DE102005028562A1 - Hydraulic device for a vehicle braking system comprises a pulsating damping unit having two different damping components arranged between a pressure side of a pump and the hydraulic consumer - Google Patents

Abstract

Hydraulic device (1) comprises a pulsating damping unit (6) having two different damping components arranged between a pressure side of a pump and the hydraulic consumer. Preferred Features: The different damping components are connected parallel to each other or in series in a cascade formation. The damping components are provided in a common bore (7). The damping components have a membrane (16) made from an elastic material having an inlet (9) with an inlet chamber (10) running from an outlet with an outlet chamber (12).

Description

The The invention relates to a hydraulic unit for a vehicle brake system a receiving body with electro-hydraulic valves, with at least one hydraulic Pump, and with channels for connecting the pump to at least one hydraulic consumer, being between a pressure side of the pump and the hydraulic consumer at least one pulsation damping unit is provided. The hydraulic pump supplies, for example electronically controlled braking system with hydraulic energy. there find - until with a few exceptions - eccentric-driven Radial piston pumps use. The mentioned hydraulic units are in use millions of times.

One Compromise between legal framework conditions, more fundamentally Function, effort minimization and operating comfort is to that each brake circuit per a delivery piston is provided. The piston displacement during each eccentric rotation can in a suction stroke (0 - π) and in a pressure stroke (π - 2π) divided become. Because each liquid column accelerates but also delayed be leads this on a suction side, as well as on a pressure side respectively too sinusoidal Instantaneous pressure gradients. The fluctuating instantaneous pressure profiles require a pulsation damping unit. The pulsation damping unit is of formed as dimmed Pulsationsdämpfungskammer. Their effect is to smooth the momentary pressure curve by inside the damper chamber A dynamic pressure is generated due to internal elasticity and friction is balanced in the pressure medium. The amount of smoothing is essentially dependent from the fluid volume, that is, from the volume of the pulsation damping chamber.

One receiving body for a Electronic braking system is a highly complex and highly compressed Structures, because in a confined space to represent a variety of holes are. There is therefore a conflict between the goal of another Miniaturization of the hydraulic unit and the goal of improved damping by means of the largest possible Pulsationsdämpfungskammer.

To increase the damper chamber volume at a given hydraulic unit is in the DE 103 02 681 B3 proposed that the damping unit protrudes outwards over the receiving body. A dimmed damper chamber protrudes into a housing from an electronic control unit. As a result, the installation space is restricted in the electronic control unit.

To Pulsationsminderung is already a multi-piston pump as in the DE 24 04 762 A1 has been proposed, wherein on a delivery side of a plurality of outlet valves, a space connects, which connects all the sources of supply with each other, and is connectable to a conveyor channel, and wherein a wall is formed elastically yielding. The elastic wall separates a gas filled area from a fluid filled area. The multi-piston pump is unsuitable for dual-circuit brake systems, because all sources are connected together.

The known elastomeric membrane damper suffer at the disadvantage that they only in a relatively limited pressure range or only with a short lifespan. The stress collective In any case, a pronounced fatigue of the elastomer material appears in a motor vehicle brake system to cause.

Though has already been proposed in another context, elastomeric material to replace with a foil-like metal membrane. Such solutions can be relative be designed durable. However, the membrane has a limited expansion behavior. metal bellows enable although an enlarged recording volume but require a costly Production and a relatively large installation space.

Of the The invention is therefore based on the object, the effectiveness of Pulsation damping at the supply of hydraulic consumers in a dual-circuit Vehicle braking system, while providing a solution their life in proportion to the known Pulsationsdämpfungseinheiten - in an unrestricted miniaturized Construction - is extended.

According to the invention solved task, by the pulsation damping unit at least has two different pulsation damping means. The The invention is therefore based on the basic idea of the pulsation damping means redundant and further provided of different type. advantageous Effects of the invention are in an extended scope and in an elevated Reliability. Because if one of the Pulsationsdämpfungsmittel is ineffective, the other Pulsationsdämpfungsmittel can continue to effect unfold.

In Another embodiment of the invention are the different Pulsation damping after Type of cascade connected in series or in parallel.

According to one advantageous embodiment of the Invention, one of the Pulsationsdämpfungsmittel a membrane made of elastic material having an inlet with an inlet chamber separates from an outlet with an outlet chamber. Another pulsation damping device has a dimmed channel which the inlet or the inlet chamber connects to the outlet or the outlet chamber.

