JP3000835B2 - Disc brake device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc brake device mounted on a vehicle such as an automobile.

[0002]

2. Description of the Related Art Conventionally, a vehicle such as an automobile is equipped with a disk brake device.
No. 0362.

[0003] As shown in FIG. 3, in this disk brake device, pressure oil is guided into the caliper cylinder by operation of a master cylinder 82 in response to operation of a brake lever 80, and a pair of left and right outer sides of a brake disk 84 is provided. Are pressed against each other and act to close each other. Further, at least one of the pair of pads 86 is a movable type, and a servo piston 88 interlocked with the pad 86 is provided. Therefore, when the pad 86 moves in the rotation direction of the brake disk 84 (the direction of the arrow W in FIG. 3), the servo piston 8
8, a servo oil pressure is generated, and the pad 86 holds the brake disk 84 more firmly.

[0004]

However, in this disk brake device, the servo hydraulic pressure by the servo piston 88 increases as the pad 86 moves in the rotation direction of the brake disk 84, and the upper limit of the servo hydraulic pressure is increased. Not regulated. Further, when the servo mechanism malfunctions, the braking force may be insufficient.

In view of the above facts, the present invention provides a disk brake device which can prevent a servo hydraulic pressure from increasing to a predetermined value or more and can obtain a predetermined braking force even when a servo mechanism malfunctions. Is the purpose.

[0006]

According to a first aspect of the present invention, there is provided a disk brake device having a first chamber to which a master cylinder hydraulic pressure is supplied, and a wheel cylinder for pressing a pad against a rotor, and the pad pressing the rotor. A servo hydraulic pressure generating device for generating a servo hydraulic pressure by a braking reaction force generated at the time, a first chamber and a second chamber defined by both end faces of a piston sliding in a cylinder in a liquid-tight manner, and a valve interlocking with the piston Third member whose communication with the second chamber is interrupted by a member
A pressure increase control valve having a chamber, a master cylinder oil pressure is supplied to a first chamber of the pressure increase control valve, a servo oil pressure is supplied to a second chamber, and a third chamber is communicated with a second chamber of the wheel cylinder. And the pressure in the second and third chambers of the pressure increase control valve is equal to the first pressure.
The communication between the second chamber and the third chamber is cut off when the pressure of the master cylinder supplied to the chamber exceeds a predetermined value or more, and the supply of the servo oil pressure to the second chamber of the wheel cylinder is cut off.

According to a second aspect of the present invention, there is provided the disk brake device according to the first aspect, wherein a servo hydraulic pressure is provided in a hydraulic passage connecting the second chamber of the pressure increasing control valve and a servo hydraulic pressure generating device. When the pressure becomes smaller than a predetermined pressure set according to the master cylinder oil pressure, a cut valve is provided for cutting off the communication between the servo oil pressure generator and the second chamber of the pressure increase control valve.

[0008]

In the disk brake device according to the first aspect, when the pressure in the second chamber and the third chamber of the pressure increase control valve becomes more than a predetermined multiple of the master cylinder oil pressure supplied to the first chamber, the second chamber and the third chamber are switched. Since the communication of the chambers is cut off and the supply of the servo oil pressure to the second chamber of the wheel cylinder is cut off, it is possible to prevent the servo oil pressure from increasing to a predetermined value or more.

Further, in the disk brake device according to the second aspect, when the servo hydraulic pressure generating device malfunctions, the cut-off valve cuts off the second chamber of the pressure increase control valve from the servo hydraulic pressure generating device. Accordingly, the hydraulic pressure supplied from the third chamber of the pressure increase control valve to the wheel cylinder is increased to a predetermined value by the pressure increase control valve and supplied to the wheel cylinder even when the servo hydraulic pressure generator is malfunctioning. Extremely low power can be prevented.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the disc brake device according to the present invention will be described with reference to FIG.

As shown in FIG. 1, in this disc brake device, a master cylinder 10 that generates a hydraulic pressure based on an operation of a brake pedal is moved by a hydraulic passage 12.
Wheel cylinder 1 formed on cylinder body 14
No. 6 communicates with the first chamber 16A. A piston 18 is inserted into the wheel cylinder 16, and the first chamber 16A
Area of the end face 18A of the piston 18 that defines a has a S _1.

