JPH0415564Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to a vehicle brake device that reduces the operating force of the parking brake.

[Conventional technology]

Conventional brake devices designed to reduce the force required to operate the parking brake include the first type, which operates the service brake at the same time as the parking brake is operated, and the first type which operates the service brake at the same time as the parking brake is operated. There is a second method in which

[Problem that the invention attempts to solve]

By the way, according to the first method described above, since braking is applied twice by the parking brake and the service brake, even if the braking force of the parking brake is insufficient, the driver may leave the vehicle without realizing it. However, if the operating pressure of the service brake leaks while the vehicle is parked for a long period of time, there is a problem that sufficient braking force for parking cannot be obtained.

On the other hand, according to the second method, since the parking brake is operated and the service brake is released at the same time, the purpose of reducing the parking brake operating force cannot be sufficiently achieved, and the vehicle may slip backwards. When I put it away, I had a problem.

This invention attempts to solve these problems.

[Means for solving problems]

In order to solve the above problems, this invention is equipped with a service brake having a braking force retention function and a parking brake.
a detection means for detecting that the parking brake has been operated and outputting a signal; and a detection means for receiving a signal from the detection means during the operation of the service brake, measuring a predetermined time, and sending a signal after the elapse of the predetermined time. The present invention is characterized in that it includes a controller that outputs a signal, and a release means that releases the service brake in response to a signal from the controller.

[Effect]

According to the above configuration, the parking brake is activated while the service brake is in operation, that is, with the shoe being pressed against the drum in the case of a drum brake, and the pad being pressed against the disc in the case of a disc brake. Therefore, the operating force for the parking brake can be reduced.

Furthermore, since the service brake is automatically released after a predetermined period of time (for example, 1 to 3 seconds) has elapsed, the driver will immediately notice that the car will skid backwards if the parking brake's braking force is insufficient. Therefore, sufficient braking force can be provided by increasing the parking brake at this point. In this case, only a small amount of additional force is needed for operation.

〔Example〕

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

FIG. 1 shows a vacuum booster (hereinafter referred to as a booster) for a vehicle brake system according to an embodiment of the present invention.
FIG. 2 is a diagram showing the configuration of the control system.

First, an overview of the booster will be explained based on this diagram. This booster is activated when the brake pedal of a service brake (not shown) is depressed and the input shaft 33
is pushed forward (to the left in the figure), or when air is introduced into the working pressure chamber D and the plunger 28 is pushed forward, the output shaft 22 is pushed forward,
It drives a master cylinder (not shown) connected to the output shaft 22, so that the force applied to the input shaft 33 or plunger 28 is amplified within the booster and transmitted to the output shaft 22. . That is, the booster includes a power piston 4 (this is a piston 6, a piston holder 7,
(consisting of a valve body 8) defines a constant pressure chamber A at the front and an operating pressure chamber B at the rear,
While chamber A is maintained in a vacuum state, when force is applied to input shaft 33 or plunger 28, operating pressure chamber B is
Atmosphere is introduced into the engine, this pressure pushes the power piston 4 forward, and this pressure is transmitted to the output shaft 22 to boost the power.

Further, a space (control chamber) 11 is formed within the power piston 4, and the control chamber 11 also includes the control piston 1.
3 defines a constant pressure chamber C in the front and an operating pressure chamber D in the rear, and while maintaining the chamber C in a vacuum state, the control valve 5 controls the plunger 28 by letting atmospheric air in and out of the chamber D. It is now possible to increase or decrease the braking force of the brakes.

This will be explained in more detail below. In FIG. 1, reference numeral 1 denotes a booster body surrounded by a front shell 2 and a rear shell 3. Inside this body 1, a power piston 4 is moved forward and backward by a diaphragm 5 held between the shells 2 and 3. The power piston 4 is supported so as to be movable in its direction, and has a first constant pressure chamber A in front of the power piston 4 and a first working pressure chamber B in the rear thereof. The power piston 4 consists of a piston 6 fixed to a diaphragm 5, a piston holder 7 forming the front part of the power piston 4, and a valve body 8 forming the rear part. A control chamber 11 is formed therebetween. Inside this control chamber 11, a control piston 13 is supported so as to be movable in the longitudinal direction by a diaphragm 12 held between a piston holder 7 and a valve body 8, and a second constant pressure chamber C is provided in front of the control piston 13. , a second working pressure chamber D is defined at the rear.

