SU988614A1 - Pressure reducer in counterblocking brake system - Google Patents

Abstract

An anti-skid modulating valve i) of the kind shown in Figure 1 with an inlet 7 and an outlet 8 to a brake cylinder. An expander piston is moved to the right by a spring 10 to close valve 5 and expand the volume of the chamber 9, so reducing the brake pressure. The piston is normally held in the position shown by a solenoid 6. In the modification according to the invention (Figure 2), the piston is in two parts 3a and 3b. A spring 12 urges them apart, causing detents 11 to lock the part 3a to the housing 13. When the solenoid 6 is energised, the parts 3a, 3b move together against the force of the spring 12, and if the solenoid is subsequently de-energised, the composite piston can move to the right to reduce the brake pressure. <IMAGE>

Description

(54) PRESSURE REDUCER IN ANTI-LOCK BRAKING DEVICE

The invention describes a pressure reducer in an anti-lock braking system. For direct-action braking systems that are equipped with automatic brake torque regulators, the reduction in pressure in the wheel cylinder of the brake is achieved by pumping the fluid from the wheel cylinder of the brake back to the main brake cylinder by the executive unit. In order to prevent brake pedal reverse pushing, this pumped-out amount of fluid must be pumped into a battery that simultaneously performs the functions of a pressure limiter to prevent the actuator assembly from working against the uncontrolled high pressure that can be created in the master cylinder by the driver. The disadvantages of the system are that in addition to the actuating unit, there must also be a battery with a pressure limiter; The actuating unit must always work against the pressure created by the driver, up to the amount of pressure set by the limiter. Known anti-slip regulators are available with actuating nodes controlled by electromagnetic devices. For the correct function of these controllers, it is important that the piston of the actuator assembly, after the end of each anti-blocking period, is in its original position. In known anti-slip regulators, this is achieved in the following ways. One of them is to use a spring pushing the piston of the actuator assembly to its original position. However, the use of this spring necessitates the presence of the safety margin of the actuating electromagnet of the actuating unit, since its action on the piston must overcome, apart from the pressure of the brake fluid caused by the brake pedal, also the force of this spring. The second method consists mainly in the use of a freely installed piston of the actuating unit, which occupies the initial position only under the influence of pressure differences on both sides of the piston, which in practice is rather problematic, since it should be

full tightness of the closing valve is ensured. In the case of unresolved compaction, fluid penetrates the brake space, as a result of which the piston, after the end of the anti-blocking period, no longer returns to its original position, by an amount corresponding to the volume of the missed fluid. This process can be repeated during the repeated anti-blocking period up to the state where it is almost impossible to unload the brake, and thus the anti-skid regulator is basically turned off from work. The system in this case requires the release and new pressure on the brake pedal, which does not contribute to an increase in active safety. This disadvantage may also occur in spring-loaded discharge pistons, if this spring is not designed with an adequate margin of safety or its original performance changes, for example, due to the fatigue of the spring material.

It is also known a device comprising an actuating unit for an anti-skid regulator, controlled by an electromagnet, in which the discharge chamber is differential, and its working area, subjected to pressure from the main cylinder, is larger than its working area, which is acted upon by pressure from the wheel the brake cylinder, and the inter-cylinder space between the working surfaces, communicates with the atmosphere. The known actuating unit for the anti-skid regulator ensures the correct function of the anti-lock assembly, since the discharge piston of the actuating unit always takes up its basic position after the end of the anti-blocking period. This is achieved only through the use of a discharge differential piston. The actuator assembly of the anti-lock device is operated by switching on the current.

The aim of the invention is to provide a device with an actuating unit that allows fluid to flow during normal braking from the master cylinder to the brake and vice versa, so that the flow from the regulator to the impulse from the master cylinder closes and the fluid from the brake returns to the actuating unit in the brake. When the pulse is attenuated from the regulator, the fluid is pushed back into the brake, and the passage to the master cylinder opens.

The goal is achieved in that the anti-lock device of the brake system allows fluid to flow freely during the normal braking process and is closed. impulse from the regulator, the fluid flow for the duration of the impulse while lowering the pressure in the part of the brake system associated with the wheel brake cylinders.

Measles which are made in the form of a differential pressure, the working area of which is subjected to pressure from the master brake cylinder is larger than the working area affected by pressure

the wheel brake cylinder, measles is made of two parts, the outer part is formed by a hollow cylinder, in which the inner part is movably inserted in the axis, pressed from the outer part by a spring, ending with a conical surface, which is conjugated to the cylindrical surface of the inner part, and forms a guide for the balls supported on it and pressed against the outer part by a holder with a spring.

In addition, the ratio of the spring force to the mass of the inner part of the core is determined by the equation.

F SO-S

HZ

tp

m GP1 + Shg,

where F is the spring force; S is the piston area; ffli is the mass of the outer part of the core;

, is the mass of the inner part of the core.

The proposed pressure reducer is put into operation by switching off the current, and the regulation process is accelerated, and in addition, in this case, only one piston functions as an operating member, which replaces numerous systems of versions known up to now.

FIG. Figure 1 shows schematically a pressure reducer; in fig. 2 is a version of a pressure reducer that ensures free passage of fluid and with the absence of VII electrical current; in fig. 3 - structural modification of FIG. one.

The device consists of a cylinder-shaped body 1, in which the pistol 2 moves, moving to the right in measles 3 and to the left in

- a rod 4 bearing a valve 5 at its end. A solenoid 6 is mounted around the core 3 in the housing 1. The valve 5 controls the flow of the fluid supplied to the housing 1 through the inlet 7 from the master cylinder and flowing through the outlet 8 after the chamber 9 passes through. The fluid flow is controlled by said valve 5, pressed by the spring 10.