The Membrane is suspended elastically, by this one-sided firmly clamped in the receiving body. On the other hand the other regions of the membrane are elastically yielding for the purpose of pulsation damping.

A simplified handling and assembly of the membrane is achieved when this is cylindrical, with a radially outward one Recording socket is provided. The receiving socket can be made of metal material be formed, and serves to attach the elastic membrane in the receiving body.

In Furthermore advantageous embodiment is radially inward a receiving socket for the Aperture and provided for the formation of the channel. Also this recording socket can be formed of metal material.

The damping effect will be further improved if, so to speak, another damping means is provided by the inlet chamber a larger volume than the outlet chamber in particular, and that the inlet chamber is approximately twice up to three times larger volume as the outlet chamber.

In Continued modification of the invention, it is conceivable that the Aperture an additional aperture is downstream.

A sibling solution the problem concerns according to claim 12 a receiving body with electro-hydraulic valves, with at least one hydraulic Pump, and with channels for connecting the pump to at least one hydraulic consumer, between a pressure side of the pump and the hydraulic Consumers at least one chamber with a, integrated in the receiving body arranged, pulsation damping unit is provided, which has a wall element which against a Resetting force displaceable guided is provided, and wherein for generating the restoring force a hermetically closed metal hollow body is provided. The restoring force is inventively Deformation of the metal hollow body generated. This allows for low space requirement a rigid spring characteristic, so that the damping means even at high pressures is effective.

Preferably is the metal hollow body in relation to thin-walled to its diameter educated. The cavity is under a predetermined gas Pressure filled. By adjusting the internal pressure, the spring characteristic can be influenced.

To the preferred embodiment is the metal hollow body on the one hand, indirectly or directly on the movable wall element, and on the other hand indirectly or directly to a fixed wall element of the recording body supported. It is possible that the solid wall element is designed as a lid, and that the lid on the receiving body is fixed. Furthermore, it is very essential that the metal hollow body in Displacement direction, ie behind the movable wall element, in a pressure medium-free space is arranged. This measure serves to the fact that the wall element is always freely displaced. if necessary a seal between the wall element and the receiving body is provided around the pressure-medium-loaded area of a pressure medium-free Separate area.

Of the Metal hollow body takes up very little installation space when it is designed as a hollow ball. A further preferred variant is that the metal hollow body as Hollow ring is formed. To vote, in particular to reinforce the Spring action it is possible several metal hollow bodies provided.

A Variant of the invention is various damping means for one to combine improved action by the chamber for the displaceable Wall element further comprises a Pulsationsdämpfungskammer with an inlet and with an outlet. An advantageous conception exists in that the movable wall element directly to the Pulsationsdämpfungskammer borders. The combinatorial effect and the integrated construction are particularly suitable for Comfort-oriented, compact hydraulic units. The combinatorial Effect is further pronounced by the pulsation damping chamber has an aperture which is upstream of the outlet.

A further sidelined solution to the problem in question concerns according to claim 21, a hydraulic unit comprising a receiving body with electro-hydraulic valves, with at least one hydraulic pump, and with channels for connecting the pump with at least one hydraulic consumer, wherein between a pressure side of the pump and the hydraulic Consumers at least one chamber with a, integrated in the receiving body arranged pulsation damping unit is provided, the one Wall element which is provided displaceably guided against a restoring force, and wherein the wall element is designed as a translation piston with a pressure medium-loaded active surface and with a restoring force acted effective surface, and that the pressure medium-loaded effective area is smaller than the restoring force applied effective area. According to the invention, it is a piston damper, which makes use of a translation effect of different effective diameters, in that the pressure-medium-loaded active surface is made smaller than the effective surface on which the return means act. This creates the possibility of allowing pneumatic restoring forces to act on the booster piston. Furthermore, a support for return springs is created. The installation of the return springs on the booster piston, as well as the receiving body can be made directly or indirectly.

at a preferred embodiment serve plate springs to generate the restoring force. By the disc springs can be arranged in parallel or in series, as desired and in a simple way and progressive or degressive characteristics are formed. It is also conceivable that the disc springs combined at will to be arranged in series and in parallel.

to Extension of the range of action and redundancy according to the invention is a combination, in particular a parallel connection with at least one further Damping means in particular a damping chamber and / or an aperture provided. In this case, the two damping means provided integrated within a chamber of the receiving body be.

Further Details, and advantageous effects of the invention will be given below from the description using an exemplary embodiment.

