JPH0653486B2 - Breaking device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention is provided on a vehicle or the like, and is capable of automatically retaining and releasing brake fluid pressure at the time of stopping and starting on an uphill road so that it can be used on The present invention relates to a brake device that realizes the safety of starting the vehicle and the ease of operation, and in particular, holds and releases the brake fluid pressure in accordance with a change in the direction of action of the friction force acting on the brake friction material in the wheel brake device. It relates to a braking device that is supposed to perform.

(Prior Art) As for this type, the applicant of the present invention has a Japanese Patent Application No. 60-105.
No. 500 (Japanese Patent Laid-Open No. 61-263858) or Japanese Patent Application No. 60-131544 (Japanese Patent Laid-Open No. 61-291255).
No.), a pressure generating device having two pressure chambers for independently generating brake pressure, such as a tandem master cylinder, and a different wheel such as a front wheel and a rear wheel. At least two wheel brake devices that press the brake friction material against the brake friction surface that rotates with the wheels by the operation of the wheel cylinders, and the wheel cylinders of the two wheel brake devices and the two pressure chambers are independently connected 2 Of the two piping systems, a solenoid valve device provided in one of the two piping systems and capable of holding the pressure on the wheel cylinder side in accordance with a command, and a friction force between the brake friction material and the brake friction surface in the wheel braking device. There is a switch provided with a switch configured to detect the change in the action direction and issue the command.

The effects of this technique are as follows. It is assumed that the brakes are applied to stop the vehicle on the way up the slope.
The brake acts to stop the forward movement of the vehicle until the vehicle is completely stopped. However, once the vehicle has come to a complete stop, the brakes then act to prevent the vehicle from rolling backwards on the slope. Therefore, in the wheel brake device, a phenomenon occurs in which the action direction of the frictional force between the brake friction material and the brake friction surface changes. Therefore, by utilizing this phenomenon, when the change is detected, the solenoid valve is actuated to maintain the brake fluid pressure, whereby the backward movement of the vehicle on the uphill road can be effectively prevented. On the other hand, when the driving force of the engine is transmitted to the wheels at the time of starting the vehicle, the brake by the holding hydraulic pressure acts in the direction in which the forward movement of the vehicle is hindered. Therefore, the action direction of the frictional force in the wheel brake device changes again. When this change is detected and the solenoid valve is deactivated, the retained hydraulic pressure is released, and the vehicle can start on an uphill road.

As described above, the brake fluid pressure is held and released by opening and closing the solenoid valve by the forward and reverse brakes acting on the wheels themselves or the acting force of the engine driving force, so it is better to start on an uphill road. There is an advantage that it can be performed stably. When applying the technology with such advantages to the general two-system piping system, the vehicle is not fully retracted on the uphill road by providing only one piping system without providing the solenoid valve for both systems. Can be Therefore, an electromagnetic valve is provided only in one system, and a wheel brake device belonging to the system in which this electromagnetic valve is provided is further provided with a switch for detecting a change in the acting direction of the frictional force.

(Problems to be Solved by the Invention) In the technique described above, a change in the direction of action of the frictional force in the wheel brake device must be detected both when the vehicle is stopped and when the vehicle is started. Therefore, the wheel brake device provided with the switch must be connected to a system that holds the brake fluid pressure by the solenoid valve. As a result, the switch is switched while the brake is being applied by the holding hydraulic pressure, and when the switch is switched,
There is a problem that a large load acts on a member for switching the switch and durability is deteriorated.

That is, in the previously proposed one, the switch itself is fixedly provided in the wheel brake device, but a friction material such as a pad for a disc brake and a shoe for a drum brake is integrated as a member for activating the switch. Associated members that support the pad or shoe, since the members are used to move the frictional force in the acting direction in accordance with the change in the acting direction of the frictional force, and the switch is switched by the movement of the pad or shoe. Will be damaged in a short period of time. Especially if you make the pad or shoe strong,
Prying of the piston of the wheel cylinder that presses them, damage to the sealing member, and damage to the shims in the disc brakes can cause extremely serious problems.

Therefore, it is an object of the present invention to provide a brake device in which damage of each related member is prevented and durability is improved when the switch is operated.

(Points of view of the invention) In order to properly maintain and release the brake fluid pressure on an uphill road, it is first important to correctly detect each stop and start time on the uphill road. As such detection means, A. In addition to the method of detecting a change in the action direction of the frictional force of the brake friction material (for example, Japanese Patent Laid-Open No. 61-119458), B.I. A method for detecting a change in stress of a brake constituent member (for example, micro film of Japanese Utility Model Application No. 58-18273 (Japanese Utility Model Application No. 59-124761)), and C.I. There is a method of detecting the wheel speed by an electric wheel speed sensor (for example, Japanese Patent Publication No. 50-5452).

However, considering that the principle of braking converts the kinetic energy of the vehicle into heat energy by friction, the method A is a method that is directly connected to the braking operation as compared with the other methods B and C. You can Therefore, the method A detects the brake operation state itself, and the state can be grasped most directly.

