JPH05170077A - Brake fluid pressure control device - Google Patents

Abstract

PURPOSE:To prevent the kick-back of a brake pedal and obtain a constant pedal feeling by providing an orifice and a valve body at a piston in the housing of a flow control valve provided at the by-pass passage of brake fluid and opening/closing the inlet side communicating hole of the housing. CONSTITUTION:The housing 37 of a flow control valve 33 is partitioned into a pump communicating chamber 44 and a master cylinder communicating chamber 43 communicated with the master cylinder 2 side of a bypass passage 8 by a piston 38. When the line pressure on the master cylinder 2 side is high, the piston 38 is pressed to the pump communicating chamber 44 side by the energizing force of a spring 49, so that a valve body 46 is brought into contact with the opening part 47 of a pump inlet side communicating hole 41. The opening part 47 is thereby closed, and brake fluid flows onto the master cylinder 2 side from an orifice 48. When the line pressure is low, brake fluid flows onto the master cylinder 2 side from the orifice 48, and also the piston 38 moves to separate the valve body 46 from the opening part 47 so as to let excessive braking liquid escape.

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 antilock brake control used in a brake device of a vehicle or the like.

[0002]

2. Description of the Related Art As a brake fluid pressure control device for anti-lock brake control adopted in a vehicle brake device for the purpose of preventing a tire from falling into a locked state during braking, a master cylinder and a wheel brake are connected. A main path, a bypass path bypassed from the main path, a reservoir provided on the wheel brake side of the bypass path for storing the brake fluid from the wheel brake, and a reservoir provided on the master cylinder side of the bypass path, A structure having a pump or the like that sucks the brake fluid from the reservoir and discharges it toward the main path is used.

This brake fluid pressure control device causes the brake fluid from the wheel brakes to flow into the reservoir in order to reduce the brake fluid pressure during antilock brake control, and the brake fluid in the reservoir is transferred to the wheel brakes. The pump sucks and discharges it toward the main route for the reason of repressurizing.

[0004]

In the brake fluid pressure control device having the above structure, the discharge pressure (discharge flow rate) of the brake fluid discharged from the pump to the main passage side is the pipe pressure (hereinafter referred to as the master cylinder side) connected to the master cylinder. The line pressure on the master cylinder side increases when the line pressure on the master cylinder side is relatively low, and decreases when the line pressure is high. The discharge flow rate of the pump is set so as to secure the discharge flow rate at this time. Further, since the flow rate returned to the wheel brake side for repressurizing the wheel brake is almost constant, the discharge flow rate of the pump is too large when the line pressure is relatively low, and the master route provided on the main path side is too large. There was a problem that the brake fluid suddenly returned to the cylinder, causing a sudden kickback of the brake pedal. Then, in order to solve this problem, it has been considered to use a metering pump, but this method has not been adopted because it involves a significant cost increase.

Therefore, an object of the present invention is to provide a brake fluid pressure control device which can always obtain a constant pedal feeling without causing a sudden kickback in the brake pedal.

[0006]

In order to achieve the above object, a brake fluid pressure control device of the present invention includes a main path connecting a master cylinder and a wheel brake, and a bypass path bypassed from the main path. A reservoir provided on the wheel brake side of the bypass path for storing and storing the brake fluid from the wheel brake when the brake fluid pressure of the antilock brake control is reduced; and a reservoir provided on the master cylinder side of the bypass path, A pump for sucking the brake fluid and discharging it toward the main path, wherein a flow rate control valve is provided in the bypass path on the discharge side of the pump, and the flow rate control valve includes a housing and the housing. And a pump communication chamber that is provided inside and communicates the inside of the housing with the pump discharge side of the bypass path. A master cylinder communication chamber that communicates with the master cylinder side of the bypass path is divided into two chambers, and a biasing means that biases the piston toward the pump communication chamber side. A chamber that communicates with the master cylinder communication chamber, and a valve body that is provided on the pump communication chamber side of the piston, and the piston is biased by the biasing member in the housing. It is characterized in that it is closed by the valve body when the valve body is in contact with the valve body, and a pump suction side communication hole communicating with the suction side of the pump is provided.

