JPH079983A - Vehicle braking system - Google Patents

Abstract

(57) [Summary] [Purpose] First master chassis operated by brake pedal
The second master cylinder operated by the Linda and the motor
In a braking system that switches with a valve, a master cylinder
Common use reservoir and simplification of the structure of the valve. [Configuration] First master cylinder Mc having a reservoir 2
₁Oil passage L extending from_FL, L_FR, L_RIs a simple opening of the structure
Closed valve 3 and second master cylinder without reservoir
Mc₂Brake caliper C through the oil chamber of_FL, C_FR，
C_RL, C_RRConnected to. Normally open / close valve 3 is closed
2nd master cylinder Mc ₂Drive
The braking is performed by the
Open the valve 3 and press the brake pedal 1 to the first master cylinder.
Da Mc₁Braking is performed by driving.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a first master cylinder operated by a brake pedal and a second master cylinder operated by an actuator, and a brake hydraulic pressure generated by the second master cylinder by normally driving the actuator. The present invention relates to a vehicular braking device that performs braking with the brake hydraulic pressure generated by the first master cylinder when the control system fails.

[0002]

2. Description of the Related Art Such a vehicle braking system is disclosed in Japanese Patent Laid-Open No. 4-3.
It is already known from Japanese Patent No. 62454. In the vehicle braking device described in the above publication, an oil passage connected to the first master cylinder and an oil passage connected to the second master cylinder are independently provided, and both oil passages are braked via a spool valve. By selectively connecting to the oil passage connected to the caliper, the brake hydraulic pressure generated by the second master cylinder during normal operation and the brake hydraulic pressure generated by the first master cylinder during failure are transmitted to the brake caliper. .

[0003]

However, in the above-described conventional vehicle braking device, the oil passages connected to the first master cylinder and the oil passages connected to the second master cylinder are provided independently of each other, and therefore both master cylinders are provided. Not only is there a need to provide a reservoir for each, increasing the number of parts, but there is also the problem that a spool valve with a complicated structure must be used to switch between the two oil passages, increasing the cost.

The present invention has been made in view of such circumstances, and makes it possible to share the reservoirs of both master cylinders and replace a spool valve having a complicated structure with an opening / closing valve having a simple structure. Therefore, the purpose is to reduce the cost.

[0005]

To achieve the above object, the present invention provides a first master cylinder operated by a brake pedal, a reservoir provided in the first master cylinder, and a second master operated by an actuator. A cylinder, an oil passage for transmitting the brake oil pressure generated by the first master cylinder to the wheel brakes via the oil chamber of the second master cylinder, and an opening / closing provided in the oil passage between the first and second master cylinders. It is characterized by comprising a valve and a control means for controlling the operation of the actuator and the opening / closing valve.

[0006]

Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 show an embodiment of the present invention. FIG. 1 is an overall configuration diagram of a vehicle braking device, and FIG.
It is a longitudinal cross-sectional view of a master cylinder.

As shown in FIG. 1, a brake of a vehicle braking system is shown.
A first master cylinder having a reservoir 2 on the rake pedal 1.
Md Mc₁Is connected to this first master cylinder
Mc ₁3 oil passages L branching from and extending from_FL, L_FR, L_R
Of the first oil passage L_FLLeft front wheel W_FLBrake carrier
PA C_FLConnected to the second oil passage L_FRRight front wheel W_FRof
Brake caliper C_FRConnected to the third oil passage L_R
Is bifurcated and left rear wheel W_RLBrake caliper C_RLOver
And right rear wheel W_RRBrake caliper C_RRRespectively connected to
Be done. The three oil passages L_FL, L_FR, L_RTo each of
Is a second master cylinder Mc having the same structure.₂…When,
A normally open solenoid valve 3 ... Is interposed in series. Previous
The solenoid valve 3 ... is the oil passage L._FL, L_FR, L_RSo
It consists of an on-off valve that opens or closes.

The electronic control unit U comprising a microcomputer includes a brake pedal switch 4 for detecting the operation of the brake pedal 1, a load cell 5 for detecting the pedaling force of the brake pedal 1, a left front wheel W _FL , a right front wheel W _FR , Wheel speed sensor 6 provided on each of the left rear wheel W _RL and the right rear wheel W _RR
... and are connected. The brake pedal switch 4
Can be replaced by a stop lamp switch. The electronic control unit U arithmetically processes each output of the brake pedal switch 4, the load cell 5, and the wheel speed sensor 6 on the basis of a predetermined program to control the opening / closing of each solenoid valve 3 ... And each second master. The motors 7 provided on the cylinders Mc ₂ are controlled by a motor driver 8.

Next, the structure of the second master cylinder Mc ₂ will be described with reference to FIG.

The second master cylinder Mc ₂ has a first casing 11 formed in a bottomed cylindrical shape and a first casing 1.
A second casing 12 formed in a cylindrical shape having a diameter smaller than 1.
And a cylinder 13 having a smaller diameter than the second casing 12 and having a bottomed cylindrical shape.
The bottom portion of the first casing 12 and one end of the second casing 12 are connected by a plurality of bolts 14 ..., and the other end of the second casing 12 and the open end of the cylinder 13 are a plurality of bolts 15.
Are joined by.

