JPH076045Y2 - Break hydraulic pressure control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a brake fluid pressure control device provided in a vehicle as an electronically controlled anti-lock device, and more specifically, to an atmosphere provided on the opposite side of a pneumatic chamber. The present invention relates to an air-over-hydraulic brake fluid pressure control device in which the chamber is improved to improve the operation response of a valve element such as a power piston.

[Conventional technology]

Many proposals have been made as an anti-lock device for preventing the skid caused by the locking of the rear wheels due to the sudden braking of the vehicle while the vehicle is running.

In the case of the anti-lock device by the air over hydraulic type brake fluid pressure control device developed by the applicant of the present application, the air pressure generated by the depression of the brake pedal at the time of braking is boosted and boosted by the air master cylinder, This is converted into brake fluid pressure and introduced into the fluid pressure chamber of the brake fluid pressure control valve.

On the other hand, the vehicle speed sensor detects the vehicle speed during sudden braking, various electronic controls are performed in the control unit based on the detection signal sent, and the controlled output signal is sent to the solenoid valve. This control signal actuates the solenoid valve to switch the port, adjusts the air pressure generated by the depression of the brake pedal corresponding to this port, and adjusts this air pressure to the pneumatic pressure of the brake fluid pressure control valve. Operate in the room.

That is, in this braking hydraulic pressure control valve, the pneumatic chamber and the atmospheric chamber are separated from each other on both sides of the pressure receiving piston portion of the power piston, and by providing the atmospheric chamber, the operation response when the power piston slides Performance, the brake fluid pressure sent from the air master cylinder is reduced by air pressure sliding the power piston to balance it, and this brake control fluid pressure is supplied to the front and rear wheel cylinders. It is a system that does.

[Problems to be solved by the invention]

By the way, generally speaking in the system developed by the applicant of the present application, and in the braking hydraulic pressure control valve of this type of system, when the internal volume of the pneumatic chamber is set large, the air pressure sent from the air master cylinder is Effectiveness, that is, responsiveness decreases. If the internal volume of the atmosphere chamber is smaller than the standard, the atmosphere is compressed by the sliding of the power piston in the forward direction and receives resistance, and in the backward movement it becomes negative pressure and receives suction resistance. Reduce the responsiveness of the power piston.

However, if the internal volumes of the pneumatic chamber and the atmospheric chamber are designed in consideration of the above points, there is a problem that the entire braking hydraulic pressure control valve becomes large in the sliding axis direction of the power piston. is there.

The present invention has been made in view of the above problems, and it is desirable to secure the inner volumes of the air chamber and the air chamber that are adjacent to each other, thereby affecting the operation response of the power piston. It is an object of the present invention to provide an air-over-hydraulic brake fluid pressure control device that does not have to be large and that can suppress the increase in size of the entire valve device.

[Means for solving problems]

In order to achieve this object, the brake fluid pressure control device according to the present invention has the following configuration.

That is, in this brake fluid pressure control device, the air pressure generated by the depression of the brake pedal 1 (in the air tank 2) is converted into the brake fluid pressure by the air master cylinder 3, and this brake fluid pressure is adjusted by the brake fluid pressure. It is introduced into the hydraulic chamber (I) of the device V. In conjunction with this, the control unit U
The port of the solenoid valve is switched by the control signal output from the brake fluid pressure adjusting device V by switching this port.
The air pressure introduced into the air pressure chamber (II) is regulated. This regulated air pressure acts on the pressure-receiving piston portion 6c so that the power piston 6 can slide airtightly on the large-diameter cylinder portion 5b of the housing 5, and at this time, air pressure is generated via the pressure-receiving piston portion 6c. The internal volume of the back pressure chamber (III) open to the atmosphere provided on the opposite side of the chamber (II) increases or decreases, and the power piston 6
The brake hydraulic pressure in the hydraulic chamber (I) controlled by the sliding of the wheel is supplied to the wheel cylinder of the wheel.

In such a brake fluid pressure control device, the large diameter cylinder portion 5b is provided on the side surface of the pressure receiving piston portion 6c on the back pressure chamber (III) side.
A peripheral flange 6d that fits in and slides in an airtight manner is projected, and a space formed between the peripheral flange 6d and the inner wall surface of the large-diameter cylinder portion 5b and the pressure receiving piston portion 6c is formed. It is secured as a back pressure chamber (III) when the internal volume is minimum.

