DE1897281U - MASTER CYLINDER FOR HYDRAULIC BRAKE SYSTEMS WITH SEPARATE CIRCUITS, IN PARTICULAR FOR VEHICLES. - Google Patents

Description

PA 375 714 * 5/26/64

^; PATENT LAWYERS

"dR.-ING. H. FINCKE 8 Munich 5, ₂ 6» May 196%

DIPL.-ING. H. BOHR M0llerstrasse 31

DIPL.-ING. S. STAEGER

*. Telephone: 22 4941 - Telegrams: Claims Munich
Postal checking account: Munich 27044

* Bank details:

C * Bayerische Vereinsbank Munich, account 620404

Folder No. - - -M 5085 - W / H

Please indicate in the answer

* " F 25 119 / 65C Gm

description

to the utility model

of the company FIAT Societd per Azioni, Turin / ITALIEIT,

concerning

"Master cylinder for hydraulic braking systems with separate Circles, especially for vehicles ".

PRIORITY : March 29, 1962 - 'ITALIEF.

The! Price increase concerns a master cylinder for hydraulic brake systems with separate circles, especially for vehicles.

It is already known a master cylinder of the type mentioned, which is formed by a cylinder, in which a first and a second piston are arranged for movement, between wel-

There is a leather that is used for this purpose, this constantly to keep at a distance? so that the pistons in the cylinder

\ which limit a first pressure chamber, while a second spring./ is arranged between the second piston and a stationary element in the cylinder, through which the corresponding cylinder - the end is kept at a distance from the second piston in such a way that _ that the latter delimits a second pressure chamber in the cylinder, which is near the mentioned end of the cylinder, .Each, the piston between its opposite ends with

"A hat is formed which delimits an annular chamber with the inner wall of the cylinder, which is constantly in communication with a separate container, and sealing elements are in sliding contact with the inner wall of the cylinder, which are provided at the opposite ends of each piston and of which those sealing elements which are arranged at the ends of the first and second pistons facing the first and second V-th pressure chambers are shaped so that they act as valves for the communication between the adjacent inlet chamber and the pressure chamber , in which the spring is arranged, which acts on the associated piston , to switch off when the let '· tere acts against the .Werkung / this spring, and to re-establish the mentioned connection after the piston / has performed its bending stroke The first and the second chamber are always connected to one of the two separate brake circuits of the vehicle, which .. on both pistons: we kenden. -spring

are tensioned, their properties as well as the dimensions

"■. ■ - '■ -."
. "All.-" components are chosen so that in the rest position of the system, the first and second chambers are each connected to their containers through openings provided in the cylinder wall, which are located a short distance from the top of the sealing elements mentioned that act as valves-and _{turn: carried} by the pistons. - ".". --'----:

In the master cylinders of the type described above, the Bias of the second spring greater than the bias of the first spring, which is made possible in that a stop is provided in the cylinder, which a displacement of the second Piston prevented beyond a given limit. This choice of preload of the springs has the specialist part that when initiating the two pistons in the master cylinder instead of at the same time begin their forward movement to ".", their forward movement, start one after the other. Initially the first moves Piston forward. Only after its you acting as a valve,: processing element has "interrupted the connection between the first pressure chamber and its reservoir, the forward movement of the second piston begins, creating a braking effect in the second Circuit connected to the second pressure chamber, is initiated what happens after the als.Ventil acting sealing element, which from. second piston is carried,

- ". The connection between the second pressure chamber and the tBxl. jiur, _. ~~ * -

■ f 4 **

orderly container has switched off. This leads to a behavior nism ig long idle stroke of the brake pedal, which of course a serious disadvantage is that this increases the length of the working stroke the brake pedal is decreased. -:.

The innovation relates to the formation of a master cylinder described type, in which the disadvantages mentioned are avoided are. .

According to the innovation, this is essentially achieved by “that the two springs in the cylinder in a known manner around different Amounts are biased that are dimensioned so that the bias of the spring arranged between the two pistons exceeds the bias of the 'spring, which between the second piston and a fixed element arranged in the cylinder is.

Furthermore, according to the innovation, the springs are dimensioned in such a way that the same flexibility is obtained, which is chosen so that the moment the sealing elements act as valves, the connection between their respective pressure chambers connected to the separate brake circuits of the vehicle at the same time and switch off the respective containers, whereby the total load of the second spring, ie its preload plus der_Last.by pressing j the same -or preferential-

is slightly less than the preload of the first spring arranged between the \ two_ pistons.

Further features of the innovation can be seen from the following Description of exemplary embodiments based on schematic Drawings. -, - ■ "-..."

It shows:

Fig. 1 is a view in longitudinal section of a first embodiment -;. "shape of the new main cylinder;

Fig. 2 is a view in longitudinal section of a component group of master cylinder shown in Fig. 1;

FIG. J is a view in elevation of part of that shown in FIG Component group ;. "■. -...

