JP3496775B2 - Brake booster with automatic brake device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention makes it possible to easily start a vehicle, such as an automobile, on a slope, and to eliminate the need to wait for a signal or to continue to depress the brake pedal on a congested road. Side brakes are used to maintain traction control when the vehicle is idling, to keep the vehicle stopped on slopes, to control the inter-vehicle distance while driving, and to prevent the vehicle from traveling at a low speed on downhills. The present invention relates to a brake booster equipped with an automatic brake device that is used to prevent forgetting to apply the brake.

[0002]

2. Description of the Related Art Recently, in automobiles, it is possible to easily start a vehicle such as an automobile on a slope without requiring a sudden pedal change operation from a parking brake or a brake pedal to an accelerator pedal. For,
Alternatively, a brake booster equipped with an automatic brake device has been developed in order to reduce the fatigue caused by the brake operation by making it unnecessary to keep pressing the brake pedal while waiting for a signal or in a traffic jam.

In a brake booster equipped with such an automatic brake device, if the driver wants to perform abrupt deceleration by pedaling during automatic brake operation if the brake pedal moves during automatic brake operation. Since the brake pedal is not in the normal non-actuated position, the driver may step off the brake pedal. For this reason, not only the driver cannot reliably operate the brake, but also the pedal feeling at the time of operating the brake is greatly different from that of the normal brake, and the driver feels uncomfortable. In addition, when the driver's foot is under the brake pedal when the brake is not operated, the brake pedal may move when the automatic brake operates, which may cause the driver's foot to be caught between the vehicle body and the pedal. is there.

Therefore, Japanese Patent Application Laid-Open No. 57-130845 proposes a brake booster equipped with an automatic braking device that prevents the brake pedal from moving during automatic braking. FIG. 4 is a diagram schematically showing the brake booster disclosed in this publication.

As shown in FIG. 4, the brake pedal 51
A brake master cylinder 52, a known vacuum booster 53 disposed between the brake pedal 51 and the brake master cylinder 52, and a brake booster 53 disposed between the brake pedal 51 and the vacuum booster 53. Coupling 54
It consists of and.

As shown in FIG. 5, the coupling 54 is
A pair of front shell 55 and rear shell 56 that form an internal space, a diaphragm 59 that partitions the internal space of the coupling 54 into a front chamber 57 that is switched and connected to the atmosphere or a negative pressure source, and a rear chamber 58 that is in constant communication with the atmosphere.
And a valve actuating rod 60 that penetrates the front shell 55 in an airtight and slidable manner, fixes and supports a diaphragm 59, and operates a control valve (not shown) of the vacuum booster 53, and a rear shell 56 in a slidable manner. In addition, the pedal side rod 61 fitted to the rear end of the valve operating rod 60 and slidably fixing and supporting the rear end, and the diaphragm 59 and the valve operating rod 60 are returned to urge the brake non-operating position. A control valve 63, which is composed of a spring 62, is connected to the front chamber 57 for switching control so as to connect the front chamber 57 to the atmosphere during normal operation and to connect to a negative pressure source during automatic braking. When the brake is not operated, the rear end of the valve operating rod 60 and the pedal side rod 61 are in contact with each other without a gap.

At the time of non-operation of the brake, the atmosphere is introduced into the front chamber 57 and the atmosphere is always introduced into the rear chamber 58. In normal brake operation, the brake pedal 51 is depressed, and the pedal side rod 61 and the valve operating rod 60 both move forward to move the vacuum booster 5
3 control valves are switched. As a result, the vacuum booster 53 generates an output obtained by boosting the depression input of the brake pedal 1 at a predetermined boost ratio, and the piston of the master cylinder 52 is operated by this output to operate the normal brake.

In the automatic brake operation, when the automatic brake operation condition is satisfied, the control valve 63 is switched by the controller (not shown), the air in the front chamber 57 is discharged, and the inside of the front chamber 57 becomes negative pressure. Therefore, a differential pressure is generated between the rear chamber 58 and the front chamber 57, and this differential pressure causes the diaphragm 59 to move forward as shown in FIG. As a result, the valve operating rod 60 moves forward, the control valve of the vacuum booster 53 is switched, and the automatic brake is operated, as in the above-described normal brake.

[0009]

By the way, in the brake booster equipped with the automatic brake device disclosed in this publication, only the valve operating rod 60 moves forward when the automatic brake is operating. A relatively large gap α is generated between the side rod 61 and the side rod 61. Therefore, when the automatic brake is activated,
When the driver depresses the brake pedal 51 to further increase the braking force, even if the pedal side rod 61 moves forward, it contributes to the braking force until the valve operating rod 60 abuts and the gap α disappears. It is not lost and it becomes a loss stroke. Since the gap α is relatively large, this loss stroke is large, and therefore the pedaling feeling when the driver depresses the brake pedal is largely different from that when the driver normally brakes, and the driver feels uncomfortable.

The present invention has been made in view of such a problem, and an object thereof is to change the operation feeling of the driver's brake operation member to the operation feeling at the time of normal braking during the automatic brake operation. It is an object of the present invention to provide a brake booster equipped with an automatic brake device that can prevent a large change.