A pad 20 is fixed to the other end face 18B of the piston 18. End face 18B of piston 18
A substantially half of the side has a larger shaft diameter than the end face 18A side. The part on the pad 20 side of the wheel cylinder 16 is also
Corresponds to the large diameter portion of the piston 18, the wheel cylinder 16 and the intermediate wall portion 18C of substantially axial area S ₂ formed in the center ring-shaped piston 18, a large diameter portion of the piston 18 Two chambers 16B are defined.

The first chamber 16 of the wheel cylinder 16
The space between A and the second chamber 16B is sealed by a piston ring 22, and the second chamber 16B is sealed by a piston ring 24.

The cylinder body 14 is provided with an extended portion 14A which straddles a rotor 25 which rotates integrally with the wheel. A pad 26 is fixed to the extended portion 14A at a position facing the pad 20. ing.

The cylinder body 14 is slidably supported by a shaft 28 and is movable along the shaft 28 in the axial direction of the wheel cylinder 16. Therefore, when hydraulic pressure is generated from the master cylinder 10 by operating the brake pedal, the piston 18 moves in the direction of the rotor 25 (the direction of the arrow A in FIG. 1), and the extending portion 14A moves in the direction of the rotor 25 (the direction of the arrow B in FIG. 1). Direction) and move to pad 2
The rotor 25 is sandwiched between the pad 0 and the pad 26.

The cylinder body 14 includes the rotor 2
5 (in the direction of arrow C in FIG. 1 and the direction of arrow D in FIG. 1), and servo cylinders 30 and 32 as servo hydraulic pressure generating devices are formed in these extending portions. In the servo cylinder 30, the piston ring 3
A servo piston 34 having an oil pressure chamber 3 is inserted therein, and forms a hydraulic chamber 35. Hydraulic chamber 3 of servo piston 34
Area of the end face 34A defining the 5 is a S _3,
The servo piston 34 is in contact with a vehicle body 36 by a rod 38.

Similarly, a servo piston 40 having a piston ring 39 is inserted into the servo cylinder 32 to form a hydraulic chamber 42. Servo piston 4
Area of the end face 40A defining a hydraulic chamber 42 of 0 is the S _3, the servo piston 40 is in contact with the rod 42 to the vehicle body 36.

A return spring 44 is inserted into each of the hydraulic chamber 35 and the hydraulic chamber 42, and urges the cylinder body 14 in a reference position (position in FIG. 1).

The hydraulic chambers 35, 42 are connected to both ends 50A, 50B of a balance piston 50 as a change valve by hydraulic passages 46, 48. The rotation direction of the rotor 25, that is, the forward movement of the vehicle, is performed by the balance piston 50. Alternatively, the hydraulic chamber is switched to the hydraulic chamber on the side where the servo pressure is generated by the reverse travel. That is, in the balance piston 50, a piston valve 52 having seal members 53 at both ends is provided in the axial direction of the balance piston 50 (arrow E in FIG. 1).
(Or the direction of arrow F) so as to block a hydraulic passage having a lower hydraulic pressure among the hydraulic chambers 35 and 42. Further, the balance piston 50 prevents movement of oil between the hydraulic chamber 35 and the hydraulic chamber 42 when the servo pressure is generated.

The balance piston 50 is connected by a hydraulic passage 54 to a second chamber 56A of a pressure increasing control valve 56 having a piston 55 which slides in a cylinder in a liquid-tight manner.
The second chamber 56A is defined by one end face 55B of the piston 55. The pressure increase control valve 56 has a first chamber 56 </ b> B, and the first chamber 56 </ b> B
5A. Further, piston rings 47 and 49 are provided between the second chamber 56A and the first chamber 56B.

In the pressure increasing control valve 56, the first chamber 56B connected to the master cylinder 10 has the largest diameter. Area of the end face 55A of the piston 55 is the S _4, the second
The chamber 56A has a smaller diameter than the first chamber 56B and the piston 55
The area of the end face 55B is the (S ₅ + S _6).

At the center of the end face 55B of the piston 55,
The shaft 55 protrudes. Outside this shaft portion 55D,
An outer cylinder 60 as a valve member is provided so as to be interlocked with the piston 55 in the axial direction of the piston 55 (the direction of arrow G or the direction of arrow H in FIG. 1) with a gap therebetween. A sealing material 61 is provided.

