JPH07267065A - Brake fluid pressure control device - Google Patents

Abstract

PURPOSE:To adjust pressure increasing speed by constituting an orifice arranged in a piston of flow valves so that a column part slidingly moves in the lengthwise direction in a circular pipe part formed in the piston, and changing orifice passage resistance by adjusting a lap length of both. CONSTITUTION:A circular pipe part 70 having an inner peripheral surface having a diameter smaller than holes 39 and 40 and having a prescribed axial directional length, is formed in a part between the upper hole 39 and the lower hole 40 of a piston 38 of flow valves 7 and 8. An inserting hole 71 is coaxially downward formed in the center on a lower end surface of a cylinder part 9 of a casing 10. A large diameter hole part 72 having a diameter larger than the other is formed in an axial directional intermediate part of the inserting hole 71. A column part 73 is inserted in the inserting hole 71 by forming a clearance, and the tip of the column part 73 is inserted in the circular pipe part 7O.1A specific clearance is formed between the circular pipe part 70 and the column part 73, and an orifice 41 is formed. The column part 73 is moved in the axis direction by a moving device 74, and passage resistance of the orifice 41 is adjusted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake fluid pressure control device for anti-skid control for preventing wheel lock during brake operation.

[0002]

2. Description of the Related Art As shown in FIG. 3, a brake fluid pressure control device for anti-skid control for preventing wheel lock during brake operation includes a master cylinder communication port 81 communicating with a master cylinder 80 and a wheel cylinder 8 as shown in FIG.
2, the wheel cylinder communication port 84 communicating with 2,83,
A casing 90 having a reservoir communication port 87 communicating with the variable capacity reservoir 85 via a normally closed valve 86 and a pump communication port 89 communicating with the discharge side of a pump 88 for sucking and discharging the brake fluid on the side of the reservoir 85; Some are equipped with flow valves 92, 93 slidably provided inside a casing 90 and having a piston 91 for switching between communication and interruption of the port.

Here, as shown in FIG. 3, when the piston 91 is in a stationary state urged by the piston spring 94 when the anti-skid control is not operated, the master cylinder communication port 81 and the wheel cylinder communication port 84 are connected to each other. The brake fluid pressure from the master cylinder 80 is transmitted to the wheel cylinders 82 and 83 by communicating with each other.

Further, at least when the piston 91 is in a moving state (not shown) moved against the urging force of the piston spring 94 by the differential pressure generated on both sides at the time of repressurization of the anti-skid control (not shown), the master cylinder communication port. 81 is substantially closed and the influence of the discharge of the pump 88 is affected by the master cylinder 80.
Side and the pump communication port 89
The wheel cylinder communication port 84 and the wheel cylinder communication port 84 are communicated with each other through an orifice 95 provided therein, and the discharge pressure of the pump 88 is transmitted to the wheel cylinders 82 and 83 (the piston 91 has both sides. The opening amount of the pump communication port 89 is controlled including the blockage by balancing the differential pressure of the above. In the conventional brake fluid pressure control device, the orifice 95 is formed in the piston 91 with a constant diameter and a constant length.

[0005]

As described above, in the conventional brake fluid pressure control device, the orifice is formed in the piston so as to have a constant diameter and a constant length.
The differential pressure before and after the orifice with respect to the flow rate of the brake fluid passing through the orifice at the time of repressurization of the anti-skid control becomes constant, so that the speed at which the brake fluid pressure is increased in the wheel cylinder is kept constant. As described above, in the conventional brake fluid pressure control device, the speed of boosting the brake fluid pressure in the wheel cylinders is kept constant, so that the speed of boosting the wheel cylinders is adjusted by, for example, suddenly boosting or slowly boosting the wheel cylinders. You cannot do it.

Therefore, an object of the present invention is to provide a brake fluid pressure control device capable of adjusting the speed of boosting the wheel cylinder such as a sudden boost or a slow boost when the anti-skid control is repressurized. That is.