In the drawing shows:

1a , b two schematic sketches to illustrate the effect of pressure pulsations in a brake system,

2 a part of a receiving body with a damping unit comprising a plurality of damping means, enlarged and in section,

3 a schematic circuit diagram to illustrate 2 .

4 a schematic circuit diagram of another variant of the invention,

5 the variant according to 4 comparable in a graphic representation 2 .

6 a sibling solution in a graphic representation comparable 2 .

7 relating to a schematic circuit diagram 6 .

8th another sibling solution,

9 relating to a schematic circuit diagram 8th , and

10 an additional alternative, also on the scheme 9 based.

A hydraulic unit 1 for a vehicle brake system comprises a receiving body 2 with electro-hydraulic valves, with at least one hydraulic pump 3 , which preferably has only one piston per brake circuit, and with channels for connecting the pump 3 with at least one hydraulic consumer. The pump 3 is designed as Exzentergetriebene radial piston pump, and supplies the electronic brake system with energy, for example, to perform tasks such as Parkbremsaktuatorik, anti-skid control or driving stability control. A complete eccentric rotation causes each a suction stroke and a displacement stroke of the delivery piston. The accelerated and delayed liquid columns produce pressure surges, which are expressed by pulsations. On the pressure side DS - that means with the consumer - is therefore in addition to an averaged pressure level 4 also a sinusoidal rising and falling momentary pressure curve 5 ascertainable. This course is more or less balanced around the mean pressure level 4 , To reduce the pulsations is therefore a pulsation damping unit 6 intended. 1a illustrates a pressure build-up in a brake system without pulsation damping unit 6 , and 2 shows an example of the course with several Pulsationsdämpfungsmitteln.

The following description is based exclusively on the example of a part of a brake circuit of a vehicle brake system. In the sectional drawings is only one part of a receiving body 2 shown. Although not apparent from the drawing, a second brake circuit can be provided with corresponding Pulsationsdämpfungsmitteln, without departing from the basic idea of the invention. In the drawings, matching features are identified by corresponding reference numerals.

Below we will detail the 2 received. This shows only a small part of the block-shaped receiving body 2 with its hydraulic components. The unit further includes an electric motor drive for the pump, not shown 3 and an electronic control unit, not shown, for controlling the drive and the electromagnetic valves.

For an integrated housing of the pulsation damping unit 6 has the receiving body 2 a receiving hole 7 on. This is with a pressure side DS of the pump 3 connected. For hydraulic connection to the pump 3 a canal opens 8th with his inlet 9 radially into an inlet chamber 10 the receiving bore 7 , On a floor 11 the receiving bore 7 there is an outlet chamber 12 with an outlet 13 , At the outlet 13 closes a channel 14 which leads to the respective consumer. The channel 14 is a blind 15 preceded by a diameter of about 1 mm or less.

As continues from the 2 shows is between inlet chamber 10 and outlet chamber 12 a thick-walled membrane 16 provided of elastic material. The membrane 16 is formed hollow cylindrical. It is radially outward of a cylindrical receiving socket 17 edged. In the center has the membrane 16 over a relatively narrow bore 18 with a diameter of about 1 mm or less, with a cylindrical receiving socket 19 is lined. The two recording sockets 17 . 19 are preferably made of metal material. The radially outer bush 17 serves to clamp the membrane 16 in the receiving body 2 by removing the receiving socket 17 into the receiving hole 7 is pressed. The radially inner bush 19 wears a visor 20 with a diameter of about 1 mm or less. This is between inlet chamber 10 and outlet chamber 12 the above aperture 20 effective. In the direction of the environment is the receiving bore 7 from a lid 21 locked.

How out 2 can be seen, all damping means are located together within the stepped receiving bore 7 ,

The 3 clarifies the function of the damping unit 6 , Via suction and discharge side SS, DS of the pump 3 the pressure medium passes through the inlet channel 8th and inlet 9 in the inlet chamber 10 the pulsation damping unit 6 , The pressure pulsations are equalized by several effective damping means. On the one hand, it is possible that pressure pulses to elastic-reversible deformations of the elastically suspended membrane 16 contribute. The membrane tuning described here develops a spring stiffness of about 10000 N / mm or less. Further attenuation contributions are through inlet chamber 10 , Cover 20 and outlet chamber 12 and aperture 15 done. Although the inlet chamber 10 and the outlet chamber 12 are designed so small that their total volume of about 5 cc (or less) would be sufficient in any case to be effective as an isolated damping chamber, it was found that a cascade-like series connection of several damping means with at least one chamber / aperture combination together with the blended membrane 16 an effective Pulsationsminderung allows. In comparison with the volume of conventional damper chambers, the space requirement for the pulsation damping unit according to the invention is therefore reduced.

