DD153478A3 - TWO-WHEEL PROTECTION VALVE WITH THROTTLE DEVICE FOR VEHICLE BRAKING SYSTEMS - Google Patents

Abstract

The invention relates to the field of vehicle construction. The aim of the invention is to ensure in a simple manner at Erstauffuellungvon brake systems with an existing defective circuit, that certainly open the protective valve of the intact circuit and the intact circuit is filled. For each two circles only one such device should be required. The object of the invention is to avoid known disadvantages, to reduce the design effort and to reduce manufacturing accuracies. The features of the invention are that in a per se known dual-circuit protection valve with a piston 4, a Voreilfeder 15 to the defined opening sequence of the circles and a floating plate 9, which secures the defect each broken circle, the piston of two piston parts 4a and 4b exists, which are arranged axially displaceable to each other and whose axial movement is limited to each other by stop 19. Between the piston parts 4a and 4b a veraenderlicher throttle seat 18 and an additional spring 14 is arranged.

Description

H * 22037 9

title

Dual circuit protection valve with throttle device for vehicle brake applications

The main application of the invention are compressed air systems in automotive engineering objects of the application are preferably Druckluftbrems ~ systems of motor vehicles.

There are known protection valves _s for initial filling of a system in a defective circuit, have additional facilities to open the safety valves of the intact circuits for initial filling with certainty · A random opening of the protection valve of the defective circuit in such a way that the entire fed pressure medium again can escape via the leak of the defective circuit is avoided.

These devices consist of constant chokes * which are arranged parallel to each protection valve of each circuit and secured with additional check valves against backflow from the respective circuits.

Other designs have incorporated variable restrictors in the main stream by adding cones or pins into one

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Drill a hole that releases small or larger cross sections depending on the position of the pins. Changed versions have at each valve seat of the protective valve cupper seats with small and larger cross-section, in each case only the smaller cross-section ventilates and throttle effect is also achieved. Only after certain filling the seat opens with a larger cross section and releases the full passage. Due to the throttling effect, back pressure is reached in front of all valve seats of the protection valve, whereby all valves are forced to open or, in parallel, a certain filling of the circuits bypassing. the protective devices is achieved, whereby the protective valves of the intact circuits are opened by the upcoming pressure in the circuits.

These mentioned solutions are described in DE-AS 21 43 7331 DE-OS 25 53 818 and DD patent 130 323. All versions have in addition to the high design complexity! Disadvantages that can constantly leak pressure medium at the leak in parallel connection via the throttle that cones or pins in the main stream require very accurate Pertigungsaufwand and their effect is very dependent on the constantly fluctuating F: örd er stream of the pressure medium.

Constant chokes in the main stream are in their dimensions for the reasons mentioned.kaub to control.

The aim of the invention is to ensure in a simple manner at Erstffüllung of brake systems with an existing defective circle that certainly opens the protective valve of the intact circuit and the intact circuit is filled.

After filling up the intact circuit, further normal functions will result in permanent leakage through chokes

.35 to avoid. Pur two circles, only one of the like device should be required.

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Dependencies on the flow rate of the pressure medium are to be reduced to a large extent ·

It is to be avoided that during the first filling over a relatively long period of time a large part of the pumped-up pressure medium can escape via the leak,

Darleguns_des_Wesens_der_Erfindung

The technical problem is to avoid the disadvantages of known solutions, to reduce the design effort, entfaeem required manufacturing accuracies, bypassing additional throttle holes, additional check valves or required double valve seats and largely avoiding the direct dependence on the flow of the pressure medium the same To achieve function.

The features of the invention are that in a known 2-circuit protection valve with. a piston, a Voreilfeder the defined opening sequence of the circles and a floating plate, which at. Defect the respective defective circuit ensures that the piston consists of two piston parts, which to each other. are arranged axially displaceable and their axial movement is limited to each other by a stop. A variable throttle seat and an additional spring are arranged between the two piston parts. The throttle seat can also be designed as a sealing seat, with a throttle bore arranged parallel to this sealing seat in the piston wall, which becomes ineffective after opening the sealing seat.

In the entrance to the protective device, a check valve is arranged

 When filling the empty system opens by the aforementioned Voreilfeder the upper, located behind the throttle seat circle first «Through the throttle seat forms

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Below the piston from a dynamic pressure, which also ventilates the lower seat of the floating plate and. fills the bottom circle.

In the event of a defect in the upper circuit, it is thus ensured that the intact lower circuit is filled by the throttling action present there .The throttle seat remains closed, so that leakage losses occur only over the throttle seat until the lower circuit exceeds the defined opening pressure. is filled and then within the opening and closing span of the protection valve the upper circle is closed by the upper valve seat of the floating plate .. In case of defect of the lower circle the intact upper circle is first filled via the throttle seat while

Durch5 flows through the impending dynamic pressure, a portion of the flow rate in the lower circle on the leak and that until a certain pressure has built up in the upper circle, which then opens the throttle seat by axial divergence of the two piston parts, the intact circle filled with free passage and the defective lower circuit is secured.

