JPH0656010A - Brake controller - Google Patents

Abstract

PURPOSE:To improve pressure control precision by reducing without drastic weight increase hysteresis loss caused by the slide friction of seals used in a hydraulic control valve. CONSTITUTION:A pilot changeover valve 4 to obtain pilot control pressure that is according to master cylinder pressure is provided, and seal rings 48 are provided between a body 40 and a plunger 44 to make the master cylinder pressure act on a pilot spool 41. As a result, the effect of the slide friction of the seal rings 48 can be reduced by enlarging the pilot control pressure receiving area of the pilot spool 41 without enlarging the maximum thrust of the proportion solenoid 51 of a hydraulic control valve 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake control device for arbitrarily controlling the braking force applied to each wheel.

[0002]

2. Description of the Related Art As a conventional brake control device, the present applicant has previously filed Japanese Patent Application No. 2-201010. This brake control device controls the brake pressure supplied to the wheel cylinders by a hydraulic control valve that adjusts the hydraulic pressure according to the pressure generated by the master cylinder.

That is, the hydraulic control valve is provided in the middle of the external hydraulic source and the wheel cylinder, and the spool changes the control pressure by switching the oil passage. This spool is a stepped spool so that the control pressure acts as a feedback pressure in the direction that shuts off the communication between the external hydraulic power source and the wheel cylinder, and this spool is a force obtained by multiplying the master cylinder pressure by the pressure receiving area. The force of the plunger that pushes to the control pressure increasing side, the proportional solenoid that pushes the spool to the control pressure reducing side with a force according to the current value, and the spring that is provided between both ends of the spool and the valve body wall to center the spool. The control pressure is determined by the balance of.

By the way, since the hydraulic control valve uses a spool, in order to reduce the leakage of the sliding portion,
It uses hydraulic oil that has a higher viscosity than the brake fluid. The sealing material used for the hydraulic fluid system from the hydraulic source to the wheel cylinders via the hydraulic control valve and the sealing material used for the brake fluid system from the master cylinder to the hydraulic control valve are The non-erodible one is used. Therefore, when the master cylinder chamber into which the brake fluid flows and the end face chamber that is formed in the spool end face chamber and into which the hydraulic oil flows, the sliding parts of the plunger that are loosely inserted are mixed with each other. In order to prevent deterioration of durability against erosion, a seal ring having durability against both hydraulic oil and brake fluid is provided to ensure reliable sealing performance.

[0005]

However, since the seal ring provided on the plunger sliding portion needs to ensure a reliable sealing property, the sliding friction of the plunger sliding surface becomes large, so that the hydraulic control valve operates. Causes hysteresis loss.

This will be described below using the equation of the balance of the forces acting on the spool in the hydraulic control valve.

The master cylinder pressure is PM, the wheel cylinder pressure is PW, the master cylinder pressure receiving area of the plunger is A11, the pressure receiving area difference of the stepped portion of the spool that receives the control pressure is A12, and the force generated by the proportional solenoid is FS. , The magnitude of the sliding friction is FR, and considering the force of the spring that presses both ends of the spool to center it, the balance equation is given by A12 ・ PW + FS = A11 ・ PM + FR (Equation 1) , The wheel cylinder pressure PW is

[0008]

[Equation 1]

[0009]

That is, FR / A12 in (Equation 2) corresponds to the hysteresis loss, and it can be reduced by setting the pressure receiving area difference A12 large. However, at the same time, it is also necessary to greatly change FS / A12 in order to make the control range of the wheel cylinder pressure PW large. Therefore, in order to increase the pressure receiving area difference A12, it is necessary to provide a large proportional solenoid having a large maximum thrust, that is, there is a problem that the weight is significantly increased.

For example, assuming that the weight of the conventional proportional solenoid is 0.5 kg and the diameter is 4.5 cm, FS must be quintuple in order to reduce the hysteresis loss to ⅕. If a power source is used, a proportional solenoid in which the length of the coil winding is 5 times, the wire diameter of the winding is √5 times, and the volume of the plunger is 7.5 times is required, and the weight is about 3 kg and the diameter is about 3 kg. It will be 8 cm.
As described above, it is difficult to reduce the hysteresis loss without significantly increasing the weight.

In view of the above, the present invention has as its object to provide a brake control device in which hysteresis loss is reduced without significantly increasing the weight.

