JPH1024824A - Reflux type anti-lock brake device - Google Patents

Abstract

[PROBLEMS] To reduce a kickback amount in a recirculation type anti-lock brake device and alleviate a sense of discomfort due to a kickback. SOLUTION: The reservoir 20 has a small diameter portion 21 on the entrance side.
And two parts, a large diameter part 22 at the back, and each part 21, 22
Are set with pistons 23 and 24 and springs 25 and 26, respectively. The valve opening pressure Pi of the inlet valve 35 of the suction pump 30 is greater than the pressures P1 and P2 of the springs 25 and 26.
The relationship P1 <Pi <P1 + P2 is set. The brake fluid discharged from the wheel cylinder 15 at the time of pressure reduction is initially stored by compressing the spring 25, and the piston 23
After contacting 24, both springs are compressed and stored. Only the brake fluid stored by contracting both springs is recirculated by the suction pump 30, and the master cylinder 13
Until the pressure is reduced, the brake fluid stored by contracting only the spring 25 is not recirculated. As a result, the kickback amount can be reduced, and the sense of discomfort can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a recirculation type anti-lock brake device.

[0002]

2. Description of the Related Art Conventionally, there is known a recirculation type anti-lock brake device in which brake oil discharged from a wheel cylinder is returned to a master cylinder by a suction pump when the wheel cylinder pressure is reduced by anti-lock control. Have been.

[0003] In such a recirculation type anti-lock brake device, there is a problem that the driver feels uncomfortable and uncomfortable due to the kickback phenomenon of the brake pedal caused by the recirculation of the brake fluid. For this reason,
It is known that the brake fluid is not recirculated immediately after the start of the antilock control so that the suction pump is driven to start the recirculation after the pressure reduction integrated time after the start of the antilock control exceeds a predetermined value (particularly, Kaihei 6-305407
issue).

[0004]

However, in these conventional techniques, the absolute amount of kickback due to the brake fluid recirculated to the master cylinder is suppressed only by delaying the recirculation start timing of the brake fluid. Is not done.

Accordingly, an object of the present invention is to reduce the amount of kickback in the recirculation type anti-lock brake device, and to alleviate the discomfort caused by kickback.

[0006]

In order to achieve the above object, the following means for solving the problems are employed. That is, claim 1
The recirculation type anti-lock brake device described above ensures that a predetermined amount of the brake fluid remains in the reservoir even when the suction pump that sucks the brake fluid stored in the reservoir and returns the fluid to the master cylinder side is driven. A second recirculation means for recirculating the brake fluid from the reservoir to the master cylinder without passing through a suction pump when the master cylinder is depressurized is provided.

According to the first aspect of the invention, the brake fluid discharged when the wheel cylinder is depressurized is temporarily stored in the reservoir, and a part of the brake fluid is returned to the master cylinder by the suction pump. Is done. As much as some brake fluid is left in the reservoir,
The amount of kickback of the brake pedal during recirculation is reduced. Since the remaining brake fluid is recirculated when the master cylinder is depressurized, the above function can be repeatedly exerted.

[0008] In this case, as in claim 2, claim 1
The recirculation type anti-lock brake device according to claim 1, wherein the reservoir has a first portion that is sucked by the suction pump and a second portion that is not sucked by the suction pump and is recirculated when the master cylinder is depressurized. Can be configured.

According to the second aspect of the present invention, since the reservoir has the second portion that is not sucked by the suction pump, a predetermined amount of brake fluid can be reliably stored in the reservoir even while the suction pump is being driven. Will be left. Claim 3
3. The recirculation type anti-lock brake device according to claim 2, wherein the second portion starts storing brake fluid before the first portion, and the storage amount of the second portion reaches a limit. It is preferable that the brake fluid is started to be stored in the first portion after the above operation.

According to the third aspect of the present invention, even if the pressure of the wheel cylinder is reduced, the brake fluid is stored only in the second portion at first, so that the brake fluid is not recirculated. Therefore, when the pressure reduction amount of the wheel cylinder is small, kickback can be prevented from occurring,
Even when the pressure is greatly reduced, the effect of alleviating the driver's discomfort can be exhibited by delaying the kickback occurrence timing.

