DE8521133U1 - Pressure amplifier and modulator - Google Patents

Description

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1891/ot/mu

26.04.1985

ROBERT BOSCH GMBH, 7000 Stuttgart 1 Pressure amplifier and modulator

State of the art

The invention is based on a pressure booster and modulator according to the type of the main claim and finds a preferred field of application as a brake pressure booster and at the same time modulator in the manner of an integrated anti-lock braking system for carrying out ABS functions in vehicle braking systems. For example, in a hydraulic braking system, for example with multi-circuit ^ tandem master brake cylinders, it is known (DE-OS 27 23 734) that

To assign ABS functions to the brake system, for example to switch electrically operated multi-way solenoid valves into the output brake pressure lines to the wheel brake cylinders, which implement the desired and required ABS control functions. In the event of a pressure drop, these solenoid valves close the respective pressure line from the master brake cylinder to the connected wheel brake cylinders and, if necessary, feed pressure medium to the return flow. If the pressure increases again as desired, the connection to the master brake cylinder is then re-established, in each case with

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any printing time profile and with the possibility of printing

i holding functions to be implemented. Prerequisite for such vehicle |

braking systems always require the presence of an energy source, |

which supplies the brake fluid to the master cylinder under high pressure |·

so that this can then be achieved in accordance with the [

Braking effect can be controlled in the pressure lines to the wheel brake cylinders. Such a separate energy supply is required. 1

source, which usually includes a pump, an electric motor that drives it |

tromotor and corresponding pressure switches, also in the reactor |.

ization of ABS functions, since the previous electrically controlled vk

operated multi-way solenoid valves pressurized brake s|

medium or brake fluid is practically "lost" and must subsequently be pumped back to the high pressure that
is required for the braking process. Furthermore, it is necessary
When implementing AiBS functions, systems that have a
Interruption of the brake lines and a discharge of the |

located pressure medium, very reliable and fail-safe | _s ;

'φ so that in case of malfunction there is no danger of

that too much brake fluid under high pressure was released %

or in some cases not even the wheel brake cylinders j

can be supplied. i

In the area of implementation of ABS functions it is also important .

(US-PS 3 690 736; US-PS 3 731 979), a parallel branch f in the from the master brake cylinder to the respective wheel brake cylinders
leading cables and connect this branch with a room

which is operated by an electrically operated cylinder piston j

aggregate depending on the control of an actuating coil against the pressure m

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a spring is variable, so that pressure volume can be taken from the brake line and fed back in again - so-called plunger principle. In this case, the brake circuit also remains closed; however, means are required to interrupt the further supply of high-pressure brake fluid from the master brake cylinder during ABS functions, so that the pressure fluid extraction through the variable space can actually take effect up to the wheel brake cylinders. This interruption can also be made possible by (US-PS 3,690,736) the receding piston simultaneously releasing a ball valve to close the master brake cylinder supply line. If the system fails at this point, however, it is no longer possible to act from the master brake cylinder, i.e. through beta-f?

to build up any braking pressure at all without depressing the brake pedal.

The invention is based on the object of creating a brake pressure booster and modulator, particularly for vehicle brake systems, which, without the need for an external pressure supply, is able to provide a correspondingly increased or increased pressure to the wheel brake cylinders following the controlled brake pressure and is at the same time designed in such a way that a modulation of the brake pressure at the wheel brake cylinders is possible to implement ABS functions without major effort using basic and identical pressure booster components.

Advantages of the invention

This task is solved by the pressure amplifier according to the invention and

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-modulator, in particular for the brake pressure in vehicle brake systems with the characterizing features of the main claim and has the advantage that with a completely closed design of the brake pressure booster and modulator with only one input for supplying the brake pressure from the master brake cylinder and one output for connection to the wheel brake cylinder or several wheel brake cylinders

1. no external energy source is required to increase the brake pressure, but the force required to increase the brake pressure during the respective braking process is obtained by storing potential energy and is recovered again at the end of the braking process, i.e. essentially without any energy loss, with the exception of minor hysteresis losses;

2. Due to the absence of an external energy supply - with the exception of electrical control energy that is supplied to excitation coils, the brake pressure booster and modulator is not only more cost-effective than conventional brake boosters, but

3. also significantly more reliable, as fewer parts can fail, which should be taken into account especially with an external pressure supply and therefore

4. is much more reliable and safer in its operation.