[0007]

In order to achieve the above object, a brake fluid pressure control device of the present invention comprises a master cylinder communication port communicating with a master cylinder, a wheel cylinder communication port communicating with a wheel cylinder, and a variable capacity. A casing having a reservoir communication port communicating with the reservoir via a normally closed valve and a pump communication port communicating with the discharge side of a pump for sucking and discharging the brake fluid on the reservoir side, and a casing slidably provided inside the casing. , When the anti-skid control is not activated, the master cylinder communication port and the wheel cylinder communication port are communicated with each other in a stationary state urged by a piston spring, and a differential pressure generated on both sides at least when anti-skid control is repressurized. Is in a moving state in which it has moved against the biasing force of the piston spring. A flow valve having a piston that allows the pump communication port and the wheel cylinder communication port to communicate with each other through an orifice provided therein, the orifice having a predetermined length formed in the piston. And a cylindrical portion that is inserted into the circular pipe portion while maintaining a constant gap with the inner peripheral surface thereof and that is movable along the length direction of the circular pipe portion. Is characterized by.

[0008]

According to the brake fluid pressure control device of the present invention, the orifice provided in the piston of the flow valve has a circular pipe portion of a predetermined length formed in the piston and the inner peripheral surface of the circular pipe portion. Since the cylindrical portion is inserted while maintaining a constant gap and is movable along the length direction of the circular pipe portion, the circular cylindrical portion is moved with respect to the circular pipe portion. By adjusting the lap length between the cylindrical portion and the column portion, the channel resistance of the circular tube portion and the column portion, that is, the channel resistance of the orifice changes.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A brake fluid pressure control device according to an embodiment of the present invention will be described below with reference to FIGS.
In addition, the upper and lower sides used in the following description are used for convenience sake.

First, the overall configuration of the brake fluid pressure control device will be described. In the figure, reference numeral 1 is a brake fluid pressure control device,
Reference numeral 2 is connected to the brake pedal 3 to generate a brake fluid pressure in response to the depression of the brake pedal 3 or the like, and to transmit the brake fluid pressure to, for example, two systems of brake fluid pressure control circuits A and B which are cross-piped. A tandem type master cylinder having two brake fluid pressure generating chambers 2A and 2B is shown. Since the brake fluid pressure control circuit B side has the same configuration as the brake fluid pressure control circuit A side, only the brake fluid pressure control circuit A side will be illustrated and described.

The brake hydraulic pressure control circuit A has a path 4 connected to the brake hydraulic pressure generating chamber 2A of the master cylinder 2, and the path 4 is divided into paths 5 and 6, and these paths 5 are divided. , 6 are provided with flow valves 7, 8, respectively. Each of the flow valves 7 and 8 includes a casing 10 having a cylindrical cylinder portion 9 extending in the vertical direction and a plurality of ports provided from the inner peripheral side to the outer side of the cylinder portion 9.

Here, the port is a first port (pump communication port) 11 provided at a predetermined position orthogonal to the axis of the cylinder portion 9 so as to communicate with the master cylinder 2 via a path 4 and the like. A second port (wheel cylinder communication), which is provided at a reciprocal position below the one port 11 by a predetermined amount and communicates with the wheel cylinders 14 and 15 which are brake hydraulic pressure actuating devices of, for example, disc brakes and drum brakes via paths 12 and 13. And a third port (reservoir communication port) 17 provided at the lower end of the cylinder portion 9 orthogonal to the axis of the cylinder portion 9. The second port 16 is provided parallel to the upper port 19 at a predetermined amount lower reciprocal position of the first port 11 and a predetermined amount lower side of the upper port 19 in parallel with the upper port 19. It is composed of a lower port 20 communicating with the upper port 19.

The third port 17 of the flow valves 7 and 8 is connected to the paths 21 and 22 and the path 23 where these are joined.
Via a variable capacity reservoir 24, and electromagnetic normally closed valves (normally closed valves) 25, 26 are provided on the paths 21, 22.
Is provided. A path 27 is connected to the path 23, and a pump 29 is provided on the path 27. Here, the pump 29 is driven by a motor 30 common to the brake fluid pressure control circuit B to perform suction and discharge, a suction valve 32 provided on the reservoir 24 side of the pump body 31, and a pump. The main body 31 is composed of a discharge valve 33 provided on the opposite side of the suction valve 32, and the brake fluid from the reservoir 24 side is sucked and discharged from the discharge valve 33.