[Action]

In the braking fluid pressure adjusting device V, when the power piston 6 is stopped at the steady position due to the equilibrium between the brake fluid pressure and the air pressure, the peripheral flange 6d of the pressure receiving piston portion 6c is the inner wall surface of the large diameter cylinder portion 5b. A minimum internal volume of atmospheric pressure (II
I) is secured. As a result, when the power piston 6 is pushed back in the direction of contracting the air pressure chamber (II) by the brake fluid pressure and retracts, the internal volume of the atmosphere chamber (III) increases. At the time of this power piston 6 retreating, since the required air is secured in the atmosphere chamber (III) of the initial minimum internal volume, suction negative pressure does not occur, and the power piston 6 retreats. Does not affect the responsiveness of.

On the other hand, when air pressure is applied to the air pressure chamber (II) and the power piston 6 is slid in the forward direction, when the peripheral flange 6d comes into contact with the inner wall surface of the large diameter cylinder portion 5b, the atmosphere chamber (III )
Since the minimum required air volume in
The pressure piston 6c does not compress air,
There is no influence on the responsiveness of the piston 6 during forward movement.

〔Example〕

Hereinafter, an embodiment of a brake fluid pressure control device according to the present invention will be described with reference to the drawings.

In FIG. 1, the air pressure adjusted in the air tank 2 by depressing the brake pedal 1 is introduced into the air master cylinder 3 via the pneumatic tube A ₁ , and the air master cylinder 3 is operated at a predetermined pressure. The pressure is increased by a factor and output as brake fluid pressure. The output side of the air master cylinder 3 communicates with the introduction port P ₁ of the braking fluid pressure adjusting device V via the hydraulic pipe O ₁ , and the brake fluid pressure is transferred from this introduction port P ₁ to the fluid pressure chamber (I). It is being introduced.

Further, for example, a vehicle speed sensor S is set around all the front and rear wheels (represented by the symbol Ff), and the vehicle speed is detected by the rotational speed (rpm) of the wheels. On the basis of this vehicle speed signal, the control unit U performs control such as comparison calculation by a microcomputer, and outputs the controlled signal to the solenoid valves S / V.
It is designed to be sent to.

In the solenoid valve S / V, the port P is activated by the control signal.
Switching of ₁₀ to P ₁₃ is performed. The air tank 2 is connected to, for example, the port P ₁₁ of the solenoid valve S / V via the pneumatic pipe A _2, and when the pneumatic tank A ₂ is connected to the port P ₁₁ , the pneumatic pipe A ₂ brake fluid pressure. It communicates with the air pressure chamber (II) of the adjusting device V, and the air pressure from the air tank 2 acts on this air pressure chamber (II).

Here, the configuration of the braking fluid pressure adjusting device V is as follows:
The rear open end of 5A is closed by a lid 5B in a liquid-tight manner by bolting, and the inside of the lid 5B is a pneumatic chamber (II).
That is, one of the ports P _{10 to} P ₁₃ of the solenoid valve S · V switched to the intake port 5c provided on the lid 5B is connected.

The power piston 6 is axially slidable in the housing body 5A. The rod body 6a of the power piston 6 is slidably fitted in the small diameter cylinder portion 5a so as to be slidable, and the front end surface of the rod body 6a serves as a brake fluid pressure receiving surface 6b. Further, the pressure receiving piston portion 6c at the rear portion of the rod body 6a is liquid-tightly fitted to the large diameter cylinder portion 5b of the housing body 5A, and inside the large diameter cylinder portion 5b, there is an empty space on both sides of the pressure receiving piston portion 6c. A pressure chamber (II) and an atmosphere chamber (III) are formed.

Further, in the power piston 6, the pressure receiving area ratio between the front pressure receiving surface 6b of the rod body 6a and the rear pressure receiving piston portion 6c is the pneumatic and hydraulic pressure receiving piston area in the air master cylinder 3 described above. It is formed in the same ratio.

A peripheral flange 6d is provided on the pressure receiving piston portion 6c so as to project toward the atmosphere chamber (III) side, and has a dish shape. That is, while the peripheral flange 6d is airtightly fitted and slid on the inner peripheral surface of the large-diameter cylinder portion 5b, as shown in the figure, the peripheral flange 6d contacts the inner wall surface of the large-diameter cylinder portion 5b, and the minimum internal volume is reduced. The atmosphere room (III) is set to be secured.