[0011]

In order to solve the above-mentioned problems, the present invention according to claim 1 operates in response to an input shaft connected to a brake operating member and an input from the input shaft, and responds to this input. Equipped with a booster mechanism for generating a boosted force, and an output shaft for outputting the force generated by this booster mechanism to operate the master cylinder, and by an output boosted according to the input of the input shaft. In the brake booster for operating the master cylinder, the input shaft includes a first rod connected to the boost mechanism and a second rod connected to the brake operating member, and the first rod includes And a second rod, a first piston provided on the first rod and slidably arranged in the cylinder in a liquid-tight manner, and a second rod provided on the second rod. Liquid tightly slides in the cylinder A second piston that is freely arranged and comes into contact with the first piston when not in operation, a hydraulic chamber defined between the first piston and the second piston in the cylinder, and It is characterized by comprising a control valve for supplying / discharging the pressure hydraulic fluid and for setting the hydraulic chamber in the closed state, and a controller for controlling the control valve.

According to the invention of claim 2, an input shaft connected to the brake operating member, and a booster mechanism which is actuated by an input from the input shaft to generate a boosted force according to the input. A brake booster that outputs the force generated by the booster mechanism and operates the master cylinder, and operates the master cylinder by an output boosted according to the input of the input shaft, A cylinder provided with an output shaft including a first rod connected to the master cylinder and a second rod connected to the booster mechanism, the cylinder being arranged between the first rod and the second rod; , The first
A first piston provided on a rod and slidably arranged in the cylinder in a liquid-tight manner, and a first piston provided on the second rod so as to be slidable in a liquid-tight manner in the cylinder and set in the inoperative state A second piston that contacts the first piston, a hydraulic chamber that is defined between the first piston and the second piston in the cylinder, and supplies and discharges the hydraulic fluid to and from the hydraulic chamber. It is characterized in that it is provided with a control valve for setting the hydraulic chamber in the closed state and a controller for controlling the control valve. Furthermore, the invention of claim 3 is
It is characterized in that the first piston and the second piston have the same pressure receiving area on which the pressure hydraulic fluid acts. Further, the invention of claim 4 is characterized in that the brake booster is a vacuum booster.

[0013]

According to the present invention having such a configuration, during normal braking, the input shaft is advanced by the operation of the brake operating member and the brake booster outputs from the output shaft, whereby the input of the brake operating member is predetermined. The servo is boosted and the brake normally operates.

During automatic braking, the controller controls the control valve of the hydraulic pressure circuit to supply the pressure working fluid from the hydraulic pressure circuit to the hydraulic pressure chamber in the cylinder, and the hydraulic pressure in the hydraulic pressure chamber rises. The first piston and the first rod move forward. As a result, the brake booster outputs from the output shaft or directly from the output shaft without passing through the brake booster, and the automatic brake operates. When the hydraulic pressure in the hydraulic pressure chamber reaches the control pressure, the controller controls the control valve to close the hydraulic pressure chamber and the automatic brake has a braking force according to the control pressure.

Further, when the normal brake operation is performed by the operation of the brake operation member during the automatic brake operation, the second rod and the second piston advance, but the advance of the second piston is sealed in the hydraulic chamber. Is transmitted to the first piston via the pressure hydraulic fluid, and the first piston and the first rod move forward. At this time, since the hydraulic chamber is in a sealed state, the first piston moves forward without causing a loss stroke with respect to the forward movement of the second piston. That is, the brake operating member moves without loss stroke, and the operation feeling of the brake operating member is almost the same as the operation feeling when the normal brake is used, which is good. Due to the forward movement of the first rod, the normal brake works together with the automatic brake, and the braking force increases.

Further, when the automatic brake operation is performed during the normal brake operation, the first piston and the first rod move forward by the pressure hydraulic fluid supplied to the hydraulic chamber. Due to the forward movement of the first rod, the automatic braking operates together with the normal braking, and the braking force increases.

Further, even if the hydraulic circuit of the automatic brake fails, the normal braking can be surely performed by the operation of the brake operating member, so that the brake can be operated safely and surely on the vehicle. Become.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a partial sectional view showing a first embodiment of a brake booster equipped with an automatic brake device according to the present invention. As shown in FIG. 1, the brake booster includes a conventionally known negative pressure booster 1.
Includes a front shell 2 and a rear shell 3 which are connected to each other by, for example, a bayonet connection.

A valve body 4 is arranged so as to penetrate through the rear shell 3, and the valve body 4 is supported by the rear shell 3 and the seal member 5 in an airtight and slidable manner. The valve body 4 has both shells 2, 3
The power piston member 6 arranged in the inner space is connected. On the back of this power piston member 6, shell 2,
A diaphragm 7 is provided between the valve body 3 and the valve body 4. The power piston member 6 and the diaphragm 7 constitute a power piston 8, and the power piston 8 divides the space inside the shells 2 and 3 into a constant pressure chamber 9 and a variable pressure chamber 10.