[0013]

In order to achieve the above object, a brake control apparatus according to a first aspect of the present invention includes a master cylinder for generating a master cylinder pressure according to a pedaling force applied to a brake pedal, a hydraulic pressure source, A wheel cylinder that brakes each wheel with the output hydraulic pressure from the hydraulic pressure source, and the output hydraulic pressure from the hydraulic pressure source, which is provided between the hydraulic pressure source and the wheel cylinder, is used as a control pressure according to the pedaling force applied to the brake pedal. A hydraulic control valve for controlling, a spool provided on the hydraulic control valve, the spool having a control pressure receiving surface for increasing and decreasing the control pressure by switching the oil passage and receiving the control pressure in the direction of reducing the control pressure, and the spool. In contrast to the spool, it has an actuator that applies a force in the direction of reducing the control pressure and a pressure receiving surface that receives the hydraulic pressure according to the pedaling force applied to the brake pedal. In a brake control device including a first pressing unit that applies a pressing force in a direction to increase the control pressure, the output hydraulic pressure from the hydraulic pressure source is controlled to a pilot control pressure according to the master cylinder pressure, and the pilot control is performed. A pilot control valve for applying a pressure to the pressure receiving surface of the first pressing means, and a pilot control valve provided in the pilot control valve for increasing or decreasing the pilot control pressure by switching the oil passage and reducing the pilot control pressure. Second pressing means having a pilot spool having a pilot control pressure receiving surface for receiving a control pressure and a master cylinder pressure receiving surface for receiving a master cylinder pressure, and applying a pressing force to the pilot spool in a direction to increase the pilot control pressure. And an output oil from the hydraulic source, which is provided between the pilot control valve body and the second pressing means. And sealing means for sealing the brake fluid for transmitting the master cylinder pressure and the hydraulic fluid for transmitting in which the provided.

In order to achieve the above object, the brake control device according to the present invention is characterized in that a relief means for relieving the pilot control pressure when the pilot control pressure of the pilot control valve exceeds a predetermined pressure is provided. The brake control device according to claim 1.

[0015]

In the brake control device according to the first aspect of the present invention, the pilot control valve pushes the pilot control pressure against the pilot spool in a direction in which the pilot control pressure is increased. The pilot control pressure is controlled by the balance between the pressing force multiplied by the pressure and the pilot control pressure against the pilot spool in the direction of reducing the pilot control pressure. The pressing force obtained by multiplying the pilot control pressure receiving area of the pilot spool by the pilot control pressure. . The pilot control pressure is transmitted to the first pressing means, and the hydraulic control valve pushes the spool in the direction of increasing the control pressure, and the pressing force obtained by multiplying the pressure receiving area of the first pressing means by the pilot control pressure, The control pressure is a balance between the thrust of the actuator that pushes the control pressure to the spool and the push force that pushes the control pressure to the spool to reduce the control pressure to the spool. To control.
By the way, the seal means for sealing the brake fluid and the hydraulic oil is provided in the pilot control valve, but sliding friction occurs in the direction of impeding the movement of the pilot spool due to the characteristics of the seal. This sliding friction is FR and the master cylinder pressure is P
M, pilot control pressure PP, second master cylinder pressure receiving area A21, pilot spool pressure pilot pilot pressure receiving area A22, control pressure PC, actuator thrust FS, first pressure receiving area Let A11 be the control pressure receiving area of the spool, and A12 be the control pressure receiving area of the spool.

[0016]

[Equation 2]

It is In addition, the formula of the balance of the spool in the hydraulic control valve is

[0018]

[Equation 3]

[0019] When PP is erased from the above (Formula 3) and (Formula 4), the control pressure PC with respect to the master cylinder pressure PM becomes

[0020]

[Equation 4]

[0021]

(A11 / A12) (FR / A2)
Although 2) corresponds to the hysteresis loss, even if the pilot control pressure receiving area A22 is increased in order to reduce this, there is nothing to do with FS / A12. That is, the hysteresis loss can be reduced without increasing the thrust of the proportional solenoid. At this time, the total weight of the hydraulic control valve and the pilot control valve is, for example, a new pilot control valve applicable to the hydraulic control valve using the conventional proportional solenoid (weight 0.5 kg, diameter 4.5 cm) described above. However, even if the hysteresis loss is reduced to 1/5, the increase is only about 100 g. In the brake control device according to claim 2, in addition to the action of the brake control device according to claim 1, the pilot control pressure applied from the pilot control valve to the pressing surface of the first pressing means is a predetermined pressure. When the pilot control pressure is relieved, the actuator needs only to generate thrust that opposes the pressing force obtained by multiplying the pressure when the pilot control pressure is relieved and the first pressure receiving area. It is not necessary to provide a larger one.

[0023]

Embodiments of the present invention will now be described in detail with reference to the drawings.

First, a first embodiment will be described with reference to FIGS. FIG. 1 is an overall view showing a brake control device of the first embodiment. This brake control device is provided in each of the master cylinder 2 that generates the master cylinder pressure PM in response to the depression of the brake pedal 1 and the disc brake device 8 for each wheel, and in accordance with the master cylinder pressure PM from the master cylinder pressure 2. A wheel cylinder 9 for braking each wheel by means of a hydraulic pressure, a hydraulic pressure source 7 for supplying hydraulic oil, and an accumulator pressure PS from this hydraulic pressure source 7 to the master cylinder pressure PM.
A pilot control valve 4 for controlling the pilot control pressure PP according to the control pressure, and a hydraulic control valve 5 for adjusting the accumulator pressure PS from the hydraulic source 7 to the control pressure PC according to the pilot control pressure PP of the pilot control valve 4. A brake fluid system 10 including a master cylinder 2, a hydraulic synthesizer 12 and a wheel cylinder 9, and a hydraulic synthesizer 12 for setting the control pressure PC of the hydraulic control valve 5 to the wheel cylinder pressure PW.
0, hydraulic pressure source 7a, pilot control valve 4, hydraulic control valve 5
And a hydraulic oil system 101 including a hydraulic synthesizer 12.