According to a fourth aspect of the present invention, in the recirculation type anti-lock brake device according to the second or third aspect, the second portion supplies the master brake fluid through a bypass passage opened when the master cylinder is depressurized. You may comprise so that it may return to a cylinder. In returning the brake fluid from the second part to the master cylinder, for example, the brake fluid can be returned by adjusting the control position of the pressure control valve of the wheel cylinder. Control becomes complicated, such as the need to control the opening timing. On the other hand, according to the device described in claim 4, for example, only by providing a bypass with a check valve, the brake fluid of the second portion can be automatically recirculated when the master cylinder is depressurized, There is an effect that reliable reflux can be performed with a simple configuration.

Further, as described in claim 5, claims 2 to 4
Wherein the valve opening pressure of the inlet valve of the suction pump is set to a pressure at which the valve can be opened only while the brake fluid pressure in the reservoir exceeds a predetermined set pressure. In addition, the first part of the reservoir is provided with first pressure means for pressurizing the brake fluid to a pressure exceeding the set pressure, and the second part of the reservoir is provided with the brake fluid at a pressure equal to or less than the set pressure. You may make it provide the 2nd pressurizing means which pressurizes.

According to the fifth aspect of the present invention, since the first portion is pressurized by the first pressurizing means to a pressure exceeding the set pressure of the pump inlet valve, the pump inlet valve is opened and suction by the suction pump is performed. Enable. On the other hand, the second
Since the portion is pressurized only to a pressure equal to or lower than the set pressure by the second pressurizing means, if the brake fluid of the first portion is sucked, the pump inlet valve closes, and the brake fluid is sucked from the second portion. Never. As a result,
Until the master cylinder is depressurized, part of the brake fluid can be reliably left.

Further, as a more specific configuration, in the recirculation type anti-lock brake device according to the fifth aspect, the inlet side of the reservoir is the second side.
The first and second portions are set such that the first pressing portion starts pressing after the pressing capability of the second pressing portion reaches a limit. What is necessary is just to make the operation timing of a pressurization means cooperate.

With this configuration, the first portion and the second portion can be provided by one reservoir. On the other hand, claim 7
As described, in the recirculation type anti-lock brake device according to any one of claims 2 to 5, the first portion and the second portion may be configured as separate structures connected by piping. That is, the reservoir may be completely divided into two.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a system configuration according to the first embodiment. This system includes a master cylinder 13 for pressurizing brake fluid in accordance with a depression operation of a brake pedal 11, a wheel cylinder 15 for generating wheel braking force by introducing the brake fluid pressurized by the master cylinder 13, a master cylinder 13
An inlet valve 17 that is provided between the wheel cylinder 15 and adjusts the amount of brake fluid introduced into the wheel cylinder 15; and an outlet valve 19 that discharges the brake fluid in the wheel cylinder 15 to depressurize the wheel cylinder 15. A reservoir 20 for storing brake fluid discharged through the outlet valve 19, a suction pump 30 for sucking the brake fluid in the reservoir 20 and returning the brake fluid to the master cylinder 13, and a brake returned by the suction pump 30. A damper 41 for reducing pressure pulsation of liquid and a damper orifice 43 provided between the damper 41 and the master cylinder 13 are provided.

The reservoir 20 has a small-diameter portion 21 on the entrance side.
And two large-diameter portions 22 at the back.
Pistons 23 and 24 and springs 25 and 26 are set in 1 and 22, respectively. As shown in the figure, the small-diameter portion piston 23 has a cylindrical portion 23a extending toward the back of the reservoir. The large-diameter portion piston 24 allows the small-diameter portion spring 25 to penetrate and The partial piston 23 has a hole 24a through which it cannot pass.

The suction pump 30 is configured to perform suction and discharge by reciprocating a plunger 33 by an eccentric cam 31 rotated by a motor (not shown). Pumps are provided on the inlet side and the outlet side, respectively. Inlet valve 35, pump outlet valve 37
It has. Here, the valve opening pressure Pi of the pump inlet valve 35 is equal to the pressure P1 of the springs 25 and 26 described above.
The relationship of P1 <Pi <P1 + P2 is set for P2.

In the present system, a bypass passage 45 is provided in the pipe connecting the wheel cylinder 15 and the reservoir 20 to bypass the suction pump 30 and communicate with the inlet side of the damper 41. The bypass passage 45 is provided with a check valve 47 which can be opened by the pressing force P1 of the small diameter portion spring 25. The wheel cylinder 15 and the master cylinder 13
Is also provided, and a check valve 51 is also provided here.