The valve body 4 is formed with a recessed fitting portion 11 that opens into the constant pressure chamber 9, and the bottom portion of the recessed fitting portion 11 is formed with a protrusion 4a whose central portion projects toward the constant pressure chamber 9 side. ing. The recessed fitting portion 1 is provided substantially at the center of the protrusion 4a.
1 is formed in the first hole 12, and the second hole 13, the third hole 14, the fourth hole 15 and the atmosphere are formed successively from the first hole 12 toward the rear (to the right in the figure). Fifth holes 16 that open in the respective holes are formed. Further, the valve body 4 is provided with an axial passage 17 that connects the constant pressure chamber 9 and the fourth hole 15.

A valve plunger 18 is slidably fitted in the first hole 12 of the valve body 4. A valve operating rod (corresponding to the first rod of the present invention) 19 is connected to the right end portion of the valve plunger 18. A radial hole 20 is formed in the valve body 4 so as to be orthogonal to the second hole 13, and a key member 21 is fitted through the hole 20 into the valve plunger 18 so as to be relatively movable in the axial direction. ing. Further, the key member 21 can move axially along with the valve plunger 18 by the width of the hole 20, and the key member 21 allows the valve plunger 18 to move.
Is prevented from coming out of the valve body 4. Further, the valve body 4 is provided with a passage 22 that opens to the variable pressure chamber 10 so as to be orthogonal to the second hole 13. The passage 22 also communicates with the third hole 14.

A control valve 23 is provided in the fifth hole 16 of the valve body 4. The control valve 23 is attached to the valve body 4 and is constantly operated by the elastic force of a spring 24 provided between the valve body 1 and the valve operating rod 19.
Valve body 25 biased in the direction 8 and the valve plunger 1
The first valve seat 26 formed at the right end of the valve body 8 and the valve body 4
And a second valve seat 27 formed on the. The control valve 23 communicates the constant pressure chamber 9 with the variable pressure chamber 10 while the valve element 25 is seated on the first valve seat 26 and separated from the second valve seat 27, and also connects the variable pressure chamber 10 and the atmosphere. When the valve body 25 is separated from the first valve seat 26 and seated on the second valve seat 27 so that the communication is cut off, the constant pressure chamber 9 and the variable pressure chamber 1
Switching control is performed so that the communication with 0 is cut off and the variable pressure chamber 10 is communicated with the atmosphere.

The recessed portion 11 of the valve body 4 is provided with a large-diameter portion on the right end of the output shaft 28, and the concave portion formed on the large-diameter portion on the right end slides on the protruding portion 4a of the valve body 4. It is fitted freely. A reaction disc 29 is housed in the recess of the large diameter portion at the right end between the protrusion 4 a of the valve body 4 and the output shaft 28. A predetermined gap is set between the valve plunger 18 and the reaction disc 29.

The output shaft 28 is prevented from coming out of the valve body 4 by a retainer 31 which is urged to the right by a return spring 30 which returns the valve body 4 to the inoperative position. In addition, the left end portion of the output shaft 28 is the seal member 3
It is supported airtightly and slidably by 2 and projects outward from the front shell 2, and its left end is interlocked with a piston of a master cylinder (not shown) attached to the front shell 2.

The valve body 4 and the respective power pistons 8 connected thereto are normally held in the illustrated inoperative position by a return spring 30. In this non-operating state, the key member 21 is in contact with the inner surface of the rear shell 3 to restrict the rightward movement of the valve plunger 18 and hold the valve plunger 18 at the retracted limit position. When the valve operating rod 19 is not operated, the key member 21 is in a position advanced with respect to the valve body 4, and at this time, the valve body 25 is seated on the first valve seat 26 and the second valve seat 27. And a small gap is maintained, and the variable pressure chamber 10 communicates with the constant pressure chamber 9.

The constant pressure chamber 9 communicates with, for example, an intake manifold of an engine (not shown) via a negative pressure introducing pipe 33 attached to the front shell 2. Therefore, a negative pressure is always introduced into the constant pressure chamber 9.

The rear end portion of the valve operating rod 19 slidably enters the inside of a cylinder 34 mounted at a predetermined position of the vehicle body, and the rear end portion of the valve operating rod 19 inside the cylinder 34 is in the middle thereof. A first piston 35 is formed on the. The first piston 35 is fluid-tightly slidable with respect to the inner peripheral surface of the cylinder 34. Further, a pedal rod (corresponding to a second rod of the present invention) 36 whose rear end is connected to a brake pedal (not shown) is disposed coaxially with the valve operating rod 19, and its front end portion is the cylinder 3
It has slidably entered the inside of 4. The valve operating rod 19 and the pedal rod 36 constitute the input shaft of the negative pressure booster 1.