Fig. 4 is a view in longitudinal section;

Fig. 0 and β views in section along the line V-V and VI-VI in Fig. 3 "or 4l

7 and 8 a plan view and a side view, respectively, of a further rope of the component group shown in FIG. 2;

Fig. 9 is a view in section / along the line IX-IX in Fig. 5;

Fig. 10 is a view in longitudinal section of the central part of a white. Lower embodiment of the new main cylinder \ . "".

11 is a view in longitudinal section of a component group of the in Fig. 10 shown embodiment of the new master cylinder;

Fig. 12 and 13 a view in longitudinal section "and a Torderan-

-.-- "sees part of the construction shown in Fig. 11. . "- subgroup." ■ ■ ".-"

The master cylinder shown in the drawings has a: cylindrical G-housing 1, which is closed at one end by a screw plug 2. The housing T is formed at one end with a transverse flange 3, which has through bores 4 ² ^ r connection of the master cylinder to the vehicle. .

Within the cylindrical housing 1, a piston 5 is slidably arranged in the vicinity of that part of the same which carries the flange 3. The transmission of motion to the piston is effected by a pressure piece 6, which is prevented from the cylinder by a snap ring \ slipping out, - in a "in

the cylinder inner wall provided hanging groove. Bas printing block 6 is formed with a stepped part 8 of a sealing ring.9 made of elastic material, for example Rubber, is added. The outside diameter of the stepped Part 8 of the pressure piece 6 is smaller than the diameter of the Inner opening of the ring 9 and the axial length of the stepped Part 8 is also smaller than the axial dimension of the ring 9. The pressure block 6 therefore acts on the piston 5 after it the ring 9 has compressed, whereby the latter firmly against the inner wall of the cylinder 1 is pressed. The ring 9 has a substantially right-angled cross-section and has a curved profile on its outer circumference that corresponds to its Transverse median plane is symmetrical *

At its central part, the piston 5 is designed with a hat 10, which together with the inner wall 1a of the cylinder a Annular chamber 11 limited. With the groove 10 is a filling hole 12 for the supply of liquid from an internal thread connected for the nipple of a pipeline leading to a container, not shown. . _ ■. _

The length of the groove 11 in the axial direction of the piston is such that the bore 12 regardless of which position the Piston 5 assumes during operation of the master cylinder -with-. the ring chamber 11 is constantly in "Terbindxtng"

* ~ f \ ■ -

"Another.Eingnut I4 in the outer surface of the basket 5 is used for receiving a ring 15 · The inner surface of the ring 15 is located see the bottom of the groove in decency while its -External surface in cross-section has a curved profile that leads to The transverse median plane of the Hinges is symmetrical. And is in sliding contact mtb is the inner wall 1a of the cylinder. The fat of the ring I5 is smaller than the width of the groove 14 · The ring can therefore move freely in the axial direction between the annular Shoulders 16 and 17 move the hat I4 sideways limit. - _ '_

The outside diameter of each of the shoulders 16, 17 is essential smaller than the diameter of the inner surface 1a of the cylinder, so that ring channels between the "circumference of the shoulders. and the Area la are available * If the shoulders are to serve as a guide instead of an annular channel, sector-shaped channels can be provided. ". - - ■ - ■ - ■■" ■ "" -. "; -" -

The groove 14 is connected at its Grund.mit the pressure chamber 18 of the piston 5 by channels 19, which in an axial bore open, which extends partially through a cylindrical extension 21 of the piston 5 u * id through the piston body. the Pressure chamber 18 of the piston 5 is in turn through a bore 22 with an internal connection thread 22ä for a not shown -connected, which leads to a supply line for one of the

■ - 9 .-

-separated brake circuits of the vehicle.

The pressure chamber 18 is on the ¹ side facing the plug 2, limited by a second piston 23. which is provided with two -nuts 24 »25. The groove 24 forms a hanging chamber 26 with the surface 1a of the cylinder, while the ring 25 serves to accommodate a floating ring 27, the inner surface of which is at a distance from the base of the groove 25 and which is in contact with the wall 1a located outer surface is freely displaceable in the axial direction between two radial shoulders 28, 29 which laterally delimit the groove 25. The description given above for the shoulders 16, Tj also applies to the shoulders 28, 29.

The bottom of the groove 25 is formed by a number of radial channels 30 connected to a cylindrical recess 31, which is partly * - by a cylindrical extension 32 of the piston 23 and extends through the piston body. The extension 32 acts, among other things, as a guide for the spring 33s its one end against the shoulder 28 and at its other end is supported against the plug 2 with a certain bias.

