JP4449729B2 - Brake control device - Google Patents

Description

  The present invention relates to a brake control device capable of controlling the working fluid pressure to the brake cylinder of each wheel separately from a master cylinder that boosts the working fluid pressure by depressing a brake pedal.

As a conventional brake control device, for example, a stroke simulator into which hydraulic fluid corresponding to the operation amount of a brake pedal is introduced from a master cylinder is provided, and a plurality of disc springs are installed in the stroke simulator, and a slide between disc springs is provided. It is known that the relationship between the amount of depression of the brake pedal applied by the stroke simulator by the dynamic resistance force and the depression force, in particular, the hysteresis characteristic thereof is obtained (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 6-211124

However, in the conventional brake control device, since hysteresis is generated by the frictional force of the disc spring, there is an unsolved problem that the hysteresis characteristic changes due to wear of the disc spring. Further, there is an unsolved problem that there is no difference in the sliding resistance force between the disc springs when the brake pedal is depressed and when the pedal is depressed, and the hysteresis is insufficient.
Therefore, an object of the present invention is to provide a brake control device that can obtain a predetermined hysteresis characteristic in the relationship between the depression amount and the depression force of the brake pedal.

In order to achieve the above object, a brake control device according to the present invention generates a sliding resistance force by sliding a friction member on a rod, and a sliding resistance force change means according to the stroke direction of the rod. The sliding resistance is changed.
The sliding resistance changing means increases the sliding resistance when the brake pedal is stepped back more than when the brake pedal is depressed, and is a pressing force changing means that changes the friction member according to the stroke direction of the rod. Change the pressing force to press against the rod.
The pressing force changing means is composed of an elastically deformable member. Then, the contact side of the friction member and the rod with respect to the fixed side fixed at a position where the brake pedal does not move in the outer diameter direction of the rod, the rod shaft in the direction in which the rod strokes when the brake pedal is depressed. By tilting toward the center, the friction member is bent in the compression direction when the brake pedal is stepped back, and the pressing force when the brake pedal is stepped back is greater than when the brake pedal is stepped on.

  According to the present invention, since the sliding resistance is changed according to the stroke direction of the rod, the sliding resistance of the rod can be differentiated between when the brake pedal is depressed and when the pedal is returned. A predetermined hysteresis can be generated in the characteristics of the stroke and the depression force of the brake pedal, and an effect that the driver can perform a brake operation without feeling uncomfortable is obtained.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a schematic configuration diagram of a brake control device according to the first embodiment. In the figure, reference numeral 1 denotes a brake pedal, and reference numeral 2 denotes a master cylinder whose pressure is increased according to the depression amount of the brake pedal 1. .
The master cylinder 2 has pressure generating chambers 2a and 2b, and these pressure generating chambers 2a and 2b are formed by pistons 2c and 2d in the cylinder. A spring 2e is installed in the pressure generation chamber 2a, and a spring 2f is installed in the pressure generation chamber 2b.

The piston 2c and the brake pedal 1 are connected via a rod 2g, and when the brake pedal 1 is depressed by the driver, the rod 2g moves to the master cylinder 2 side and the piston 2c is pushed. Yes.
And the working fluid pressure according to the depression amount of the brake pedal 1 is each output from the pressure generation chambers 2a and 2b. That is, the master cylinder 2 has two output systems, and outputs the working fluid pressure to these output systems. Hereinafter, the output system from the pressure generating chamber 2a is referred to as a primary system, and the output system from the pressure generating chamber 2b is referred to as a secondary system.

These working fluid pressures generate braking force on the wheels 5a and 5b via the master cylinder cut valves (open in the normal state) 3a and 3b and the normally open solenoid valves (open in the normal state) 4a and 4b. It is supplied to the wheel cylinders 6a and 6b.
Master cylinder pressure sensors 7a and 7b, which are pressure sensors for detecting the working fluid pressure, are interposed on the output sides of the master cylinder 2.