Further, the piston holder 7 has constant pressure chambers A and C.
A communication hole 16 is formed to communicate with the
A pipe-shaped protrusion 17 is formed that protrudes forward, and a passage 18 within the protrusion 17 is connected to the valve body 8.
It communicates with the working pressure chamber D via a passage 19 formed in the . Further, a stepped hole 20 is formed in the center of the piston holder 7, and a flange 23 formed at the rear end of the output shaft 22 is formed in the large diameter portion of the entire stepped hole 20. It is inserted.
A recess 24 is formed in the flange 23, and a reaction disk 21 made of an elastic member such as rubber is fitted into the recess 24.

On the other hand, the rear end portion of the valve body 8 protrudes rearward from the rear shell 3, and the seal member 25
It is supported by the rear shell 3 via the front and rear shells so as to be movable in the front-rear direction. In the center of this valve body 8,
A stepped through hole is formed coaxially with the output shaft 22 and includes a large diameter valve hole 26 and a small diameter cylinder hole 27.

A plunger 28 whose outer periphery is fitted with a sealing 29 is slidably inserted into the cylinder hole 27 . A stepped portion is formed at the front of the plunger 28, and the rear stepped portion is inserted and fixed into each center hole of the control diaphragm 12, control piston 13, and fixing member 30, while
The smallest diameter portion of the front end is slidably fitted into the small diameter portion of the stepped hole 20 of the piston holder 7. In this way, the control piston 13 is connected to the plunger 2.
8, and presses and drives the output shaft 22 forward via the reaction disk 21.

A recess 32 is formed at the rear end of the plunger 28, and a spherical part 3 is formed at the tip of the input shaft 33.
4 is fitted into the input shaft 33, and a brake pedal (not shown) is connected to the rear end of the input shaft 33. and,
When the brake pedal is depressed, the input shaft 33 is pushed forward, and the plunger 28 moves forward. At this time, the valve seat 36 formed at the rear end of the plunger 28 separates from the poppet valve 37, and the atmosphere flowing in from the rear of the poppet valve 37 flows into the working pressure chamber B through the passage 43, pushing the power piston 4 forward. A boosting effect is performed.

On the other hand, when the brake pedal is released, the plunger 28 moves rearward due to the reaction force from the output shaft 22, and the valve seat 36 comes into contact with the poppet valve 37. 27) is separated from the poppet valve 37.
One end of the passage 42 formed in the piston holder 7 and the valve body 8 is opened, and the passages 42, 43 are opened.
The constant pressure chamber A and the working pressure chamber B are communicated through the constant pressure chamber A and the working pressure chamber B. As a result, the pressures in both chambers A and B become equal, and the power piston 4 moves rearward. The poppet valve 37 is formed with a spring receiver, and a spring 39 inserted between the poppet valve 37 and a spring receiver 38 provided on the input shaft 33 urges the poppet valve 37 forward. When not operating, valve seat 3
5 and 36 are in contact with the poppet valve 37, and the operating pressure chamber B is in a sealed state. Note that the boosting effect described above is performed in exactly the same way when air is introduced into the working pressure chamber D and the plunger 28 moves forward.

Next, the front shell 2 has a connection port 48 communicating with the constant pressure chamber A and a connection port 4 communicating with the passage 18.
9, and the connection port 49 and the passage 18 are isolated from the constant pressure chamber A by a retractable seal member 50. The connection port 48 is connected to a vacuum source, while the connection port 49 is connected to a control valve (release means) 51. This control valve 51 switches the communication destination of the connection port 49 under the control of the controller 52.
The connection port 49 is communicated with a vacuum source or with the atmosphere via an electromagnetic valve or a throttle valve (not shown). As a result, the working pressure chamber D has passages 18 and 19.
Air is supplied or removed through the control piston 13, and the control piston 13 is moved in the front and back direction.
The plunger 28 is moved back and forth.

Next, input signals such as a vehicle speed signal E, an accelerator state signal F, and a vehicle weight detection signal G are supplied to the controller 52, and a parking brake switch (detection means) that is turned off when the parking brake is not activated and turned on when the parking brake is activated ) 53 are connected.