A second piston 37 is formed at the front end of the pedal rod 36 in the cylinder 34. The second piston 37 has a diameter equal to that of the first piston 35, and the inner surface of the cylinder 34 is the same. And can slide in a liquid-tight manner. A hydraulic chamber 38 is defined between the first and second pistons 35, 37 inside the cylinder 34. Therefore, the pressure receiving areas of the first piston 35 and the second piston 37 that receive the hydraulic pressure of the hydraulic chamber 38 are set to be equal. The first piston 35 is constantly urged rearward by a return spring 39 arranged in the cylinder 34, and in the brake inoperative state shown in the figure, the second piston 37 contacts the inner surface of the cylinder 34 and further rearward. Is blocked, and the rear end 19a of the valve operating rod 19 comes into contact with the second piston 37 to block further rearward movement.

The hydraulic chamber 38 in the cylinder 34 is connected to an accumulator 41 via a normally closed inlet valve 40, which is an electromagnetic valve, and the accumulator 41 is connected to a pump 42 so that it can be driven by the pump 42. When the inlet valve 40 is open, the pressure of the accumulator 41 is introduced into the hydraulic chamber 38. The hydraulic chamber 38 is connected to the reservoir 45 via a normally open outlet valve 43 and a check valve 44 which are electromagnetic valves. When the outlet valve 43 is open, the hydraulic fluid in the hydraulic chamber 38 is stored in the reservoir. It is designed to be discharged to 45. And the pump 42 is the reservoir 4
The hydraulic fluid in 5 is supplied to the accumulator 41 to accumulate the pressure in the accumulator 41.

These inlet valve 40 and outlet valve 43 are
When the automatic brake operating condition is satisfied, the controller (not shown) controls the inlet valve 40 to open and the outlet valve 43 to close. The pump 42 is also driven and controlled by the controller when the pressure of the accumulator 41 becomes lower than a predetermined value.

Next, the operation of the first embodiment will be described. When the brake booster is in the illustrated non-actuated position, the valve element 25 of the control valve 23 is seated on the first valve seat 26 and maintains a slight clearance from the second valve seat. Further, the inlet valve 40 is closed and the outlet valve 43 is closed.
2 is open, no hydraulic pressure is introduced into the hydraulic chamber 38, and the rear end 19a of the valve operating rod 19 is in contact with the second piston 37 as shown in FIG. There is.

First, the operation of the normal brake will be described. When the brake pedal is depressed during normal braking, as shown in FIG.
And the valve operating rod 19 advances toward the valve body 4. At this time, since there is no gap between the pedal rod 36 and the valve operating rod 19, the pedal stroke is transmitted to the valve operating rod 19 without causing a loss stroke. As the valve operating rod 19 advances, the valve plunger 18 moves to the key member 21 and the valve body 4.
The valve body 25 of the control valve 23 is seated on the second valve seat 27, and the valve body 25 moves from the valve body 25 to the first valve seat 26.
, The vacuum valve closes and the atmospheric valve opens. As a result, the air at atmospheric pressure allows the fifth hole 16, the gap between the valve body 25 and the first valve seat 26, the passage 14 of the third hole 14 and the second hole 13.
It flows into the variable pressure chamber 10 through a and the passage 22.

Since the power piston 8 is actuated by the air flowing into the variable pressure chamber 10 and the valve body 4 is moved forward, the brake booster 1 produces an output from the output shaft 28 to actuate the piston of the master cylinder. . This allows
The brake normally operates. When the valve body 25 is seated on the first valve seat 26 and the atmospheric valve is closed, air does not flow into the variable pressure chamber 10 and the forward movement of the valve body 4 is stopped. In this way, the brake booster 1 comes to generate the output boosted by the predetermined servo ratio according to the input. In that case,
The valve body 4, the power piston 8 and the control valve 23 constitute the boosting mechanism of the present invention.

When the brake pedal is released to release the brake normally, the pedal rod 36 retracts and the valve operating rod 19 retracts. This causes the valve plunger 18 to retract relative to the valve body 4 until the key member 21 abuts the rear surface of the hole 20. Due to the backward movement of the valve plunger 18, the valve body 25 is separated from the second valve seat 27 and the vacuum valve is opened, so that the air introduced into the variable pressure chamber 10 passes through the passage 22, the valve body 25 and the second valve seat 27. Gap, passage 1
7, it flows out through the constant pressure chamber 9 and the negative pressure introducing pipe 33, and the pressure in the variable pressure chamber 10 decreases. Thereby, the return spring 30
The valve body 4 and the power piston 8 are both retracted by the elastic force of, and the brake is weakened. 1 and 2 in which the second piston 37 comes into contact with the inner surface of the cylinder 4 and the rear end 19a of the valve operating rod 19 comes into contact with the second piston 37 to stop the backward movement of these rods 19, 36.
The non-operating state shown in FIG.

Next, the operation of the automatic brake will be described. When the predetermined operating condition of the automatic brake is reached, the controller opens the inlet valve 40 and closes the outlet valve 43.
As a result, the hydraulic fluid in the accumulator 41 is introduced into the hydraulic chamber 38, and the pressure in the hydraulic chamber 38 rises. As the pressure inside the hydraulic chamber 38 rises, the first piston 35 and the valve operating rod 19 move forward as shown in FIG. 2 (c). At this time, since the pressure in the hydraulic chamber 38 acts on the second piston 37 in the backward direction, the second piston 37 and the pedal rod 36 do not move forward. That is, the brake pedal never strokes. Further, a predetermined gap β is formed between the rear end 19 a of the valve operating rod 19 and the second piston 37. As the valve operating rod 19 moves forward, the negative pressure booster operates and outputs as in the normal brake described above. As a result, the automatic brake operates.