On the other hand, a pump 9 as a fluid pressure generating means is connected to a reservoir 8 provided in parallel with the master cylinder 2. The pump 9 is composed of an electric motor 9a and a hydraulic pump 9b that is rotationally driven by the electric motor 9a. The braking pressure output from the pump 9 is between the master cylinder cut valve 3a and the normally open electromagnetic valve 4a. Supplied to the fluid path. The fluid path between the master cylinder cut valve 3a and the normally open solenoid valve 4a and the fluid path between the master cylinder cut valve 3b and the normally open solenoid valve 4b are normally closed (closed in a normal state). ) Is connected via a system shutoff valve 10 which is an electromagnetic on-off valve.
Further, the wheel cylinders 6a and 6b and the reservoir 8 are connected via normally closed solenoid valves (closed in a normal state) 11a and 11b to control the discharge of hydraulic pressure from the wheel cylinders 6a and 6b to the reservoir 8. Is configured to do.

  A stroke simulator 12 is connected to the upstream side of the master cylinder cut valve 3b on one output side of the master cylinder 2 via a stroke simulator cut valve 13 which is a normally closed (normally closed) electromagnetic on-off valve. Has been. When the brake control device (brake-by-wire system) is activated and normal, the master cylinder cut valves 3a and 3b are closed to disconnect the master cylinder 2 and the wheel cylinders 6a and 6b, and the stroke simulator cut valve 13 is energized. In this state, the output side and the stroke simulator 12 are connected. When the stroke simulator cut valve 13 is in the open state, the stroke simulator 12 is configured to absorb the working fluid pressure output from the master cylinder 2.

The stroke simulator 12 includes a cylinder, a piston 12a slidably disposed in the cylinder, and a coil spring 12b that urges the piston 12a, and a pedal corresponding to the stroke of the brake pedal 1. Generate reaction force.
Further, a friction member 14 is disposed on the brake pedal 1 side of the master cylinder 2 so as to be in sliding contact with the rod 2g and generate a sliding resistance force. The friction member 14 is integrally formed with a rubber boot 15 as a dust cover fixed to the cylinder body of the master cylinder 2. The friction member 14 causes a difference in the pressing force (vertical drag) acting in the direction perpendicular to the axis of the rod 2g according to the stroke direction of the rod 2g, that is, when the brake pedal 1 is stepped on and when it is stepped back. Thus, the sliding resistance force is changed. This configuration corresponds to the pressing force changing means.

The brake control device further includes a stroke sensor 18 for detecting the amount of depression of the brake pedal 1 and wheel cylinder pressure sensors 19a and 19b for detecting the working fluid pressure of the wheel cylinder.
The master cylinder cut valves 3a and 3b, the normally open type solenoid valves 4a and 4b, the system shutoff valve 10, the normally closed type solenoid valves 11a and 11b, and the stroke simulator cut valve 13 are each supplied to a solenoid control unit 30. The open / closed state is controlled by the control signal from, and when the control signal is in the off state (non-energized state), it is in the normal state, and when in the on state (energized state), it is configured to switch to the offset position Yes.

  The control unit 30 is configured via an arithmetic processing device such as a microcomputer, for example. The control unit 30 determines whether an abnormality (failure) has occurred in any of the control unit 30 itself, the master cylinder pressure sensors 7a and 7b, the pump 9, and the stroke sensor 18, and the abnormality is detected. If not, the master cylinder cut valves 3a and 3b are controlled to be closed, the master cylinder 2 and the wheel cylinders 6a and 6b are disconnected, and the stroke simulator cut valve 13 is controlled to be open. The master cylinder 2 and the stroke simulator 12 communicate with each other, and the stroke simulator 12 absorbs the depression of the brake pedal 1.

Then, the pump 9 is operated to generate a hydraulic pressure, and the normally open solenoid valves 4a and 4b and the normally closed solenoid valves 11a and 11b are controlled so that the hydraulic pressure in the wheel cylinders 6a and 6b is detected by the master cylinder pressure sensor. The wheel is braked by being controlled to be a brake fluid pressure command value calculated from the value and the detected value of the stroke sensor.
On the other hand, when an abnormality occurs, the master cylinder cut valves 3a and 3b are opened to allow the master cylinder 2 and the wheel cylinders 6a and 6b to communicate with each other, and the hydraulic pressure of the wheel cylinders 6a and 6b is directly applied by the hydraulic pressure of the master cylinder 2. Is generated. At this time, by closing the system shut-off valve 10, the primary and secondary systems of the master cylinder generate hydraulic pressure independently.
When this abnormality occurs, the stroke simulator cut valve 13 is closed so that the brake fluid does not flow into the stroke simulator 12, and the loss stroke due to the brake fluid absorption in the stroke simulator 12 is reduced.