The discharge side of the pump 29 of the path 27 is connected to the path 6, and the pump 29 is provided between the discharge side of the pump 27 of the path 27 and the connection position to the path 6.
A noise chamber 37 that reduces the discharge pulsation is provided. The connection position between the route 27 and the route 6 and the route 23 are connected by the route 48.
Is provided with a relief valve 49. The relief valve 49 monitors the discharge connection side of the pump 29 of the path 48, and opens at a constant hydraulic pressure according to the brake hydraulic pressure at the monitor position. This relief valve 49 opens when the discharge pressure of the pump 29 becomes higher than necessary, and the surplus discharge pressure of the pump 29 is removed.
To the intake side of the flow valve 7, the first port 11 of the flow valve 7,8
The abnormal increase of the discharge pressure of the pump 29 is prevented.

Here, the paths 51 and 52 are connected to the open / close positions of the paths 21 and 22 by the electromagnetic normally closed valves 25 and 26, respectively. Then, in the state where the electromagnetic normally closed valves 25 and 26 are closed, the third ports 17 side of the routes 21 and 22 are closed, and the reservoir 24 side of the routes 21 and 22 and the route 51,
52 and the electromagnetic normally closed valve 2
In a state in which 5, 26 are opened, the routes 21 and 22 are communicated with the routes 51 and 52. These routes 51 and 52 are corresponding routes 12 and 13, respectively.
And then join each other to form a path 53, which is connected to the path 4. Routes 12 and 1 of routes 51 and 52
3 is closer to the electromagnetic normally closed valves 25 and 26 than the electromagnetic normally closed valves 25 and 26.
A check valve 55 that opens when the brake fluid pressure on the 26 side becomes higher than the brake fluid pressure on the paths 12 and 13 by a predetermined value is provided. Indicates that the brake fluid pressure on the paths 12 and 13 is the path 5
A check valve 56 is provided that opens when the brake fluid pressure on the 3rd side exceeds a predetermined value.

These check valves 55 and 56 are provided, for example, when the brake pedal 3 is loosened and the brake fluid pressure on the master cylinder 2 side is lowered while the brake fluid pressure remains in the reservoir 24 during anti-skid control. For the purpose of properly returning the brake fluid in the reservoir 24 to the master cylinder 2 side, and immediately returning the brake fluid of the wheel cylinders 14 and 15 directly to the master cylinder 2 side without passing through the flow valves 7 and 8. It is provided. In addition,
The check valves 55 and 56 are set to have valve opening pressures and the like so as not to open except for the above operation. Route 4, Route 5,
A check valve 58 is provided between the branch point position to 6 and the connection position to the path 53. This check valve 58
Is opened when the brake fluid pressure on the master cylinder 2 side acting on one side becomes higher by a predetermined value than the brake fluid pressure on the discharge side of the pump 29 acting on the other side, which is limited as necessary by the relief valve 49. As a result, the brake fluid pressure on the master cylinder 2 side is guided to the first port 11.

Next, the flow valves 7 and 8 will be described. As shown in FIGS. 2A to 2C, a cylindrical piston 38 is fitted in the cylinder portion 9 of the casing 10 of the flow valves 7 and 8 so as to be vertically slidable. The piston 38 has an upper hole 39 having a predetermined diameter formed axially in the center from the upper end to an intermediate predetermined position, and the upper hole 39 from the lower end to an intermediate predetermined position.
And a lower hole 40 which is bored coaxially with the same diameter and communicates with the third port 17 at all times.
A variable orifice 41 is provided between the lower hole 40 and the lower hole 40. The opening at the lower end of the lower hole 40 is larger in diameter than the other portions by a predetermined amount, and the piston spring 4 whose lower end abuts the lower end surface of the cylinder portion 9 is provided in this opening.
The upper end of 2 is inserted. Then, the urging force of the piston spring 42 urges the piston 38 upward with a predetermined urging force.