A particular advantage of the present invention is that

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the brake pressure booster and modulator

5. consists of only a few parts, which are therefore easy to assemble and

6. has a very simple construction; in addition,

7. the design of the brake booster and -raoc ¹ viars robust and

8. low maintenance and

9. Compact in a comparatively small space and therefore also close to the wheel brake cylinders.

Further advantages of the present invention are that the brake pressure booster, using essential basic components, can also simultaneously, by supplying appropriate electrical control signals to an excitation stage

10. in the form of a so-called integrated anti-lock braking system

j systems in continuous transition and immediately effective

can realize large ABS functions, whereby, based on this ability

11. by arranging just one additional excitation coil a simple extension is also possible for traction control (ASR) functions.

12. Finally, the pressure modulation in the area of implementation of ABS functions requires only a very low energy requirement, whereby

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13. there is no reaction of the pressure modulation on the brake pedal - on the other hand, the driver can of course be informed via indicator lights etc. and finally

14. The brake pressure booster can be expanded to generate the desired pressure by simply connecting additional brake pressure boosters on a magnetic basis.

The measures listed in the subclaims enable advantageous further developments and improvements of the pressure amplifier and modulator specified in the main claim.

drawing

An embodiment of the invention is shown in the drawing and is explained in more detail in the following description. The drawing shows in cross section the compact structure of a brake pressure booster and modulator according to the invention, housed within a closed housing.

Description of the embodiments

The basic idea of the present invention is to use the storage of existing potential energy for brake pressure amplification with the possibility of recovery and preferably using magnetic systems and at the same time for brake pressure modulation the pressure amplification

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Pressure chamber is connected via a valve to another relief chamber, the volume of which is determined by another, movable magnetic part.

In the drawing, the brake pressure booster and modulator according to the invention - hereinafter referred to simply as a pressure modulator for the sake of simplicity - is designated by 10; it has a housing ₁₁ which is formed from two housing halves 1a and 1b, both of a generally pot-shaped form with internal recesses or chambers 15a, 15b, which are cylindrical in the case of a rotationally symmetrical general housing shape. The two hollow cylinder shapes 15a, 15b formed in this way are separated by an approximately central partition 16; the entire housing 1 forms a one-piece component with a pressure inlet at 17 and a pressure outlet at 18. The pressure inlet 17 is formed by a nozzle with an internal bore 17a, which can be connected in a suitable manner to a pressure line coming from the master brake cylinder if the pressure modulator is used in the preferred application in vehicle braking systems, while the outlet 18 is to be connected to one or more lines leading to wheel brake cylinders, preferably over the shortest possible route, since the pressure modulator, due to its compact and therefore small construction, is preferably located directly adjacent to Wheel brake cylinder can be arranged.

In the embodiment shown in the drawing, the actual spaces dealing with pressure amplification and pressure modulation are opposite the housing recesses 15a, 15b in the circumference

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significantly reduced - it goes without saying that the invention is not restricted to this special embodiment, which merely represents a special adaptation to certain practical requirements. In the embodiment shown, inner cylindrical pressure chambers 6a and 6b are therefore formed, preferably in one piece starting from the partition wall 16, open on both sides by corresponding cylindrical ring walls 19a, 19b, in which cylindrically shaped inner pistons or plungers 5 and 7 are guided in a sliding and sealed manner. As will be explained further below, the first piston or plunger 5 can be part of a larger sliding element, namely a permanent magnet 3, or can be attached to it, while the piston or plunger 7 is part of another permanent magnet 4 or is at least attached to it.