In FIG. 1, 45 is a silencer, 44 is an air cleaner, 46 is a gap that exists between the rear surface of the reaction disk 21 and the front surface of the plunger 28 when the booster is not in operation, and 47 is a space for attaching the power piston 4 to the rear. It is a return spring that exerts force.

Next, an embodiment of the present invention will be described with reference to the flowchart shown in FIG.

At step SP1 in FIG. 2, when predetermined conditions for stopping the vehicle are met, such as the vehicle speed being 0.6 km or less and the accelerator being released, the controller 52 checks whether the parking brake switch 53 is off ( step SP2), and if it is on, loop L1 consisting of steps SP1 and SP2 is circulated. On the other hand, if it is off, the control valve 51 is operated to supply atmospheric air to the working pressure chamber D, and braking by the service brake is executed. That is, when the atmosphere is supplied to the working pressure chamber D and the plunger 28 is moved forward, the valve seat 36 separates from the poppet valve 37, and the atmosphere flows into the working pressure chamber B, pushing the power piston 4 forward, which causes the output shaft to move forward. 2
2, and braking is performed. In this way, the vehicle remains stationary.

Then, the controller 52 performs step SP4,
SP5 detects the next operation the driver takes,
If the driver performs a starting operation such as depressing the accelerator again (step SP4), the step described below will be executed.
Release the service brake at SP7.

On the other hand, when the driver applies the parking brake and the parking brake switch 53 is turned on (step SP5), the controller 52 receives this on signal and measures a predetermined time T (step SP6). After T has elapsed, proceed to step SP7 and release the service brake.
That is, the controller 52 outputs a signal to the control valve 51 to control it, connects the working pressure chamber D to a vacuum source, and removes the air in this chamber D. With this, the control piston 13,
The plunger 28 moves rearward, and the valve seat 36 comes into contact with the poppet valve 37, while the valve seat 35 separates from the poppet valve 37, and the working pressure chamber B communicates with the constant pressure chamber A through the passages 43 and 42, and the power piston 4 Then, the output shaft 22 returns to the non-operating position shown in FIG. 1 and the service brake is released. When the release is completed, the controller 52 cycles through a loop L3 consisting of steps SP1 to SP7 and waits for the driver's next operation. In addition, in step SP5, the parking brake switch 5
3 is off, the controller 52 cycles through a loop L2 consisting of steps SP3 to SP5,
Detects starting motion or parking brake operation.

According to this embodiment, for the reasons already described in the [Operation] section, the operating force of the parking brake can be reduced and sufficient braking by the parking brake can be achieved.

Note that this example is an example in which the steady pressure is a vacuum and the operating pressure is atmospheric pressure, which is applied to a vacuum booster.
The operating pressure may be negative pressure. Further, the present invention is applicable to all so-called braking force holding devices, such as a type that closes the brake hydraulic piping and a type that holds the brake pedal in the depressed position. When applied to conventional automatic brakes that have such a braking force retention function, the above-mentioned functions and effects can be achieved by simply changing part of the control circuit, so the cost increase is minimal. It's over. In particular, if the control circuit uses a microprocessor, only the program needs to be changed, so the cost increase can be ignored.

[Effect of idea]

As explained above, in this invention, the service brake is released after a predetermined period of time after the parking brake is operated, so it is possible to reduce the operating force of the parking brake and to obtain sufficient braking force of the parking brake. be able to.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the configuration of a vacuum booster (booster) for a vehicle brake system and its control system according to an embodiment of the present invention, and Fig. 2 is a flowchart for explaining the operation of the embodiment. be. 51...Control valve (release means), 5
2...Controller, 53...Parking brake switch (detection means).

Claims (1)

[Scope of claim for utility model registration] A service brake with a braking force retention function,
A vehicle brake device comprising a parking brake, comprising: a detection means for detecting that the parking brake has been operated and outputting a signal; and a detection means for detecting that the parking brake has been operated and outputting a signal, A vehicle brake device comprising: a controller that measures a predetermined time and outputs a signal after the elapse of the predetermined time; and a release means that releases the service brake in response to a signal from the controller.