JPH0611260Y2 - Front brake control system for automobiles - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a control device for a front brake of an automobile,
More specifically, the present invention relates to a front brake control device for an automobile, in which the braking force of the front brake system can be artificially weakened according to the condition of the road surface.

<Prior Art> A conventional front brake control device for an automobile of this type is disclosed in, for example, Japanese Patent Application Laid-Open No. 60-56661. It is constructed as shown in FIG.
The inlet 2a of the manually operated opening / closing valve 2 and the inlet 3a of the limiting quick release valve 3 are connected to the air outlet 1a of the front brake system provided in the dual type brake valve 1, and the outlet of the opening / closing valve 2 is connected. The control port 3b of the limiting quick release valve 3 is connected to 2b, and the outlet 3c of the limiting quick release valve 3 is connected to a booster or a brake chamber (not shown). 1b is an outlet of the rear brake system, 3d is an exhaust port of the limiting quick release valve 3, 4a is a front tank, and 4b is a rear tank.

In such a front brake control device, the on-off valve 2
Since the air is supplied only to the control port 3a of the limiting quick release valve 3 when the lever 2c is closed at the position shown in the figure, the depressurized air is output to the booster or brake chamber of the front brake. If the lever 2c is tilted to the left in the figure and the on-off valve 2 is opened, air is also supplied to the control port 3b of the limiting quick release valve 3, so that the air output from the brake valve 1 remains as it is. Supplied to the brake chamber. Therefore, it is possible to selectively use the braking force of the front brake in the normal state and the state in which the braking force of the front brake is limited only by switching the lever 2c to open and close the on-off valve 2, and the front wheel tends to occur on a slippery road surface or the like. It is possible to reduce the lock of the and secure steering performance.

<Problems to be solved by the invention> By the way, in a vehicle equipped with such a front brake control device, if the rear brake system fails when the braking force of the front brake is limited, There is a problem that the braking force as a whole is significantly reduced because only the limited braking force by the brake acts.

The present invention has been made in view of such a situation,
An object of the present invention is to provide a front brake control device capable of improving the safety in the event of failure of the rear brake system while reducing the lock of the front wheel on a slippery road surface and ensuring the steering performance of the vehicle.

<Means for Solving Problems> In order to achieve the above object, the present invention provides a pressure reducing function in a vehicle in which a front brake system path and a rear brake system path are controlled by dual-type brake valves. The air passage of the front brake system is constituted by a main path having no pressure and a sub path having a pressure reducing function connected in parallel to the main path via a switching valve. or,
It is characterized in that the switching valve is constituted by an air pressure sensing type manual switching valve that switches the path of the front brake system to the main path side when the air pressure of the rear brake system drops.

<Operation> Due to such a structure, for example, when traveling on a slippery road surface, the switching valve is operated to select the sub route, so that the air output from the brake valve is reduced by a limiting release quick release valve or the like. The pressure can be sent to the booster or the brake chamber of the front brake system after the pressure is reduced in the sub route provided with.

On the other hand, during normal traveling, the switching valve selects the main path that does not have the pressure reducing function. Therefore, during normal traveling, the air having the same pressure as the air output from the brake valve can be sent to the booster or the brake chamber of the front brake system, and the desired braking force can be obtained.

Also, when the rear brake system fails and the air pressure in the rear brake system falls in the depressurized state in which the sub route is selected, the switching valve that had manually selected the sub route until then operates automatically. Select the main route. Therefore, in such a case, the restriction effect on the front brake is immediately released, so that the reduction of the braking force of the entire vehicle can be suppressed, and the safety is improved. Further, since the switching valve is constituted by an air pressure sensing type manual switching valve that switches the path of the front brake system to the main path side when the air pressure of the rear braking system drops, the handle of this manual switching valve is Whether or not the rear brake system is normal can be immediately known from the state, and safety is further enhanced.

<Embodiment> An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 and FIG. 2 show an embodiment of the present invention. A brake valve 10 having a brake pedal 10a that is operated by a driver is a dual dual brake system in which a front brake system and a rear brake system are independent. It is composed of a brake valve of the type, and the inlet 11a of the manual switching valve 11 is connected to the air outlet 10b of the front brake system. 10c is an air outlet of the rear brake system, 12a and 12b are a front tank and a rear tank.
Air is supplied to the front and rear brake systems from a and 12b, respectively.