FIG. 2 is a diagram showing details of the friction member 14 and the rubber boot 15.
A friction material 14 a integrally formed with the rubber boot 15 is supported on the brake pedal 1 side in the cylinder body of the master cylinder 2. The friction material 14a is made of a material such as elastically deformable rubber, and is fixed to a fixed position (supported by the friction material 14a) in a position where the brake pedal 1 is not depressed in the outer diameter direction of the rod 2g. The contact side with the rod 2g is inclined toward the axis of the rod 2g in the direction in which the rod 2g strokes when the brake pedal 1 is depressed. In this embodiment, when the brake pedal 1 is depressed, the rod 2g strokes toward the master cylinder. That is, the friction material 14a is arranged at a predetermined angle α with respect to the traveling direction of the rod 2g so that the contact side with the rod 2g is located on the master cylinder side with respect to the support side of the friction material 14a.

Accordingly, the sliding resistance can be changed by changing the pressing force that presses the friction material 14a against the master cylinder 2 in accordance with the stroke direction of the rod 2g.
When the brake pedal 1 is depressed, the rod 2g slides toward the master cylinder 2 as shown in FIG. At this time, the friction material 14a maintains the angle α with the rod 2g, and the vertical drag (the friction material pressing force) N ₁ has a substantially constant value.

When the brake pedal 1 is stepped back, the rod 2g slides toward the brake pedal 1 as shown in FIG. 2 (b). At this time, since the friction material 14b is bent in the compression direction and the reaction force is increased, the pressing force N ₂ is larger than the pressing force N ₁ when the brake pedal 1 is depressed.
The sliding resistance force F between the rod and the friction material is the product of the friction coefficient μ between the friction material and the rod, the pressing force N of the friction material against the rod, and the contact area A between the friction material and the rod ( F = μ × N × A), the sliding resistance force when the brake pedal 1 is returned is larger than the sliding resistance force when the brake pedal 1 is depressed. As a result, as shown in FIG. 3, a hysteresis characteristic is obtained in the relationship between the depression force of the brake pedal and the stroke.

Next, the operation of this embodiment will be described.
When the driver depresses the brake pedal 1 in a state where no abnormality has occurred, the working fluid corresponding to the amount of depression of the brake pedal 1 is introduced into the stroke simulator 12, and the piston 12a is coiled by the hydraulic pressure. 12b is shrunk. As the coil spring 12b contracts, its resilience increases, so the reaction force that the coil spring 12b applies to the piston 12a also increases. Here, since the pressing force of the friction material 14 against the rod 2g of the master cylinder 2 is substantially constant, the reaction force according to the elastic force of the coil spring 12b becomes the pedaling force of the brake pedal 1.

Therefore, when the brake pedal 1 is depressed, the greater the depression amount (stroke) of the brake pedal 1, the greater the increase in the depression force. The relationship between the stroke of the brake pedal 1 and the depression force is represented by the curve (A) in FIG. It becomes like this.
When the driver depresses the brake pedal 1 from this state, the piston 12a is pushed back by the elastic force of the coil spring 12b, and the working fluid in the stroke simulator 12 is discharged to the master cylinder 2 accordingly. Therefore, the brake pedal 1 is pushed back. That is, the rod 2g of the master cylinder 2 is returned to the brake pedal 1 side.

  At this time, as shown in FIG. 2B, the reaction force of the friction material 14a increases the sliding resistance between the rod 2g and the return of the rod 2g is hindered. Therefore, the relationship between the stroke of the brake pedal 1 and the pedaling force when the brake pedal 1 is stepped back is as shown by the curve (b) in FIG. 3, and a hysteresis characteristic is obtained as a whole.