When the pressure in the hydraulic chamber 38 reaches a pressure controlled by the controller, the controller controls the inlet valve 40
Is closed, the valve actuation rod 19 stops.
At this time, the hydraulic chamber 38 and the conduits from the hydraulic chamber 38 to the inlet valve 40 and the outlet valve 43 are in a sealed state. Further, the output of the negative pressure booster is an output boosted at a predetermined boost ratio corresponding to the stroke amount of the valve operating rod 19 controlled by the controller. Although not shown, the hydraulic pressure in the hydraulic chamber 38 is detected by a well-known pressure detecting means such as a pressure sensor or a pressure switch and sent to the controller.

When the automatic brake operating condition is canceled in the automatic brake operating state, a release control signal is output from the controller and the outlet valve 43 is opened. Therefore, the hydraulic fluid in the hydraulic chamber 38 is discharged to the reservoir 45, and the pressure in the hydraulic chamber 38 drops. As a result, the valve operating rod 19 retracts, so that the automatic brake is released in the same manner as the above-mentioned normal brake. When the valve operating rod 19 comes into contact with the second piston 37, the retreat of the valve operating rod 19 is stopped and the valve operating rod 19 is brought into the inoperative state shown in the figure.

Since the brake pedal does not move during the operation of the automatic brake, even if the driver's foot is under the brake pedal when the brake is not operated, the foot is caught between the brake pedal and the vehicle body. There is no such thing.

Next, during the normal brake operation by the driver depressing the brake pedal, when the automatic brake operation condition is satisfied, the inlet valve 40 is opened and the outlet valve 43 is closed by the controller in the hydraulic chamber 38 as described above. The hydraulic pressure of the accumulator 41 is introduced.

Therefore, in this case, first, as shown in FIG. 2 (b), the pedal rod 36 and the valve operating rod 19 are advanced toward the valve body 4 by depressing the brake pedal, as in the normal brake operation described above. The pressure booster 1 outputs and the normal brake operates.

Further, as the hydraulic pressure in the hydraulic chamber 38 rises, only the valve operating rod 19 further advances as shown in FIG. As a result, the automatic brake operates. When the hydraulic pressure in the hydraulic chamber 38 reaches a pressure controlled by the controller, the inlet valve 40 is closed, the hydraulic chamber 38 is maintained at the control pressure, and the valve operating rod 19 is stopped. In this way, the braking force by the automatic braking is added to the braking force by the normal brake,
The overall braking force is increased.

When the automatic brake operating condition is eliminated, the outlet valve 43 is opened, the hydraulic fluid in the hydraulic chamber 38 is discharged to the reservoir 45, and the hydraulic pressure in the hydraulic chamber 38 drops to the atmospheric pressure, as described above. . As a result, the valve operating rod 19 retracts, and when the rear end 19a thereof comes into contact with the second piston 37,
The valve operating rod 19 is stopped, and only the normal brake operation shown in FIG.

Further, when the depression of the brake pedal is released, the brake is deactivated as described above. When the brake pedal is released and the normal brake is released from the state in which both the normal brake and the automatic brake shown in FIG. 2D are operating, the second piston 3 is released.
7 and pedal rod 36 retract. Therefore, the hydraulic pressure in the hydraulic chamber 38 decreases, but when the decrease in the hydraulic pressure in the hydraulic chamber 38 is detected, the controller opens the inlet valve 40 to further introduce the hydraulic pressure in the accumulator 41 into the hydraulic chamber 38. To be done. As a result, the hydraulic pressure in the hydraulic chamber 38 rises, and when the hydraulic pressure in the hydraulic chamber 38 reaches the control pressure, the inlet valve 40 is closed again by the controller. Thus, the hydraulic chamber 38 is maintained at the control pressure and the automatic brake is maintained in the activated state. In this way, even when the normal brake is being operated, when the automatic brake operating condition is satisfied, the automatic braking is surely operated.

Next, when the driver depresses the brake pedal in order to further increase the braking force during the automatic braking operation, the pedal rod 36 advances.

Therefore, in this case, since the automatic brake operation condition is first established, the inlet valve 40 is opened and the outlet valve 43 is closed by the controller as described above, and the hydraulic pressure of the accumulator 41 is introduced into the hydraulic chamber 38. Is
The valve operating rod 19 moves forward as shown in FIG. As a result, the negative pressure booster 1 outputs and the automatic brake operates. As described above, when the automatic brake is operated, a predetermined gap β is formed between the rear end 19a of the valve operating rod 19 and the second piston 37.