The hydraulic pressure source 7 is composed of an oil pump 7a, a check valve 7b and an accumulator 7c, and working oil is supplied from an accumulator oil passage 10a to an input port 5a of the hydraulic control valve 5 described later. The accumulator oil passage 10a is provided with an electromagnetic switching valve 81 that is normally opened to prevent the hydraulic oil from leaking by closing the valve when the brake control device fails such as hydraulic oil leak. Further, the TCS pressure P based on the accumulator pressure PS is provided on the branch oil passage 10b of the accumulator oil passage 10a, and the valve is opened.
An electromagnetic switching valve 82 is provided which causes T to act on the pressure increasing side of the spool 51, which will be described later, via a TCS port 5e, which will be described later, of the hydraulic control valve 5.

The pilot control valve 4 has a branch oil passage 10c of the accumulator oil passage 10a and a pilot oil passage 1 of the hydraulic control valve 5 which leads to a pilot control pressure chamber 57 described later.
0d, communication between the pilot oil passage 10d and the drain oil passage 10g, and a pilot spool 41 for switching communication between the oil passage and shutoff, and the pilot spool 41 is pushed in the direction of communicating the pilot oil passage 10d and the drain oil passage 10g, That is, the spring (elastic means) 42 for pushing the pilot control pressure PP in the direction of reducing it and the pilot spool 41 for pushing the accumulator branch oil passage 10c and the pilot oil passage 10d in the direction of communication, that is, the direction of increasing the pilot control pressure PP And a plunger (second pressing means) 44 which is pushed to.

The pilot spool 41 is a body forming the pilot control valve 4 (pilot control valve body).
In the longitudinal direction of 40, it is slidably inserted into an insertion hole 43 formed so as to have a small diameter portion on the left side in the drawing and a large diameter portion on the right side in the drawing. An annular groove 43a is provided in the small diameter portion of the insertion hole 43, and an annular groove 43c is provided in the large diameter portion. And
The input port 4a that connects the annular groove 43a and the accumulator branch oil passage 10c, the annular groove 43c and the drain oil passage 10
A drain port 4c communicating with g and an output port 4b communicating with the insertion hole 43 and the pilot oil passage 10d are provided between the annular grooves 43a and 43c. In the pilot spool 41, an annular groove 41b is formed in the center, lands 41a that slide on the small diameter portion of the insertion hole 43 and lands 41c that slide on the large diameter portion of the insertion hole 43 are formed on both sides of the annular groove 41b. 43a and the land 41a form a diaphragm 410, and the annular groove 43c and the land 41c form a diaphragm 411. When the diaphragm 410 is opened or closed, the input port 4a and the output port 4b are connected or disconnected, and when the diaphragm 411 is opened or closed. The port 4b and the drain port 4c are connected and disconnected. In the land 41c,
A pilot control pressure receiving surface 412 having a pressure receiving area obtained by subtracting the small diameter cross-sectional area from the large diameter cross-sectional area of the pilot spool 41 is formed.

The spring 42 is press-fitted in a chamber 46 formed by the insertion hole 43 and the left end surface of the pilot spool 41 in the drawing, and the chamber 46 and the drain oil passage 1
A drain port 4d communicating with 0 g is provided.

The plunger 44 is loosely inserted in the longitudinal direction in the body 40, and the left end of the plunger 44 in the drawing and the right end surface of the pilot spool 41 in the drawing are in contact with each other. On the right end surface of the plunger 44 in the drawing,
Master cylinder chamber 4 communicating with the master cylinder 2
7, the plunger 44 is pressed to the left side in the figure by a force obtained by multiplying the master cylinder pressure receiving surface 441 formed by the end surface of the plunger 44 and the master cylinder pressure. Further, the spring 45 is press-fitted in a chamber 49 formed by the pilot spool 41 and the insertion hole 43, and the chamber 49 and the drain oil passage 1
A drain port 4e communicating with 0 g is provided, and a seal ring (sealing means) is provided on the sliding surface of the plunger 44 so that the hydraulic oil in the chamber 49 and the brake fluid in the master cylinder chamber 47 do not mix with each other. 48 are provided.