A first spring 8 is provided in the air pressure chamber (II), and by this first spring 8, the pressure receiving piston portion 6b is
The entire power piston 6 is urged on the sliding axis as shown in FIG. At the front part of the rod body 6a of the power piston 6, a small-diameter pressing rod 7 is fitted and fixed on the coaxial line and protrudes.

On the other hand, at the inner end of the housing body 5A, a plug 10 and a plug sheet 11 which are integrally coupled to each other and form a spool valve shape are liquid-tightly fitted, and a cap 12 as a stopper is formed by enclosing them. Is screwed to the front open end of the housing body 5A. That is, the plug 10 and the plug seat 11 are positioned by screwing the cap 12 at a position where the plug seat 11 contacts the front pressure receiving surface 6b of the rod body 6a.

A hydraulic chamber (I) is formed in the plug 10 and the plug seat 11 by integral connection, and the upstream end of this hydraulic chamber (I) communicates with the introduction port P ₁ and the downstream end thereof Similarly, it communicates with the outlet port P ₂ provided on the housing body 5A. The brake hydraulic pressure from the air master cylinder 3 introduced into the hydraulic chamber (I) acts on the front pressure receiving surface 6c of the rod body 6a and the front end surface of the plug seat 11. Outlet port P ₂ is wheeled via hydraulic line O _2.
It communicates with the wheel / cylinder W / C of Ff, and the brake fluid pressure in the fluid pressure chamber (I) is supplied.

Further, in the hydraulic chamber (I), a ball valve 17 which is a check valve is installed in an operable state, and the second spring 18 provided adjacent to the ball valve 17 moves the ball valve 17 to the plug seat 11. The method is urged to abut the formed valve seat 11a. The ball valve 17 is in a position where a predetermined gap C is formed between the ball valve 17 and the valve seat 11a in a steady state. That is, at the position where the front end surface of the rod body 6a of the power piston 6 abuts on the rear end surface of the plug seat 11 and is prevented from further advancing, the pressing rod 7 at the tip moves the ball valve 17 to the second position.
It slightly pushes back against the spring 18 to form a gap C with the valve seat 11a.

Next, the operation mode and operation of the embodiment having the above configuration will be described.

First, during normal traveling of the vehicle, the brake fluid pressure in the fluid pressure chamber (I) and the air pressure chamber (II) in the braking fluid pressure adjusting device V.
The air pressure and the first and second springs 8 and 18 applied thereto keep the power piston 6 in equilibrium at the steady position.

During normal braking during traveling, when the brake pedal 1 is depressed, the air pressure generated in the air tank 2 is introduced into the air master cylinder 3 via the pneumatic tube A ₁ . In the air master cylinder 3, the air pressure is converted into a brake hydraulic pressure increased by a predetermined ratio and introduced into the hydraulic chamber (I) of the braking hydraulic pressure adjusting device V via the hydraulic pipe O ₁ .
In parallel with this, on the one hand, the rotation speed (rpm) of the wheel Ff when the brake pedal 1 is depressed is detected by the vehicle speed sensor S, and the control unit U is based on the vehicle speed signal equivalent to this rotation speed. The microcomputer performs control such as comparison calculation, outputs a control signal and sends it to the solenoid valves S and V. This control signal causes the solenoid valve S / V port P ₁₁
Is connected to the pneumatic tube A ₂ , and the pneumatic tube A ₂ communicates with the pneumatic chamber (II) of the braking fluid pressure adjusting device V. That is, the air pressure generated by the depression of the brake pedal 1 is introduced into the air pressure chamber (II). Therefore, due to the action of the brake fluid pressure introduced into the fluid pressure chamber (I), a force that pushes back the power piston 6 from the steady position to the right in the figure acts on the power piston 6, but the pneumatic pressure is used to prevent this. The air pressure on the chamber (II) side acts on the pressure receiving piston portion 6c. The pressure balance at this time is because the piston pressure receiving area ratio in the power piston 6 is equal to the piston pressure receiving area ratio in the air master cylinder 3. As a result, the power piston 6 remains stationary in the steady position, and the ball valve 17 and the valve seat 11a in the hydraulic chamber (I) are kept.
A clearance C between the _two is also maintained, and brake fluid pressure is supplied from the outlet port P ₂ to the wheel cylinder W / C of the wheel Ff via the hydraulic pipe O ₂ .