By further depressing the brake pedal, as shown in FIG.
As shown in (d), the pedal rod 36 and the second piston 37 move forward. At this time, the diameters of the first and second pistons 35 and 37 are equal, and the inlet valve 40 and the outlet valve 43 are both closed, so that the hydraulic chamber 38 and the conduit extending from the hydraulic chamber 38 to the inlet valve 40 and the outlet valve 43. Is sealed and the working fluid is an incompressible fluid, the hydraulic chamber 38
Of the second piston 37 and the volume of the conduit extending to the inlet valve 40 and the outlet valve 43 are kept constant, the second piston 37 moves forward, and at the same time, the first piston 35 holds the gap β while the second piston 37 moves. While moving forward by the same amount as the amount of forward movement, the brake pedal moves without loss stroke. By the forward movement of the first piston 35, the valve operating rod 19 moves forward by the same amount, and the negative pressure booster outputs to operate the normal brake. In this way, the braking force of the normal braking is further added to the braking force of the automatic braking, and the total braking force is increased.

When the brake pedal is released and the normal brake is released, the first and second pistons 35 and 3 are released.
No. 7 moves backward while maintaining the gap β, as shown in FIG.
Only the automatic brake shown in (c) is activated. Furthermore,
When the automatic brake operation condition is canceled, the automatic brake is released in the same manner as described above, and the brake non-operation state shown in FIG. In addition, when both the automatic brake and the normal brake shown in FIG. 2D are in operation and the automatic brake operation condition is canceled and the automatic brake is released, the first brake
Only the piston 35 retracts, and the rear end 1 of the valve operation 19
9a comes into contact with the second piston 37, and only the normal brake shown in FIG. 2B is activated. Further, when the brake pedal is released, the brake operating state shown in FIG.

Thus, even during the automatic braking operation, the normal brake can be reliably operated and the braking force can be increased by depressing the brake pedal. Also, when the driver depresses the brake pedal during automatic braking, the brake pedal moves without loss stroke, so there is almost no difference from the pedal feeling when the pedal feeling is only the normal brake, and a good pedal Feeling is obtained, and the driver can operate the brakes with peace of mind. Furthermore,
Even if the hydraulic circuit of the automatic brake fails due to a failure of the pump 42, the inlet valve 40, the outlet valve 43, or the like, the normal brake can be reliably performed by depressing the brake pedal, so the brake can be safely and reliably applied to the vehicle. Can be activated.

FIG. 3 is a view similar to FIG. 1 showing a second embodiment of the present invention. The same components as those in the first embodiment described above are designated by the same reference numerals, and detailed description thereof will be omitted. In that case, in the first embodiment, the pedal rod 36 connected to the brake pedal and the valve operating rod 19 are separately configured, but in the second embodiment, these rods are integrally configured. For convenience, the valve actuating rod 19 is shown.

In the first embodiment, a device for automatic braking such as the cylinder 34 is provided on the input side of the negative pressure booster, but in the second embodiment, the cylinder 34 is used as shown in FIG. A device for automatic braking such as is provided on the output side of the negative pressure booster.

That is, the front end of the output shaft 28 is inserted into the cylinder 34, and the second piston 37 capable of sliding in a liquid-tight manner on the inner peripheral surface of the cylinder 34 is provided at the front end. Further, a piston operating rod that operates the piston of the master cylinder (corresponding to the first rod of the present invention)
A rear end portion of the cylinder 46 enters the cylinder 34, and a rear end portion of the cylinder 34 is provided with a first piston 35 capable of sliding in an inner peripheral surface of the cylinder 34 in a liquid-tight manner. Therefore, in the second embodiment, the output shaft of the negative pressure booster 1 is composed of the output shaft (corresponding to the first rod of the present invention) 28 and the piston operating rod 46.

The return spring 39 constantly urges the piston operating rod 46 rearward, and the rear end of the piston operating rod 46 contacts the second piston 37 when the automatic brake ratio is activated. Further, in the cylinder 34 between the first and second pistons 35, 37, a hydraulic chamber 38 for automatic braking is provided.
Are formed. The state of each component when the brake is not operated, and other configurations such as a hydraulic circuit for automatic braking are the same as those in the first embodiment.

Next, the operation of the second embodiment thus constructed will be described. In normal braking,
When the brake pedal is depressed, the valve operating rod 19 advances. As a result, the negative pressure booster operates in the same manner as in the first embodiment described above, and the output shaft 28 advances due to the output obtained by boosting the input at the predetermined servo ratio. Along with this, the second piston 37, the first piston 35, and the piston operating rod 46 move forward, the master cylinder generates brake pressure, and the normal brake operates. Further, when the brake pedal is released, the negative pressure booster 1 returns to the non-actuated state, and the second piston 37, the first piston 35 and the piston actuating rod 46 move backward as in the first embodiment. Further, the piston of the master cylinder returns to the non-operating position, and the normal brake is released.

