DE2911074A1 - Braking system pressure amplifier - has spring holding valve body off inlet seat when non-pressurised - Google Patents

Abstract

The pressure amplifier is for a motor vehicle braking system, having a differential piston in a valve housing, and a double-valve body working in a bore in the piston, producting an outlet pressure in a set proportion to the inlet pressure. A spring holds the vale body (25) when unpressurised in a position opening the inlet seat. The body can be thrust by a spring (17), acting against it, into the position shutting the vent, while a further spring (21) supported in the housing (1) acts against the other side of the piston (1), keeping the inlet open.

Description

KNORR-BREMSE GMBH Munich, March 6, 1979

Moosacher Strasse 80 TPl-hn / m
8000 Munich 40 - 1566-

Intensifier

The invention relates to a pressure intensifier according to the generic term of claim 1.

Pressure intensifiers or pressure transducers of this type can be found there Use where supply or control pressures are to be reduced proportionally. The pressure exerted by the pressure intensifier is thereby used regulated in a fixed constant ratio to the set pressure.

Disadvantageous with the compressed air proportional ones currently on the market Pressure valves of the type in question are that they regulate from the beginning, i.e. practically from 0 bar applied pressure. This has the consequence that especially with large rule ratios the . Apply pressure of the wheel brake only at disproportionately high pressure

"ken is reached on the uncontrolled axes. Correct in the partial pressure area accordingly the braking force distribution contrary to the original intention do not match. In addition, the control of 0 bar worsens the response time of the brake.

Proceeding from this, the object of the invention is to design a pressure booster or pressure transducer of the type in question in such a way that control is possible from 0 bar, so that the fastest possible response is to be achieved. Such an application pressure control should be achievable with extremely simple structural means.

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The solution to this problem consists of the features of the characterizing part of claim 1.

With the help of the structurally simple, retrofittable spring arrangement the inlet seat is held in the open position when the pressure is depressurized, so that if there is a slight increase in pressure, immediate control

IQ tion of the pressure and thus a quick response of the brake system is possible. If the force of the spring effecting the through-control is correctly designed, the differential piston closes the inlet seat at a predetermined brake cylinder pressure, e.g. at 0.6 bar; from this point in time on, the control is ended and then becomes

^ 5 the pressure is reduced in the ratio of the differential areas. By a Appropriate choice of the spring effecting the through-control can accordingly be the inflection point in the course of the controlled pressure almost arbitrarily be relocated.

Advantageous embodiments of the invention are listed in further claims.

The invention is described below using exemplary embodiments Explained with reference to the accompanying drawing.

Fig. 1 is a sectional view of a pressure intensifier according to the invention;

Fig. 2 is a graph of output pressure versus input pressure Pressure, showing the kink point that exists as a result of the control.

In Fig. 1 of the drawing, a pressure transducer or pressure booster is shown, in the housing of a differential piston 1 arranged displaceably is. The differential piston 1 consists of the as shown upper differential piston part 3 and the lower one as shown

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Different! Al piston part 5. The upper Different! Al piston part 3 has r has a smaller diameter and accordingly a smaller area than that lower differential piston part 5. Both the differential piston part 3 as well as the differential piston part 5 are connected by means of a seal 7 or 9 sealed with respect to assigned valve housing sections. Between the two different piston parts there is an annular space 11.

IQ seen, which via a bore 13 with the outside air in connection stands. In the illustrated embodiment, the upper section is of the valve housing provided with an intermediate ring 15, which the Determines the outer diameter of the upper differential piston part. Of the Pressure intensifiers can of course also be used without such an intermediate ring be equipped.

The spring arrangement acting on the differential piston consists in the illustrated embodiment of three springs, from the smaller spring 17 acting on the underside of the differential piston the larger spring 19, which also acts on the underside of the differential piston, and the spring 21 acting on the upper side of the differential piston of the double valve body 25 to press the intensifier while the spring 19 endeavors to separate the double valve body 25 from that in the Representation of the lower valve seat 27 to be lifted off in such a way that the outlet of the pressure booster is opened. The upper spring in the illustration 21 presses on the differential piston so that it is depressurized State is held in a position in which the between the Ven valve seat 27 and the double valve body existing outlet closed is, while the existing inlet on the sealing ring 23 remains open. This ensures that the pressure intensifier responds quickly, since the pressure arriving via inlet 29 is initially transmitted via the inlet without having to move any valve devices or pistons. Conclusion 31 1n the brake cylinder can get. With correct interpretation the force of the spring 21, the differential piston closes the seal

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processing ring 23 of the double valve body existing inlet at a bec correct brake cylinder pressure, e.g. at 0.6 bar; for this purpose, for example, a spring 21 with a spring force of 6 kp is at the operating point necessary. From this point on, the pressure is then reduced in proportion to the differential areas of the differential piston. In Fig. 2 is the mode of operation of the spring arrangement of the pressure booster is shown in a diagram, with the inflection point of the pressure output represents the working point at which the differential piston the Inlet seat closes.

The invention is not limited to the illustrated spring arrangement, i.e. instead of the two springs 17 and 19, a single one can be attached to the Underside of the different! Alk piston acting spring be provided. An arrangement of several springs can also be used instead of the upper spring 21 if the structural conditions or Conditions of use should require.

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Claims (1)

• · · It • C · Il KNORR-BREMSE GMBH Munich, March 6, 1979 8000 Munich 40 - 1566- Moosacher Strasse 20 TPl-hn / m 1 CLAIMS I ίο $ [ 1., / Pressure intensifiers, especially for braking systems of motor vehicles, with a piston and differential arranged in a valve housing I ^ 5 a double valve guided in a bore of the differential piston ji body, which the outlet pressure of the pressure intensifier in a pre- >) correct relationship to the set pressure regulates, labeled ? ^; : by a spring arrangement that pushes the double valve body (25) J ^ holds the loose state in a position that opens the inlet seat. I ^2o f; 2. Pressure booster according to claim 1, characterized in that the ; ■ Double valve body (25) by means of an on the Different! al piston supported % th spring (17) can be tensioned in a position closing the vent S- / is, and that on the opposite side of the differential ^{piston I 25 (1} J a spring (21) supported on the valve housing of the pressure booster . | f attacks in such a way that the inlet seat is in a position for controlling the When the inlet pressure is kept open. K 3. Pressure booster according to claim 1 or 2, characterized in that Ί 30 that on the opposite side of the differential piston with respect to the spring (21) in addition to the spring (17) at least one more The spring (19) engages, which is attached to the valve housing of the pressure booster. ;; is supported and counteracts the spring (21) causing the control. 35 i 030039/0412 • tit t t · t · · ) ItIt tt · ' - ι ) I I t · t «· I)) J- ¹ II It tt 0 C 291107A 4. Pressure booster according to one of the preceding claims, characterized characterized in that at least one further spring (2Γ ...) is provided parallel to the spring (21). 0 30039/0412 -1566- 1 Reference number: Different! Al piston 5 1 Di fferenti alkoibentei1 3 Di fferenti alcohol parts1 5 poetry 7th poetry 9 Narrow space 10 11 drilling 13th Intermediate ring 15th feather 17th feather 19th feather 15th 21st Sealing ring 23 Double valve body 25th Valve seat 27 Inlet 29 Connection 20th 31 030039/0412