Hereinafter, the embodiment according to 4 and 5 received. In essence, only the differences are compared with other embodiments.

The membrane 16 only shows the hole 18 but no integrated aperture and no radial inner receiving socket 19 on. Instead, there is a bypass channel 22 provided that allows the bore 18 to get around by the bypass channel 22 directly from the inlet chamber 10 is branched off, and behind the aperture 15 in the outlet channel 14 empties. The bypass channel 22 also has a bezel 23 with a diameter of about 1 mm or less, which provides a completely unimpeded pressure medium discharge from the inlet chamber 10 prevented. bypass channel 22 and aperture 23 represent a separate damping means which is parallel to the membrane 16 with the hole 18 and parallel to the outlet chamber 12 and the aperture 15 is arranged.

After 5 the parallel circuit described above is formed by the bypass channel 22 essentially parallel to the receiving bore 7 is arranged, and on the exhaust duct 14 the outlet chamber 12 meets. This is made possible by the exhaust duct 14 in relation to the mounting hole 7 diagonally and in the direction of the bypass channel 22 is executed inclined. To get a cost-effective branch from the inlet chamber 10 to allow, the inlet channel 8th preferably so over the receiving bore 7 be drilled out that he on that bore section of the bypass channel 22 meets, which parallel to the receiving bore 7 runs.

The 6 and 7 is another solution to the problem. The receiving bore 7 forms a chamber into which an inlet channel and an outlet channel 14 with inlet and outlet 9 . 13 open out. The outlet channel 14 is a blind 15 upstream. The receiving bore 7 is from a lid 21 locked. This forms the Chamber as it were an independent damping means. In addition, a piston damper with a movable wall element 24 formed as follows. The movable wall element 24 is inside the mounting hole 7 against a restoring force F slidably and preferably arranged to be movable guided guided sealed. Between wall element 24 and lid 21 is for this purpose a spring element 25 intended. The system of the spring element 25 on the adjacent components 21 . 24 takes place directly or indirectly. When the spring element 25 as shown, is formed as a metal hollow body, and also seals metal to the adjacent components, even a dynamic seal on the movable wall element 24 omitted. The spring element 25 is designed as a hermetically sealed metal hollow body. Preferably, the hollow metal body is a hollow sphere or a hollow ring. The hollow metal body is thin-walled in relation to its diameter, wherein the cavity formed 26 filled with compressed gas. The gas is preferably air at ambient pressure. By this measure, the wall element 24 at low height elastic to the lid 21 supported. The lid 21 is on the receiving body 2 attached. The metal hollow body is in a pressure medium-free space 27 between wall element 24 and lid 21 arranged. In principle, it is conceivable, a plurality of metal hollow body in the room 27 provided. To support the restoring force F, it is also conceivable in an advantageous manner, the room 27 to fill with compressed gas.

As with the other embodiments, the bezel is 15 as a separate component on a carrier 28 for a filter 29 educated.

From the wiring diagram to 7 is to be read that the pulsation damping unit has two parallel damping means, which adjoin one another directly, as well as in the same receiving bore 7 are arranged ( 6 ) namely a combination of inlet chamber 10 and aperture 15 in connection with the movable wall element 24 , which is effective under the action of the restoring force F as a separate piston damper.

From the 8th and 9 is another solution to the problem with a piston damper. According to 9 is parallel to an inlet chamber 10 said piston damper with a translationally movable formed wall element 24 provided, which is acted upon by the restoring force F. The wall element 24 is graduated as a translator piston is formed. It has a sealing element 30 for sealing in the receiving bore 7 , A pressurized active surface 31 of the wall element 24 is formed smaller than a restoring force applied surface 32 , The pressure fluid impacted effective surface 31 can therefore be at the end of a pin 33 be formed with a relatively small diameter. In contrast, the resiliency-loaded effective area 32 far educated and thus particularly well suited to a short-building spring element 25 to be acted upon by high spring stiffness. Several spring elements 25 can on a rear journal 34 of the wall element 24 be arranged guided. For example, the spring element 25 designed as a plate spring. The use of several disc springs allows a simplified influencing and adaptation of the spring characteristic, because the individual springs can be installed in parallel or in series or alternately bundled as a spring package. This solution is therefore particularly space-friendly and flexible adaptable. The disc springs are directly or indirectly on the wall element 24 or on the lid 21 supportable. If the lid 21 in the receiving body 2 can be screwed, by varying depth screwing the lid 21 even an adjustment of the preload force done.