In the automatic brake operation, the automatic brake operation condition is established, the hydraulic pressure of the accumulator 41 is introduced into the hydraulic pressure chamber 38 of the cylinder 34, and the first piston 35 is moved in the same manner as in the first embodiment. Therefore, the description thereof will be omitted. Since the piston operating rod 46 moves forward with the forward movement of the first piston 35, the master cylinder generates a brake pressure and the automatic brake operates. When the hydraulic pressure chamber 38 reaches the control pressure, the piston actuation rod 46 stops, and the braking force of the automatic brake becomes a predetermined magnitude controlled by the controller. In the second embodiment, unlike the first embodiment, the automatic braking is not performed by the output of the negative pressure booster 1, but is operated by the hydraulic pressure introduced into the hydraulic chamber 38. Further, the automatic brake operation condition is canceled, the hydraulic fluid in the hydraulic chamber 38 of the cylinder 34 is discharged to the reservoir 45, and the first piston 35 is retracted, which is exactly the same as in the first embodiment. Is omitted. Since the piston operating rod 46 retracts as the first piston 35 retracts, the master cylinder is deactivated and the automatic brake is released.

Next, when the operating condition of the automatic brake is established during the normal brake operation, the hydraulic pressure of the accumulator 41 is introduced into the hydraulic pressure chamber 38 as described above. Therefore, in this case, first, the negative pressure booster 1 outputs by depressing the brake pedal, and the output shaft 28 and the piston operating rod 46 are output.
2 move forward together, that is, the pedal rod 36 is connected to the output shaft 28 in FIG.
9 is replaced by the piston operating rod 46 (hereinafter, in the description of the second embodiment, FIG.
In quoting (d), the description will be made by substituting in the same manner, and these rods will be indicated by reference numerals in parentheses in FIGS. 2 (a) to (d)). As a result, the brake normally operates.

Further, as the hydraulic pressure in the hydraulic chamber 38 rises, only the piston operating rod 49 moves further forward in FIG. 2 (d), and the master cylinder generates the brake pressure, as in the automatic braking operation described above. As a result, the automatic brake operates. When the hydraulic pressure in the hydraulic chamber 38 reaches the control pressure, the valve operating rod 19 stops. In this way, the braking force by the automatic brake is further added to the braking force by the normal brake, and the total braking force is increased.

When the automatic brake operating condition is canceled, the hydraulic fluid in the hydraulic chamber 38 is discharged to the reservoir 45, the valve operating rod 19 is retracted, and the normal brake operating shown in FIG. It becomes a state of only. Further, when the depression of the brake pedal is released, the brake is deactivated as described above. Further, when the brake pedal is released and the normal brake is released from the state in which both the normal brake and the automatic brake shown in FIG. 2D are operating, the automatic brake is performed in the same manner as in the first embodiment. Are kept active. Thus, also in the second embodiment, when the automatic brake operating condition is satisfied during the normal brake operation, the automatic brake operates reliably.

Next, when the driver depresses the brake pedal in order to further increase the braking force during the automatic braking operation, the valve operating rod 19 advances. Therefore, in this case, the hydraulic pressure of the accumulator 41 is first introduced into the hydraulic pressure chamber 38 during the automatic braking operation, as shown in FIG.
The piston operating rod 46 shown in (c) is in the advanced state, and the automatic brake operates in the same manner as described above. During this automatic braking operation, the rear end 4 of the piston operating rod 46 is
A predetermined gap β is formed between 6a and the second piston 37.

By further depressing the brake pedal, as shown in FIG.
As shown in (d), the output shaft 28 and the second piston 37
Moves forward. At this time, similarly to the first embodiment, the second piston 37 moves forward, and at the same time, the first piston 35 also has the gap β.
Is held and moves forward by the same amount as the forward stroke of the second piston 37, and the brake pedal moves without loss stroke. As the first piston 35 moves forward, the piston operating rod 46 moves forward by the same amount and the normal brake operates. In this way, the braking force of the normal braking is further added to the braking force of the automatic braking, and the total braking force is increased.

When the brake pedal is released and the normal brake is released, the first and second pistons 35 and 3 are released.
No. 7 moves backward while maintaining the gap β, as shown in FIG.
Only the automatic brake shown in (c) is activated. Furthermore,
When the automatic brake operation condition is canceled, the automatic brake is released in the same manner as described above, and the brake non-operation state shown in FIG. In addition, when both the automatic brake and the normal brake shown in FIG. 2D are in operation and the automatic brake operation condition is canceled and the automatic brake is released, the first brake
Only the piston 35 retracts, and the piston operating rod 46
The rear end 46a contacts the second piston 37, and
Only the normal brakes shown in are activated. Further, when the brake pedal is released, the brake operating state shown in FIG.

In this way, also in the second embodiment, the normal brake can be reliably operated and the braking force can be increased during the automatic braking operation. The second
The other operational effects of the embodiment are the same as the operational effects of the first embodiment, so the description thereof will be omitted.

In each of the above-described embodiments, the diameters of the first and second pistons are set equal, but if the hydraulic chamber can be set to a closed space, the pistons of the first and second pistons can be set. The diameters can also be different from each other.
In this case, the cylinder 34 is formed as a stepped cylinder having different diameters and the movement amounts of the first and second pistons are different, but the brake pedal moves without loss stroke.

In each of the above-described embodiments, the present invention is applied to the negative pressure booster, but the present invention is not limited to the negative pressure booster, but is also applicable to other hydraulic boosters. It can also be applied to the booster.