With the above configuration, in the system of this embodiment, when the brake pedal 11 is depressed, the inlet valve 17 is set to the open position and the outlet valve 19 is set to the closed position according to the behavior of the wheels. Control to increase the pressure inside the wheel cylinder 15 and the inlet valve 1
Control to reduce the pressure in the wheel cylinder 15 by setting the outlet valve 19 to the open position and to control the pressure in the wheel cylinder 15 by setting both the inlet valve 17 and the outlet valve 19 to the closed position. The antilock control is executed so that the wheel slip ratio becomes the target slip ratio.

The brake fluid discharged from the wheel cylinder 15 at the time of pressure reduction in the antilock control is initially stored in the small diameter portion 21 of the reservoir 20. After the small-diameter portion piston 23 retreats to a position where it contacts the large-diameter portion piston 24, the large-diameter portion piston 24 also starts retreating in cooperation with the retreat operation of the small-diameter portion piston 23. Then, the brake fluid is further stored. As a result, the internal pressure of the reservoir 20 changes as shown in FIG. In FIG. 2, V1 corresponds to the limit storage amount until the piston 23 comes into contact with the piston 24.

As shown in FIG. 2, when the brake fluid exceeding the limit storage amount V1 is discharged from the wheel cylinder 15, the pump inlet valve 35 can be opened, and the brake fluid in the reservoir 20 is sucked. Pump 3
It is sucked by 0 and returned to the master cylinder 13 side. As a result of this recirculation, when the amount of brake fluid stored in the reservoir 20 decreases to V1, the pump inlet valve 35 closes, and no more recirculation of the brake fluid is performed.

Therefore, the kickback amount of the brake pedal 11 is smaller than that of the conventional system by an amount corresponding to the V1 brake fluid remaining in the reservoir 20. When the discharge amount of the brake fluid from the wheel cylinder 15 due to the pressure reduction control is equal to or less than V1, no kickback occurs. Furthermore, since the reflux does not start until the brake fluid exceeding V1 is discharged,
The kickback start timing can be delayed. In addition, since the brake fluid recirculated by the suction pump 30 is temporarily stored in the damper 41 and then slowly returned to the master cylinder 13 via the damper orifice 43, a sudden kickback is also avoided.

When the brake pedal 11 is returned and the master cylinder 13 is depressurized, the check valve 47 in the bypass 45 is opened by the pressure of the brake fluid remaining in the small-diameter portion 21, and the small-diameter portion 21 is opened. The remaining brake fluid is finally returned to the master cylinder 13.

As described above, according to the present embodiment, the amount of kickback during antilock control can be reduced.
In addition, since kickback occurrence timing is delayed and sudden kickback occurrence can be avoided, the uncomfortable feeling and discomfort given to the driver can be greatly reduced.

Next, a second embodiment will be described. Since the second embodiment is generally the same as the first embodiment, the same components are denoted by the same reference numerals as in the first embodiment, and description thereof is omitted. What is different is the structure of the reservoir. In the present embodiment, a first reservoir 61 and a second reservoir 62 which are connected to each other by a communication pipe 60 are provided. Pressure P3 of first reservoir spring 63 and pressure P of second reservoir spring 64
No. 4 is set to have a relationship of P3 <Pi <P4.

As a result, also in the present embodiment, the first
The same operation and effect as those of the embodiment can be exerted, and a feeling of strangeness due to kickback during antilock control can be reduced. The embodiment of the present invention has been described above, but the present invention is not limited to this, and can be implemented in various other modes.

For example, when the master cylinder 13 is depressurized without providing the bypass passage 41, the outlet valve 19 is opened so that the brake fluid remaining in the reservoir can be removed from the master via the check valve 51 or the inlet valve 17. The gas may be returned to the cylinder 13.