The device works as follows.

If current flows through solenoid 6, measles 3 is pulled to body 1 (in the left direction) and the piston 2 that is associated with it pushes valve 5 off the seat with a brush 4, so that fluid flow can freely flow through the inlet 7 from the main cylinder of the chamber 9 to the outlet 8 and from there to the brake. If the brake is under pressure and the current is interrupted in the solenoid 6, then the magnetic force between the corona 3 and the housing 1 is damped, the piston 2

the pressure in the chamber 9 is pressed to the right side, by the action of the spring 10 the valve 5 is pressed against the seat and the flow from the main cylinder is closed. In the chamber 9 and the brake connected to it, the pressure is now reduced without restriction, since the piston 2 can be freely displaced from the housing 1 (in the right direction). If a current is switched on again in the solenoid 6, then the magnetic force between the core 3 and the housing 1 presses the piston 2 to the left, and the pressure in the chamber 9 and consequently, in the brake, rises to the initial level. If the measles rests on the end of the housing 1, the valve 5 is pressed by the stem 4 and opens again, and the pressure of the main cylinder acts again on the brake.

In order to ensure free flow of fluid in the device and in the event of a power failure, the next one can be switched on, its additional device operating on the principle of inertia, which in the quiescent state (solenoid bo: 3 current) mechanically holds the measles in the leftmost position, however, when the current of the solenoid is stopped — after its previous excitation — it allows the measles to move freely to the right and thereby reduce the pressure in the brake.

The additional device is shown in FIG. 2. It is characterized by a two-part core, the outer part of the Zor core and its inner part 36. The outer part of the Zor core, in its hollow cylindrical part, surrounds the inner part of the core 36, there are several radial holes in which the balls 11 are located Both parts in the rest position (solenoid 6 without current) are separated from one another by a spring 12, with the outer part of the core behind pressed in the left side to the housing 1, the inner part of the core 36 pressed in the direction so that its conical surface pushes the radial balls11, which in this case rests on the cover 13, which closes the housing 1, and in this position prevents the outer part of the core Za, and the piston 2 and the rod 4 connected to it, move to the right. The free flow of fluid through the valve 5 from the master cylinder to the brake and back in this case is provided (braking in the absence of current).

The pressure reducer with the optional device works as follows

If the current in the solenoid 6 is turned on, the inner part of the core 36 is attracted to the left to the outer part of the Zor core, and both parts together adhere to electromagnetic force on housing I (normal braking). If the action of a pressure reducer stops the flow of current into the solenoid 6 and the chamber 9 is under pressure, the piston 2 together with both parts of Pro and 36 is displaced to the right side and

brake pressure drops. The balls 11 do not interfere with this movement, since they are not pushed radially and therefore do not block the outer part of the core against the cover 13. However, the condition of the described function is the need for the acceleration imparted by the pressure of the piston 2 and both parts of the core and 36 , there was more than an acceleration that the spring 12 of the inner part of the core 36 can communicate so that, in such a way, both parts of the core, when moving to the right, remain connected and do not repel each other. This condition is feasible if the inner part of the core 36 is sufficiently heavy and the spring 12 is weak and if the ratio of the force of the spring 12 to the mass of the inner part of the core 36 is determined by the equation

Jl yr

Shd gp

20

mi +

m

where is the force of the spring;

& piston area;

t is the mass of the outer part of the core;

2 weight of the inside of the box.

If the current in the solenoid 6 is turned on at the end of the action of the pressure reducer, both parts of the Za and 36 cores are pulled to the left side of the housing 1, and the load 2 increases again the pressure in the brake to

the original value. After reaching the outer part of the core in contact with the front part of the housing 1, the valve 5 opens and the master cylinder is connected to the brake, which ensures normal braking. After the end of the braking pressure in

chamber 9 is canceled and the current in the solenoid 6 is turned off. A spring 12 separates both parts of the Za and 36 cores from one another, and the balls 11 are located radially against the cover 13 and thereby block the outer

the part, the core Cor, and with it the piston 2 and the valve 5 comes to a state of rest, so that the device becomes freely flowing.

Structural change of the blocking unit (Fig. 3) is that

The inner side of the core 36, instead of the radial holes for the balls 11, creates a cylindrical device on which the balls 11 lie in the fixed position of the core 11. To the outer part of the core, the balls are pressed against the holder 14,

which, by means of a spring 15, presses them against the body 1 and thereby simultaneously holds the outer part of the core 3 in the initial position in which it rests on the end wall of the body 1.

Claims (2)

1. Pressure reducer in the antilock braking system. allowing, during normal braking, fluid to flow freely and overlap the flow from the regulator to the fluid flow for the duration of the pulse while simultaneously reducing the pressure in the part of the brake system connected to the wheel brake cylinders, the measles of which are made in the form of differential pressure, whose working area subject to pressure from the master brake cylinder, larger than its working area, subject to pressure from the wheel brake cylinder, characterized in that The flax is in two parts, the outer part is formed by a hollow cylinder, B which is internally inserted internally into the axis 36, pressing out from the outer part behind the spring 12, ending with a conical surface, mating with the cylindrical surface of the inner part 36, and forming a ball guide 11 based on 15 w pressed against the outer part of the holder with a spring. 2. Decrease p. 1, characterized in that the ratio of the force of the spring 12 to the mass of the inner part of the core 36 is determined by the equation -I- 30i5 ni2GI m W) + ma where G is the spring force; S is the piston area; Ttti is the mass of the outer part of the core; TPZ - the mass of the inner part of the box. It is recognized as an invention according to the results of the examination carried out by the Office for the Invention of the Czechoslovak Socialist Republic. 777777777,