A plurality of holes are formed in the piston 38 at right angles to the upper hole 39 and the lower hole 40. These holes are provided below the upper end of the piston 38 by a predetermined amount, and the piston 38 is urged by the piston spring 42 so that the upper end portion is in contact with the upper surface of the cylinder portion 9 (FIG. 2A). (State shown in FIG. 2), the communication between the upper hole 39 and the first port 11 is substantially cut off, and the piston 38 is moved by the differential pressure generated on both sides during the anti-skid control (FIG. 2 ( b)), a first hole 43 that connects the upper hole 39 and the first port 11 to each other, a predetermined amount below the first hole 43, and the upper hole when the piston 38 is in the stationary state. 39 and the upper port 19 of the second port 16, and the second hole 44 that substantially blocks the communication between the upper hole 39 and the upper port 19 when the piston 38 is in the above-described moving state, and the second hole 44. From a predetermined amount Of the lower port 40 and the lower port 20 of the second port 16 when the piston 38 is in the stationary state, and substantially blocks the communication between the lower hole 40 and the lower hole 40 when the piston 38 is in the moving state. It is a third hole 45 that communicates with the port 20 (note that the piston balances the differential pressure between both sides during movement, as will be described later, and blocks the communication amount between the first port 11 and the first hole 43. 2), and the state in which the opening amount is small is shown in FIG. 2B).

In addition, on both axes of the flow valves 7 and 8 above the cylinder portion 9 of the casing 10, substantially the same diameter is formed in the upper hole 39 of the piston 38 in a stationary state, and the fourth port (master) is formed. Cylinder communication port) 60 is formed, and the fourth port 60 of the flow valve 7 is connected to the path 5
The valve 51 is connected to the check valve 56 and the connection position of the check valve 56 to the path 52 via the switch 9. Further, the fourth port 60 of the flow valve 8 is connected via the path 61 between the connection positions of the path 53 to the path 4 and the path 52.
A valve chamber 62 is provided in the fourth port 60, and a spherical valve body 63 and a valve body spring 64 that biases the valve body 63 toward the upper hole 39 are provided in the valve chamber 62. It is provided. Then, the piston 38 has a gap at the upper end thereof which is large enough not to cause resistance to the flow of the brake fluid in the fourth port 60 so as to protrude toward the valve chamber 62 in the direction of the fourth port 60. Protrusion 6 that can be inserted
5 is fixed, and a predetermined number of communication holes 66 are formed at the base of the projection 65, the communication holes 66 having a sufficient size so as not to generate a resistance to the flow of the brake fluid that allows the gap to communicate with the upper hole 39. .

As shown in FIG. 2A, the projection 65 projects into the valve chamber 62 when the piston 38 is in a stationary state by the urging force of the piston spring 42, and the valve body 63 is formed.
Is pressed against the urging force of the valve body spring 64, and is moved away from the seat portion 67 of the valve chamber 62 on the side of the upper hole 39, whereby the upper hole 39 passes through the communication hole 66 and the path 5 passes.
It will be connected to 9,61. Also, the protrusion 65 is
As shown in FIG. 2B, when the piston 38 moves against the urging force of the piston spring 42, it retreats from the inside of the valve chamber 62 and releases the pressure on the valve body 63, whereby the valve body 63 is released. Is to be seated on the seat 67 by the urging force of the valve body spring 64 and the brake fluid pressure from the master cylinder 2 generated at this time, so that the communication between the upper hole 39 and the paths 59 and 61 is completely cut off. Become. Here, the biasing force of the valve body spring 64 is set to be smaller than the biasing force of the piston spring 42. The valve body 63, the valve body spring 64, the valve chamber 62, and the protrusion 65 form a cut valve 68.

Next, the variable orifice 41 of this embodiment will be described. The piston 38 has an upper hole 39 and a lower hole 4.
A portion between 0 and 0 is a circular pipe portion 70 having an inner peripheral surface having a diameter smaller than these and having a predetermined axial length.
Has its axis coaxial with the axes of the piston 38, the upper hole 39 and the lower hole 40.