As shown in FIG. 4A, a spring 7 having a short and high spring constant is placed in a reservoir 70 having a constant diameter.
The same operation and effect as in the first embodiment can be exerted even if the 1 and the long and low spring constant spring 72 are arranged in a double manner. Further, as shown in FIG. 7B, a high spring constant spring 73 and a low spring constant spring 74 may be arranged in series. Further, the pressure in the reservoir is reduced as shown in FIG.
As shown by L1 and L2, a pressurizing means that continuously changes from a pressure lower than the valve opening pressure Pi of the pump inlet valve to a pressure exceeding Pi may be provided. For example, if an air spring is provided on the back surface of the piston instead of the coil spring, it is possible to adopt a configuration in which the pressing force is gradually increased by one spring member.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a system according to a first embodiment.

FIG. 2 is a graph showing a relationship between the reservoir internal pressure and a brake fluid storage amount.

FIG. 3 is an overall configuration diagram of a system according to a second embodiment.

FIG. 4 is an explanatory diagram showing a modified example.

FIG. 5 is an overall configuration diagram of a conventional system.

[Explanation of symbols]

11 ... Brake pedal, 13 ... Master cylinder, 15 ... Wheel cylinder, 17 ... Inlet valve, 19 ... Outlet valve, 20 ... Reservoir, 21 ... Small diameter part, 22 ..Large diameter portion, 23
..Piston for small diameter part, 24 ... Piston for large diameter part, 25 ... Spring for small diameter part, 26 ...
・ Spring for large diameter part, 30 ・ ・ ・ Suction pump, 3
5 ... Pump inlet valve, 41 ... Damper, 43
... Damper orifice, 45 ... Bypass path, 47
... Check valve, 60 ... Piping for communication, 61 ...
・ First reservoir, 62 ... Second reservoir, 63 ...
Spring for the first reservoir, 64 ... Spring for the second reservoir, 70 ... Reservoir, 71 ... Spring with a short and high spring constant, 72 ... Spring with a long and low spring constant, 73 ... High spring with high spring constant,
74: A spring having a low spring constant.

Claims (7)

[Claims] 1. A master cylinder for pressurizing brake fluid in response to a braking operation by a driver, a wheel cylinder for generating a wheel braking force by introducing the brake fluid pressurized by the master cylinder, and the wheel A wheel cylinder depressurizing means for discharging the brake fluid introduced into the cylinder to decompress the wheel cylinder, a reservoir for storing the brake fluid discharged from the wheel cylinder by the wheel cylinder depressurizing means, and a reservoir stored in the reservoir. A recirculation type anti-lock brake device comprising a first recirculation means constituted by a suction pump for sucking the brake fluid and recirculating the brake fluid to the master cylinder side, even if the suction pump is driven. A predetermined amount of brake fluid is left and the remaining brake fluid is When Linda vacuum, reflux type antilock brake system characterized by comprising a second recirculation means for recirculating to said master cylinder from the reservoir. 2. The recirculation type anti-lock brake device according to claim 1, wherein, as the second recirculation means, the reservoir is not sucked by a first portion sucked by the suction pump and by the suction pump. A second portion that is recirculated when the master cylinder is depressurized. 3. The recirculation type anti-lock brake device according to claim 2, wherein the second portion starts storing brake fluid before the first portion, and a storage amount of the second portion reaches a limit. A recirculation type anti-lock brake device characterized in that the brake fluid is started to be stored in the first portion later. 4. The recirculation type anti-lock brake device according to claim 2, wherein the second portion is configured to recirculate the brake fluid to the master cylinder via a bypass which opens when the master cylinder is depressurized. A reflux type anti-lock brake device characterized by the above-mentioned. 5. The recirculation type anti-lock brake device according to claim 2, wherein the valve opening pressure of the inlet valve of the suction pump is increased when the brake fluid pressure in the reservoir exceeds a predetermined set pressure. The first part of the reservoir is provided with first pressure means for pressurizing the brake fluid to a pressure exceeding the set pressure, and the second part of the reservoir is provided with A recirculation type anti-lock brake device comprising a second pressurizing means for pressurizing the brake fluid to a pressure equal to or lower than the set pressure. 6. The recirculation type anti-lock brake device according to claim 5, wherein an inlet side of the reservoir is the second part and a back side is the first part, and the pressurizing ability by the second pressurizing means. After reaching the limit,
A recirculation type anti-lock brake device wherein the operation timings of the first and second pressurizing means are linked so that the first pressurizing means starts pressurizing. 7. The recirculation type anti-lock brake device according to claim 2, wherein the first portion and the second portion have a separate structure connected by a pipe. Type anti-lock brake device.