Next, at the time of sudden braking during running, the wheel Ff goes to a locked state, the vehicle speed sensor S detects the rotation speed of the wheel Ff at this time, and the control unit U controls it based on this detection signal. Signal is sent to the solenoid valves S and V. This control signal causes the solenoid valve S · V to switch from port P ₁₃ to port P ₁₀ so that the air pressure in the air pressure chamber (II) communicates with the atmosphere and opens.

By opening the air pressure chamber (II) to the atmosphere, the power piston 3
The force acting on the pressure receiving piston portion 6c is only the first spring 8. Thus, in the power piston 3,
The pressure balance with the brake fluid pressure introduced from the air master cylinder 3 into the fluid pressure chamber (I) is lost, and the brake fluid pressure corresponding to the differential pressure acts on the front pressure receiving surface 6b of the power piston 6, The power piston 3 is moved backward in the right direction in the figure against the first spring 8. Due to the movement of the power piston 3, the regulation of the ball valve 17 is released, and the second spring 18 pushes and moves the ball valve 17 in the right direction in the figure, closing the valve seat 11a and shutting off the hydraulic chamber (I), thereby reducing the downstream side. Contain it. The internal volume of the confined downstream hydraulic chamber (I) is
The power piston 6 will increase due to the backward movement of the power piston 6, and will be in a state of being depressurized from the initial brake fluid pressure introduced (pressure reduction mode).

The brake fluid pressure reduced corresponding to the backward movement amount of the power piston 3 is supplied from the outlet port P ₂ to the wheel cylinder W / C of the wheel Ff via the hydraulic pipe O ₂ . That is,
By reducing the high-pressure brake fluid pressure generated by stepping on during sudden braking, it is possible to prevent the skid of the wheel Ff that faces the lock.

Also, at this time, with the backward movement of the power piston 6,
The atmospheric chamber (III) gradually increases from its reserved minimum internal volume. Due to the increase of the internal volume, the atmosphere is sucked through the breather 20. This atmosphere chamber (III) and breather 20
The action of ensures the required actuation response of the power piston 6. That is, when the power piston 6 moves suddenly, even if the breather 20 becomes a resistance to the air suction, the large volume of the atmosphere chamber (III) is secured, and therefore the suction chamber 3 is sucked when the backward movement is performed. It is not pulled by pressure.

When the power piston 6 retracts and the brake fluid pressure in the fluid pressure chamber (I) drops, and the state in which the wheel Ff is expected to be locked is resolved, the solenoid valve S is released by the control signal from the control unit U. Atmosphere opening port P _{10 of} V is closed and power piston 6 is stopped. At this time, wheel / cylinder
W / C brake fluid pressure is kept constant (holding mode).

After this, by detecting the rotational speed of the wheel Ff in the holding mode state, the solenoid valve S.
V port P ₁₁ is switched and connected to pneumatic tube A ₂ ,
The air pressure from the tank 2 is again introduced into the air pressure chamber (II). This air pressure pushes the power piston 6 toward the steady position to the left in the figure, until the ball valve
The downstream side of the hydraulic chamber (I) which is closed in 17 is compressed. The brake fluid pressure thus increased is sent from the introduction port P ₂ to the wheel / cylinder W / C, and eventually the pressing rod 7 presses the ball valve 17 against the second spring 18, so that the valve seat 11a is released. Is provided with a gap C. By opening the fluid pressure chamber (I), the brake fluid pressure from the air mast cylinder 3 is restored to the wheel cylinder W /
Supplied to C (pressurized mode).

At this time, the internal volume of the atmosphere chamber (III) is reduced by the forward movement of the power piston 6 toward the steady position. With this reduction, the peripheral flange 6d of the pressure receiving piston portion 6c contacts the inner wall surface of the large diameter cylinder portion 5b, so that the minimum inner volume of the atmosphere chamber (III) is secured. Due to the sudden movement of the power piston 6 at this time, the required amount of air is satisfied even if a resistance to discharge air is generated, and the forward movement of the power piston 6 does not compress the power piston 6. -There is no hindrance to the operation response of the piston 6. On the other hand, when the brake pedal 1 is released from the state where the pressurization mode is set, the air pressure from the air tank 2 sent to the air master cylinder 3 returns to a steady state, and the braking fluid pressure adjusting device V The brake fluid pressure acting in the pneumatic chamber (II) also becomes a steady pressure. Then, the front end pressure receiving surface 6b of the power piston 6 contacts the rear end surface of the plug seat 11 and stays in the normal return position.