In this case, opposite the plunger 5 and connected to it for carrying out a joint displacement, preferably formed in one piece with it, another piston or plunger 2 is arranged in a tapered cylinder guide 20 of one housing part la, so that its front face is under the pressure of the brake fluid coming from the master brake cylinder, with parts of the permanent magnet 3 extending over the respective inner cylinder guides 21a and 21b, which are formed by the ring walls 19a, 19b, in the free space formed by the recesses 15a, 15b and thus having a significantly larger extension in terms of area and volume, with correspondingly improved and reinforced functional processes in permanent magnets, which will be discussed further below. The polarization of the permanent magnets

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magnets 3 and 4 can be arranged as shown in the drawing, so that corresponding attractive forces arise between the two strong permanent magnets 3 and 4, which are both slidably mounted in the recesses 15a, 15b, which will be discussed further below in connection with the functional discussion. The middle partition wall 16 is preferably provided with openings in the outer ring area, i.e. outside the central ring wall parts 19a, 19b forming cylinder guides 21a and 21b, which also extend over a wide area, so that, as indicated, parts of the permanent magnet 4 - these parts are designated A' and are wedge-shaped - also extend into the housing formation 15a on the left in the plane of the drawing, so that it is possible to reduce the distance between the two permanent magnets accordingly and to bring the permanent magnet 3 close enough with its "south pole" to the "north pole" of the permanent magnet 4 in order to achieve the greatest possible attractive and effective forces. In other words, the permanent magnet 4 extends with extensions or legs through the holes or openings of the partition wall 16 in the direction of the permanent magnet 3, whereby both preferably have complementary external shapes, as shown - the permanent magnet 3 thus tapering or tapering towards the permanent magnet 4, while the permanent magnet 4 opens conically with its extensions to accommodate the correspondingly projecting parts of the permanent magnet 3.

It is further understood that the plungers 5 and 7 as well as 2 can also be made of a different material than the permanent magnets 3 and 4.

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and finally, the entire permanent magnet 3 can also be just a piece of magnetizable material, for example steel or soft iron. A pre-tension spring 13 arranged in the pressure chamber 6a serves to keep the two permanent magnets 3 and 4 apart in the rest position - i.e. when the brake pedal is not actuated, with the proviso that in this case the permanent magnet 4 is at its left stop in the plane of the drawing. The permanent magnet 4 maintains this stop in the rest C in any case due to the mutual attraction force.

The pressure chamber 6a is connected via a valve 9 to the outlet connection 18 to the wheel brake cylinders and the additional relief chamber 6b which receives brake fluid, which is only indicated when the permanent magnet 4 is in the stop position and can also act as a pressure chamber at the same time, depending on the sequence of any ABS functions that may be carried out. The valve 9 is designed in such a way that a valve ball 9a is pressed by its own preload spring 9b onto a seat which blocks the outlet of the pressure chamber (6a) to the outlet connection 18 and to the relief pressure chamber 6b, but a narrow pressure rod or a pin 8 is arranged on the plunger 7, which lifts the valve ball 9a from its seat when the permanent magnet 4 is in the stop position and therefore connects the pressure chamber 6a to all outlet connections.

Adjacent to the permanent magnet 4 there is also an excitation coil 11 surrounding it, which, when an electric current is supplied, initially drives the

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Permanent magnet 4 can move from its stop in the plane of the drawing to the right, whereby the relief pressure chamber 6b increases when the valve 9 is closed at the same time. The detailed structure of the pressure modulator shown in the drawing therefore comprises a first pot-shaped housing part la, covered by the partition wall 16, which can be screwed to it; a second ring wall Ib, which is placed on the partition wall 16 with corresponding ring fits, which is completed by a cover indicated at Ic and placed on to form the second housing pot shape Ib. The excitation coil 11 can be covered from the recess and the chamber Ib by another ring wall, preferably made of diamagnetic material.

The following basic function then results, whereby the pressure amplification is discussed first. It is assumed that the brake pressure from the brake pedal (master brake cylinder) is present at the input connection 17. This pressure exerts a force acting to the right in the plane of the drawing on the plunger 2, which is either firmly connected to the permanent magnet 3 or is at least a part of it. The permanent magnet 3 is also attracted to the right in every position by the strong permanent magnet 4 in the plane of the drawing, so that the force with which the plunger 5 is driven to the right and exerts a corresponding pressure force on the brake fluid or brake liquid in the pressure chamber 6a is the sum of the two forces acting to the right just mentioned. In this way, the brake pressure is amplified by the pressure present at the input to the pressure in the pressure chamber 6a, whereby this brake pressure when the valve ball 9a is lifted from its seat