The switching valve 11 is provided with a plunger 11b which is manually operated in the vertical direction in the figure, and when the plunger 11b is held at the lower end position shown in the figure, the valve element 11d provided on the lower surface of the plunger 11b is Although the inlet 11a and the outlet 11c are closed by closing, when the plunger 11b is pulled up and moved upward in the figure, the valve body 11c opens to hold the inlet 11a in communication with the outlet 11c. Further, the switching valve 11 is provided with a spring 11e for urging the plunger 11b upward, and a chamber 11f is formed on the upper end surface of the plunger 11b. By connecting the air outlet 10c of the rear brake system provided in the brake valve 10 and the chamber 11f, the plunger 11b is pressed and held against the spring 11e by the pressing force of the air pressure of the rear brake system. I am trying to let you. Reference numeral 11g is a locking mechanism for elastically locking the plunger 11b in the raised position and the lowered position, respectively, and the brake is activated by making the pushing force by the spring 11e slightly smaller than the locking force by the locking mechanism 11g. When not (when the air pressure of the front brake system is not acting on the lower surface of the plunger 11b), the plunger 11b
Can be locked at either the upper or lower position.

Further, the limiting quick release valve 1 is installed at the air outlet 10b of the front brake system of the brake valve 10.
The inlet 13a of 3 is connected, the control port 13b of the limiting quick release valve 13 is connected to the outlet 11c of the switching valve 11, and the air output from the outlet 13c of the limiting quick release valve 13 is front braked. It supplies it to the booster of the system.

In addition, the limiting quick release valve 13 is
A deformed piston 13e is inserted in a stepped cylinder provided in the valve body 13d so as to be vertically movable in the figure, and a hole 13f is formed to vertically penetrate the deformed piston 13e. Then, a spherical feed valve 13g seated on the upper end (valve seat) of the hole 13f and an upper end (valve seat) of the exhaust port 13h provided on the bottom of the valve body 13d are opposed to each other from above with a predetermined clearance. Exhaust valve 13i and rod 13j passing through the hole 13f
Guide 13k that is fixed to the valve body 13d by connecting via
A spring 131 between the deformed piston 13e and the lower surface of the deformed piston 13e, the piston 131e is pushed up by the spring 131 to hold the field valve 13g, and the air introduced from the inlet 13a is transferred to the deformed piston 13e. Applied to the small diameter end face (upper surface) of
The air supplied from 1 to the control port 13b is applied to the stepped surface of the deformed piston 13e. As a result, the force acting on the upper surface of the deformed piston 13e becomes the same as the force acting on the lower surface, and air that is not decompressed is output.

In the front brake control device for an automobile having such a structure, when the automobile is used for traveling on a normal road surface, the plunger 11b of the switching valve 11 is pulled up as shown in FIG. By opening, the air pressure output from the air outlet 10b of the brake valve 10 is applied to the small-diameter end surface and the stepped surface of the deformed piston 13e of the limiting quick release valve 13. Therefore, in this state, since the air pressure supplied to the inlet 13a is output from the outlet 13c with almost the same pressure, an intended braking force that is not limited (corrected for reduction) can be obtained.

On the other hand, when the vehicle is used for traveling on a slippery road surface, as shown in FIG. 1, the plunger 11b of the switching valve 11 is pushed down to the position shown in the figure and is moved to the control port 13b of the limiting quick release valve 13. Stop the air pressure supply. Then, in this case, the limiting quick release valve 13 acts to reduce the pressure, so that the air reduced in pressure by the valve 13 is supplied to the booster. Therefore, the braking force of the front brake system is weakened by the amount of pressure reduction by the limiting quick release valve 13, and the front wheel is prevented from being locked on a slippery road surface or the like.

Incidentally, the depressurizing action by the limiting quick release valve 13 as described above is caused by the pressure of the air output to the booster and the upper surface of the deformed piston 13e to which the pressure of the air output from the brake valve 10 is applied. This is performed by the difference in pressure receiving area with the lower surface of the deformed piston 13e.

When air is supplied to the upper surface of the deformed piston 13e, the deformed piston 13e descends and the exhaust valve 1
3i is seated to close the exhaust port 13h, but when the air supply to the upper surface of the deformed piston 13e is stopped by opening the brake pedal 10a, the deformed piston 13e is moved to the position shown by the pressure difference between the upper and lower surfaces. Ascend and return to exhaust port 13
To open h, the air from the limiting quick release valve 13 to the booster is rapidly exhausted.
The depressurizing action (limiting action) and the quick release action are the same as those in the related art, and the specific structures of the limiting quick release valve 13 and the switching valve 11 are not limited to the embodiments.

