WO2010017998A1

WO2010017998A1 - Brake system with adaptively controllable brake lining clearance

Info

Publication number: WO2010017998A1
Application number: PCT/EP2009/005929
Authority: WO
Inventors: Heinz Leiber; Thomas Leiber; Valentin Unterfrauner; Christian KÖGLSPERGER
Original assignee: Ipgate Ag
Priority date: 2008-08-14
Filing date: 2009-08-14
Publication date: 2010-02-18

Abstract

The invention relates to a hydraulically acting brake system with a master brake cylinder, the at least one working space of which is connected via at least one hydraulic line to at least one wheel brake or parking brake of the vehicle, wherein an actuator adjusts at least one brake lining (52) of a wheel brake in order to bring about clearance (BLSi).

Description

- IL ¬

Brake system with adaptively controllable brake pad clearance

State of the art

The invention relates to a hydraulically acting brake system with a master cylinder whose at least one working space is connected via at least one hydraulic line with at least one wheel brake or parking brake of the vehicle.

After braking, especially in brake systems with disc brakes, a residual braking effect is created since the jerk forces on the brake piston are insufficient to lift the brake pad sufficiently far from the brake disk. To solve this problem, among other things, a roll-back seal was developed, which moves the brake piston and with him the brake pad from the brake disc after the completion of braking. However, the roll-back property of the sealing ring is limited to the brake piston and is not sufficient to fully compensate for soiling, aging and elastic deformation in the caliper and friction linings. Remedies with an air gap between brake pad and brake disc / brake piston are in DE 44 18 701 and DE 196 01 434 described. The proposed solutions according to the aforementioned documents have not been introduced because the additional effort in relation to the effect is unsatisfactory and also occurs through the set air clearance during subsequent braking a pedal travel loss, which disadvantageously the braking distances are at full braking longer.

According to the current state of development of brakes, mid-range vehicles have an additional consumption of approx. 0.251 = 6g CO ₂ / km on the test stand for determining the NEDC consumption due to the residual braking effect mentioned above. This value applies to a new vehicle without aging effects and is considerable in view of the future CO ₂ goals.

Object of the present invention is therefore to further develop a hydraulically acting brake system to the effect that the residual braking effect is reliably avoided.

This object is achieved erfmdungsgemaß characterized in that an actuator adjusts at least one brake pad of a wheel brake to achieve an air clearance. Further advantageous embodiments of the inventive brake system according to claim 1 result from the features of the dependent claims.

The invention is based on the idea that an actuator, which can be actuated actively or passively, that is, on its own, lifts off the brake pad from the brake disc for generating an air clearance. If the actuator is actively controllable, eg by the control device which controls the entire braking system, then the air clearance can be adjusted adaptively. Thus, it is possible to adjust or regulate the clearance depending on the driving condition or the driving situation and the brake pad wear. The brake system according to the invention is advantageously characterized in that it is simple in design, diagnosable and also adaptive. The brake system according to the invention can be used in both electro-pneumatic and electro-hydraulic braking systems.

If an air clearance has been set, this can mean an additional loss or a longer response time during braking, resulting in a Bremswegverlangerung depending on the actuation speed of the brake. In a full braking to prevent a rear-end collision, this can cost crucial meter and lead to the accident. In order to avoid Bremswegverlangerung, the invention provides to apply the brake shoes to the brake disc before the start of the brake actuation, i. to pick up the air play. The brake system must thus recognize when and if a brake actuation will occur. For this purpose, it is advisable to control the brake shoes with a small braking force with rapid acceleration of the accelerator pedal or alternatively to control this via a distance sensor from the foot to the brake pedal. Also, the signal or data from a distance measuring system, which determines the distance to the vehicle ahead or obstacle, are used to determine a soon to be initiated braking operation. The vehicle speed can also be taken into account in the evaluation.