  As described above, the first embodiment includes a friction member that slides against the master cylinder rod to generate a sliding resistance, and the sliding resistance changes according to the stroke direction of the rod. Therefore, the sliding resistance force can be made different between when the brake pedal is depressed and when the pedal is returned, and a predetermined hysteresis characteristic can be obtained in the relationship between the stroke of the brake pedal and the depression force.

Also, by placing the friction member so that the contact side with the rod is positioned on the master cylinder side with respect to the support side, the friction member is deflected in the compression direction when the brake pedal is stepped back to increase the reaction force. Since the pressing force against the rod can be increased, the sliding resistance force when the brake pedal is stepped back can be increased compared to when the pedal is depressed.
Furthermore, since the friction member is integrally formed with the existing rubber boot, it can be realized at a very low cost.

In addition, the design flexibility is high due to the thickness of the friction member, the contact length in the axial direction of the rod, the axial length, the hardness, etc., so there is a predetermined hysteresis in the relationship between the brake pedal stroke and the pedal effort. The characteristics can be obtained, and the degree of freedom in setting the hysteresis characteristics can be increased as compared with the conventional apparatus.
In the first embodiment, the friction member may be arranged in an annular shape in the axial circumferential direction of the rod or may be arranged only in a part in the axial circumferential direction.

In the first embodiment, the case where the friction member is inclined at a predetermined angle has been described. However, the present invention is not limited to this, and the pressing force of the friction member according to the stroke direction of the rod. Any configuration may be used as long as a difference is generated. For example, as shown in FIG. 4, the thickness of the friction material 14a may be different between the support side of the friction material 14a and the contact side of the rod 2g. That is, the angle α ′ does not need to be an acute angle, and as shown in FIGS. 4A and 4B, if the angle α ″ is set larger than the angle α ′, the pressing force when the brake pedal 1 is returned is reduced. It can be larger than when it is depressed.
Furthermore, although the case where the friction member is integrally formed with the rubber boot has been described in the first embodiment, the invention is not limited to this, and the friction member may be configured by another member.

Next, a second embodiment of the present invention will be described.
In the second embodiment, the friction member in the first embodiment described above is installed so that the contact area with the rod is different between when the brake pedal is depressed and when the brake pedal is depressed.
That is, the details of the friction member 14 and the rubber boot 15 in the second embodiment are shown in FIG. 5, except that the friction material 14b is arranged instead of the friction material 14a in the first embodiment described above. 2 having the same configuration as in FIG. 2, the same reference numerals as those in FIG. 2 are given to the portions having the same configuration as in FIG.

The friction material 14b is integrally formed with the rubber boot 15 and is made of a material such as elastically deformable rubber. The friction material 14b has two surfaces with different areas on the contact side with the rod 2g, and one of the two surfaces comes into contact with the rod 2g according to the stroke direction of the rod 2g. It is configured.
That is, when the brake pedal 1 is depressed, as shown in FIG. 5A in which the portion B is enlarged, the friction material 14b bends to the left and comes into contact with the rod 2g with the contact area A1, and when the brake pedal 1 is depressed, As shown in FIG. 5B, the friction material 14b bends to the right and contacts the rod 2g with a contact area A2 larger than the contact area A1. This configuration corresponds to the contact area changing means.

As described above, since the sliding resistance force F = μ × N × A, when the contact area A increases, the sliding resistance force increases even if the friction coefficient μ and the pressing force N are constant. Therefore, the sliding resistance force when stepping back with a large contact area with the rod 2g is larger than the sliding resistance force when stepping on.
Therefore, as shown in FIG. 3, the relationship between the stroke of the brake pedal and the depression force obtains the same hysteresis characteristic as that of the first embodiment described above.

  As described above, in the second embodiment, the contact area of the friction member is different depending on the stroke direction of the rod so that the contact area when the brake pedal is stepped back is larger than the contact area when the brake pedal is depressed. Therefore, the sliding resistance when the brake pedal is stepped back can be made larger than when the brake pedal is depressed, and a predetermined hysteresis characteristic can be obtained in the relationship between the stroke of the brake pedal and the depression force.