The open end of the first casing 11 is closed by an end plate 17 fixed by a plurality of bolts 16 ... And the motor 7 is supported outside the end plate 17. A rotary shaft 19 is supported on the bottom of the first casing 11 via roller bearings 18, and both ends of the rotary shaft 19 extend into the first casing 11 and the second casing 12, respectively.

Inside the first casing 11, there is housed a torque limit mechanism 21 which connects the output shaft 20 of the motor 7 penetrating the end plate 17 and one end of the rotary shaft 19. The torque limit mechanism 21 includes a bottomed cylindrical outer housing 22 fixed to the output shaft 20 of the motor 7.
, A plurality of friction plates 23 splined to the open end side of the outer housing 22, and a plurality of friction plates 23 splined to the outer periphery of the rotary shaft 19 and alternately laminated with the friction plates 23 on the outer housing 22 side. Friction plate 24 ...
And a spring seat 26 fixed to the right end of the rotary shaft 19 with a bolt 25, and the spring seat 26 and the friction plate 24 located at the right end in a contracted manner.
, 24 are urged toward the flange 19 ₁ provided on the rotary shaft 19 and two springs 27, 28.

When the load on the rotary shaft 19 is small,
The torque of the motor 7 is transferred from the outer housing 22 to the friction plate 2
3 is transmitted to the rotary shaft 19 via the friction plates 24,
When the load on the rotary shaft 19 exceeds a predetermined value and increases, the upper limit of the torque transmitted from the motor 7 to the rotary shaft 19 is restricted by the slip generated between the friction plates 23 ,.

Inside the second casing 12, the rotary shaft 1
A ball screw mechanism 29 for converting the rotational movement of 9 into a reciprocating movement in the axial direction and taking it out is housed. Ball screw mechanism 2
9 is the ball groove 30 ₁ and the second
The second casing 1 is provided with a plurality of balls 31 fitted into the ball grooves 12 _{1 formed} on the inner circumference of the casing 12
The output member 30 is supported so as not to be rotatable relative to 2 and slidable in the axial direction. The balls 31 ... Are prevented from falling off by a pair of front and rear clips 32, 33 provided on the output member 30. Then, the female screw 30 ₂ engraved inside the output member 30 and the male screw 1 engraved on the outer periphery of the rotary shaft 19
Between 9 _2, number of balls 34 are fitted.

When the rotary shaft 19 is rotated in one direction, the output member 30 advances to the left in the figure via the ball screw mechanism 29, and when the rotary shaft 19 is rotated in the opposite direction, the ball screw mechanism 29 is rotated. The output member 30 retreats to the right in the figure via.

Seals 35 and 37 are provided on the front and rear portions, respectively.
And a piston 38 slidably fitted inside the cylinder 13 that includes an oil chamber 3 defined on the bottom side of the cylinder 13.
It is biased in the backward direction (on the right side in the drawing) by a return spring 40 that is contracted at 9, and its backward end is restricted by a stopper 41 fixed to the open end of the cylinder 13. The oil chamber 39 has an input port 43 connected to the first master cylinder Mc ₁ and a brake caliper C _FL (C _FR , C
Output port 44 connected to _RL , C _RR ) is formed.

When the piston 38 pressed against the tip of the advancing output member 30 moves forward against the return spring 40, a brake hydraulic pressure is generated in the oil chamber 39, and the brake hydraulic pressure passes through the output port 44. It is transmitted to the brake caliper C _FL (C _FR , C _RL , C _RR ).

Next, the operation of the embodiment of the present invention having the above structure will be described.

When the driver depresses the brake pedal 1 to turn on the brake pedal switch 4, the three solenoid valves 3 ... Are closed by a command from the electronic control unit U, and the first master cylinder Mc ₁ and the three master valves Mc ₁ are closed. The communication with the second master cylinder Mc ₂ ... Is cut off. The electronic control unit U receiving the signal from the load cell 5 for detecting the pedaling force of the brake pedal 1 is, for example, the second control unit U provided in the oil passage L _FL .
The motor 7 of the second master cylinder Mc ₂ is driven via the motor driver 8 in order to generate a predetermined brake hydraulic pressure in the master cylinder Mc ₂ according to the pedaling force. The driving force of the motor 7 advances the piston 38 via the torque limit mechanism 21 and the ball screw mechanism 29 to generate a brake hydraulic pressure in the oil chamber 39. At this time, since the input port 43 of the oil chamber 39 is closed by the solenoid valve 3 that is closed, the brake hydraulic pressure is transmitted to the brake caliper C _FL to brake the left front wheel W _FL .

When the driver depresses the brake pedal 1 and the solenoid valve 3 fails and locks in the open position, the oil chamber is released when the seal 35 on the front side of the piston 38 exceeds the input port 43. The communication between 39 and the oil passage L _FL is cut off, and the brake oil pressure can be generated in the oil chamber 39.