However, since the method A detects the displacement of the brake friction material, there is a problem peculiar to the method A that the surroundings of the members related thereto are damaged early. Such damage is
It will be larger when the acting force by the brake fluid pressure is applied. Then, when detecting each of the above-mentioned time points, it suffices that the acting force due to the brake fluid pressure is not applied to the related members that detect the time points.

(Means for Solving the Problems) In the present invention, the switch is provided in the wheel brake device connected to the system of the two piping systems on the side where the solenoid valve is not provided.

(Operation) The vehicle is stopped by applying the brake, and the brake fluid pressure is held in one system by operating the solenoid valve. At this time, in the other system, the brake fluid pressure is released in response to the driver's brake release, and at this time, the member for activating the switch is not acted upon by the brake fluid pressure, so that the vehicle can be started. When switching the switch, a large load is not applied to a member that operates the switch. When using a pad as a member to operate a switch in a disc brake, etc., move the pad slightly in the direction in which the wheels move backward before activating the solenoid valve to activate the switch. After making sure to hold the brake fluid pressure in one system,
The driver releases the brakes. Then, the pad is held by a drag force (which occurs when the disc rotor and the pad are not completely separated) in a position moved by the hydraulic pressure, and the switch is switched by the drag force even at the time of starting. Moved in the direction. On the other hand, when the hydraulic pressure is released like the shoe of the drum brake and the shoe and the drum are completely separated from each other, the switch can be changed only once. Therefore, when a switch is provided on the drum brake, the switch is operated by using the hydraulic pressure held in one system to leave a residual pressure in the other system that presses the shoe and the drum with a small force. It can be switched again. That is, a means for maintaining the shoe, which is a brake friction material, in a sliding contact state with the brake friction surface (drum) even when the brake is not in operation may be provided.

(Embodiment) FIG. 1 is a system diagram showing an embodiment of the present invention, and FIG.
The figure is a diagram showing a specific installation example of the switch.

First, the overall system of the brake device will be described with reference to FIG. In FIG. 1, the braking system is indicated generally by the numeral 10. The brake system 10 has a two-system tandem master cylinder 12, and a brake pedal 14 generates a brake pressure in an independent hydraulic pressure generation chamber inside. One hydraulic pressure generating chamber of the master cylinder 12 is connected to the left front wheel braking device 18L and the right rear wheel braking device 20R through the electromagnetic valve 16, and the other hydraulic pressure generating chamber is connected to the right front wheel braking device 18R and the left hydraulic braking chamber. The rear wheel braking devices 20L are in communication with each other.

The solenoid valve 16 located in the middle of one of the pipes is connected to a power source (not shown) and a switch 22 provided in the right front wheel brake device 18R. Solenoid valve 16 is switch 2
When 2 is closed, it is excited to brake devices 18L and 2L.
The brake fluid pressure on the 0R side is closed so as not to be released to the master cylinder 12 side, while it is demagnetized when the switch 22 is open to allow free communication between both sides. A check valve is provided inside the solenoid valve 16 to allow liquid to move from the master cylinder 12 side to the brake devices 18L and 20R sides even in the excited state.

Each of the braking devices 18L, 20R, 18R, 20L is a disc brake or a drum brake. For example, it is general that the front wheel side is a disc brake and the rear wheel side is a drum brake, or all the front and rear wheels are disc brakes.

Next, an installation example of the switch 22 will be briefly described with reference to FIG. In the illustrated example, the switch 22
The brake device 18R for installing is a disc brake. The disc brake 18R includes a mounting bracket 24 fixed to a vehicle body (not shown) of the vehicle, and a caliper 30 supported by the left and right pin members 26 and 28 with respect to the mounting bracket 24. The caliper 30 has a cylinder portion 32, and the cylinder portion 32 is supplied with hydraulic pressure from the master cylinder 12 through a supply hole 34. When such a hydraulic pressure is supplied, a pair of pads 38 (one of which is not shown), which are arranged opposite to the brake disc 36 and supported by the mounting bracket 24, can be pressed against the disc 36. The pair of pads 38 are mounted on the mounting bracket 24 via the pair of left and right retainers 40 and 42.
A gap 44 is provided between the retainer 42 and the retainer 42, which allows the pad 38 to be displaced in the circumferential direction. The switch 22 having the detector 22a that projects into the gap 44 and comes into contact with the side end of the pad 38 is housed in a hole 46 provided in the mounting bracket 24 and extending in the circumferential direction.

In FIG. 2, the circle indicated by the alternate long and short dash line shows the outer shape of the wheel, the reference F is the forward direction of the vehicle, S is the uphill road surface, and R is the uphill road surface.
Indicates the rotation direction of the wheel when moving forward, and A and B indicate the direction of action of the braking force.

Next, the braking device or system 10 described above
The operation of will be described in each step. The basic operation is the same as that previously proposed.

