake is a disc brake.

The braking system according to claim 8, wherein a braking oil pressure is generated before the driver depresses the brake pedal by a difference (S2-S1) of a retreating movement stroke of the piston (2) Advance movement
Wherein the disc brake is a disc brake.

The method according to claim 6, wherein the point at which the invalid stroke is minimum is determined by a difference in braking hydraulic pressure for moving the piston (2) when a braking force is generated;
The difference between the braking hydraulic pressures is a difference between the braking hydraulic pressure P1 required to move the piston 2 toward the disc 5 and the braking hydraulic pressure P2 required when the brake drag does not occur when the brake drag occurs Thing
Wherein the disc brake is a disc brake.

The braking device according to claim 10, wherein the braking hydraulic pressure corresponding to the difference (P2-P1) of the braking hydraulic pressure is generated in advance before the brake pedal is depressed by the driver so that the piston (2)
Wherein the disc brake is a disc brake.