Further, when the pressing force against the rod is changed as in the first embodiment described above, the pressing force due to deformation of the friction member does not change unless the rigidity of the rubber boot that receives the reaction force of the pressing force is taken into consideration. On the other hand, when the contact area with the rod is changed as in the second embodiment, it is sufficient that the rubber boot has normal rigidity and can be designed relatively easily. .
In the second embodiment, the shape of the friction material 14b is set not only so that the contact area with the rod 2g changes between when the brake pedal 1 is depressed and when the brake pedal 1 is stepped back. As in the first embodiment, a configuration in which the friction material 14b is arranged obliquely may be added.

Next, a third embodiment of the present invention will be described.
In the third embodiment, a link mechanism is provided in the first embodiment described above, and the pressing force of the friction member against the rod is different between when the brake pedal is depressed and when the brake pedal is depressed due to the action of the link mechanism. It is a thing.
That is, as shown in FIG. 6 in detail of the friction member 14 and the rubber boot 15 of the third embodiment, the friction member 14 and the rubber boot 15 are constituted by separate members, and a link member 15a as a link mechanism is provided on the rubber boot 15. 2 except that the link member 15a and the friction member 14 are connected to each other. Parts having the same configuration as in FIG. 2 are assigned the same reference numerals as in FIG. 2, and detailed descriptions thereof are omitted.

The link member 15a is formed in an L-shape, and the L-shaped corner (link fulcrum O) is attached to the rubber boot 15, passes through the link fulcrum O, and is far from the rotation axis in the axial direction of the rod 2g. It is possible to move. Two link members 15a are provided, and these two link members 15a are arranged to face each other with the rod 2g interposed therebetween.
The end portions (link fulcrum P) of each link member 15a on the brake pedal 1 side are connected to a common friction material 14c via a support member 14m. The friction material 14c is formed in an annular shape having the same axial center as the rod 2g, and always contacts the rod 2g and functions as a friction material for link operation.

Further, the friction member 14d is supported on the end portion (link fulcrum Q) on the master cylinder 2 side of the link member 15a via the support member 14n. The support member 14n has such a length that the friction material 14d is separated from the rod 2g when the brake pedal 1 is depressed, and the friction material 14d contacts the rod 2g when the brake pedal is stepped back.
Further, the two friction members 14d opposed to each other in the axial direction of the rod 2g are connected by a connecting member (not shown), and the lower friction member 14d and the support member 14n rotate around the link fulcrum Q from the rod 2g. It will not fall down in the direction of leaving. The connecting member has a predetermined length and shape so as not to contact the rod 2g, and is configured so as not to hinder the movement of the friction material 14d in response to the depression of the brake pedal 1.

  With such a configuration, when the brake pedal 1 is depressed, the fulcrum Q moves away from the rod 2g, and when the brake pedal 1 is depressed, the fulcrum Q moves closer to the rod 2g. When the fulcrum Q moves away from the rod 2g, the friction material 14d also moves away from the rod 2g. When the fulcrum Q moves away from the rod 2g, the friction material 14d also presses against the rod 2g. Move in the direction.

  That is, when the brake pedal 1 is depressed, the friction material 14c moves to the master cylinder 2 side as the rod 2g moves to the master cylinder 2 side as shown in FIG. The member 15a rotates around the link fulcrum O and the link fulcrum Q moves in a direction away from the rod 2g. As a result, the friction material 14d is separated from the rod 2g.

On the other hand, when the brake pedal 1 is stepped back, the friction material 14c moves to the brake pedal 1 side as shown in FIG. 6B, so that the link fulcrum P also moves to the brake pedal 1 side. As a result, the link member 15a rotates around the link fulcrum O, and the link fulcrum Q moves to the rod 2g side. Thereby, the friction material 14d is pressed against the rod 2g.
Therefore, since the pressing force of the friction material 14d against the rod 2g when the brake pedal 1 is stepped back is greater than that when the brake pedal 1 is depressed, the relationship between the stroke of the brake pedal and the pedaling force is as described above with reference to FIG. The same hysteresis characteristic as that of the first embodiment is obtained.