The pressure chamber.34 in which the spring 33 is located is through a bore 35 with a connection internal thread 35a for

«10«

connected to a Hippel, not shown, who szt. is connected to the second separate brake circuit of the vehicle. The: annular chamber 26 is constantly connected via a bore 36 with an internal connection thread 37 f ^ z * a _nipple in connection, wel-. rather, it is connected to a second container, not shown . ■■ "■ _ ■■""'." ■

The length of the annular groove 26 is such that, regardless of the position of the piston during operation of the master cylinder, the bore 36 is constantly in connection with the annular chamber 26. Immediately following den.Bohrungen 12, 36 in the direction of the movements of the pistons for conveying fluid to the brake circuits, small compensating bores 38, 39 are provided, which are connected to the lane side of the Frppel 13,37. The compensating bores are arranged in such a way that they are in communication with the pressure chambers 18, 34 when the main cylinder and the parts associated with it are in their idle state, and a very small distance from the top * of the circumference of the sealing elements 1: 5 »27. made of elastic material, so that the connection between the balancing bores 3 ⁸ > 39 and the pressure chambers 18, 34 is switched off after a very short stroke of the pistons 5> 23»

A sealing ^{ring 40 is similar to a 3-r} äem ring 9, - seals-between the ^ Kammerfi 16 and 26 from. The ring 40 is "between the- '

«11

. _ y j

Surface of the piston 25 'which faces 18 of the pressure chamber, and an annular waistband 41 disposed a cylindrical Druckstüekes 42 * The latter is "charged, the SFisehen the collar 4I uftcl a flange 44 ^a disposed of" by a spring 45 on the free end of the side wall of a cup-shaped part 44 made of pressed sheet metal, .. is provided, which is pushed onto the hollow projection 21 of the piston 5 «

The pressure piece 42 is formed with a tubular extension 42a which extends into the inner opening of the ring 40. The outside diameter of this: ^{the extension is smaller than the:} diameter of the inner opening of the ring 40 »while the length of the extension in the axial direction of the cylinder is smaller than the thickness of the ring. This results in a satisfactory seal by the ring 40> when the pressure piece 42 is subjected to a pressure in the direction of the piston 25. The inner cavity 45 of the pressure piece 42 extends beyond the collar 4I and in this area is connected to the outside of the pressure piece through circumferential slots 46. The pressure piece 42 carries a shaft 48j which extends into the cup-shaped part 44 through a radial slot 49 in the bottom wall 44h of the cup-shaped part and ends with a head 50, the diameter of which is greater than the width of the slot 49 and such that the

- 12--

Braid in the inner bore 20 of the projection 21 of the piston 5 can slide. For the arrangement of the cup-shaped! Part 44 ^a11 f shaft 4 & and for the removal of this is; the slot 49 extends the peripheral wall of the cup-shaped part and widened at its end to form a T-shaped opening 51.

Between the inner bore 20 in the extension 21 of the piston 5 and the pressure chamber 18, as a result of the arrangement of radial bores 52 in the peripheral wall of the cup-shaped part 44 ¹ ^ a. from radial bores 53 in. In the wall of the extension 2t there is a constant flow of oil. .

The assembly of the part 42, the spring 43 and the cup-shaped part 44 forms "the so-called preload or preload unit. This assembly can be built into the cylinder" or removed from it without its parts being disassembled and acts as an intermediate member, which is used to transmit pressure between: the pistons 5 ^and 23. The extension 4.2a of the part 42 of the mentioned unit can serve as that part which carries the Hing 40 during the installation of the unit in the cylinder. -. .

The design of the preload unit allows the spring 43 a higher "preload than the spring 53 can be given, since that

■ -Ί3 "-

Compression of the spring 43 is made possible by the head 50 located on the shaft 48, which is located in the bore or * slides in the chamber 20 in the direction of the piston 5} whereby the cup-shaped part 44 rests with its bottom 44k a-a end of the projection 21.

Fig. 10-13 show a further embodiment of the preload ' Stungseinheit, which differs from that described above in that the pressure piece carrying the shaft 48 through a cylindrical extension 48a of the shaft is replaced, in the circumference of which continuous grooves 54 extending in the longitudinal direction are cut and their outer diameter dem Diameter of the projection 42a of the pressure piece 42 shown in FIGS. 1 and 2-6 is adapted. The Bund 4I acts as a separate one Element and is arranged on a stepped part of the extension 48a, the diameter of which is suitably the diameter of the head exceeds 50. The cylinder works like

follows. . , - "" - ".- ■■; ■

When the brake pedal, not shown, is depressed, a pressure in the direction of the plug 2 on part 6. The latter transfers the pressure to the piston 5> so that the pressure is transferred to the door loading unit arranged in the chamber 18. "" " and from this to the piston 23 «Da, -the preload of the

If spring 43 exceeds the preload of spring 3 $, the latter is first compressed, so that pistons 5 and 25 simultaneously execute a movement in the direction of stopper 2 until the connection of pressure chambers 18, 34 ^with their containers is simultaneously cut off -will * The braking effect therefore begins in the circuit connected to the pressure chamber 34 and subsequently in the brake circuit connected to the chamber 18. ■■■ '..-.- ^: ■■ -_. "- -". ".". "■" ..