Further, an insertion hole 71 is formed coaxially downward at the center of the lower end surface of the cylinder portion 9 of the casing 10, and the diameter of the intermediate portion of the insertion hole 71 in the axial direction is larger than that of the other portions. The large-diameter hole portion 72 is formed. A cylindrical rod-shaped cylindrical portion 73 is inserted into the insertion hole 71 with a gap, and the cylindrical portion 73 is driven by a moving device 74 attached to the lower end surface of the casing 10. The columnar portion 73 is formed from the insertion hole 71 to the lower hole 40.
And is inserted coaxially on the inner peripheral side of the circular tube portion 70, and its outer diameter is such that a certain small gap is provided between the outer diameter and the inner peripheral portion of the circular tube portion 70 to form an orifice. It is set. That is, when the brake fluid flows through the gap between the lap portion between the circular pipe portion 70 and the column portion 73, the hydraulic pressure drops between the inlet side and the outlet side of the lap portion, and this serves as an orifice.

The moving device 74 internally has a moving mechanism in which a gear is combined with a linear solenoid or a stepping motor that operates according to a command from an anti-skid control unit (not shown). The amount of movement can be accurately controlled in the direction. Here, an annular seal member 75 that prevents the brake fluid in the flow valves 7 and 8 from leaking to the moving device 74 side is fitted in the large-diameter hole portion 72 of the insertion hole 71.

In this embodiment, the moving device 74
When the columnar portion 73 is located at the most projecting position (the state shown in FIG. 2A, referred to as the projecting side position), the upper end surface of the circular pipe portion 70 of the piston 38 and the columnar portion 7 in the stationary state.
3 is flush with the upper end surface of the circular pipe 3, and at this time, the axial length of the gap portion where the circular pipe portion 70 serving as an orifice and the cylindrical portion 73 are wrapped (referred to as the lap length) is The maximum length is the same as the length of the portion 70. As a result, the variable orifice 41 has the maximum flow path resistance.

Further, when the moving device 74 positions the columnar portion 73 at a position where the protruding amount thereof is smallest (FIG. 2).
(The state shown in (b), referred to as the retracted position), the position of the upper end surface of the cylindrical portion 73 is lower than the upper end surface of the circular pipe portion 70 of the piston 38 in the moving state, and the circular pipe portion 70 and the cylindrical portion 73 are arranged. And the wrap length with is shorter than the length of the circular pipe portion 70 (however, 0
Not). Thereby, the variable orifice 41 is
The flow path resistance becomes small.

Further, when the moving device 74 positions the cylindrical portion 73 at a predetermined position intermediate between the protruding side position and the retracting side position (the state shown in FIG. 2C, referred to as the intermediate position), the moving state is set. The upper end surface of the circular pipe portion 70 of a certain piston 38 and the upper end surface of the cylindrical portion 73 are substantially flush with each other. At this time, the lap length of the circular pipe portion 70 and the cylindrical portion 73 is a circle. The maximum length is the same as the length of the pipe portion 70. As a result, the variable orifice 41 has the maximum flow path resistance. Of course, the moving device 74 can position the columnar portion 73 at any position without being limited to the protruding side position, the intermediate position, and the retracting side position. Here, the piston 38 moves due to the differential pressure generated on both sides, and the moving amount at this time is the casing 10.
The position of the cylindrical portion 73 is determined in advance based on the relationship between the position of the port and the position of the hole of the piston 38.

The operation of the brake fluid pressure control device 1 of the present embodiment having the above-mentioned structure will be described below. Since the anti-skid control is executed for each wheel, there may be a situation where the anti-skid control is executed for the wheel cylinder of one wheel and the anti-skid control is not executed for the wheel cylinders of the other wheels. However, in the following description, for the sake of convenience, a case where both wheel cylinders of both wheels are subjected to anti-skid control will be described as an example.