  As described above, in the third embodiment, the link mechanism is used to reduce the pressing force of the friction member when the brake pedal is depressed, and to increase the pressing force of the friction member when the brake pedal is depressed. The sliding resistance force at the time can be made larger than when the pedal is depressed, and a predetermined hysteresis characteristic can be obtained in the relationship between the stroke of the brake pedal and the depression force.

In addition, since the pressing force of the friction member can be adjusted depending on how the link ratio is set in the link mechanism, the degree of freedom in setting the hysteresis characteristics can be increased compared to the conventional device.
Furthermore, unlike the first and second embodiments described above, it is not necessary to consider the elastic deformation of the friction member, so that it can be designed relatively easily.

In the third embodiment, the case where the friction material 14c is in contact with the rod 2g has been described. However, the present invention is not limited to this, and the friction material 14c and the rod 2g are bonded. Also good.
In the third embodiment, the case where the link fulcrum Q is provided has been described. However, the present invention is not limited to this, and the link member 15a and the support member 14n are integrally formed without providing the link fulcrum Q. It may be.
Further, in the third embodiment, the configuration is such that the friction material 14d is disposed obliquely as in the first embodiment described above, and the brake pedal is stepped back as in the second embodiment described above. In this case, a configuration in which the contact area with the rod 2g is increased may be added.

Next, a fourth embodiment of the present invention will be described.
In the fourth embodiment, the coefficient of friction between the rod and the friction member is set to a different magnitude when the brake pedal is depressed and when the brake pedal is stepped back in the first embodiment described above. .
That is, as shown in FIG. 7 in detail of the friction member 14 and the rubber boot 15 of the fourth embodiment, instead of the friction material 14a, the friction material 14e disposed at a predetermined angle β with respect to the traveling direction of the rod 2g. And a friction material 14f disposed at a predetermined angle β with respect to the traveling direction of the rod 2g, and the friction coefficient μ1 of the surface in contact with the friction material 14e of the rod 2g is set to the friction of the surface in contact with the friction material 14f. Except for the fact that it is set lower than the coefficient μ2, it has the same configuration as that of FIG. 2, parts having the same configuration as in FIG.

The rod 2g has two surfaces with different friction coefficients, one surface is in contact with the friction material 14e, and the other surface is in contact with the friction material 14f.
The friction members 14e and 14f are integrally formed with the rubber boot 15 and are made of a material such as elastically deformable rubber. The friction material 14e is disposed so as to be inclined so that the contact side with the rod 2g is located on the brake pedal 1 side with respect to the support side with the friction material 14e, and the friction material 14f is in contact with the rod 2g. The side is inclined so as to be positioned on the master cylinder 2 side with respect to the support side of the friction material 14f. Thereby, each friction material 14e, 14f changes the pressing force to the rod 2g according to the stroke direction of the rod 2g.

  That is, when the brake pedal 1 is stepped on, as shown in FIG. 7 (a) in which the portion D is enlarged, the friction material 14e is bent in the compression direction, and the reaction force increases and the pressing force against the rod 2g increases. At this time, the friction material 14f maintains the angle β, and the pressing force has a substantially constant value. On the other hand, when the brake pedal 1 is stepped back, as shown in FIG. 7 (b), the friction material 14f is bent in the compression direction and the reaction force is increased to increase the pressing force against the rod 2g. At this time, the friction material 14e maintains the angle β.

Thus, the friction material pressed against the rod 2g can be varied according to the stroke direction of the rod 2g. This corresponds to different contact surfaces between the rod and the friction material according to the stroke direction of the rod 2g.
Here, as described above, the friction coefficient between the friction material 14e and the rod 2g is set low, and the friction coefficient between the friction material 14f and the rod 2g is set high, so that it depends on the stroke direction of the rod 2g. Thus, the friction coefficient of the contact surface between the rod and the friction material is different. Then, the sliding resistance force when the friction material 14f is pressed back is greater than the sliding resistance force when the friction material 14e is pressed. This configuration corresponds to the friction coefficient changing means.