The hydraulic control valve 5 is provided with a spool 51 for switching between communication and cutoff between the accumulator oil passage 10a and the oil passage 10e reaching the hydraulic synthesizer 12, and communication between the oil passage 10e and the drain oil passage 10h. This spool 5
A proportional solenoid (actuator) 52 which pushes 1 in a direction in which the oil passage 10e and the drain oil passage 10h communicate with each other, that is, in a direction in which the control pressure PC is reduced, and an accumulator oil passage 10a and an oil passage depending on the pilot pressure PP. Plunger (first pressing means) 5 that pushes in the direction of communicating with 10e
4 and.

The spool 51 is slidable in an insertion hole 53 having a small diameter portion on the left side in the drawing and a large diameter portion on the right side in the drawing in the longitudinal direction of the body 50 forming the hydraulic control valve 5. Has been inserted. The annular groove 5 is formed in the small diameter portion of the insertion hole 53.
3a, an annular groove 53c is formed in the large diameter portion of the insertion hole 53, and an input port 5a that connects the annular groove 53a and the accumulator oil passage 10a, and a drain that connects the annular groove 53c and the drain oil passage 10h. Port 5c, annular groove 53a
And 53c, an output port 5b that connects the insertion hole 53 and the oil passage 10e is provided. Also, on the spool 51,
An annular groove 51b is formed in the central portion, and insertion holes 53 are formed on both sides
Of the land 51a that slides with the small diameter portion of the insertion hole 53, and a land 51c that slides with the large diameter portion of the insertion hole 53, and forms an aperture 510 with the annular groove 53a and the land 51a. The diaphragm 511 is formed so that the opening and closing of the diaphragm 510 connects and disconnects the input port 5a and the output port 5b, and the opening and closing of the diaphragm 511 connects and disconnects the output port 5b and the drain port 5c. On the control pressure receiving surface of the land 51c, a control pressure receiving surface 512 having a pressure receiving area obtained by subtracting the small diameter sectional area from the large diameter sectional area is formed.

The proportional solenoid 52 corresponds to the body 5
0 is provided on the left side of the drawing, and includes an electromagnetic coil 52a and a plunger 52b that is moved to the right in the drawing by a force corresponding to the value of the current flowing through the electromagnetic coil 52a. A part of the plunger 52b is loosely inserted into the body 50 in its longitudinal direction, and the right end in the figure and the left end in the figure of the spool 51 are in contact with each other. Further, a spring 66 is press-fitted in an oil chamber 67 formed by the insertion hole 53 and the left end surface of the spool 51 in the drawing, so that the oil chamber 67 and the drain oil passage 10h.
A drain port 5d is provided for communicating with.

The plunger 54 is provided in the body 50 so as to be loosely inserted in the longitudinal direction thereof, and the left end portion in the figure and the right end surface of the spool 51 in the figure are brought into contact with each other. A pilot control pressure chamber 57 communicating with the pilot oil passage 10a is formed on the right end surface of the plunger 54 in the figure, and the force is obtained by multiplying the pilot control pressure by the pressure receiving surface 541 formed on the end surface of the plunger 54. 54
Is pressed to the left side in the figure. Also, the oil chamber 63 formed by the right end surface of the spool 51 in the drawing and the insertion hole and the drain oil passage 1
A drain port 5f communicating with 0h is provided, and a spring 64 is press-fitted in the oil chamber 63.

Further, a hole 51d is formed in the end surface of the spool 51 on the right side in the drawing in the axial direction of the spool 51 in a closed state of the end surface, and a pilot pin 55 slidable in the axial direction is formed in the hole 51d. Inserting. A part of the pilot pin 55 projects from the hole 51d and is slidably fitted in a recess of the pedestal 56 in the oil chamber 63.

A chamber 51e formed by the hole 51d and the pilot pin 55, and an annular groove 53e provided in the insertion hole 53.
And a communication hole 51h communicating with the annular groove 53e.
There is provided a TCS port 5e that connects the accumulator branch oil passage 10b to each other.

The hydraulic synthesizer 12 has a control pressure chamber 122 formed on the left side of the plunger 121 in the body 120 in the figure and a wheel cylinder pressure chamber 123 formed on the right side of the figure. A return spring 124 for biasing the plunger 121 to the left in the drawing is pressure-installed inside. Further, an input port 12a for communicating the oil passage 10e with the control pressure chamber 122, an input port 12c for communicating the brake fluid passage 10f from the master cylinder 2 with the wheel cylinder pressure chamber 123, and a brake fluid passage to the wheel cylinder 9. 10j and the output port 12b which connects the wheel cylinder pressure chamber 123 are provided, respectively.

In addition, an electromagnetic switching valve 83 is provided in the middle of the brake fluid passage 10f so as to communicate when the master cylinder pressure is zero by a command signal from the controller and to shut off when the master cylinder pressure is generated and during TCS control. It is provided. A stroke damper 3 is provided to prevent the brake pedal 1 from being depressed when the electromagnetic switching valve 83 blocks the communication between the master cylinder 2 and the wheel cylinder pressure chamber 123. This is because the chamber 3 that communicates with the oil passage 10f is connected to one of the pistons 31 that slides inside the body 30.
2 is formed and a return spring 33 is provided on the opposite side.