First, when the normal brake operation is performed in the non-operation state of the anti-skid control, the electromagnetic normally closed valves 25 and 26 are in the demagnetized state, so that the pistons 38 of the flow valves 7 and 8 are moved to the piston spring 42. It is in a static state urged by. Therefore, the cut valve 68 provided in the fourth port 60 of both flow valves 7 and 8 is
It is pressed by the protrusion 65 of the piston 38 to be in the open state (the state shown in FIG. 2A). Therefore, the brake fluid pressure generated from the master cylinder 2 in response to the brake operation is introduced into the fourth port 60 in the flow valve 7 via the route 59 and the like, and in the flow valve 8 via the route 61 and the like. Via the fourth port 60. The brake fluid pressure is the communication hole 66, the piston 3
8 is transmitted to the wheel cylinders 14 and 15 via the upper hole 39, the second hole 44, the upper port 19 of the second port 16, the paths 12 and 13, and the like. At this time, in the moving device 74, the columnar portion 73 is located at the protruding side position, the lap length is maximized, and the flow path resistance of the variable orifice 41 is maximized.

At this time, since the pump 29 is in the non-operating state, the brake fluid pressure on the master cylinder 2 side is
A predetermined value higher than the brake fluid pressure on the discharge side of the pump 29 opens the check valve 58, and is guided to the first port 11 of both flow valves 7 and 8 via the paths 4 to 6, but is in a stationary state. At 38, since the communication between the first port 11 and the second port 16 is substantially cut off, the first port 11
Brake fluid pressure on the master cylinder 2 side does not flow to the wheel cylinders 14 and 15 side. Further, the brake fluid pressure generated from the master cylinder 2 is introduced into the relief valve 49 from the path 48 or the like, but the relief valve 49 is opened so that the brake fluid pressure on the master cylinder 2 side does not open. Since the pressure is set, it is not transmitted before the relief valve 49.

During the braking operation as described above,
When the antiskid control unit (not shown) determines that the wheels are in a wheel lock tendency based on information from a wheel speed sensor (not shown) provided on each wheel, and the antiskid control is performed, the antiskid control unit is used. The electromagnetic normally closed valves 25 and 26 are opened by the signal from the. by this,
The brake fluid on the side of the lower hole 40 of the flow valves 7 and 8 flows into the reservoir 24 via the paths 21 to 23, whereby the differential pressure generated on both sides of the variable orifice 41, which maximizes the flow path resistance, The piston 38 moves downward to retract the protrusion 65 from the valve chamber 62. The withdrawal of the protrusion 65 from the valve chamber 62 causes the valve body 63 to be seated on the seat portion 67 by the urging force of the valve body spring 64 and the brake fluid pressure on the master cylinder 2 side, thereby closing the cut valve 68. Become.

In addition, the piston 38 has a lower port 20
And the third hole 45 are communicated with each other, and the wheel cylinders 14 and 15 and the reservoir 24 are connected to the lower port 20,
The brake fluid in the wheel cylinders 14 and 15 is caused to flow into the reservoir 24 to communicate with each other through the third hole 45, the lower hole 40, the third port 17, and the like, and the brake fluid pressure is further reduced. Thus, the first port 11 and the first hole 43 communicate with each other.

Here, during the anti-skid control, the pump 29 is always driven by the signal from the anti-skid control section, and during the above-mentioned depressurization, the brake fluid sucked and discharged from the pump 29 on the side of the reservoir 24 is relieved. The valve 49 sets a predetermined value level and introduces it into the first port 11 of the flow valve 7 via the paths 6 and 5 and into the first port 11 of the flow valve 8 via the path 6. Then, it is introduced from the first port 11 into the upper hole 39, and circulates to the reservoir 24 through the variable orifice 41, the lower hole 40, the third port 17, and the like.