The end of the shaft 55D of the piston 55 on the end surface 55C side is gradually enlarged to form an inclined surface 55E. When the inclined surface 55E comes into contact with the end 60A of the outer cylinder 60,
A third chamber 56C is formed in which the communication path 57 with the second chamber 56A is cut off.

The piston 5 defining the third chamber 56C is also provided.
The end face of the 5 55C is diameter smaller than the second chamber 56A, the area is the S _7. The third chamber 56C has a hydraulic passage 58
Thereby, it is communicated with the second chamber 16B of the wheel cylinder 16.

Further, the first chamber 56B is connected to the
The second chamber 56 </ b> A is connected to a cut valve 64 by a hydraulic passage 62.
The cut valve 64 communicates with the master cylinder 10 and closes when the pressure of the master cylinder 10 is increased, so that the hydraulic passage 62 of the pressure increase control valve 56 to the second chamber 56A is closed.

Next, the operation of the first embodiment will be described. This disk brake apparatus of the first embodiment, when the master cylinder pressure P _M is pressure increase, the cut valve 64 closes pressure increase control valves 5
The hydraulic passage 62 to 6 is closed. At the same time, the pressure P _M acts on the first chamber 16A of the first chamber 56B (the area S ₄₎ and the wheel cylinder 16 of the pressure increase control valve 56 (area S _1).

Thus, the force S is applied to the wheel cylinder 16.
₁ P _M is generated, the friction between the rotor 25 and the pads 20, 26 is started, the rotational direction of the cylinder body 14 rotor 25, for example, swings in the direction of arrow C in FIG.
At this time, the hydraulic chamber 35 provided in the cylinder body 14
The pressure P _B acts on (area S ₃ ).

This pressure P _B is led to the second chamber 56 A of the pressure increasing control valve 56 via the balance piston 50. At this time, in the pressure increase control valves 56, a force F1 = S ₄ P _M that acts from the first chamber 56B side to the piston 55, a force acting from the second chamber 56A side to the piston _{55 F2 = (S 5 + S} 6) P _B
+ The magnitude relation between the S ₇ P _A is determined.

When F1> F2, the piston 55 of the pressure increase control valve 56 moves to the second chamber 56A side, the communication path 57 remains open, and the hydraulic chamber 35 (area) provided in the cylinder body 14 is opened. The pressure P _B generated in S ₃ ) is increased by the pressure increase control valve 5.
6 and acts on the second chamber 16B of the wheel cylinder 16 through the second chamber 56A and the third chamber 56C, so that the braking force increases.

On the other hand, when F1 <F2, the piston 55 of the pressure increasing control valve 56 moves to the first chamber 56B side, and the inclined surface 55E of the piston 55 contacts the end 60A of the outer cylinder 60, and The road 57 is blocked. Thereby, the pressure increase control valve 56
The third chamber 56C is formed. Also, the force F1 due to the hydraulic pressure
As the difference (F2-F1) between the force and the force F2 increases,
The piston 55 is provided together with the outer cylinder 60 and the first chamber 56B.
Side, the volume of the third chamber 56C increases, and the pressure P
_{Since A} decreases, an increase in the braking force due to the servo force can be suppressed.

Further, while the master cylinder pressure P _M is held at a predetermined value, the pressure increase control valves 56, the magnitude relationship is always determined that the force F1 and the force F2, the adjustment of the braking force by the servo force Is performed, a constant braking force is maintained.

Further, when the master cylinder pressure P _M is depressurized, force acting on the first chamber 56B of the first chamber 16A and the pressure regulating valve 56 of the cylinder piston 16 is reduced. Also,
Hydraulic chamber 35 (area S) provided in cylinder body 14
_Since the volume of ₃ ) increases, the pressure P _B is also reduced. Also,
The pressure increase control valve 56 determines the magnitude relationship between the force F1 and the force F2. Therefore, the master cylinder pressure P _M pressure increase,
The piston 55 of the pressure-increasing control valve 56 is moved to the second
It moves to the room 56A side.

It should be noted, the master cylinder pressure P _M is off cut valve 64 is in the vicinity of 0, if it becomes pressure P _M ≒ 0, the same becomes the pressure of all the hydraulic passage and the pressure P _M, pressure P _M = At 0, the pressures of all the hydraulic passages become 0.

