DE2645471C2 - Power boosters for hydraulic systems, in particular braking systems - Google Patents

Description

characterized in that

40

h) associated with the return (38) is a throttle member (37) which increasingly throttles the latter when the pressure in the booster chamber (14) rises is

i) the control slide (20) has a continuous longitudinal bore (24) which connects the booster chamber (14) to the bottom side of the blind bore (15) of the slide via a diaphragm (23) provided on the control slide (20) (12) connects,

j) the transverse bore (25) of the control slide (20) is arranged on the tappet side of the diaphragm (23) and the continuous longitudinal bore (24) with an annular recess (26) of the slide (12) connects,

k} the annular groove (22) of the control slide (20) has control edges (27 and 27 ') at its ends, via which the first transverse bore (16) with the annular recess (26) of the slide (12) when the control slide (20) is actuated connectable and the resilient continuation (4) can be throttled at low load on the second transverse bore (18) of the slide (12).

I) the pressure-limiting device (29) exerts a pressure against the force under the action of the pressure in the booster chamber (14) has a spring (33) in the plunger (7) retractable piston (35) via which the The control slide (20) can be actuated by the plunger (67)

2. Booster according to claim 1, characterized in that

a) the piston (35) of the pressure limiting device (29) in an axial recess 28) of the Ram (7) is arranged,

b) the piston (35) via an extension (30) in an outwardly open longitudinal bore (31) of the plunger (7) is sealed and slidably guided

c) the spring (33) assigned to the piston (35) on the tappet side on the end wall of the recess (28) is supported,

d) the piston (35) via the spring (33) to a stop (34) provided in the recess (28) is applied when the force of the spring (33) outweighs the effect of the pressure of the booster chamber (14),

e) the piston (35) has a shoulder (32) via which the control slide (20) can be actuated

3. Booster according to claims 1 or 2, characterized in that the plunger (7) has a has an annular end face formed by the recess (28), via which the slide (12) is mechanically operated

4. Power booster according to one of claims 1 to 3, characterized in that a return spring (11) is arranged in the booster chamber (14) is which on one side on the slide (12) and on the other side on a spring plate (10) supports the on a stop (9) of the plunger (7) and in the unactuated starting position of the Tappet (7) on the housing side.

5. Booster according to claim 1, characterized in that

a)

b)

the throttle member (37) has a throttle point (41) which is formed on the bottom side of a sleeve (44) that is slidably guided in a recess (40),

the recess (40) on the one hand of the sleeve (44) is connected to the booster chamber (14) and on the other hand of the sleeve (44) is connected to the return (38),

the sleeve (44) is displaceable under the action of the pressure of the booster chamber (14) against the force of a spring (42) and the return can be throttled by the sleeve (44)

The invention relates to a power booster for hydraulic systems, in particular motor vehicle brake systems, according to the preamble of claim 1.

Such power amplifiers have the purpose of amplifying a predetermined actuating force on the plunger up to a predetermined maximum value and over a To make pressure piece for the actuation of an implement, such as a master cylinder, usable.

A power amplifier of this type is known from DE-AS 01 680. This booster has a Control slide on, with which when operated over

a first control edge blocked a return, via a second control edge, a pressure medium inlet opened and a loadable continuation via a third control edge is throttled. The pressure medium inlet controlled in this way is via a filter and a throttle point with a booster chamber connected, which via a pressure limiting device formed with a check valve can be connected to a further return. It is disadvantageous that the proposed triangular control and pressure limiting device cause too expensive a structure that the resilient continued operation when the pressure medium inlet is connected to the intensifier chamber, regardless of its load is throttled and that the function of the pressure relief device from the action of a maintenance-dependent Throttle point with filter is dependent

The invention is therefore based on the object of providing a simple, while avoiding the aforementioned disadvantages and to create compact buildable power amplifiers, which reliably limit the pressure the booster chamber and a further load that can be loaded independently of the pressure of the booster chamber

This object is given by the characterizing features in claim 1 invention solved

Further developments and advantageous configurations of the invention are shown in claims 2 to 5

The advantages of the invention include: in that through the proposed return and pressure limiting arrangement an additional return control with the control slide omitted. Thus, with the control slide only the pressure medium inlet of the Amplifier chamber and the resilient continuation to control what a significantly simplified amplifier structure enables. The control slide is also considerable on the proposed basis of only two control edges easier to manufacture. It is particularly advantageous if • ■ 'ie the first and second control edge on the Ends of an annular groove are formed so that the pressure medium inlet of the booster chamber via the first control edge is controllable with unthrottled continuation if the pressure of the continuation is higher than the pressure the booster chamber and the pressure medium inlet via the second S'.euerkante with throttled continuation is controllable when the pressure in the continuation is smaller than the pressure in the booster chamber, whereby a independent of the pressure of the booster chamber supply of the continuation is made possible.

The embodiment of the pressure limiting device proposed in claim 2 enables a jerk-free and reliable pressure limitation, avoiding upstream filters, as well as via the proposed annular approach a failure-prone operation of the control slide. According to the claim 3 proposed annular end face of the plunger enables mechanical actuation of the slide in the event of a pressure failure.