At this time, when the brake fluid passes through the variable orifice 41 having the maximum flow path resistance, the piston 38 resists the urging force of the piston spring 42 due to the differential pressure generated above and below the variable orifice 41. When it further moves slightly downward, the amount of communication between the first port 11 and the first hole 43 is reduced, whereby the brake fluid passing through the variable orifice 41 is reduced. Then, the differential pressure between the upper and lower sides of the variable orifice 41 decreases, and the piston 38 slightly rises due to the urging force of the piston spring 42, and the first port 1
The amount of communication between 1 and the first hole 43 is increased. This allows
The brake fluid passing through the variable orifice 41 increases,
The piston 38 moves slightly downward. Such a small vertical movement of the piston 38 is always performed during the anti-skid control, whereby the brake fluid flows to the lower hole 40 through the variable orifice 41 at a substantially constant flow rate.

In the above state, the check valve 58
The discharge pressure of the pump 29, which is larger than the brake fluid pressure on the master cylinder 2 side, acts on the check valve 5
Due to the non-return action of 8, the discharge of the pump 29 does not affect the master cylinder 2 side. Further, the brake fluid pressure acting on the valve body 63 of the cut valve 68 is the piston 3
The minute vertical movement of 8 results in “the brake fluid pressure acting on the lower hole 40 + the differential pressure generated by the variable orifice 41”. Since this is smaller than the brake fluid pressure on the master cylinder 2 side, the cut valve 68 is closed, and its influence does not extend to the master cylinder 2 side from the cut valve 68.

Here, after the anti-skid control is started, the anti-skid control unit drives the moving device 74 to move the columnar portion 73 to the intermediate position, for example, at a timing when a predetermined time has elapsed until the piston 38 surely reaches the moving position. Will be located. However, when the piston 38 is in the moving position, even if the columnar portion 73 moves from the projecting side position to the intermediate position, the variable orifice 41 maintains the maximum flow resistance.

When the locking tendency is avoided and the depressurized state is switched to the anti-skid controlled re-pressurized state, the electromagnetic normally closed valves 25 and 26 are closed by a signal from the anti-skid control unit, whereby the pump is closed. Since the piston 38 is in the moving state, the brake fluid sucked and discharged by the reservoir 29 from the reservoir 24 side is actuated by the check valve 58 and the cut valve 68 in the closed state as in the above-described depressurization. Is completely prevented from being returned to the first port 11 and the first hole 43.
From the upper hole 39, the variable orifice 41, the lower hole 40,
Flows to the wheel cylinders 14 and 15 through the third hole 45 and the lower port 20, and the wheel cylinders 14 and 1
5 is repressurized.

When the anti-skid control is repressurized, the anti-skid control section adjusts the position of the columnar section 73 by the moving device 74, for example, according to the degree of avoidance from the wheel lock tendency of the wheels. That is, when the degree of avoidance from the wheel lock tendency of the wheels is large, the brake fluid is supplied to the wheel cylinders 14 and 15 at a larger flow rate.
In order to rapidly increase the pressure of the column, the columnar portion 73 is positioned at the retracted position. As a result, the lap length between the circular pipe portion 70 and the cylindrical portion 73 is minimized, the flow path resistance of the variable orifice 41 is minimized, and the brake flow rate passing through the variable orifice 41 can be increased.

When the degree of avoidance of the wheel from the wheel lock tendency is small (close to the wheel lock tendency), the brake fluid is flown to the wheel cylinders 14 and 15 at a small flow rate to slowly pressurize the wheel cylinders 14 and 15. Therefore, the columnar portion 73 is positioned at the intermediate position.
As a result, the lap length between the circular pipe portion 70 and the cylindrical portion 73 is maximized, the flow path resistance of the variable orifice 41 is maximized, and the brake flow rate passing through the variable orifice 41 can be reduced. Of course, the position of the cylindrical portion 73 is continuously controlled so as to adjust the lap length with the circular pipe portion 70 according to each degree of avoidance from the wheel lock tendency of the wheel.

Even when the pressure is re-pressurized, as in the case of the depressurization, the flow rate of the brake fluid passing through the variable orifice 41 is substantially adjusted according to the flow path resistance at that time by the slight vertical movement of the piston 38. It will be controlled to a constant value.