[0007]

According to the brake fluid pressure control device of the present invention, the brake fluid in the reservoir discharged from the pump enters the pump communication chamber of the flow rate control valve provided in the bypass path on the discharge side of the pump, and enters the piston. It will be throttled by the orifice provided and will flow from the master cylinder communication chamber to the master cylinder side.At this time, the piston moves due to the differential pressure generated on both sides of the piston and the extra brake fluid that cannot be throttled by the orifice is pumped in. It will escape to the suction side of the pump through the side communication hole. That is, when the line pressure on the master cylinder side is high, the discharge flow rate of the pump is small, but the piston is pressed toward the pump communication chamber side by the urging force of the urging member because the pressure difference generated on both sides of the piston is small, and the valve When the body is brought into contact with the pump suction side communication hole and the pump suction side communication hole is closed to allow the brake fluid to flow from the orifice to the master cylinder side and the line pressure on the master cylinder side is low, the pump discharge flow rate increases. , The piston moves the brake fluid from the orifice to the master cylinder side, and since the differential pressure generated on both sides increases, it moves against the urging force of the urging member to move the valve element from the pump suction side communication hole. The brake fluid is released from the pump suction side communication hole to the suction side of the pump. Moreover, the piston is balanced according to the differential pressure generated on both sides of the piston so as to appropriately adjust the opening amounts of the pump suction side communication hole and the valve body so that the brake fluid flowing from the orifice to the master cylinder side is constant. Become. Therefore, the flow rate of the brake fluid that is relieved to the suction side of the pump is appropriately adjusted according to the change in the line pressure on the master cylinder side, and the flow rate of the brake fluid that is flown to the master cylinder side through the orifice should be constant. Therefore, a sudden kickback does not occur in the brake pedal via the master cylinder.

[0008]

DETAILED 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.
It should be noted that the upper and lower parts in the following description are used for convenience sake.

In the figure, reference numeral 1 is a brake hydraulic pressure control device for anti-lock brake control, reference numeral 2 is a master cylinder which is connected to a brake pedal 3 and generates hydraulic pressure in response to an input of the brake pedal 3, and reference numeral 4 is A wheel brake that brakes the wheel by the brake fluid pressure, reference numeral 5 indicates a main path for transmitting the brake fluid pressure provided between the master cylinder 2 and the wheel brake 4, respectively.

The main route 5 is provided with a bypass route 8 bypassed from two branch points 6 and 7 of the main route 5. The bypass route 8 has a flow at the branch point 7 on the wheel brake 4 side. A valve 9 is provided. The flow valve 9 includes a master cylinder communication port 10 and a wheel brake 4 that communicate with the master cylinder 2 side in this order from the top.
A casing 1 having three ports, a wheel brake communication port 11 that communicates with a reservoir, and a reservoir communication port 14 that communicates with a reservoir 13 via an electromagnetic normally closed valve 12 described later.
5, the inside of the casing 15 is moved in the casing 15 by the differential pressure generated on both sides to switch the communication state between the ports 10, 11, 14 to switch the main path 5
And a spool 1 for appropriately controlling the flow path of the bypass path 8
6 is biased by a spring 17 and is slidably accommodated. The master cylinder communication port 10 has a first passage 18 that communicates with the outer peripheral side of the spool 16 in the casing 15 and a second passage 1 that communicates with the upper end of the spool 16.
It is branched to 9 and. In addition, the reservoir communication port 14
Also, in the casing 15, it is branched into a third passage 20 communicating with the outer peripheral side of the spool 16 and a fourth passage 21 communicating with the lower end side of the spool 16.

On the outer peripheral portion of the spool 16, a groove portion 22 is formed at a predetermined position and has a predetermined length and is recessed from the other portion by one step. Further, the spool 16 has an upper chamber 23 having a predetermined inner diameter that opens to the second passage 19 of the master cylinder communication port 10 at an upper portion thereof, and has a predetermined length smaller than the upper chamber 23 by a predetermined length on the lower side thereof. The fixed orifice 24 has a decompression chamber 25 further below the fixed orifice 24 and having a diameter larger than the fixed orifice 24 by a predetermined amount.
Each is provided along the axial direction of the spool 16.

An electromagnetic normally closed valve 1 is opened in the bypass passage 8 when the antilock brake control is depressurized to allow the brake fluid to flow into the bypass passage 8 from the main passage 5 side.
2 is provided closest to the flow valve 9 side, and the brake fluid from the wheel brake 4 is opened to the master cylinder 2 side of the electromagnetic normally closed valve 12 on the bypass path 8 when the brake fluid pressure is reduced. A reservoir 13 is provided for inflowing through the normally closed valve 12 for storage. The reservoir 13 includes a cylinder 26 and a reservoir piston 27 that is provided in the cylinder 26 and slides by the inflow of brake fluid.
And a spring 28 for urging the reservoir piston 27 with a predetermined urging force.