As mentioned, they are. Door loads of springs 3 $> 43 selected so that the preload of the spring 45 is that of the spring 33 exceeds. For example, if the preload 'of the spring' 43 has a value of 3.5. & G, the preload on the spring is 33 only 2.5 kg.

However, the elasticity of the two aforementioned springs should be the same and such that the annular seals acting as valves .15,27 simultaneously connect to the switch off the corresponding 'containers and reduce the total load on the Spring 33 in the direction of the plug 2, i.e. its bias plus the stress caused by squeezing, the same or a little less is than the preload of the spring 43

The innovation does not apply to those shown and described

Embodiments are limited, but can be within their Undergone various changes. -. "."

PROTECTIVE APPROACH

«16-

Claims (1)

. SGHÜTZAHSPRtTCHE:; -. . -. ... ■ ..: 1. ; / Master cylinder for hydraulic brake systems, in which separate circles are provided, in particular for vehicles, with a cylinder in which a first and a second piston are slidably arranged, between which a first spring is supported, which serves to keep them constantly in the _absence: to withstand another so they that a first in the cylinder. Pressure chamber limit, a second spring between the second. Piston and a stationary element is arranged in the cylinder and serves to keep the corresponding end of the cylinder from the second piston at a distance, so that the latter in the cylinder has a second pressure chamber in the vicinity of the mentioned. End of the cylinder limited, each piston being formed between its opposite ends with a hat which, together with the inner wall of the cylinder, defines a hanging chamber which is constantly in communication with the separate container, and sealing elements are also provided which. are in sliding contact with the inner wall of the cylinder and are arranged at the mentioned opposite ends of each piston, wherein the Di ehtungse lement e arranged at those ends of the first and the second piston, which face the first and second pressure chambers, are designed, that they act as -Valves..to the connection between the neighboring - -17 « Annular chamber and the pressure chamber in which the spring is arranged ^: which acts on the respective piston to switch off, / ■ if the latter moves forward against the action of this spring, "" and to re-establish the connection mentioned after the piston has its Rücfchub has executed, the first and the second chamber are each constantly connected to one of the two separate brake circuits of the vehicle, the springs acting on the two pistons are preloaded, the properties and the dimensions of all components are selected so that when the system is idle the first and second pressure chambers are each connected to their container through small bores provided in the cylinder wall, which are seen at a small distance from the top of the valves acting as valves and carried by the pistons. Sealing elements are located, characterized in that the built-in first spring has a higher preload than the other spring. 2. Master cylinder according to claim 1, characterized. draws that the flexibility or elasticity of the mentioned both springs is so large that when the sealing rings acting as valves simultaneously the connection switch off between the containers and the neighboring pressure chambers, the total load on the second spring is equal to or slightly lower than the preload of the first. Feather. - 18th .3 "- master cylinder according to claims 1 and 2, characterized in that the element transmitting the pressure" between the first and second pistons is designed as a spring which is supported at its ends on a radial flange which at the free end of the circumferential wall of a cup-shaped pushed onto a tubular extension of the first piston. gen part is provided, and is supported on an annular collar of a pressure piece intended for cooperation with the second piston and provided with a shaft which protrudes into the cup-shaped part through a bore provided in the bottom of the latter and which at its free. The end carries a head which is larger than the bore in the bottom of the cup-shaped part and is such that it can be slid in the hollow extension of the first piston in its axial direction. 4 · master cylinder according to claim 3? characterized, that the pressure piece has a hollow cylindrical part on that side of the annular collar that facing away from the end of the shaft protruding into the cup-shaped part, is provided with a tubular extension, which together with the aforementioned annular collar forms a seat to support the elastic sealing element, the .zur Support between the first pressure chamber and the annular chamber is used, which through the groove on the middle part of the second Koi- bens and the first pressure chamber is limited, the interior. of the hollow pressure piece further through with the first pressure chamber. - Openings connected in its peripheral wall on the dem .: tubular neck facing away from the annular collar are provided. 5.. -. ■ Master cylinder according to claim 3, characterized in that the pressure piece has a cylindrical body, which is provided on its circumference with continuous axial Ausfr.äsungen, the annular collar in the form of a separate Element has and on a detached part of the - ■. Shaft bearing pressure piece is arranged, which is in the cup-shaped Rope from pressed sheet protrudes " For ΪΙΑΤ Societsi per Azionit PATENTAHWÄI.TE DR.-ING. H. FINCKE, DIPL.-ING. H. BOHR DlPL-iNö. S. STAESER,