The embodiment according to 10 is based largely on matches with the embodiment 8th , Therefore, matching features have been provided with corresponding reference numerals and reference is made in principle to the relevant description above. As in 8th is a booster piston with a wall element 24 provided, which is stepped and sealed and slidably disposed in a stepped housing bore. As a result, a pressure medium-loaded effective area 31 created, which is smaller than a restoring force applied surface 32 is trained. For the provision of the stepped piston is a spring element 25 , which is designed as a helical spring, and in a closed space 35 which is filled with air, for example. The coil spring is elastic with a biasing force between the effective surface 32 and a lid 21 clamped. As well as in connection with the 9 becomes clear, the thus configured pulsation damping unit is hydraulically parallel to the inlet chamber 10 connected. In addition to these similarities arise loudly 10 following new features.

In the room 35 is a compressible elastomeric element 36 intended. The Elastoelement 36 Changes the return characteristic of the pulsation damping unit, because it allows a supplementary volume absorption when the air in the room 35 is compressed due to piston displacement. An essential advantage of this arrangement is that the volume of air in the room 35 - with improved voting options - is still hermetically chambered. This reduces the risk that the stepped piston - as with ventilated piston - corroded or blocked by externally penetrating reagents. In the illustrated embodiment, the elastomeric element 36 on the wall element 24 arranged and together with this relative to the receiving body 2 displaceable. For this purpose, the elastomer element 36 formed as a hollow ring, is preferably made of rubber or plastic material, and is on the pin 34 postponed. For the purpose of the holder is the pin 34 is provided with a circumferential groove into which the elastomeric element 36 snaps.

In addition to the difference 8th has the wall element 24 via one or more throttle holes 37 which the room 35 with the inlet channel 8th connect. In addition to the dynamically stressed, and O-ring-shaped sealing element 30 is another sealing element 38 provided, which in a circumferential circumferential groove of the wall element 24 is used.

1

hydraulic power unit

2

receiving body

3

pump

4

average pressure level

5

Currently, pressure profile

6

Pulsationsdämpfungseinheit

7

location hole

8th

inlet channel

9

inlet

10

inlet chamber

11

ground

12

outlet

13

outlet

14

exhaust port

15

cover

16

membrane

17

receiving socket

18

drilling

19

receiving socket

20

cover

21

cover

22

bypass channel

23

cover

24

wall element

25

spring element

26

cavity

27

room

28

carrier

29

filter

30

sealing element

31

effective area

32

effective area

33

spigot

34

spigot

35

room

36

Elastoelement

37

throttle bore

38

sealing element

A

drive

F

Restoring force

DS

pressure side

SS

suction

HCU

hydraulic control unit (Hydraulic Control Unit)

ECU

electronic control unit (Electronic Control Unit)

Claims (27)