The drawings belonging to the exemplary embodiment show in FIG. 1 a section through a two-circuit protection valve with a divided working piston for the initial injection.

at. a defective circuit Fig.2 another example of the throttle effect.

Fig. 1 shows a per se known 2-circuit protection valve, consisting of valve housing 1, adjusting spring or springs 2, adjusting screw 3 »a floating plate 9, which is guided by short plunger 10 and 11 with axial play. The game is limited by the stops 12 and 13. · Φ

On the floating plate 9 are located opposite the valve seats 16 and 17 *:

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At the height of the floating plate 9 is located in the housing 1 via check valve 20 of the input E, from the Energiequelle.kommend ·

In the amount of the piston 4 is in the housing 1 of the line termination for circuit I, in the housing bottom of the line connection for circuit II.

The springs 2 are supported on the one hand via the adjusting screw 3 against the housing 1 and on the other hand against the piston 4, which is arranged between the springs 2 and the floating plate 9.

The piston 4 consists of the lower part 4a with sealing ring 8 and the upper part 4b with sealing ring 7. In a depressurized state, the throttle seat 18 forms a throttle point between both piston parts 4a and 4b. Both piston parts 4a and 4b are axially displaceable relative to one another until the stop 19 the divergence of the piston parts 4a, 4b, supported by the spring 14, limited

 A small spring 15 supports the plunger 10 against the upper piston part 4b.

If the system is depressurized, the valve seats 16 and 17 and the throttle seat 18 are kept closed by the spring force of the spring 2. By the spring 15, the closing force on the valve seat 17 relative to the valve seat 16 is slightly larger.

If pressure medium flows from the energy source via input E and check valve 20 into the valve, first the annular surface of the piston lower part 4a, which is formed between the closed valve seat 16 and the piston outer end knife of the piston 4, is pressurized.

When a certain opening pressure has been reached, the piston is pressed up against the spring force of the springs 2 and 15. The valve seat 16 is released. By the force of the spring 15 valve seat 17 is still closed. After vented valve seat 16 is formed in room 6, a back pressure, as over the closed

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Throttle seat · 18 nor can a very small part of the pressure medium fed in via E be discharged into circuit I. ,

"The pending dynamic pressure causes a further piston movement of the piston 4 upwards, so that valve seat 17 is also lifted by means of stop 12. Thus, valve II is filled against the opening pressure, while pressure builds up in circuit I via throttle seat 18 only very slowly.

After reaching a predetermined pressure in circuit I, which should be very low, the pressure present in circuit I, which is also in the annular space formed between the outer diameters of the throttle seat 18 and the piston 4, opens with the support of the leather 14 against the pressure applied by the input E throttle seat 18, which then also free passage to the circle I is present.

When a circuit is defective and thus there is a drop in pressure, piston 4 moves initially in a stretched position, i. with opened throttle seat 18 nach.-below and closes the valve seats 16 and 17 * If the defect in the circle I emerged, valve seat 16 remains closed, while valve seat 17 opens again. If circuit II is defective, the process is reversed.

The valve seats 16 or 17 of the associated defective circuits I or II release only when the opening pressure of the protection valve is reached. The pressure medium delivered via the opening pressure flows into the respective leak.

When filling the pressureless system and defective circuit II ventilate again, as previously described, both valve seats 16 and 17. The promoted via the opening pressure pressure medium flows through the leak of the circle II so long until a predetermined pressure has built up in the circle I, which opens the throttle 18 and gives free passage to the circle I,

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In this case, the valve seat 17 closes the defective circuit When filling the pressureless system and defective circuit I, circuit II is filled, while a small amount of the pressure medium flows into the defective circuit I via the seat 18. '·

Since no pressure can build up in the defective circuit I,. throttle seat 18 remains closed. After the pressure has dropped, for example due to consumption in circuit II or by constant outflow via the leak in circuit I, both valve seats 16 and 17 close when the safety pressure is reached. In the event of further make-up, valve seat 16 remains. closed, while valve seat 17 airs immediately again, whereby only pressure medium in the intact circuit II promoted / ird.

FIG. 2 shows a modified embodiment of the throttle seat 18. The throttle seat 18 is replaced by the sealing seat 21 and a throttle bore 22 arranged in parallel. The throttle bore 22 may be formed relatively defined and adapted as needed to the respective requirements. ,

Claims (2)

220379 Brfindungsansüruch Two-circuit protection valve with throttle device for vehicle braking systems, consisting of a known housing, a piston, a Voreilfeder and a floating plate, which secures the defect each case failed circle by closing a valve seat, characterized in that a piston (4) from each other axially displaceable piston parts (4a; 4b) and between the two piston parts (4a; 4b) a variable throttle seat (18) and a spring (14) and on the piston part (4a) a stop (19) are arranged, Double-circuit protection valve with throttle device according Pkt.1, characterized in that between the axially displaceable piston parts (4a, 4b) a sealing seat (21) and parallel to this a throttle bore (22) are arranged. Double-circuit protection valve with throttle device according to Pkt. 1 and 2, characterized in that at the input (E) a check valve (20) is arranged. For this 2 sheets of drawings!