DE2923018A1 - HYDRAULIC BRAKE REGULATOR - Google Patents

Description

, 552 4 · · ···· ·
• · · · · ■ · · · · 1 R. 5.1979 He / Kö 16.

ROBERT BOSCH GMBK ₅ 7OOO Stuttgart Hydraulic brake force regulator State of the art

The invention is based on a brake force regulator according to the preamble of the main claim. Such a brake force relay is known (FR-PS 1 177 115). With such brake force regulators, the brake pressure for one of two brake circuits, preferably for that of the rear axle ^ is passed through the brake force regulator in order to regulate it down as a function of load changes on the corresponding vehicle thing. In this way, the brake pressure on the vehicle rear axle can be ^{reduced from a ratio of 1: 1 to a ratio of approximately 1} J: 1. The pressure curve achieved is at least largely linear.

Although DE-OS 17 80 560 already discloses a brake force regulator of the type mentioned above, which works with a degressive characteristic. When adjusting in the dynamic range, i.e. when braking the vehicle and when the load is shifted accordingly - braking means in an intermediate storage

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rather drained. Such a setup is cumbersome, prone to failure and it does not work in the ideal range for all delays that occur. The dynamic Regulation is difficult because the balance arm bearing can only be adjusted after the brake pressure has built up accordingly takes place, because the rear axle springs out first. In addition, the absorption volume of the intermediate storage limited and therefore exhaustible.

Advantages of the invention

The brake force regulator according to the invention with the characterizing features of the main claim has on the other hand the advantages that it works as a degressive controller to control the front and rear even when the vehicle is braked Rear axle to be able to take advantage of the same frictional connection. This already takes place with the initial pressure build-up the control ratio changed, and pressure medium with the intended pressure level reaches the brake cylinder, However, the pressure medium consumption is already lower during the pressure build-up than with other brake force regulators. The reduction is also independent of the pressure build-up time.

It is also advantageous that no additional Control units or piston-cylinder units are required, the use of which leads to inaccuracies and / or delays.

drawing

An embodiment of the invention is shown in the drawing

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tion and explained in more detail in the following description. FIG. 1 shows a “brake force regulator in section and FIG. 2 shows a pressure diagram over the course of the pressure.

Description of the embodiment

A hydraulic brake force regulator 1 is inserted in a brake line 2, 3 between a hydraulic master cylinder 4 and a wheel brake cylinder 5 _S, preferably a wheel brake cylinder of a vehicle rear axle. The brake force regulator 1 has an input channel 6 which leads into a working space 7 which is delimited by a piston member 8 as a movable wall. The piston member 8 carries a tappet 9 whose end facing away from the piston member 8 is provided with a pressure cap 10.

A channel 11 branches off from the input channel 6, the passage of which is monitored by a regulator valve 12. The regulator valve 12 has a valve tappet 13 which can protrude into a working space 14 and there can be actuated by a piston member 15 in the sense of opening and closing the regulator valve 12. The working space Ik is connected to a housing connection bore 16, from which the brake line 3 takes its exit. In this way, when the regulator valve 12 is open, the piston member 15 is subject to the brake pressure in the entire brake line 2 and 3 and, when the regulator valve 12 is closed, only to the brake pressure in the part 3 of the brake line 2 leading to the wheel brake cylinder 5,

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The piston member 15 is angoerdnet parallel to the piston member 8 and, just like this, carries a plunger 19 with a pressure dome 20. The piston member 15 with its plunger 19 is for direct cooperation with the one side of a balance beam 17 is determined, while the piston member 8 with its plunger 9 on the other side of the balance beam 17 acts.

The balance beam 17 is rotatably mounted on a pin 18 which is attached to a carriage which is on a base plate to the left and right can slide. The slide and base plate are not shown. Of the The carriage is adjustable by a fork 22 which is mounted at 23 and which depends on its mounting 23 is pivotable from the change in the distance of a vehicle axle from a vehicle body. By this pivoting of the fork 22 and displacement of the carriage change when the load changes effective lengths of the lever arms of the balance beam 17.

The piston member 8 is designed in two parts and has two concentric partial pistons 24 and 25 · the outer one Partial piston 24 carries an annular sealing collar 26, the sealing lip of which faces the working space 7. It has an annular guide surface at each of its two ends 27 and 28, one of which is adjacent to the working space 7 and the other on a spring plate 29 is provided. The spring plate 29 serves as an abutment for a spring 30 which is inserted into a sleeve 31 and the other end of which rests against a sleeve base 32 on the inside. The plunger 9 has close to its pressure tip an annular groove into which a snap ring 33 is inserted.

