JPH069951B2 - 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 holding and releasing brake fluid pressure when stopping and starting on a climbing road so that it can be used on the climbing road. 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 according to 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 to 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 act to prevent the vehicle from rolling back on the uphill road. 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 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 operation of the solenoid valve is released, the retained hydraulic pressure is released, and the vehicle can start on the climbing road.

As described above, the brake fluid pressure is retained 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 easier to start on the uphill road. There is an advantage that it can be performed stably. When applying the technology having such advantages to a general two-system piping system, the vehicle is not sufficiently retracted on the uphill road by providing only one piping system without providing solenoid valves 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 inside the wheel brake device, but as a member for operating this switch, a friction material such as a pad for the disc brake and a shoe for the drum brake is used. Supports the pad or shoe because the members that are integrated are used, and these are made to move in the direction of the friction force following changes in the action direction of the friction force, and the switch is switched by the movement of the pad or shoe. This causes a problem that the member is 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.

As a method of solving such a problem, it is considered that a switch is provided in the wheel brake device connected to the system on the side where the solenoid valve is not provided in the two piping systems.
However, in that case, the brake remains applied when the command to switch the solenoid valve to the holding position is detected, whereas the brake is not applied when the command to switch the solenoid valve to the release position is detected.
In the drum brake, the shoe and the drum are completely separated from each other, which causes a new problem that switching cannot be performed.

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

(Means for Solving Problems) In the present invention, a movable body that moves in accordance with the pressure on the wheel cylinder side of the solenoid valve is provided in a system that does not include the solenoid valve.
A valve position is provided so that the pressure for maintaining the operation of the switch according to the movement of the movable body can be retained as a residual pressure.

(Operation) According to the present invention, since the residual pressure is retained in the system provided with the switch, the pad or the shoe does not separate from the opposing friction surface, and therefore, it responds well to the change in the action direction of the friction force. The switches can be switched, and since the residual pressure is low, the deformation and load of each part are small.

(Embodiment) FIG. 1 is a system diagram showing an embodiment of the present invention as a whole, FIG. 2 is a diagram showing a concrete installation example of a switch, and FIG. Structural examples are shown respectively.

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 two systems of tandem master cylinders 12, and a brake pedal 14 generates a brake pressure in an independent hydraulic pressure generating chamber. One of the hydraulic pressure generating chambers of the master cylinder 12 has a solenoid valve 16
To the left front wheel braking device 18L and the right rear wheel braking device 20R, and the other hydraulic pressure generating chamber is connected to the right front wheel braking device 18R and the left rear wheel braking device 20L, respectively.

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, the front wheel side is a disc brake and the rear wheel side is a drum brake, or all of the front and rear wheels are generally 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 indicates the outer shape of the wheel, the reference F is the forward direction of the vehicle, S is the climbing road surface, and R is the climbing 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.

Now, returning to FIG. 1 again, in the present invention, from the master cylinder 12 to the brake devices 18L, 20R, 18R,
The valve device 50 is provided so as to extend over two independent piping systems to 20L.

This valve device 50 is a feature of the present invention. Therefore, the valve device 50 will be described with reference to FIG.

The valve device 50 has a body 54 having a stepped hole 52 formed therein. The stepped hole 52 opens at the right end of the body 54, and the open end is closed by a plug 56. A piston 58 is movably inserted into the large diameter portion of the stepped hole 54. On the outer periphery of the piston 58, a lip seal 60 is provided on the bottom side of the hole 52, and an O-ring 62 is provided on the plug 56 side. As a result, inside the stepped hole 52, the inlet chamber 66 communicating with the connection hole 64 communicating with the master cylinder 12 from the bottom of the hole 52 toward the opening side.
And an outlet chamber 70 communicating with the connection hole 68 communicating with the brake device 18R, and the brake devices 18L, 2 of the solenoid valve 16.
A control room 74 communicating with the connection hole 72 communicating with the 0R side is divided. The effective pressure receiving areas on both sides of the piston 58, which are determined by the lip seal 60 and the O-ring 62, are equal to each other.