The arrangement of the return spring proposed in claim 4 has a supporting effect which enclose the plunger of the pressure relief device The spring on the one hand and the one holding the slide in ange on the pressure piece and the control slide against the spring loading the plunger on the other hand, whereby these two springs are economically advantageous can be interpreted.

An embodiment of the invention is shown in the drawing and is described in more detail below.

The figure shows a longitudinal section through a power amplifier.

The figure outlines the booster with its cylinder I, the cylinder bore 2 of which has a pressure medium inlet 3, a continuation 4 and sealing pieces introduced into the cylinder on both sides 5 and

6 has

The locking pieces 5 and 6 have through holes axially to the cylinder bore on, in which on the one hand in the closure piece 5 a plunger

7 for the actuation of the booster and, on the other hand, a pressure piece 8 in each case sealed in the closure piece 6 and are slidably arranged.

In the cylinder bore 2 is a on the pressure piece 8 under the action of a on one on the closure piece 6 and on a given stop 9 on the plunger 7 abutting spring plate 10 supporting return spring 11 adjoining slide 12, which is slidably displaceable in the cylinder bore 2, w-iicher the cylinder bore 2 in a limited by him and by the printing block 8 return chamber 13 and in one of him and by the plunger 7 limited booster chamber 14 divides

The slide 12 has a plunger side axially to the cylinder receipt, üng 2 introduced blind hole 15, which has a transverse hole 16 and an annular groove 17 of the Slide 12 with the pressure medium inlet 3 and a further transverse bore 18 and an annular groove 19 with the continuation 4 is connected.

In the blind bore 15 of the slide 12 there is a control slide 20 which interacts with the tappet 7 slidably arranged and displaceable against the force of a spring 21 supported on the bottom of the blind bore 15, which one the two transverse bores 16 and 18 of the slide 12 and thus the pressure medium inlet 3 and the annular groove 22 connecting the continuation 4 and one with the booster chamber 14 on the one hand and one on the other via a diaphragm 23 with the space of the spring 21 connected longitudinal bore 24 which when actuated of the plunger 7 via a transverse bore 25 of the control slide 20 and an annular recess 26 of the blind hole 15 of the slide 12 and via the annular groove 22 of the control slide 20 with the Drockmitteleinlaß 3 is connectable.

The annular groove 22 of the control slide 20 has control edges 27 and 27 'on its lateral boundary which, when the plunger 7 is not actuated, blocks the connection between the longitudinal bore 24 and the pressure medium inlet 3 and the connection of the continuation 4 to the pressure medium inlet 3 is fully open and when actuated The plunger 7 as a function of a load on the continuation 4 with a decreasing load on the continuation <i the connection of the continuation 4 to the pressure medium inlet 3 increasingly dros «elbar and the connection of the longitudinal bore 24 to the pressure medium inlet 3 increasingly is unlockable.

The plunger 7 has a recess 28 made on the slide side and axially to the cylinder bore 2, in which a pressure limiting device 29 is arranged so that the plunger 7 interacts via the pressure limiting device 29 with the control slide 20 and, when the pressure limiting device 29 is played over, with its on the wall of the recess 28 given ι ', ng-shaped end face with the facing, annular end face of the slide 12 can be cooperated.
The pressure limiting device 29 comprises a

arranged with play in the recess 28, on the one hand with an extension 30 in an outward direction open longitudinal bore 31 of the plunger 7 slidably and sealed guided and on the other hand with an approach 32 cooperating with the control slide 20, under the force of one on the end wall of the recess 28 supported spring 33 below one by the cross section of the extension 30 and the force of the Spring 33 predeterminable pressure in the booster chamber 14 on a slide side in the recess 28 given by a snap ring stop 34 resting and under the action of the predetermined Pressure in the booster chamber 14 against the force of the spring 33 displaceable plunger 35.

The booster chamber 14 is connected to a return 38 via a bore 36 and a throttle member 37.

The throttle member 37 is on the one hand over the abutment of the plunger 35 of the Druckbcgrcn / .iingscinrichtung 29 at the stop 34 while driving the control slide resting against the shoulder 32 of the plunger 35 20 against the force of the spring 21, wherein the Stcucrschicber 20 on the one hand the connection of the booster chamber 14 via the longitudinal bore via its control edge 27 ' 24 and the transverse bore 25 of the control slide 20, the annular recess 26 of the slide 12, the annular groove 22 of the control slide 20, the transverse bore 16 and

ίο the annular groove 17 of the slide 12 to the pressure medium inlet

3 releases and, on the other hand, via its control edge 27, the connection of the pressure medium inlet 3 to continue running

4 corresponding to the loading of the continuation 4 with decreasing loading of the continuation 4 increasing throttles and thus in the booster chamber 14 is a desired independent of the load on the continuation 4 Causes pressure build-up. The pressure built up in this way in the booster chamber 14 produces

Bore 36 with the booster chamber! 4 and another one in relation to the Bciätigüngskraft F ί in the ratio

on the other hand via an annular recess 39 with the return 38 connected, cylindrical recess 40 and has a slidingly introduced into the cylindrical recess 40, the booster chamber 14 connecting via a throttle point 41 to the return 38, under the action of the pressure of the booster chamber 14 displaceable against the force of a spring 42 and thereby connected to the return 38, annular recess 39 increasingly blocking and when the booster chamber 14 is not pressurized under the force of the spring 42 rests against a stop 43 given in the cylindrical recess 40 and while the annular recess 39 to the cylindrical recess 40 opening sleeve 44.