A pump 29 sucks the brake fluid from the reservoir 13 and discharges it toward the main passage 5 on the bypass passage 8 on the master cylinder 2 side of the reservoir 13.
Is provided. The pump 29 is provided with a pump body 30, and an intake valve 31 and a discharge valve 32 that are provided on the suction side (reservoir 13 side) and the discharge side (master cylinder 2 side) of the pump body 30 to regulate the flow direction of the brake fluid. (All are check valves).

Further, in the present embodiment, the pump 2 is provided on the bypass path 8 on the master cylinder 2 side of the pump 29.
A flow rate control valve 33 for controlling the discharge flow rate of the brake fluid from the reservoir 13 by the valve 9 is provided.
As shown in FIG. 2, the flow control valve 33 includes a central cylindrical portion 34 and an upper surface portion 3 provided so as to close both sides thereof.
5, a housing 37 having a lower surface portion 36, and a piston 38 slidably fitted in the housing 37 along the axial direction thereof.

A master cylinder communication hole 39, which communicates with the master cylinder 2 side of the bypass path 8, is provided at a predetermined position on the upper surface portion 35 of the housing 37. A pump suction-side communication hole 41, which communicates with the bypass path 8 on the suction side of the pump 29 via the communication path 40, is provided in the lower surface portion 36 of the housing 37 at a predetermined position substantially in the center thereof. Pump suction side communication hole 41 of portion 36
A pump discharge-side communication hole 42 that communicates with the discharge-side bypass path 8 of the pump 29 is provided at a predetermined position that does not interfere with. The housing 37 has a master cylinder communication chamber 43 communicating with the master cylinder 2 side of the bypass passage 8 by the piston 38 via the master cylinder communication hole 39, and a pump discharge side communication hole 42 for the pump 29. It is partitioned into a pump communication chamber 44 that communicates with the bypass path 8 on the discharge side and communicates with the suction side of the pump 29 via the pump suction side communication hole 41.

Further, the piston 38 has a protruding portion 45 that protrudes from the predetermined position at the center thereof toward the pump communication chamber 44 by a predetermined length, and a spherical valve element 46 fixed to the tip of the protruding portion 45. Are provided, and when the valve body 46 abuts the opening 47 of the pump suction side communication hole 41 on the pump communication chamber 44 side, the pump suction side communication hole 41 is closed. In addition, the piston 38 is provided with an orifice 48 having a predetermined diameter for communicating with the master cylinder communication chamber 43 and the pump communication chamber 44.
8, a spring (biasing member) 49 with a predetermined biasing force is fitted between the master cylinder communication chamber 43 side and the housing 37 facing the master cylinder communication chamber 43, with one end thereof fitted to the convex portion 50 of the piston 38. It is provided. If the orifice 48 allows the master cylinder communication chamber 43 and the pump communication chamber 44 to communicate with each other in a predetermined flow passage area, a clearance is provided, for example, between the outer peripheral portion of the piston 38 and the inner peripheral portion of the housing 37. It is of course possible to use this as an orifice.

The operation of the brake fluid pressure control device 1 of the present embodiment having the above-described structure will be described below.

First, when the anti-lock brake control is not operated, the electromagnetic normally closed valve 12 is in the closed state, and the spool 16 of the flow valve 9 is at the position moved upward (the position shown in FIG. 1). Thus, a large flow path is formed from the master cylinder communication port 10 to the wheel brake communication port 11 via the groove portion 22 formed on the outer peripheral portion of the spool 16, and the brake fluid pressure from the master cylinder 2 is generated by this large flow path. It is transmitted to the wheel brake 4 as it is via.