Also, if the rear brake system fails during the restriction of the front brake due to such pressure reduction, the chamber 11 of the switching valve 11
Since the internal pressure of f decreases, the pushing force of the plunger 11b decreases. Then, the sum of the downward pressing force of the rear brake system due to the air pressure and the locking force of the locking mechanism 11g is the spring 11e.
Since it is smaller than the sum of the push-up force due to and the push-up force due to the air pressure of the front brake system, the plunger 11b is automatically pushed up simultaneously with the depression of the brake pedal 10a as shown in FIG. Stop the depressurizing action by. Therefore, when the rear brake system fails during the restriction of the front brake, the restriction is immediately released, so that the reduction of the braking force of the entire vehicle is suppressed and the safety is improved.

Further, since the switching valve 11 is constituted by an air pressure sensing type manual switching valve that switches the path of the front brake system to the main path side as the air pressure of the rear brake system decreases. Whether or not the rear brake system is normal can be immediately known from the state of the handle, and the safety is further enhanced.

Limiting quick release valve in the above example
Since the front brake is limited depending on whether or not air is supplied to the control port 13b of 13, the pressure due to the sliding resistance of the deformed piston 13e of the limiting quick release valve 13 is selected. Loss can be a problem.

However, for example, as shown in FIGS. 3 and 4, a switching valve 11 having two inlets 11a and 11h is provided, and this switching valve 1
The air output from the brake valve 10 is directly supplied to one inlet 11a of the 1 and the inlet 13a of the limiting quick release valve 13 is also connected to the air outlet 10b of the brake valve 10. By connecting the outlet 13c to the other inlet 11h, it is possible to output air without passing through the limiting quick release valve 13 during normal traveling.

Therefore, in this case, the air pressure equivalent to the air pressure of the rear brake system can be supplied to the front brake system when the limiting quick release valve 13 is not functioning, so that the braking force of the front brake system during normal traveling is increased. At the same time, there is no possibility of causing a decrease, and at the same time, the safety in the event of a rear brake failure can be increased. 11i is a valve body.

In each of the embodiments, the air is supplied to the booster of the front brake system, but the air can be supplied to the relay valve or the brake chamber.

<Effects of the Invention> As described above, according to the present invention, when the vehicle is used for traveling on a normal road surface, the air is sent to the front brake system without performing the pressure reducing action by the limiting quick release valve or the like. On the other hand, when the vehicle is used for traveling on a slippery road surface, the decompressed air is sent to the air of the front brake system, so the braking force of the front brake system during normal traveling is reduced. You can prevent the front wheel from locking on slippery roads without inviting you. Further, when the rear brake system fails when the front brake is limited due to the pressure reduction, the switching valve automatically switches to stop the pressure reducing action, so that it is possible to suppress the reduction in the braking force when the rear brake fails. At the same time, such a failure of the rear brake system can be immediately grasped from the state of the handle of the manual switching valve, so that the safety is improved.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a brake circuit showing an embodiment of the present invention, and FIG. 2 is a sectional view showing an operating state of a switching valve,
FIG. 3 is a schematic block diagram of a brake circuit showing another embodiment of the present invention, FIG. 4 is a sectional view showing an operating state of the switching valve, and FIG. 5 is a schematic block diagram of a brake circuit showing a conventional example. is there. 10 …… Brake valve, 10a …… Brake pedal 10b …… Front brake system air outlet 10c …… Rear brake system air outlet 11 …… Switching valve, 11a, 11h …… Inlet 11b …… Plunger, 11c… … Outlets 11d, 11i …… Valve disc, 11e …… Spring 11f …… Chamber, 11g …… Locking mechanism 13 …… Limiting quick release valve 13a …… Inlet, 13b …… Outlet 13c …… Control port

Claims (1)

[Scope of utility model registration request] 1. An automobile in which an air passage of a front brake system and an air passage of a rear brake system are controlled by dual type brake valves, and a main path having no pressure reducing function and a switching valve are provided in the main path. And an air passage for connecting the front brake system to the main route side when the air pressure of the rear brake system is reduced while the air passage of the front brake system is configured by a sub route having a pressure reducing function connected in parallel. A front brake control device for an automobile, characterized in that the switching valve is constituted by a sensing operation type manual switching valve.