[0064]

As is apparent from the above description, according to the brake booster having the automatic brake device of the present invention, when the normal brake is operated by the operation of the brake operating member during the automatic brake operation, Since the input shaft or output shaft can move forward relative to the shaft moving member that performs automatic braking, the normal brake can be reliably operated even during automatic braking and the braking force Can be larger.
Moreover, when the brake operating member is operated, there is no lost stroke due to automatic brake operation, so the operation feeling of the brake operating member is almost the same as the operation feeling of the brake operating member during normal brake operation. Will be good. This allows the driver to operate the brakes with peace of mind.

On the contrary, when the automatic brake is operated during the normal brake operation, the input shaft or the output shaft can be moved forward by the shaft moving member for performing the automatic brake operation. Can reliably operate the automatic brake and can further increase the braking force. Furthermore, since the brake operating member does not move during the automatic brake operation, it is possible to reliably prevent the driver from being adversely affected by the movement of the brake operating member.

Further, even if the hydraulic circuit of the automatic brake fails, the normal braking can be surely performed by the operation of the brake operating member, so that the brake can be operated safely and surely on the vehicle. .

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing a first embodiment of a brake booster equipped with an automatic brake device according to the present invention.

FIG. 2 is a diagram for explaining the operation of the first and second embodiments.

FIG. 3 is a partial sectional view showing a second embodiment of the present invention.

FIG. 4 is a view schematically showing a brake booster equipped with a conventional automatic braking device.

5 is a diagram showing an automatic brake device of the conventional brake booster shown in FIG.

6 is a diagram showing an operating state of the conventional automatic brake device shown in FIG.

[Explanation of symbols]

1 ... Negative pressure booster, 2 ... Front shell, 3 ... Rear shell, 4 ... Valve body, 6 ... Power piston member, 7 ...
Diaphragm, 8 ... Power piston, 9 ... Constant pressure chamber, 10
… Transformer chamber, 16… Control valve, 17… Passage, 18… Valve plunger, 19… Valve operating rod (part of input shaft), 23
... Control valve, 25 ... Valve body, 26 ... First valve seat, 27 ... Second valve seat, 28 ... Output shaft, 29 ... Reaction disk, 30
... Return spring, 33 ... Negative pressure introducing pipe, 34 ... Cylinder, 35
... first piston, 36 ... pedal rod (other part of input shaft), 37 ... second piston, 38 ... hydraulic chamber, 39 ... return spring, 40 ... inlet valve, 41 ... accumulator, 42 ... pump, 43 ... outlet Valve, 45 ... Reservoir, 46 ... Piston operating rod

─────────────────────────────────────────────────── --Continued from the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B60T 13/00-13/74 B60T 7/12 F15B 15/00-15/28

Claims (4)

(57) [Claims] 1. An input shaft connected to a brake operating member , and actuated by an input from this input shaft to respond to this input.
A booster mechanism that generates a boosting been force Flip, and an output shaft for operating the booster mechanism output to the master cylinder the force generated by, were boosted in response to input of the input shaft output
Wherein the brake booster actuating a master cylinder, the input shaft, a first rod connected to the booster mechanism, at a second rod connected to said brake operating member by
Configured, a cylinder disposed between the first rod and the second rod, a first piston which is slidably disposed in fluid-tight provided in the first rod in the cylinder, the liquid-tight by slidably distribution in provided in the cylinder to a second rod
A second piston you abuts on the first piston is location during non-operation, the first piston and the second piston within the cylinder
A hydraulic chamber which is defined and formed between the emission and control valve for setting the hydraulic pressure chamber with supply and discharge the pre-Symbol pressure hydraulic fluid to the hydraulic pressure chamber in the closed state, controls the control valve A brake booster equipped with an automatic braking device, which is provided with a controller. 2. An input shaft connected to a brake operating member.
And the input from this input shaft activates and responds to this input.
And a booster mechanism that generates a boosted force.
Output that outputs the force generated by the operation of the master cylinder
And an output boosted according to the input of the input shaft.
Brake booster that operates the master cylinder by
Position, the output shaft is connected to a first cylinder connected to the master cylinder.
And a second rod connected to the booster mechanism.
And a cylinder disposed between the first rod and the second rod.
And a liquid provided in the cylinder provided on the first rod.
The densely slidably arranged first piston and the second piston
It is mounted on the lid and is slidably and liquid-tightly arranged in the cylinder.
The second piston that is placed and abuts the first piston when not in operation.
Stone, the first piston and the second piston in the cylinder
And a hydraulic chamber defined between the hydraulic chamber and the
The hydraulic chamber is supplied and discharged while the hydraulic chamber is sealed.
Control valve that is set to the open state and the controller that controls this control valve.
Automatic brake device characterized by being equipped with
Brake booster equipped with. Wherein said first piston of the second piston
The brake booster equipped with the automatic brake device according to claim 1 or 2, wherein the pressure receiving areas on which the pressure hydraulic fluid acts are equal. 4. The brake booster is a vacuum booster according to claim 1, wherein the brake booster is a vacuum booster.
A brake booster equipped with the described automatic braking device.