When the antilock brake control is depressurized, the brake fluid is discharged from the reservoir communication port 14 toward the reservoir 13 by opening the electromagnetic normally closed valve 12 provided in the bypass passage 8. As a result, a differential pressure is generated between the spool 16 of the flow valve 9 (on the side of the upper chamber 23 and the side of the pressure reducing chamber 25), and
Will move downward in. Then, the upper end outer peripheral portion 16a (the portion where the groove portion 22 is not formed) of the spool 16 closes the first passage 18 of the master cylinder communication port 10 to close the large passage, and the spool 16 is further closed. When it moves downward, its groove 22 simultaneously opens in the third passage 20 of the wheel brake communication port 11 and the reservoir communication port 14, and through the third passage 20 of the wheel brake communication port 11, groove 22 and reservoir communication port 14. As a result, the brake fluid is discharged from the wheel brake 4 to the reservoir 13, and the brake fluid pressure of the wheel brake 4 is reduced.

Here, the pump 29 is always in a driving state during the antilock brake control, and the brake fluid flowing into the reservoir 13 as described above is stored in the pump 2.
9 and is discharged to the main path 5 side through the flow control valve 33. The discharged brake fluid is supplied to the master cylinder communication port 10 of the flow valve 9.
Second passage 19, upper chamber 23, fixed orifice 24, decompression chamber 25, and fourth passage 21 of the reservoir communication port 14.
It returns to the reservoir 13 via the and is discharged by the pump 29 and circulates in this way as long as the electromagnetic normally closed valve 12 is open. At this time, the discharge flow rate of the brake fluid discharged from the pump 29 is kept constant by the flow rate control valve 33 (described later).

When the antilock brake control is re-pressurized, the electromagnetic normally closed valve 12 is closed so that the second passage 19, the fixed orifice 24, the decompression chamber 25, and the reservoir communication port 1 of the master cylinder communication port 10 are closed.
A small flow path connecting the fourth passage 21, the third passage 20, the groove portion 22 and the wheel brake communication port 11 is formed, and the brake fluid discharged from the pump 29 through the flow control valve 33 is the small flow. It flows through the road to the wheel brake 4 and pressurizes the wheel brake 4 at a constant flow rate. Then, the master cylinder communication port 10
When the pressure difference between the wheel brake communication port 11 and the wheel brake communication port 11 decreases, the spool 16 returns to the original position (the position shown in FIG. 1). Here, similarly to the above, the discharge flow rate of the brake fluid discharged from the pump 29 at this time is maintained constant by the flow rate control valve 33 (described later).

In this flow valve 9, the flow rate of the brake fluid to the wheel brake 4 at the time of re-pressurization of the antilock brake control is the master cylinder communication port 1
0 and the wheel brake communication port 11 regardless of the pressure difference, the metering edge 51 should always be constant.
The opening degree of a passage (variable orifice) between the reservoir communication port 14 and the fourth passage 21 is adjusted according to the pressure or the like.

When the antilock brake control is depressurized or repressurized, the pipe pressure connected to the master cylinder 2, that is, the master cylinder 2
Even if the side line pressure fluctuates, the flow control valve 3
3 keeps the discharge flow rate of the pump 29 constant. That is, the reservoir 13 discharged from the pump 29
The brake fluid inside the pump communication chamber 44 of the flow control valve 33
Then, the flow rate control valve 33 is throttled by the orifice 48 provided in the piston 38 and flows from the master cylinder communication chamber 43 to the master cylinder 2 side. At this time, the differential pressure generated on both sides of the piston 38 causes the piston 38 moves, and extra brake fluid that cannot be throttled by the orifice 48 escapes to the suction side of the pump 29 through the pump suction side communication hole 41.

Specifically, when the line pressure on the master cylinder 2 side is high, the discharge flow rate of the pump 29 is small, but since the differential pressure generated on both sides of the piston 38 is small, the piston 49 communicates with the pump by the urging force of the spring 49. Chamber 44
Side of the valve body 46, the valve body 46 is pressed toward the pump suction side communication hole 4
When the line pressure on the master cylinder 2 side is low and the line pressure on the master cylinder 2 side is low, the pump 29 However, the brake fluid flows from the orifice 48 to the master cylinder 2 side at a predetermined flow rate, and the piston 38 moves against the biasing force of the spring 49 because the differential pressure generated on both sides of the brake fluid increases. (Moving upward in FIG. 2), the valve body 46 is separated from the opening 47 of the pump suction side communication hole 41 to allow excess brake fluid to escape from the pump suction side communication hole 41 to the suction side of the pump 29. Become. Moreover, the piston 38 appropriately adjusts the opening amount of the pump suction side communication hole 41 and the valve body 46 in order to make the brake fluid flowing from the orifice 48 to the master cylinder 2 side constant according to the differential pressure generated on both sides thereof. It will be a balance to do.