Further, the proportional solenoid 52 and the electromagnetic switching valve 8
The solenoids 81a, 82a, 83a of 1, 82, 83 are drive-controlled by a command from the brake controller 13,
The brake controller 13 includes a longitudinal acceleration sensor 14 and a wheel speed sensor 1 as sensors for obtaining input information.
5, the master cylinder pressure sensor 16 and the like are connected.

That is, with the drive control by the brake controller 13, boost control for increasing the master cylinder pressure, ABS control for preventing wheel lock during braking, and TCS control for suppressing drive wheel slip during starting or sudden acceleration. Is done. It is also possible to perform control of an active brake or the like that produces a braking force difference between the left and right wheels to obtain a desired yaw rate.

The operation of the brake control system of the first embodiment having the above construction will be described below.

(A) During non-braking and non-controlling There is no depression of the brake pedal 1 and the master cylinder pressure P
When M is zero, in the pilot control valve 4, the spring force F12 of the spring 63 acting leftward in the figure, the spring force F11 of the spring 66 acting rightward in the figure, and the force generated by the proportional solenoid 52 are generated. The spool 51 is stopped at a position balanced with FS, the throttle 511 is opened, and the control pressure PC is the drain pressure.

(B) During normal braking When the brake pedal 1 is depressed, a master cylinder pressure PM is generated in the master cylinder 2 in accordance with the depression force of the brake pedal 1, and the controller 13 outputs a detection signal from the master cylinder pressure sensor 16. According to the above, the solenoid switching valve 83 is switched to cut off the communication between the master cylinder 2 and the wheel cylinder 9. Further, the master cylinder pressure PM is supplied to the master cylinder chamber 47 of the pilot control valve 4 via the brake fluid passage 10f, and the pilot spool 41 is pressed by the plunger 44 to the left in the drawing. The pressing force at this time is the pressure receiving area of the master cylinder pressure receiving surface 441 is A21,
If the elastic force of the spring 45 is F21, A21 ・ PM +
It is F21.

When the pressing force acts on the pilot spool 41, the pilot spool 41 moves leftward in the drawing to open the throttle 410, and the accumulator pressure PS is supplied from the input port 4a to the output port 4b. The pilot spool 41 has a pilot control pressure receiving surface 412.
Is pressed to the right in the figure by a force obtained by adding the pressing force obtained by multiplying the pressure receiving area of No. 2 by the pilot control pressure and the elastic force of the spring 42. The force at this time is the pilot control pressure receiving surface 4
The pressure receiving area of 12 is A22, and the elastic force of the spring 42 is F22.
If so, A22.PP + F22.

The balance of the pilot spool 41 at this time is A22.PP = A21.PM + F21-F22 (Equation 6).

Therefore, the pilot control pressure PP is proportional to the master cylinder pressure PM and is the sum of the elastic force (F21-F22).

This pilot control pressure PP is supplied to the pilot control pressure chamber 57 of the hydraulic control valve 5 via the pilot oil passage 10d. Therefore, the spool 51 is pressed leftward in the figure by the pilot pin 54. The pressing force at this time is such that the pressure receiving area of the pressure receiving surface 541 is A11 and the spring 6
If the elastic force of 4 is F11, then A11 · PP + F11.

When the pressing force acts on the spool 51,
The spool 51 moves leftward in the figure to open the diaphragm 510,
Accumulator pressure PS is supplied from the input port 5a to the output port 5b. Then, the spool 51 is pressed to the right in the drawing by a force obtained by adding the pressing force obtained by multiplying the pressure receiving area of the control pressure receiving surface 512 by the control pressure and the elastic force of the spring 66. The force at this time is A12 · PC + F12, where A12 is the pressure receiving area of the control pressure receiving surface 512 and F12 is the elastic force of the spring 66.

The balance of the spool 51 at this time is A12.PC = A11.PP + F11-F12 (Equation 7).

Therefore, the control pressure PC is proportional to the pilot control pressure PP, and is an addition of the elastic force (F11-F12).

Next, when a current is applied to the electromagnetic coil 52a,
Thrust FS proportional to the current is generated in the plunger 52b,
Push the spool 51 to the right in the figure. The balance of the spool 51 at this time is A12.PC = A11.PP + F11-F12-FS (Equation 8), and the control pressure PC is changed according to the current to the solenoid 52a.
Is controlled to increase or decrease.

The wheel cylinder pressure PW is determined by the electromagnetic switching valve 8
Since 3 blocks the communication between the master cylinder chamber 2 and the wheel cylinder 9, PW = PC, and when PP is deleted from the equations 7 and 8,

[0052]

[Equation 5]

It becomes

That is, the wheel cylinder pressure PW is proportional to the master cylinder pressure PM and can be controlled to increase or decrease according to the current to the proportional solenoid 52.