The pressure (P _A + P _B ) is reduced until the cut valve 64 is opened by the third chamber 56C of the pressure increasing control valve 56, the hydraulic chamber 35, and the second chamber of the pressure increasing control valve 56, respectively. 5
This is done by increasing the volume of 6A.

In the first embodiment, since the hydraulic chamber 35, the hydraulic chamber 42 and the balance piston 50 are provided, servo control is possible not only at the time of forward movement but also at the time of reverse movement.

In the first embodiment, the pads 20, 2
Braking force of 6 pressure increase when the friction coefficient is μ of F _B is the order 1, the servo ratio D degree two, and the pressure reduction during the braking force F _B is degree 3, the servo ratio D becomes order 4.

[0037]

(Equation 1)

[0038]

(Equation 2)

[0039]

(Equation 3)

[0040]

(Equation 4)

In the first embodiment, the pads 20, 2
For variations in the friction coefficient of 6, it is possible to significantly reduce the variation in the braking force F _B. That is, the pad 2 at the time of pressure increase
If the friction coefficient of 0,26 was changed to .mu.2 from μ1, F _B 1 the braking force when the friction coefficient is .mu.1, when the F _B 2 the braking force when the μ2, F _B 1 and F _B 2 is , Degree 5,
The degree is 6.

[0042]

(Equation 5)

[0043]

(Equation 6)

The rate of change of the braking force with respect to the change (change) of the friction coefficient μ of the pads 20 and 26 is given by the following order:

[0045]

(Equation 7)

In Equation 7, the dotted line (...) is 1
In other words, the variation ratio of the braking force to the variation of the friction coefficient μ of the pads 20 and 26 decreases.

Next, a second embodiment of the disc brake device according to the present invention will be described with reference to FIG. The same members as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 2, in the second embodiment,
Second chamber 56A of balance piston 50 and pressure increase control valve 56
Is provided with a stepped spool valve 66 as a cut valve, and a first chamber 66 </ b> A of the stepped spool valve 66 is interposed in the hydraulic passage 54. Area of the end face 68A of the piston 68 that defines a first chamber 66A is an S _8, the end face of the end face 68A opposite side of the piston 68 68B
The area of which is the S _9. The end face 68B is in the second chamber 66B.
The second chamber 66B is connected to the first chamber 56B of the pressure increase control valve 56 by a hydraulic passage 70.
Note that a return spring 72 is inserted into the second chamber 66B, and urges the piston 68 with an urging force K in the direction of the reference position (the direction of the arrow J in FIG. 2).

Next, the operation of the second embodiment will be described. In the disk brake device of the second embodiment, when the servo system is normal, that is, when the servo pressure P _B is equal to the master cylinder pressure P _M
If P _B > P _M , the force S ₈ P _B acting on the end face 68A of the piston 68 in the stepped spool valve 66 is greater than the force S ₉ P _M + K acting on the end face 68B of the piston 68. Because of this, the stepped spool valve 66 does not operate.

On the other hand, if the servo system is malfunctioning, that is, the servo pressure P _B is smaller than the master cylinder pressure P _M (P _B <P
If _M), in the stepped spool valve 66, the force S ₈ P _B that acts on the end face 68A of the piston 68 is smaller than the force S ₉ P _M + K which acts on the end surface 68B of the piston 68, a stepped spool The valve 66 moves in the direction of arrow J in FIG. 2, and the hydraulic passage 54, which is a servo system pipe, is shut off.

[0051] In a state where the hydraulic passage 54 is shut off, the master cylinder pressure P _M is generated, the piston 55 moves to the left in FIG. 2 (direction of arrow K in FIG. 2), the second chamber 56A
Volume is reduced, and / pressure _{P A = S 4 P M (} S 5 + S 6)
Occurs. The pressure P _A is through the third chamber 56C and the communicating passage 57, acts on the second chamber 16B of the wheel cylinder 16.

Therefore, the pressure increase control valve 5 is selected by selecting the areas S ₄ , S ₅ , and S ₆ including the balance with the pressure increase adjusting function.
The hydraulic pressure supplied from the wheel 6 to the wheel cylinder 16 is increased to a predetermined value and supplied to the wheel cylinder 16 even when the servo hydraulic device is malfunctioning, so that the braking force can be prevented from being extremely reduced.