Hydraulic unit ( 1 ) comprising a receiving body ( 2 ) with electro-hydraulic valves, with at least one hydraulic pump ( 3 ) and with channels for connecting the pump ( 3 ) with at least one hydraulic consumer, wherein between a pressure side (DS) of the pump ( 3 ) and the hydraulic consumer at least one pulsation damping unit ( 6 ), characterized in that the pulsation damping unit ( 6 ) has at least two different pulsation damping means. Hydraulic unit according to claim 1, characterized that the different pulsation damping means to each other hydraulically are connected in parallel. Hydraulic unit according to claim 1 or 2, characterized Marked that the different pulsation damping means hydraulically connected in series in the manner of a cascade are. Hydraulic unit according to Claim 1, 2 or 3, characterized in that the different pulsation damping means are arranged in a common, stepped receiving bore ( 7 ) are provided. Hydraulic unit according to claim 1, characterized in that the pulsation damping means comprise a membrane ( 16 ) made of elastic material having an inlet ( 9 ) with an inlet chamber ( 10 ) from an outlet ( 13 ) with an outlet chamber ( 12 ) separates. Hydraulic unit according to claim 5, characterized in that the pulsation damping means a dimmed hole ( 18 ) having the inlet ( 9 ) or the inlet chamber ( 10 ) with the outlet ( 13 ) or the outlet chamber ( 12 ) connects. Hydraulic unit according to claim 5, characterized in that the membrane ( 16 ) on one side firmly in the receiving body ( 2 ) and that other areas of the membrane ( 16 ) are elastically yielding to the pulsation damping. Hydraulic unit according to claim 7, characterized in that the membrane ( 16 ) is cylindrical, wherein radially outward a receiving bush ( 17 ) is provided. Hydraulic unit according to claim 6 and 7, characterized in that the membrane ( 16 ) is cylindrical, wherein radially inward a receiving bush ( 19 ) for the aperture ( 20 ) is provided. Hydraulic unit according to claim 5, characterized in that the inlet chamber ( 10 ) a larger volume than the outlet chamber ( 12 ), and that the inlet chamber ( 10 ) in particular about twice to three times larger volume than the outlet chamber ( 12 ) having. Hydraulic unit according to claim 9, characterized in that the diaphragm ( 20 ) an additional aperture ( 15 ) is connected downstream. Hydraulic unit comprising a receiving body ( 2 ) with electro-hydraulic valves, with at least one hydraulic pump ( 3 ) and with channels for connecting the pump ( 3 ) with at least one hydraulic consumer, wherein between a pressure side (DS) of the pump ( 3 ) and the hydraulic consumer at least one pulsation damping unit ( 6 ) is provided, which is a wall element ( 24 ), which is slidably guided against a restoring force (F), and wherein for the generation of the restoring force (F) an elastomer element ( 36 ) is provided. Hydraulic unit according to claim 12, characterized in that the elastomeric element ( 36 ) is formed as a hermetically closed metal hollow body. Hydraulic assembly according to claim 13, characterized in that the hollow metal body is thin-walled in relation to its diameter, and in that a cavity ( 26 ) is filled with compressed gas. Hydraulic assembly according to claim 13, characterized in that the metal hollow body, on the one hand, directly or indirectly on the movable wall element ( 24 ) and on the other hand indirectly or directly on a fixed wall element of the receiving body ( 2 ) is supported. Hydraulic unit according to claim 12, characterized in that the elastomer element, in particular the hollow metal body in a pressure medium-free space ( 27 ) is arranged. Hydraulic unit according to claim 13 to 16, characterized Marked that the hollow metal body as a hollow ring or ball is trained. Hydraulic unit according to claim 13 to 17, characterized gekennzichnet that several metal hollow body are provided. Hydraulic unit according to claim 15, characterized in that the fixed wall element is used as cover ( 21 ) is formed, and that the lid ( 21 ) on the receiving body ( 2 ). Hydraulic unit according to claim 12, characterized in that the receiving bore ( 7 ) an inlet chamber ( 10 ) with an inlet ( 9 ) and with an outlet ( 13 ) and that the movable wall element ( 24 ) immediately adjacent to the Pulsationsdämpfungskammer. Hydraulic unit according to claim 20, characterized in that the inlet chamber ( 10 ) an aperture ( 20 ) facing the outlet ( 13 ) is connected upstream. Hydraulic unit ( 1 ) comprising a receiving body ( 2 ) with electro-hydraulic valves, with at least one hydraulic pump ( 3 ) and with channels for connecting the pump ( 3 ) with at least one hydraulic consumer, wherein between a pressure side (DS) of the pump ( 3 ) and the hydraulic consumer at least one receiving bore ( 7 ) with a, in the receiving body ( 2 ) integrated pulsation damping unit is provided, which is a wall element ( 24 ), which is slidably guided against a restoring force (F), and wherein the wall element ( 24 ) as a translation piston with a pressure medium impacted effective surface ( 31 ) and with a resiliency-loaded effective area ( 32 ) is formed, and that the pressure-medium-loaded effective area ( 31 ) smaller than the restoring force applied area ( 32 ) is trained. Hydraulic unit according to claim 22, characterized that for the generation of the restoring force (F) provided one or more packet-like disc springs provided are. Hydraulic unit according to claim 23, characterized that multiple disc springs in series or in parallel or combined in series and in parallel. Hydraulic unit according to claim 22, characterized in that the plate springs, on the one hand, directly or indirectly on the receiving body ( 2 ) and on the other hand are indirectly or directly supported on the booster piston. Hydraulic unit with a pulsation damping unit, in particular according to one or more of the preceding claims 22 to 25, characterized by its combination, in particular parallel hydraulic circuit, with at least one further damping means, in particular an inlet chamber ( 10 ) and / or a bypass channel ( 22 ). Hydraulic unit according to claim 26, characterized by the integration of all damping means within a receiving bore ( 7 ).