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by connecting the pressure chamber 6a with the wheel brake cylinder connected to it. In order to lift the valve ball 9 from its seat by means of the pin 8, the plunger 7 must be located as part of the permanent magnet 4 or attached to it at the left stop shown in the drawing and this left stop is guaranteed in any case by the mutual attraction force, i.e. the magnetic force that the permanent magnet 4 exerts on the permanent magnet 3 or the magnetic part located there. It is understood that, since the plunger 7 or the relief pressure chamber 6b closed by it is also subjected to the wheel brake pressure due to the three-way function in the valve area, this force must be smaller than the force that the permanent magnets 3 and 4 exert on each other so that the plunger 7 remains at the left stop and the ball 9 remains lifted from its seat by the pin 8. jJAn appropriate selection of the cross-sectional area of the plunger 7 is therefore necessary.

This basic function of brake pressure amplification by potential transfer is an essential feature of the present invention; the increasing proximity of the two magnets 3 and 4 results in the corresponding increase in brake pressure, so that the energy released in this way is absorbed (stored) by the increasing pressure of the brake fluid or brake liquid applied to the wheel brake cylinder. If the brake pressure applied at inlet 17 is removed, the components are returned to the positions shown in the drawing, with the result that the high pressure at the wheel brake cylinder is regained by the distance gained, which forms a potential transfer.

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of the permanent magnet 3 to the permanent magnet remaining at the stop 4.

The function of pressure modulation, if for example it is assumed that the pressure in the wheel brake cylinder is to be reduced while the pressure at the inlet 17 is still present, is then carried out by supplying a corresponding current to the excitation coil 11, whereby the permanent magnet 4 and with it the plunger 7 are displaced to the right in the plane of the drawing depending on the extent of the electrical control. As a result, the pin 8 initially loses its contact with the valve ball 9a, so that the pressure chamber 6a is

I is closed and following this interruption the pressure -

I connection between the pressure chamber 6a and the wheel brake cylinder

jf results from further retreat of the permanent magnet

p due to the applied current a pressure reduction in the respective

I respective wheel brake cylinder due to the increase in volume in the

$ opening relief pressure chamber 6b. Any further increase in the

!| Current in the excitation coil 11 leads to a further wheel braking

f? cylinder pressure reduction and vice versa; the current in the coil

I '..) depending on the desired ABS function, then

the pressure in the wheel brake cylinder is increased accordingly, preferably in a continuous process.

·■ In this context, it is understood that the cross-sectional

; surfaces of plungers 2, 5 and 7 as well as the attraction of the permanent

J magnets are to be coordinated so that the plunger 7,

f which, by its retreat, forms the relief pressure chamber 6b,

cannot be moved to the right by brake pressure alone.

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Preferably, the cross-section or diameter of the plunger 5 is selected to be approximately smaller than that of the plunger 2 so that when the brake pedal is actuated, the pressure in the pressure chamber 6a is always greater than the brake pressure applied to the inlet connection by the master brake cylinder, so that when the brake pedal is actuated, the valve ball 9a is pressed onto its seat.

The centrally located bore 22 through the plunger 2, the Q permanent magnet 3 and the plunger 5 enables

When the brake is activated, brake fluid (brake fluid) is sucked in via the check valve 12 into the wheel brake cylinder or cylinders connected to the output. The aim of achieving favorable magnetic force ratios has already been discussed above with regard to the shape of the permanent magnets 3 and 4; it goes without saying that the permanent magnets 3 and 4 are selected in such a way that the force-displacement characteristic curve between the permanent magnets is as favorable as possible, with a favorable force-displacement characteristic curve running in such a way that with a constant (linear) increase in pressure at the input, the pressure in the wheel brake cylinder connected to the pressure modulator also increases constantly (linearly).

It can also be seen from the basic structure of the pressure amplifier and modulator according to the invention shown in the drawing that with the additional arrangement of a further excitation coil 11 ^J here in the area and therefore acting on the position of the permanent magnet 3, a wheel brake pressure modulation can be carried out even without actuating the brake pedal, because by means of a corresponding excitation current in the coil 11' the permanent magnet 3 and thus the plunger 5 in the plane of the drawing is moved to

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shifted to the right, resulting in an increase in pressure in chamber 6a and thus in the brake fluid present at the wheel brake cylinder. A correspondingly selective control therefore enables ASR functions (traction control) to be carried out in a simple manner.