The inlet chamber 66 and the outlet chamber 70 are connected to the T inside the piston 58.
The passages 76 are in communication with each other by a passage 76.
Facing the opening end on the inlet chamber 66 side of the valve seat 7
A valve element 80 is arranged as 8. This valve body 80 is
The piston 58 can be seated on the valve seat 78 immediately before moving leftward to a position where it abuts the step portion 52a of the stepped hole 52. In order to make this possible, the valve body 80 is engaged with and positioned by the spring bearing 82, and a valve spring 84 with a predetermined load is stretched between the spring bearing 82 and the valve body 80. A release spring 86 is stretched between the piston 58 and the piston 58 to press the piston 58 toward the plug 56.

When the valve seat 78 and the valve body 80 of the piston 58 are separated from each other, the inlet chamber 66 and the outlet chamber 70 are in free communication with each other through the passage 76. On the other hand, when the valve seat 78 and the valve body 80 are seated, free communication between the inlet chamber 66 and the outlet chamber 70 is limited. However, the deformation of the lip seal 60 allows the liquid to move from the inlet chamber 66 to the outlet chamber 70. Further, when there is a pressure difference exceeding the pressure determined by the seating area of the valve body 80 on the valve seat 78 and the valve spring 84, the liquid can be moved in the opposite direction from the outlet chamber 70 to the inlet chamber 66. Here, this pressure difference is
It is set to a minimum pressure that can secure the frictional force with the disk 36 required for the pad 38 to operate the No. 2 actuator. Although not shown, each brake device naturally has a wheel cylinder.

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.

-Climbing 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.

-Climbing 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 climbing 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.

At this time, in the valve device 50, the brake device 1 for the solenoid valve 16 is used.
By the pressure held on the 8L, 20R side, the piston 5
8 moves to a position where it abuts the step 52a of the stepped hole 52. This movement of the piston 58 is performed by the master cylinder 12
Needless to say, the process proceeds with the release of pressure. Therefore, since the valve body 80 is seated on the valve seat 78, the outlet chamber 7
The pressure of 0 is released up to the pressure determined by the valve spring 84 and the seating area of the valve body 80. However, the residual pressure is held in the brake devices 18R and 20L by this pressure. Due to the retained residual pressure, the pad 38 is pressed toward the disc 36, so that the switch 22 is stably retained in the closed state.

・ 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 keeps the switch 22 closed with the minimum pressure held by the valve device 50. Therefore, when the switch 22 is moved in the opening direction, the load on each member such as the pad 38 and the anti-vibration shim provided in association therewith is extremely small, and damage is prevented to improve durability. You can

In the embodiment shown in the drawing, the piping is of the X piping 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, when the brake fluid pressure is completely released, the reproduction between the shoe and the drum is completely eliminated, so that the contact between the shoe and the drum is secured and the switch can be switched. It is important that the minimum residual pressure is maintained by the retentate pressure.

Further, although the load of the valve spring 84 is defined from the above description, it is preferable that the load of the release spring 86 be as small as possible and the diameter of the piston 58 be as small as possible.

(Effect of the Invention) According to the present invention, the pressure is not completely released in the system in which the switch is installed, and the frictional engagement between the pad and the brake shoe can be reliably performed to ensure the operation of the switch. Moreover, since the pressure held for that purpose is considerably lower than the pressure for holding the vehicle stopped, the load on each member is small, the durability is improved, and the operation for activating the switch is smoothed. Therefore, it is possible to improve durability and ensure stability of operation.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing an installation example of a switch, and FIG. 3 is a sectional view showing an example of a valve device. 10 ... Brake system (brake device), 12 ... Master cylinder (pressure generating device), 16 ... Electromagnetic valve (solenoid valve device), 18R, 18L, 20R, 20L ... Wheel brake device, 22 ... Switch, 50 ... Valve device, 58 ... Piston (movable body), 78 ... Valve seat, 80 ... Valve body, 84 ... Valve spring.

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 The solenoid valve device capable of holding the side pressure, and the change in the action direction of the friction force between the brake friction material and the brake friction surface in the wheel brake device connected to the other of the two piping systems are detected to detect the command. In a brake device equipped with a switch adapted to generate a pressure, a wheel cylinder side pressure of the solenoid valve is provided on the other side of the piping system. Brake device provided capable of holding valve device pressure to sustain the operation of the switch as a residual pressure in accordance with the movement of the mobile and movable body, movable body in accordance with the.