Therefore, as shown in FIG. 3, the relationship between the stroke of the brake pedal and the depression force obtains the same hysteresis characteristic as that of the first embodiment described above.
As described above, in the fourth embodiment, the friction coefficient between the rod and the friction member when the brake pedal is stepped back is made larger than when the brake pedal is stepped on, so that the sliding resistance force when the brake pedal is stepped back is stepped on. The predetermined hysteresis characteristic can be obtained in the relationship between the stroke of the brake pedal and the depression force.

In addition, since the sliding resistance can be adjusted depending on how to set the friction coefficient of the rod, the degree of freedom in setting hysteresis characteristics can be increased as compared with the conventional device.
In the fourth embodiment, the case where two surfaces having different friction coefficients are provided on the rod of the master cylinder has been described. However, the present invention is not limited to this, and the friction material of the rod is assumed to be the same. The contact surface with the 14e rod may have a lower friction coefficient than the contact surface with the rod of the friction material 14f.
Further, in the fourth embodiment, not only the friction coefficient between the rod and the friction member is changed according to the stroke direction of the rod, but also the friction materials 14e and 14f are adjusted by adjusting the rigidity of the friction material. A configuration in which the pressing force is changed or the contact area is changed may be added.

It is a schematic structure figure showing an embodiment of the present invention. It is detail drawing of the friction member and rubber boot in 1st Embodiment. It is a figure which shows a hysteresis characteristic. It is a figure which shows another example of 1st Embodiment. It is detail drawing of the friction member and rubber boot in 2nd Embodiment. It is detail drawing of the friction member and rubber boots in 3rd Embodiment. It is detail drawing of the friction member and rubber | gum boot in 4th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Brake pedal 2 Master cylinder 3a, 3b Master cylinder cut valve 4a, 4b Normally open type solenoid valve 5a, 5b Wheel 6a, 6b Wheel cylinder 7a, 7b Master cylinder pressure sensor 8 Reservoir 9 Pump 10 System shutoff valve 11a, 11b Normally closed Solenoid valve 12 Stroke simulator 13 Stroke simulator cut valve 14 Friction member 15 Rubber boot 18 Stroke sensor 19a, 19b Wheel cylinder pressure sensor 30 Control unit

Claims (4)

In a brake control device including a master cylinder that inputs a depressing force according to a depressing amount of a brake pedal through a rod and outputs a working fluid pressure according to the input.
A friction member that slidably contacts the rod to generate a sliding resistance, and a sliding resistance change means that changes the sliding resistance according to a stroke direction of the rod ;
The sliding resistance force changing means is configured to increase the sliding resistance force when the brake pedal is stepped back compared to when the brake pedal is depressed, and the friction member is moved according to a stroke direction of the rod. A pressing force changing means for changing the pressing force pressed against the rod;
The pressing force changing means is formed of an elastically deformable member, and the friction member and the rod are fixed to a fixed side fixed at a position where the brake pedal is not moved in the outer diameter direction of the rod. By slanting the contact side toward the rod axis in the direction in which the rod strokes when the brake pedal is depressed, the friction member is deflected in the compression direction when the brake pedal is stepped back, and the brake A brake control device , wherein the pressing force when the pedal is returned is greater than when the brake pedal is depressed . The sliding resistance changing means includes contact area changing means for changing a contact area between the friction member and the rod in accordance with a stroke direction of the rod, and the contact area changing means is configured to step on the brake pedal. The brake control device according to claim 1 , wherein the contact area when returning is larger than when the brake pedal is depressed. The sliding resistance changing means includes friction coefficient changing means for changing a friction coefficient between the friction member and the rod in accordance with a stroke direction of the rod, and the friction coefficient changing means includes the brake pedal. The brake control device according to claim 1 or 2 , wherein the coefficient of friction at the time of stepping back is made larger than that at the time of depression of the brake pedal. The friction coefficient changing means is configured so that a contact surface between the rod and the friction member differs according to a stroke direction of the rod, and a friction coefficient between these contact surfaces is different. Item 4. The brake control device according to item 3 .

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