[0053]

According to the first aspect of the present invention, there is provided a disc brake device having a first chamber to which a master cylinder hydraulic pressure is supplied, a wheel cylinder for pressing a pad against a rotor, and braking generated when the pad presses a rotor. A servo hydraulic pressure generating device for generating a servo hydraulic pressure by a reaction force, a first chamber and a second chamber defined by both end faces of a piston sliding in a cylinder in a liquid-tight manner, and a valve member interlocked with the second chamber. A pressure increasing control valve having a third chamber interrupted from communicating with the chamber, a master cylinder oil pressure is supplied to a first chamber of the pressure increasing control valve, a servo oil pressure is supplied to a second chamber, and a third chamber is provided. Is communicated with the second chamber of the wheel cylinder, and when the pressure of the second and third chambers of the pressure increasing control valve becomes equal to or more than a predetermined multiple of the master cylinder oil pressure supplied to the first chamber, the second chamber and the third chamber are connected. Shut off the room communication Since a configuration that blocks the second chamber supply servo hydraulic pressure to the Eel cylinder, servo hydraulic pressure has the excellent effect of being able to prevent the boosted above a predetermined value.

According to a second aspect of the present invention, the servo hydraulic pressure is set according to the master cylinder hydraulic pressure in a hydraulic passage connecting the second chamber of the pressure increasing control valve and the servo hydraulic pressure generating device. When the pressure becomes lower than the predetermined pressure, a cut valve is provided to cut off the communication between the servo hydraulic pressure generating device and the second chamber of the pressure increase control valve, thereby preventing the servo hydraulic pressure from increasing to a predetermined value or more. In addition to this, there is an excellent effect that the braking force can be prevented from being extremely reduced even when the servo hydraulic pressure generator is malfunctioning.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a disc brake device according to a first embodiment of the present invention, in which (A) is a side sectional view showing a wheel cylinder, and (B) is a B of (A). −
It is a B sectional view.

FIG. 2 is a block diagram showing a part of a disc brake device according to a second embodiment of the present invention.

FIG. 3 is a schematic diagram showing a disc brake device according to a conventional example.

[Explanation of symbols]

 Reference Signs List 10 master cylinder 16 wheel cylinder 16A first chamber 16B second chamber 18 piston 20 pad 25 rotor 26 pad 30 servo cylinder (servo hydraulic pressure generator) 32 servo cylinder (servo hydraulic pressure generator) 34 servo piston 40 servo piston 50 balance piston 55 Piston 56 Pressure increase control valve 56A Second chamber 56B First chamber 56C Third chamber 64 Cut valve 60 Outer cylinder (valve member) 66 Stepped spool valve (cut valve)

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-54-30362 (JP, A) JP-A-57-30648 (JP, A) JP-A-57-30647 (JP, A) 83928 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) F16D 55/22 F16D 65/20 F16D 55/224

Claims (2)

(57) [Claims] A wheel cylinder having a first chamber to which a master cylinder hydraulic pressure is supplied and pressing a pad against a rotor;
A servo hydraulic pressure generating device for generating a servo hydraulic pressure by a braking reaction force generated when the pad presses the rotor; a first chamber and a second chamber defined by both end surfaces of a piston sliding in a cylinder in a liquid-tight manner; A pressure increasing control valve having a third chamber interrupted by a valve member interlocked with the piston, the master chamber hydraulic pressure being supplied to the first chamber of the pressure increasing control valve, The third chamber is communicated with the second chamber of the wheel cylinder, and the pressure of the second and third chambers of the pressure increasing control valve is supplied to the first chamber. A disc brake device characterized in that when it is twice or more, the communication between the second chamber and the third chamber is cut off and the supply of servo hydraulic pressure to the second chamber of the wheel cylinder is cut off. 2. The servo control device according to claim 1, wherein when the servo hydraulic pressure becomes lower than a predetermined pressure set in accordance with a master cylinder hydraulic pressure, a hydraulic pressure is supplied to a hydraulic passage connecting the second chamber of the pressure increasing control valve and the servo hydraulic pressure generating device. 2. The disc brake device according to claim 1, further comprising a cut valve that cuts off communication between the hydraulic pressure generating device and the second chamber of the pressure increasing control valve.