The return chamber 13 is via an annular recess made on the front side in the closure piece 6 45, a bore 46 and the annular recess 39 are connected to the return 38.

The mode of operation of the power amplifier shown in the figure is as follows:

In the figure, the booster is in its unactuated Bumps! 7 given starting position. The pressure medium inlet 3 is via the annular groove 17 and the transverse bore 16 of the slide 12 and, via the annular groove 22 of the control slide 20, the transverse bore 18 and the annular groove 19 of the slide 12 are connected to the continuation 4. Dx booster chamber 14 is pressureless, since the control slide 20 with its control edge 27 'connects the booster chamber 14 to the pressure medium inlet 3 blocks. The plunger 35 of the pressure limiting device 29 is under the action of the pretensioned spring 42 3m stop 43. The slider 12 is under the force of the spring 21 on the pressure piece 8 and the control slide 20 is under the action of the spring 21 at the approach 32 of the plunger 35 of the pressure limiting device 29 and holds the plunger 7, supported by the force of the return spring 11, in its standby position, depending on the type of installation of the booster, the path of the control slide 20 in the tappet direction, for example by a not described in detail, in the figure at a given stop in the blind hole 15 of the slide 12 snap ring can be limited. Furthermore, the sleeve 44 of the throttle member 37 is under the force of the spring 42 on the stop 43, the sleeve 44 being the connection from the cylindrical recess 40 to the return 38 connected, annular recess 39 releases.

When the plunger 7 is actuated, the plunger 7 moves under the action of the actuating force Fl while it remains The active surfaces of the slide 12 and the plunger 7 are reinforced by the pressure piece resting on the slide 12 8 usable force F 2.

The pressure given in the booster chamber 14 is also available via the bore 36 on the throttle member 37 to which via the throttle point 41 of the sleeve 44 and by the under the action of the increasing Pressure of the booster chamber 14 against the force de. Slidable spring 42 and with the Return 38 connected, annular recess 39 increasingly blocking sleeve 44 a predetermined, maximum current flow of, for example, 1.5 l / min, to the return 38 guaranteed

As soon as the pressure in the booster chamber 14 exceeds the effective area of the extension 30 of the shock absorber 35 of the Pressure limiting device 29 overcomes the force of the spring 33, the plunger 35 moves against the Force of the spring 33 at the following under the force of the spring 21 and thereby the connection of the pressure medium inlet 3 to the booster chamber 14 and its control edge 27 'increasingly blocking control slide 20, whereby the pressure increase in the booster chamber 14 ends and the pressure in the booster chamber 14 ends by the effective surface of the extension 30 of the plunger 35 of the pressure limiting device 29 and the Force of the spring 33 predetermined value for the design and safety of the transmission elements Brake system adapted manner is limited.

As soon as the actuation of the plunger 7 ends, the pressure in the booster chamber 14 is reduced via the throttle member 29 and all displaceable parts of the booster take their previously described starting position under the force of the springs assigned to them.
If the pressure fails before or during actuation of the plunger 7, the plunger 7 moves under the action of the actuating force F \ against the force of the springs 21 and 33 and the return spring 11 and finally rests with its annular end face on the end face of the slide 12, whereby a control of the actuating force F 1 to the pressure piece 8 is given without danger to the displaceable parts of the force amplifier

1 sheet of drawings

Claims (1)

Patent claims: 1. Booster for hydraulic systems, especially motor vehicle brake systems, with a) a cylinder which has a through cylinder bore b) one sealed at one end of the cylinder bore and arranged to be slidable th plunger, which has a pressure limiting device c) a slide which is slidably displaceable in the cylinder bore and can be actuated by the plunger and via which a pressure piece can be actuated, d) a blind bore axially introduced into the slide on the tappet side, which has a first Cross hole and ring groove of the slide with a pressure medium inlet and a second cross hole and ring groove with a loadable Continuation is connected, e) one which is arranged to be slidable in the blind bore and can be actuated by the plunger via the pressure-limiting device Control slide, which one the first and the second transverse bore of the slide with each other having connecting annular groove f) one longitudinal and one transverse bore each made in the control slide, via which the Sackbol'THig at the bottom of the control spool can be connected to the pressure medium inlet g) a booster chamber formed in the cylinder bore, which '.: on one side of the tappet and on the other side of the slide and the control slide and limited is connected to a throttled return,