When it is detected that the left front wheel W _FL has a tendency to lock, for example, by a signal from the wheel speed sensor 6 during the above-described braking, a command from the electronic control unit U causes the second master cylinder Mc ₂ to move. The motor 7 is driven in the reverse direction, and the piston 38 retracts. As a result, the oil chamber 39
, The brake hydraulic pressure decreases, and the braking force of the left front wheel W _FL by the brake caliper C _FL decreases. When the locking tendency is eliminated in this way, the piston 38 is driven forward again and the braking force of the left front wheel W _FL by the brake caliper C _FL increases. And Thus, by forward and reverse the motor 7 in response to the transition of the locking tendency of the left front wheel W _FL, it is possible to prevent the lock of the left front wheel W _FL and adjust the braking force of the brake caliper C _FL is generated .

Also, when the vehicle is not braking, the accelerator pedal is
If you step too much or if you are on a road surface with a low coefficient of friction
In this case, signals from the wheel speed sensors 6 ...
Wheel W _FLWhen excessive slip is detected on
The second master series is instructed by a command from the electronic control unit U.
Md Mc₂To generate a specified brake oil pressure.
Data 7 is driven. As a result, the second master cylinder Mc
₂Brake hydraulic pressure generated in the brake caliper C
_FLTransmitted to the left front wheel W_FLIs braked and the left front wheel W_FLof
Excessive slip is suppressed.

Incidentally, the left front wheel W_FLBrake carrier
PA C_FLSecond master cylinder Mc connected to₂Control of
As I have mentioned mainly, the right front wheel W_FRBrake caliper C
_FRSecond master cylinder Mc connected to₂And rear wheels
W_RL, W_RRBrake caliper C _RL, C_RRConnected to
Second master cylinder Mc₂Is also the same as above.
Control is done.

When the control system including the electronic control unit U fails, the normally open solenoid valves 3 ... Are held in the open state. Therefore, the brake hydraulic pressure generated by the first master cylinder Mc ₁ by depressing the brake pedal 1 is applied to the respective brake calipers C via the solenoid valves 3 ... And the oil chambers 39 of the second master cylinders Mc ₂ . _It is transmitted to _FL , C _FR , C _RL , and C _RR, and the braking force required in an emergency is secured.

When the brake pedal 1 is not operated, the brake calipers C _FL , C _FR , C _RL and C _RR are common to the first master cylinder Mc ₁ via the second master cylinders Mc ₂ ... It is connected to the reservoir 2 and compensates for volume changes due to expansion and contraction of the piping system and natural decrease of brake oil. At this time, since one first master cylinder Mc ₁ and three second master cylinders Mc ₂ share one reservoir 2, it is possible to reduce the cost by reducing the number of parts. Moreover, since an open / close valve having a simple structure can be used as the solenoid valves 3, ... Also, the cost can be reduced by this.

Although the embodiment of the present invention has been described in detail above, the present invention is not limited to the above embodiment, and various design changes can be made.

For example, in the embodiment, each oil passage oil passage L _FL ,
Solenoid valves 3 ... Are interposed in L _FR and L _R , respectively, but are common between the branch portions of the oil passages L _FL , L _FR and L _R shown in FIG. 1 and the first master cylinder Mc _1. The solenoid valve may be provided.

[0029]

As described above, according to the present invention, an oil passage for transmitting the brake oil pressure generated by the first master cylinder to the wheel brakes via the oil chamber of the second master cylinder is provided, and both master cylinders are provided. Since the opening / closing valve is provided in the oil passage between them to switch between the normal time and the fail time, the reservoirs of both master cylinders can be covered by the reservoirs provided in the first master cylinder to reduce the number of parts. Not only can this be done, but an open / close valve with a simple structure can be used in place of the spool valve with a complicated structure to reduce costs.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a vehicle braking device.

FIG. 2 is a vertical sectional view of a second master cylinder.

[Explanation of symbols]

1 Brake Pedal 2 Reservoir 3 Solenoid Valve (Open / Close Valve) 7 Motor (Actuator) 39 Oil Chamber C _FL , C _FR , C _RL , C _RR Brake Caliper (Wheel Brake) L _FL , L _FR , L _R Oil Path Mc ₁ No. 1 master cylinder Mc ₂ 2nd master cylinder U Electronic control unit (control means)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Daisaburo Aiso 840 Kokubu, Ueda City, Nagano Prefecture Nissin Kogyo Co., Ltd.

Claims (1)

[Claims] 1. A first master cylinder actuated by the brake pedal (1) (Mc _1), a reservoir (2) provided in the first master cylinder (Mc _1), second actuated by an actuator (7) Master cylinder (M
c ₂ ) and the brake hydraulic pressure generated by the first master cylinder (Mc ₁ ) are transferred to the oil chamber (3) of the second master cylinder (Mc ₂ ).
9) via wheel brakes (C _FL , C _FR , C _RL ,
C _RR ) oil passage (L _FL , L _FR , _LR ) and the oil passage (L ₁ ) between the first and second master cylinders (Mc ₁ , Mc ₂ ).
An opening / closing valve (3) interposed between _FL , L _FR , and L _R , and a control means (U) for controlling the operation of the actuator (7) and the opening / closing valve (3). Vehicle braking system.