This can be illustrated by the characteristics shown in FIG.
When the solenoid current is zero, the pressure increase ratio is the largest, and the characteristic shown in FIG. Then, as the solenoid current is increased, the wheel cylinder pressure PW is reduced by an amount proportional to the solenoid current, resulting in the characteristic (b).

Therefore, the wheel cylinder pressure characteristic with respect to the master cylinder pressure is set in the brake controller 13 according to the vehicle state by a function or a map, and based on the information indicating the vehicle state and the information from the master cylinder pressure sensor 16. By controlling the solenoid current, the wheel cylinder pressure can be obtained with an arbitrary boosting characteristic according to the vehicle state. That is, a boost control function with a high degree of freedom is exerted instead of a unique boost ratio.

(C) During ABS control During sudden braking or when wheel locking is likely to occur on a low μ road,
An ABS operation for preventing wheel lock is performed by a control command to the proportional solenoid 52 from the ABS control unit of the brake controller 13.

That is, as the normal boosting characteristic, for example, if the solenoid current is set so as to obtain the characteristic (e), the pressure increase to the characteristic (a) and the pressure decrease to the characteristic (b) are performed. The slip ratio of each wheel is obtained from the vehicle speed information obtained by integrating the input signal from the longitudinal acceleration sensor 14 and the wheel speed information obtained from the wheel speed sensor 15, and the slip ratio is the optimum slip ratio. The wheel cylinder pressure PW is increased, maintained, and reduced so as to fall within the range.

That is, the ABS function for securing a stable braking force during braking can be achieved with a sufficient increase / decrease range of the wheel cylinder pressure PW.

(D) During TCS control When a drive wheel slip is likely to occur due to sudden accelerator pedal operation at the time of starting or sudden acceleration, a control command from the TCS control section of the brake controller 13 to the proportional solenoid 52 and to the solenoid 82a. The TCS operation that suppresses the drive wheel slip is performed by the ON command. That is,
The slip rate of each wheel is obtained from the vehicle speed information obtained by integrating the input signal from the longitudinal acceleration sensor 14 and the wheel speed information obtained from the wheel speed sensor 15, so that the slip rate falls within the range of the optimum slip rate. In addition, the wheel cylinder pressure PW is increased, maintained, and reduced.

That is, when the ON command is output to the solenoid 82a, the electromagnetic switching valve 82 is opened, so that the accumulator pressure PS is supplied as the TCS pressure PT from the TCS port 5e of the hydraulic control valve 5 to the chamber 51e. To be done. This TCS pressure PT acts on the pilot pin 55 and pushes the pilot pin 55 to the right in the figure. However, since the pilot pin 55 is in contact with the base 56, the spool 51 is moved leftward in the drawing. At this time, the spool 51 is balanced with the pilot pin 55 having a sectional area of A3.
Then, A22.PC = A3.PT + F21-F22-FS ... (Equation 10)

Therefore, although the master cylinder pressure PM is not generated, the control oil pressure PC varies from the maximum pressure determined by the TCS pressure PT to the pressure obtained by reducing the force FS proportional to the solenoid current. It can be controlled arbitrarily. The characteristic is the characteristic shown in FIG.

That is, the braking force can be applied to the drive wheels in accordance with the amount of the drive wheel slips, and the TCS function of effectively suppressing the drive wheel slips is exhibited.

(E) When Electronic Control System and Hydraulic System Fail When the electronic control system related to the brake controller 13 fails, the current to the solenoid 52 is made zero and the electromagnetic switching valve 82 is closed.

Therefore, since the force acting on the spool 51 is A12.PC = A11.PP + F11-F12 (Equation 11), the ABS operation and the TCS operation cannot be performed, but the characteristic (a) of FIG. 2 is retained. To be done. That is, the state of maximum capacity of the brake boosting performance is ensured, and the braking action having the boosting function is guaranteed.

Due to a failure of the oil pump 7a or the like, the hydraulic pressure source 7
Therefore, when the hydraulic source pressure fails such that the accumulator pressure PS is not, the control hydraulic pressure PC is not generated by the hydraulic control valve 5. When the control oil pressure PC is not generated in this way, the solenoid switching valve 83 is switched to the communication side as shown in FIG. 1, so that the master cylinder pressure PM becomes the wheel cylinder pressure PW as it is. It is given to the wheel cylinder 9 of each wheel.

By the way, in the brake control apparatus of the present embodiment, the pilot control valve 4 is provided and the pilot control pressure is applied to the hydraulic control valve 5, so that the master cylinder pressure is directly applied to the hydraulic control valve 5. Compared with the above, the following effects can be obtained.