As described above, in the brake fluid pressure control system according to the present embodiment, the variable orifice 41 provided in the piston 38 of the flow valves 7 and 8 has the circular pipe portion 70 formed in the piston 38 and having the predetermined length. The circular pipe portion 70 is inserted into the circular pipe portion 70 while maintaining a constant gap with the inner peripheral surface thereof.
Since it is composed of a columnar portion 73 that is movable along the length direction of the, the columnar portion 73 is moved with respect to the circular pipe portion 70, and the lap length of the circular pipe portion 70 and the cylindrical portion 73 is adjusted. By doing so, the flow path resistance of the circular pipe portion 70 and the columnar portion 73 changes. In this way, when the anti-skid control is repressurized, the pump 29 moves the wheel cylinders 14, 15
Variable orifice 4 for passing the brake fluid discharged to the
By changing the flow path resistance of No. 1, it is possible to always adjust the boosting speed optimally in various situations such as sudden boosting or slow boosting of the wheel cylinders 14 and 15. Therefore, the braking performance of anti-skid control can be significantly improved.

[0041]

As described in detail above, according to the brake fluid pressure control device of the present invention, the orifice provided in the piston of the flow valve has a circular pipe portion formed in the piston and having a predetermined length. Since the cylindrical portion is inserted into the circular pipe portion while maintaining a constant gap with the inner peripheral surface of the circular pipe portion and is movable along the length direction of the circular pipe portion, By moving the cylindrical portion and adjusting the lap length between the circular pipe portion and the cylindrical portion, the flow passage resistance between the circular pipe portion and the cylindrical portion, that is, the flow passage resistance of the orifice is changed. In this way, by changing the flow path resistance of the orifice that allows the brake fluid discharged from the pump to the wheel cylinder to be re-pressurized during anti-skid control, the wheel cylinder is re-pressurized during anti-skid control re-pressurization. It is possible to adjust the boosting speed, such as sudden boosting or slow boosting. Therefore, the braking performance of anti-skid control can be significantly improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram schematically showing an overall configuration of a brake fluid pressure control device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a flow valve of a brake fluid pressure control device according to an embodiment of the present invention, in which (a) shows a piston in a stationary state and a columnar portion at a protruding side position,
(B) shows the piston in the moving state and the columnar portion in the retracted position, and (c) shows the piston in the moving state and the columnar portion in the intermediate position.

FIG. 3 is a configuration diagram schematically showing an overall configuration of a conventional brake fluid pressure control device.

[Explanation of symbols]

 1 Brake Hydraulic Pressure Control Device 2 Master Cylinder 7, 8 Flow Valve 10 Casing 11 First Port (Pump Communication Port) 14, 15 Wheel Cylinder 16 Second Port (Wheel Cylinder Communication Port) 17 Third Port (Reservoir Communication Port) 24 Reservoirs 25, 26 Electromagnetic normally-closed valve (normally-closed valve) 29 Pump 38 Piston 41 Variable orifice (orifice) 42 Piston spring 60 Fourth port (master cylinder communication port) 70 Circular pipe part 73 Cylindrical part

Claims (1)

[Claims] 1. A master cylinder communication port that communicates with a master cylinder, a wheel cylinder communication port that communicates with a wheel cylinder, a reservoir communication port that communicates with a variable volume reservoir via a normally-closed valve, and suction of brake fluid on the reservoir side. And a casing having a pump communication port communicating with the discharge side of a pump for discharging the pump, and slidably provided inside the casing and urged by a piston spring when the anti-skid control is not operated. When the cylinder communication port and the wheel cylinder communication port are communicated with each other, and the pump communication port is in a moving state in which it is moved against the biasing force of the piston spring by the pressure difference generated at least on both sides at the time of repressurization of anti-skid control And the wheel cylinder communication port are provided inside In the brake fluid pressure control device including a flow valve having a piston communicating with the orifice, the orifice has a circular pipe portion of a predetermined length formed in the piston, and the circular pipe portion has an inner circumference thereof. A brake fluid pressure control device comprising: a cylindrical portion that is inserted while maintaining a constant gap with a surface and is movable along the length direction of the circular pipe portion.