-Uphill road traveling stage In this case, the brake is not applied and the wheels are rotating in the forward direction R. The pad 38 is the disc 36
The drag force received from the abutment abuts against the mounting bracket 24 via the retainer 40 to secure the gap 44 and open the switch 22 to demagnetize the solenoid valve 16.

-Uphill road stop stage This is a case where the vehicle is stopped by depressing the brake pedal 14 at a signal, a takeoff, or the like. The brake pressure is generated in the master cylinder 12, and accordingly, the brake fluid pressure is supplied to the brake devices 18L, 20R, 18R, 20L through the respective pipes, the brake is applied, and the vehicle stops.

At this time, in the disc brake 18R, the pad 3
8 is pressed against the disk 36. As a result, the pad 38 tries to move in the A direction due to the frictional force between the pad 38 and the disc 36, but since the pad 38 is supported by the mounting bracket 24, the disc 36 is braked in the B direction.

-Brake holding stage When the vehicle is completely stopped, a moving force along the road surface S in the direction opposite to the forward direction F acts on the vehicle due to the slope of the uphill road surface S. Therefore, the wheel rotates in the direction opposite to the forward direction R (B direction), and the disk 36 rotates in the B direction together with the pad 38 (the hydraulic pressure in the master cylinder 12 is not released in this state). By this movement, the pad 38 closes the gap 44 and closes the switch 22. As a result, the solenoid valve 16 is excited and the braking devices 18L and 20R are excited.
Disable side pressure.

Thereafter, when the brake pedal 14 is released and returned to its original state, the hydraulic pressure in the master cylinder 12 is released, and the brake hydraulic pressures in the brake devices 18R and 20L are also released. However, since the brake fluid pressures of the brake devices 18L and 20R are held, the vehicle does not move backward, but remains stopped at that position.

・ Brake release stage When the driving force of the engine is transmitted to the wheels for starting,
The vehicle attempts to move forward against the braking force. Therefore, the wheels try to rotate in the forward direction R, and the disc 36
And the pad 38 move together in the direction A, the gap 44 is secured again, and the switch 22 is opened. This allows
The solenoid valve 16 is demagnetized, the brake fluid pressure of the brake devices 18L, 20R is also released, and the vehicle starts.

In this way, before the brake fluid pressure is released,
The pad 38 secures the switch 22 in the closed state by the dragging force with the disk 36. Therefore, when the switch 22 is moved in the opening direction, the load on the pad 38 and the members provided therewith is extremely small, and damage can be prevented and durability can be improved.

In the embodiment shown in the figure, the pipe is of the X pipe type, and the switch 22 is provided on the disc brake 18R. However, the present invention is not limited to this, and can be implemented in various modes.

For example, an example in which a front and rear system is used as a piping system, a switch is provided on the drum brake, and a solenoid valve is provided on the rear wheel system and a switch is provided on the front wheel disc brake, or an X piping system without a solenoid valve is provided. Examples include a switch provided on the rear wheel drum brake. In particular, when a switch is provided on the drum brake, the contact between the shoe and the drum is completely lost when the brake fluid pressure is completely released, so that the contact between the shoe and the drum is secured and the switch can be switched. It is conceivable to keep the minimum residual pressure by the holding liquid pressure. Such an idea can be applied to disc brakes in some cases.

(Effect of the Invention) According to the present invention, the switch for giving a command to the solenoid valve is
Since a wheel brake device belonging to a system different from the system that holds the hydraulic pressure by providing a solenoid valve is provided, the action force due to the holding hydraulic pressure is lost when switching to issue a command to release the hydraulic pressure. Alternatively, the load on the members that operate the switch at the time of switching the switch can be greatly reduced, and the durability of these members can be greatly improved.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention, and FIG. 2 is a diagram showing a switch installation example. 10 ... Brake system (brake device), 12 ... Master cylinder (pressure generation device), 18R, 18L, 20R, 20L ... Wheel brake device,
16 ... Solenoid valve device, 22 ... Switch.

Claims (1)

[Claims] 1. A pressure generator having two pressure chambers for independently generating a brake pressure, and at least 2 for pressing a brake friction material against a brake friction surface rotating together with the wheel by operating a wheel cylinder provided on different wheels. Wheel brake device, two pipe systems that independently connect the wheel cylinders of the two wheel brake devices and the two pressure chambers, and a wheel cylinder provided in one of the two pipe systems according to a command And a solenoid valve device capable of holding a side pressure, wherein one of the wheel brake devices is made displaceable within a predetermined range in accordance with the direction of action of the friction force between the brake friction material and the brake friction surface. In a brake device provided with a switch for detecting displacement and issuing the command, a wheel brake device provided with the switch is placed in front of Connected to the other of the two piping systems, further, the brake device comprising a means for maintaining the brake friction material of the wheel brake device to sliding contact with the brake friction surface even in the inoperative condition the brake.