The core of the invention is based on the principle of the re-storage of potential energy; if the permanent magnet moves to the right in the plane of the drawing, either under the pressure exerted by the master brake cylinder on the piston 2 or due to an excitation of the coil 11 ^J , then the magnetic force performs work which is absorbed by the brake fluid as compression energy. The more the plunger 5 moves to the right, the higher the pressure in the connected wheel brake cylinder and in the pressure chamber 6a - the higher the reaction force exerted by the brake fluid on the plunger to the left in the plane of the drawing, but this is cancelled out by the correspondingly higher magnetic force which acts on the permanent magnet 3 in a right-hand direction.

Conversely, if one initially focuses on the pure amplifier work, at the end of a braking process the previously compressed brake fluid performs work that leads to the permanent magnet 3 moving back to the left in the plane of the drawing - {increasing distance to the position of the permanent magnet 4 and corresponding recovery of the potential energy by re-storage} whereby the brake fluid also performs work when the permanent magnet 4 is in the

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Realization of ABS functions involves a shift in the drawing plane to the right; this work is absorbed by the permanent magnets 3 and 4 through their relative increase in distance. The further the permanent magnet 4 moves to the right, the brake pressure applied to the wheel brake cylinder (and thus also the force of the brake fluid acting on the plunger 7) becomes smaller and the magnetic force acting also becomes smaller. Only the difference between the magnetic force on the one hand and the force exerted by the brake fluid on the plunger on the other hand must be applied by the current flowing through the coil windings 11 for pressure modulation.

It can also be seen that in the case of a pressure modulation via the relief pressure chamber 6b, a reaction on the brake pedal is not noticeable, since the retreating plunger 7 closes the check valve 9 via the pin 8 and pressure variations therefore do not occur in the primary pressure chamber 6a.

The re-storage of potential energy that takes place in the present invention, on the one hand as a distance relationship between the magnet and on the other hand as compression pressure in the area of the wheel brake cylinder, is in contrast to the way in which conventional brake boosters work, in which potential energy stored in the brake fluid in the wheel brake cylinder and in the supply lines cannot be recovered during expansion, so that an external energy source that works as auxiliary energy is necessary for such brake boosters. In the present magnetic pressure booster and modulator according to the invention, a

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An external energy source is not required and when the potential energy is re-stored, only hysteresis losses need to be replaced.

All features presented in the description, the following claims and the drawing can be essential to the invention both individually and in any combination with one another.

Claims (5)