[Effect of device]

As described above, in the brake fluid pressure control device according to the present invention, the solenoid valve is installed in the pneumatic pipe that communicates the air pressure source with the air pressure chamber of the braking fluid pressure adjusting device. A port for communicating with the air pressure chamber and a port for opening the air pressure chamber to the atmosphere are provided, and the solenoid valve is operated by a control signal output from a control unit controlled based on a vehicle speed detection signal. Therefore, the solenoid valve is actuated simultaneously with the occurrence of the locked state of the wheels to open the air pressure chamber to the atmosphere, so that the pressure reduction response without delay can be given during the anti-lock control. Moreover, according to the brake fluid pressure control device of the present invention, the pressure receiving piston portion reduces the back pressure chamber volume in the atmosphere communicating back pressure chamber whose internal volume increases and decreases as the power piston moves in the braking fluid pressure adjusting device. Since a predetermined inner volume is secured in the back pressure chamber at the final position moved in the direction, the operation response of the power piston is hindered by the compression resistance against the air in the back pressure chamber and the suction negative pressure. As a result, it is possible to obtain the above-described certainty of ensuring good pressure reduction responsiveness.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of an embodiment of a brake fluid pressure control device according to the present invention. 1 ... Brake pedal, 2 ... Air tank, 3 ... Air
Master cylinder, 5 ... Housing, 6 ... Power piston, 6a ... Front end pressure receiving surface, 6c ... Pressure receiving piston part, 6d ... Surrounding collar,
7 ... Push rod, 17 ... Ball valve, S ... Vehicle speed sensor, S
-V ... solenoid valve, V ... braking fluid pressure adjustment, (I) ... hydraulic chamber,
(II) ... Pneumatic chamber, (III) ... Atmosphere chamber.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References Japanese Patent Laid-Open No. 51-33269 (JP, A) Actually developed 61-138661 (JP, U) Japanese Patent Publication No. 51-1824 (JP, B1)

Claims (1)

[Scope of utility model registration request] 1. A pneumatic pressure source 2 for generating air pressure, a brake,
Brake valve 4 that opens and closes when the pedal 1 is depressed
An air master cylinder 3 for converting the air pressure from the pneumatic pressure source 2 into a brake fluid pressure via a hydraulic pressure pipe O and an inlet port P ₁ and an outlet port P ₂ , and a hydraulic pipe O connected to the inlet port P _1. A hydraulic chamber (I) communicating with the air master cylinder 3 via ₁ and supplying hydraulic pressure from the outlet port P ₂ to the wheel cylinders of the front and rear wheels of the vehicle, and the air through the brake valve 4. A rod main body which internally forms pneumatic chambers (II) communicating with the pressure source 2 by pneumatic pipes A ₂ , is located in the hydraulic chambers (I), and has an end surface serving as a pressure receiving surface on which brake hydraulic pressure acts. 6a and a power receiving piston portion 6c located in the air pressure chamber and interlocking with the rod body.
A braking fluid pressure adjusting device V including a piston 6, and a back pressure chamber (III) communicating with the atmosphere on the back side of the pressure receiving piston portion 6c; and a control unit U for controlling based on a vehicle speed detection signal, An electromagnetic valve S · V provided in the pneumatic tube A ₂ and operated by a control signal output from the control unit U is provided, and the electromagnetic valve S · V includes the pneumatic source 2 and the pneumatic chamber ( II)
And a port that opens the air pressure chamber (II) to the atmosphere, and the pressure receiving piston portion 6c of the power piston that constitutes the braking fluid pressure adjusting device V is connected to the back pressure chamber (III). ) Side extending flange 6d, the pressure receiving piston portion 6c is configured to ensure a predetermined inner volume in the back pressure chamber at the final position after moving in the back pressure chamber volume decreasing direction. Brake fluid pressure control device.