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The sleeve 31 is supported with its sleeve base 32 on the snap ring 33 and is firmly seated there because the spring 30 is inserted with pretension between the partial columns 24 and the sleeve 31. Below the guide surface 28 of the piston part 24, a snap ring 36 is let into a bore widening of the housing of the brake force relay. This snap ring 36 serves as a stop for the piston part 24 when it has made a small downward switching stroke against the force of the spring 30. Oawit the effect of this partial piston 2h is limited to the spring.

The smaller partial piston 25 is fixed to the stem 9

connected, carries an O-ring seal 34 and is with

this inserted slidably into a bore 35 of the piston part 2k .

Mode of action

The brake pressure coming from the master cylinder k can initially propagate unhindered through the brake force regulator and (through its control valve 12 to the wheel cylinder 5. With further pressure control, the output brake pressure is regulated according to the respective position of the balance beam 17 in a ratio of 1: 1 to 4: 1 Due to the increasing brake pressure during braking, both sub-pistons 2k and 25 are first moved together. In the diagram according to FIG. the pressure runs along the 45 ° line (curve E, ratio 1: 1).

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Depending on the curtailment, a point A is reached with a set control ratio of H : 1 and a point B with a control ratio of 2: 1, at which the curtailment begins along a curve C or D.

When a pressure of e.g. 80 bar is reached in the inlet chamber 7, the outer partial piston goes against the force the spring 30 while passing through the stroke X down to the stop on the snap ring 36. Have in the diagram At this point, all curves C, D, E have a kink F, G, H, from which the pressure is reduced on the Doubled, i.e. from 4: 1 to 8: 1, from 2: 1 to 4: 1 and from 1: 1 to 2: 1. This is also true for all values lying between these curves C, D, E.

In this way, the braking force regulator works with a degressive characteristic curve, which is an ideal one Braking lines 37, 38 and 39 drawn in dash-dotted lines largely correspond.

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Claims (7)

·· 4 · · Il »II May 16, 1979 He / Kö ROBERT BOSCH GMBH, 7OOO Stuttgart 1 Expectations ! ^ Brake force regulator, which is in a brake line between a master cylinder and a wheel cylinder are installed and the one with a balance beam with load-dependent Change of its effective lever lengths and with two resting on opposite contact points of the balance beam Piston members are provided, one of which actuates a regulator valve, characterized in that a piston member (8) is in two parts and has two concentric partial pistons (24, 25), of which preferably the outer (24) acts on the balance beam (17) via a spring (30) and from a certain pressure through '·' A stop (snap ring 36) is limited. 2. Brake power regulator according to claim 1, characterized in that the two-part piston member (8) has an inner one Partial piston (25) which carries a plunger (9) cooperating with the balance beam (17), and an inner one Partial piston (25) surrounding outer, the force of the spring (30) subject to sub-piston (24), and that the spring (30) is biased. 030051/0109 tr ». 2923018 - ² - ^R -55 21 3. Brake force regulator according to claim 1 or 2, characterized in that that in the area of the end of the plunger (9) cooperating with the balance beam (17) on this a sleeve (31) is attached which receives the spring (30) over the greater part of its length. 4. Brake force regulator according to one of claims 1 to 3, characterized in that a stop for the outer. Partial piston (2 * 0 through one in a bore widening used snap ring (36) is formed. 5. Brake force regulator according to one of claims 1 to 4, characterized in that the outer piston part (24) at its end facing the spring (30) is enlarged to form a spring plate (29). 6. Brake power regulator according to claim 5, characterized in that the outer partial piston (24) with an annular Sealing collar (26) is fitted between two annular guide surfaces (27, 28) of the partial piston (24) is arranged, one of which faces an input channel (6) of the brake force controller (1) and the other is formed on the spring plate (29). - 3 030051/0109 - 3 - R. 55 2 7. Brake regulator according to one of claims 3 to 6, characterized in that the fastening of the sleeve (3D is formed on the plunger (9) by a snap ring (33) on which a base (32) of the sleeve (31) is held under the force of the pretensioned spring (30). 030051/0109