&bull; * * · · ere« f· R20 087 19.5.1987 Robert Bosch GmbH, 7000 Stuttgart 1 Protection claims 1. Pressure amplifier and modulator, in particular brake pressure amplifier in vehicle braking systems with integrated anti-lock protection system for the implementation of ABS and ASR functions comprising pressure modulation, characterized in that a brake pressure at least
indirectly actuated pressure chamber (6a, 6b) connected via an outlet (18) to at least one associated wheel brake cylinder within a housing (1) is arranged, that in the housing at least one permanent magnet (3, 4) forming a potential energy source and exposed to a magnetic force is slidably mounted and that the
at least one permanent magnet (3, 4) for changing the volume in the pressure chamber itself or by means of a
The plunger (5, 7) attached to it forms a wall of the pressure chamber (6a, 6b). 2. Pressure amplifier and modulator according to claim 1, characterized in that a first pressure chamber (6a), one wall of which is delimited by the first permanent magnet (3) used as a potential energy source, is connected via a ' Valve device (9) with the outlet connection (18)
ally. &bull; 1 · ■ ■ ■ 19.5.87 - 2 - 3. Pressure amplifier and modulator according to claim 1 or 2, characterized in that within the housing ■ (1) two permanent magnets (3, 4) are arranged in a mutual attraction relationship ~. 4. Pressure amplifier and modulator according to one of claims ₁ to 3, characterized in that for displacement j at least one of the permanent magnets (3, 4) at least ' an electro-magnetic field on the respective permanent magnet j. magnetic force exerting electric coil (11, I 11') is arranged in the housing (1). ) 5. Pressure amplifier and modulator according to one of claims 1 to 4, characterized in that the first movable \. Permanent magnet (3) itself or by means of another f Plungers (2) connected to the input terminal (17) j is the point at which the first movable magnet \ shifting pressure of the master brake cylinder is present. 6. Pressure amplifier and modulator according to one of the claims 1 to 5, characterized in that the plunger (2) : of the first movable permanent magnet (3) I in a tapered cylinder guide (20) of the housing (1) is mounted in a sliding manner, on which the pressure coming from the master brake cylinder acts, and that I the outlet of the first permanent magnet (3·) formed ! Pressure chamber (6a) via the valve (9) to the outlet connection &iacgr; (18) and to a relief pressure chamber (6b) whose volume depends on the position of the other, ¹ permanent magnet, which is also movable in housing guides. ■ magnets (4). I 1, pressure amplifier and modulator according to one of claims 1 to 6, characterized in that for the realization l·! &igr; · it · i &bull;O> &bull; I · Iff &bull; a·· ■· &bull; 4 &idigr;&iacgr; 19.5.87 of ABS functions on the second electromagnet (4) actuated by the associated excitation coil (Ii) an actuating arrangement is arranged which closes the valve (9) to the primary pressure chamber (6a) and at the same time the volume of the second permanent magnet (4) which is experiencing a receding increase (6b) is connected to the outlet connection (18). 8. Pressure amplifier and modulator according to one of claims 1 to 7, characterized in that the housing (1) forms two sliding guides for the two permanent magnets (3, 4), which are arranged in compartments (15a, 15b) separated by a partition wall (16), and that the approximately central partition wall comprises cylindrical sliding guides (21a, 21b) on both sides through ring walls (19a, 19b) smaller in diameter than the housing recesses (15a, 15b) to form the primary pressure chamber (6a) and the relief pressure chamber (6b), in which the plungers (5, 7) are mounted so as to slide, each of which is part of the associated permanent magnet (3, 4) or is attached to it. 9. Pressure amplifier and modulator according to one of claims 1 to 8, characterized in that the radial dimensions of the permanent magnets (3, 4) extend beyond the piston-cylinder units (21a, 21b; 5, 7) determining the respective pressure amplification and pressure modulation and that, in addition to the excitation coil (11) aligned with the second movable permanent magnet for carrying out ABS functions, a further electrical excitation coil (II ¹ ) is aligned with the first movable permanent magnet (3) for arbitrary position change of this permanent magnet and &bull; · t f · · I) 5.87 - 4 - a corresponding increase in pressure in the associated primary pressure chamber (6ä) regardless of the brake pedal position such that ASR functions (traction control) result. 10. Pressure amplifier and modulator according to one of claims 1 to 9, characterized in that the valve device (9) separating the primary pressure chamber (6a) from the relief pressure chamber (6b) is assigned a pressure pin (8) driven by the plunger (7) of the second movable permanent magnet (4) and causing the valve to open, which holds the valve device (9) in the open state as long as the second permanent magnet (4) is located at its stop determined by the central partition (16) and the mutual attraction force to the first permanent magnet (3). 11. Pressure amplifier and modulator according to one of claims 1 to 10, characterized in that the pressure pin (8) on the plunger (7) of the second permanent magnet (4) | a valve ball (9a) of the valve device (9) lifts off its seat in the stop position of the permanent magnet (4). 12. Pressure amplifier and modulator according to one of claims 1 to 11, characterized in that the partition wall (16) has openings through which extensions (4') extend from the second permanent magnet (4) remaining at its stop in the absence of ABS pressure modulations in the direction of the first permanent magnet (3) to increase mutual attraction. 13. Pressure amplifier and modulator according to claim 12, characterized I · * II « 4 &bull; ti· · ItI* ·· ■ &bull; I »It 1 *·· «ft »1**1 It Ml *· · 19.5.87 characterized in that the extensions (4') have an outwardly widening conical shape, with a correspondingly tapering front part of the first permanent magnet (3). 14. Pressure amplifier and modulator according to one of claims 12 ^eksnnzsichiist that sins vgui cinsi Pressure line (22) closed by check valve (12) leads from the inlet (17a) to the primary pressure chamber (6a).