Therefore, the flow rate of the brake fluid that is relieved to the suction side of the pump 29 is appropriately adjusted according to the change of the line pressure on the master cylinder 2 side, and the brake flowed to the master cylinder 2 side via the orifice 48. Since the flow rate of the liquid is constant, the brake pedal 3 is not suddenly kicked back via the master cylinder 2, and a constant pedal feeling can be obtained at all times.

Moreover, since the pressure between the pump 29 and the flow control valve 33 is higher than the line pressure on the master cylinder 2 side by a predetermined pressure, an unnecessary load is applied to the pump 29 and a motor for driving the pump 29. Without, pump 2
9 and its drive motor and the like, and also contributes to the steady-state rotation of these motors, and the pump noise and the noise of the motor (not shown) for driving the pump do not fluctuate. ..

The brake fluid pressure control device of the above embodiment.
No. 1 uses the flow valve with the above-mentioned configuration,
As a flow valve of at least a master cylinder,
Three reservoirs via wheel brakes and normally closed valves
Has each port communicating with
Master cylinder and wheel breaks when the trawl is inactive
Of the anti-lock brake control
When the pressure is reduced, the master valve is closed
And disconnects the wheel brake from the
Connect the brake and reservoir to connect the wheel brake
Allow the brake fluid to drain to the reservoir and then
Brake fluid returned to the master cylinder side by
The wheel break is caused by closing the normally closed valve when pressure is applied.
Those having a function of supplying to Ki preferably at a constant flow rate
Then, any structure can be applied.
Of course, if it has the above function, use a flow valve
It doesn't matter.

[0028]

As described above in detail, according to the brake fluid pressure control device of the present invention, the flow rate of the brake fluid that is relieved to the suction side of the pump is appropriately adjusted according to the change in the line pressure on the master cylinder side. As a result, the flow rate of the brake fluid flowing to the master cylinder side via the orifice becomes constant, so that a rapid kickback does not occur in the brake pedal via the master cylinder. Therefore, it is possible to always obtain a constant pedal feeling.

Moreover, since the pressure between the pump and the flow control valve is higher than the line pressure on the master cylinder side by a predetermined pressure, an unnecessary load is not applied to the pump and a motor for driving the pump, and the pump is not pumped. In addition to the protection of the drive motor and the like, it also contributes to the stabilization of these rotations, and since the pump sound and the sound of the motor (not shown) that drives the pump do not fluctuate, these sounds are not offensive. ..

[Brief description of drawings]

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

FIG. 2 is a cross-sectional view schematically showing a flow control valve and the like used in the brake fluid pressure control device according to one embodiment of the present invention.

[Explanation of symbols]

 1 Brake Hydraulic Pressure Control Device 2 Master Cylinder 4 Wheel Brake 5 Main Path 8 Bypass Path 13 Reservoir 29 Pump 33 Flow Control Valve 37 Housing 38 Piston 41 Pump Suction Side Communication Hole 43 Master Cylinder Communication Chamber 44 Pump Communication Chamber 46 Valve Body 48 Orifice 49 spring (biasing means)

Claims (1)

[Claims] 1. A main path connecting a master cylinder and a wheel brake, a bypass path bypassed from the main path, and a wheel brake side of the bypass path, which is provided on a wheel brake side of the antilock brake control when the brake fluid pressure is reduced. Brake fluid pressure control having a reservoir for inflowing and storing brake fluid from a wheel brake, and a pump provided on the master cylinder side of the bypass passage for sucking in the brake fluid of the reservoir and discharging it toward the main passage In the apparatus, a flow rate control valve is provided in the bypass path on the discharge side of the pump, the flow rate control valve is provided in a housing and a pump communication that communicates the inside of the housing with the pump discharge side of the bypass path. Master cylinder that communicates with the chamber and the master cylinder side of the bypass path It has a piston that divides into two chambers of the communication chamber and a biasing means that biases the piston toward the pump communication chamber, and the piston communicates the pump communication chamber and the master cylinder communication chamber. The valve has an orifice and a valve element provided on the side of the piston in the pump communication chamber, and the valve is in contact with the housing when the piston is urged by the urging member. A brake fluid pressure control device which is closed by a body and is provided with a pump suction side communication hole which communicates with a suction side of the pump.