In the pilot control valve 4 and the hydraulic control valve 5 described above, there is sliding friction because the spool and the like are sliding. Assuming that the magnitude of the sliding friction generated in the hydraulic control valve 5 is FR1 and the magnitude of the sliding friction generated in the pilot control valve 4 is FR2, the above (formula 9) is actually

[0069]

[Equation 6]

It becomes Most of the sliding friction in the pilot control valve 4 is the sliding friction between the plunger 44 and the seal ring 48. Compared with this, the sliding friction at the labyrinth seal portion between the pilot spool 41 and the insertion hole 43 is smaller. Almost equal to zero.

That is, (A11 · FR2) / of (Equation 12) /
(A12 · A22) corresponds to the hysteresis loss. In this embodiment, in the pilot control valve 4, the pressure receiving area A21 of the master cylinder pressure receiving surface 441 and the pilot control are set so that the ratio of the master cylinder pressure PM and the pilot control pressure PP is 1: 1. Pressure receiving surface 412
The pressure receiving area A22 is set to almost the same value. The pressure receiving area A22 of the pilot control pressure receiving surface 412
Is approximately 5 of the pressure receiving area A11 of the pressure receiving surface 541 of the hydraulic control valve 5.
It is set to double.

Therefore, the hysteresis loss is A11 / A22
= 1/5, (A11 · FR2) / in (Equation 12)
(A12 ・ A22) becomes (1/5) ・ (FR2 / A12),
Hysteresis loss FR // when the conventional master cylinder pressure shown in (Formula 2) is directly applied to the pressure receiving surface 512.
Compared to A12, if the sliding friction of the seal is FR = FR2,
It can be reduced to a fraction. That is, in FIG. 3 which is a characteristic diagram based on experimental data, the hysteresis loss of the brake control device of the present embodiment is shown by a solid line, and the hysteresis loss of the conventional brake control device is shown by a broken line. You can see that it is decreasing.
In the case of the prototype used in the experiment of the present embodiment, the body 50 of the hydraulic control valve 5 and the body 40 of the pilot control valve 4
Although it was formed integrally, it was able to be formed by about 100 g more than that of the hydraulic control valve 5 alone. In this way, the reduction of hysteresis loss could be realized while suppressing the increase in weight as much as possible.

In this embodiment, the seal ring 48 is used in the pilot control valve, but this is replaced with a bellows to further reduce the reliable liquid separation property and the sliding friction itself, thereby reducing the hysteresis loss. Can be reduced.

Further, the pilot spool 41 and the plunger 44 may be integrally provided.

Further, the pilot control valve is not limited to the spool type, and may be a poppet type valve capable of pressure control.

Further, in this embodiment, the pilot control valve 4 and the hydraulic control valve 5 are provided for each wheel. However, one pilot control valve 4 is provided and the hydraulic control valve 5 provided for each wheel is piloted. Control valve should be supplied, or 2
By providing two pilot control pressures to the hydraulic control valves 5 of the two wheels in the front and rear or diagonally, the cost and weight can be further reduced.

Next, a second embodiment will be described with reference to FIG. In this embodiment, an orifice 210 is provided in the middle of the accumulator branch oil passage 10c in the brake device shown in FIG. 1, and a relief valve (relief means) 211 is provided in the middle of the pilot oil passage 10d. Relief valve 21
No. 1 drains the pilot oil passage 10d so that the pilot control pressure does not exceed the predetermined pressure when the pilot control pressure becomes equal to or higher than the predetermined pressure. Wheel cylinder pressure, that is, control pressure is at most 1
Since only 20 kg / cm 2 is required, the ratio of the area of the control pressure receiving surface 512 and the area of the pressure receiving surface 541 is set to 1 / so that the ratio of the control pressure to the pilot control pressure is 8 times.
When set to 8, the relief pressure is 15 Kg / c
It is set to m2. The other structure is the same as that of the brake device of the first embodiment shown in FIG. 1, and therefore its explanation is omitted.

In addition to the operation of the brake control device of the first embodiment described above, the brake control device of this embodiment opens the relief valve when the pilot control pressure becomes 15 kg / cm 2 or more, and the pilot oil passage 10d is opened. Drained. At this time, the flow rate passing through the accumulator branch oil passage 10c is restricted by the orifice 210, so that the relief flow rate can be limited and wasteful energy consumption can be prevented. That is, since the pilot control pressure does not exceed 15 kg / cm @ 2, the proportional solenoid 52 only generates a thrust force that opposes the force obtained by multiplying the pilot control pressure of 15 kg / cm @ 2 by the pressure receiving area A11 of the pressure receiving surface 541. Just use the first
The size can be further reduced as compared with the brake control device according to the embodiment.

Next, a third embodiment will be described with reference to FIG. In this embodiment, a relief valve (relief means) is provided in the middle of the pilot oil passage 10d in the brake device shown in FIG.
212 is provided, and further, an orifice 213 is provided in the drain oil passage 220 extending from the relief valve 212 to the tank to connect the drain oil passage 220 and the oil chamber 46. Like the second embodiment, the relief valve 212 drains the pilot oil passage 10d so that the pilot control pressure does not exceed the predetermined pressure when the pilot control pressure becomes equal to or higher than the predetermined pressure. Second relief pressure
It is set to 15 kg / cm @ 2 as in the embodiment. The other structure is the same as that of the brake device of the first embodiment shown in FIG. 1, and therefore its explanation is omitted.

In addition to the operation of the brake control device of the first embodiment described above, the brake control device of this embodiment opens the relief valve 212 when the pilot control pressure becomes 15 kg / cm 2 or more, and opens the pilot oil passage 10d. Is drained. At this time, the accumulator branch oil passage 10c
The flow rate through the
At this time, the pressure generated in the oil passage 220 acts on the oil chamber 46 and pushes the pilot spool 41 to the right in the figure to cut off the communication between the accumulator branch oil passage 10c and the pilot oil passage 10d. It is possible to prevent wasteful consumption of energy as compared with. Further, since the pilot control pressure does not exceed 15 Kg / cm @ 2 as in the second embodiment, the proportional solenoid 52 uses the pilot control pressure 1
It is only necessary to generate a thrust force that opposes the force obtained by applying the pressure receiving area A11 of the pressure receiving surface 541 to 5 Kg / cm2, and further downsizing can be achieved as compared with the brake control device of the first embodiment.

[0081]

In the brake control device according to the first aspect of the present invention, friction generated by the seal means for sealing the hydraulic fluid transmitting the output hydraulic pressure from the hydraulic source and the brake fluid transmitting the master cylinder pressure is caused. Hysteresis loss can be reduced without a significant increase in weight.

According to the brake control device of the second aspect, in addition to the effect of the brake control device of the first aspect, the actuator can be further downsized.

[Brief description of drawings]

FIG. 1 is an overall view showing a brake control device of a first embodiment according to the present invention.

FIG. 2 is a characteristic diagram showing a relationship between a master cylinder pressure and a wheel cylinder pressure of the brake control device according to the first embodiment of the present invention.

FIG. 3 is a characteristic diagram showing a hysteresis loss of the brake control device according to the first embodiment of the present invention and a hysteresis loss of the conventional brake control device.

FIG. 4 is a partial view showing a brake control device of a second embodiment according to the present invention.

FIG. 5 is a part showing a brake control device of a third embodiment according to the present invention.

[Explanation of symbols]

1 ... Brake pedal, 2 ... Master cylinder, 4 ... Pilot control valve, 5 ... Hydraulic control valve, 7 ... Hydraulic source, 9 ... Wheel cylinder, 40 ... Body (pilot control valve body),
41 ... Pilot spool, 44 ... Plunger (second pressing means), 48 ... Seal ring (sealing means), 51 ...
Spool, 52 ... Proportional solenoid (actuator),
54 ... Pilot pin (first pressing means), 210, 21
3 ... Orifice, 211, 212 ... Relief valve (relief means), 412 ... Pilot control pressure receiving surface, 441 ...
Master cylinder pressure receiving surface 512, control pressure receiving surface, 54
1 ... Pressure receiving surface.

Claims (2)

[Claims] 1. A master cylinder for generating a master cylinder pressure according to a pedaling force applied to a brake pedal, a hydraulic pressure source, a wheel cylinder for braking each wheel with an output hydraulic pressure from the hydraulic pressure source, and the hydraulic pressure source. A hydraulic control valve which is provided between the wheel cylinder and controls the output hydraulic pressure from the hydraulic source to a control pressure according to the pedaling force applied to the brake pedal, and is controlled by switching the oil passage provided in this hydraulic control valve. Spool with a control pressure receiving surface that receives the control pressure in the direction of decreasing the control pressure and decreasing the control pressure, the actuator that applies a force to the spool in the direction of reducing the control pressure, and the pedaling force applied to the brake pedal. Brake control including a pressure receiving surface that receives a corresponding hydraulic pressure, and a first pressing unit that applies a pressing force to the spool in a direction to increase the control pressure. In the device, a pilot control valve that controls the output hydraulic pressure from the hydraulic pressure source to a pilot control pressure according to the master cylinder pressure, and causes the pilot control pressure to act on the pressure receiving surface of the first pressing means, Pilot control valve is equipped with pilot control pressure receiving surface to increase / decrease pilot control pressure and reduce pilot control pressure by switching the oil passage. A second pressing unit that has a master cylinder pressure receiving surface and applies a pressing force to the pilot spool in a direction to increase the pilot control pressure, and is provided between the pilot control valve body and the second pressing unit. Seals the hydraulic fluid that transmits the output hydraulic pressure from the brake fluid that transmits the master cylinder pressure. Brake control apparatus is characterized by providing a sealing means. 2. The brake control device according to claim 1, further comprising relief means for relieving the pilot control pressure when the pilot control pressure of the pilot control valve exceeds a predetermined pressure.