The air clearance is advantageously controlled after completion of the braking operation by the actuator moves the piston or a force associated with the brake lining Kraftubertrager by a corresponding path to produce the air clearance. The actuator may advantageously be a solenoid, an electric motor or a linear motor. The actuator may be arranged in a normal wheel brake or an electromotive parking brake. In the embodiment of a known parking brake with the erfmdungsgemaßen actuator, the actuator in the simplest case, a spring element, in particular in the form of a compression spring, which adjusts the brake piston when lots of Parkierbremse to a specific air game.

In the solution with linear motor, this acts as a linear magnet within the brake piston, the stator by a not magnetic sleeve is separated from the brake fluid. The second solution uses a simple solenoid. In both solutions, the distance to the foot is preferably measured by a (not shown) distance sensor on the brake pedal before the start of braking and the magnet system is activated or turned off when the threshold value is exceeded, so that the air clearance is turned off. With appropriate design of the dynamics of the actuators, the signal of the start of braking, for example, switching on the Bremskraftverstarkers to quickly apply the brake pad by the force of the actuator or the spring force. In the linear magnet solution, a displacement sensor can be used for brake lining wear measurement, which saves on lining wear sensors.

If, after braking, the air clearance is controlled on the brake piston side, so remains due to friction on the Fuhrungsbolzen in Radtrager a small residual force on the brake pad, which produces a braking effect. By a simple solenoid on Fuhrungsbolzen the floating caliper and this residual braking effect can be advantageously switched off. The air play can not act constantly during vehicle operation, z. B. in the rain, the pad must rest slightly or even before the start of braking after recoil of the accelerator pedal. Also, after a long journey without braking on a dry road to clean the windows, the brake pads must be applied for a short time, which in the case of o. G. Systems can also be done with a defined small braking force. It is also advantageous if at standstill of the vehicle, for. B. when parking, the air clearance is not set.

Advantageously, all the functions described above are fully diagnosable, so that, for example, B. by appropriate THZ control the air clearance when applying the brake piston to the brake pad, z. B. at vehicle standstill, to be tested.

A further development of the invention is based on the idea that in the normal braking between the actuator and the Brake piston is not connected and that only when activating the actuator, a connection of the armature of the actuator and the brake piston is generated. For this purpose, the further development of the invention provides a coupling. This coupling can be a controlled by the movement of the armature clutch in the simplest case. By means of the coupling, a frictional engagement, a force or a positive connection between the armature and the brake piston can be realized. Likewise, the wheel brake can be designed such that during the deactivation of the actuator, the clutch also remains closed until the air play canceled again or the actuator or its armature is returned to its original position.

The invention further provides that wheel brakes with an actuator for the targeted production of an air clearance by the use of storage elements a compensation volume is provided, so that when switching off the air clearance with a corresponding piston movement no negative pressure is generated.

It when the actuator is designed as a solenoid with armature, wherein the coupling is integrated or arranged with its coupling element in the armature is particularly advantageous. The advantage with the coupling element in the armature acting on the piston is that only one parameter must be tuned by the friction force to the piston is greater than the frictional force of the coupling of the piston seal. The magnetic force for generating the coupling via the lever must be dimensioned accordingly. In order to keep the magnetic force small, levers with a relatively large lever ratio are advantageously installed in the armature. The tolerances of the coupling element and the piston require an additional stroke until the coupling acts, but this means little force and is no problem for the magnet. To avoid asymmetric radial forces in the armature advantageously two levers are arranged offset by 180 °. In addition, a leg or lever arm of the lever can be formed as a return spring of the armature. Thus, if after the end of braking, the air clearance is controlled via a corresponding activation signal, the armature moves, as a result the coupling between armature and brake piston is effective and the brake piston is moved. While driving, the magnet remains energized to maintain the air play. Due to the small air gap but only a very low power is needed for this. If, in turn, braking is initiated by appropriate signals, the actuator or its solenoid is switched off. During the lifting movement of the armature to its initial position, the piston coupling is advantageously retained, so that after the end of the stroke movement, the air clearance is almost zero. The following increase in pressure in the caliper puts the brake piston to the brake pad, the clutch is now canceled due to the return of the armature to its original position and no friction forces between the brake piston and the armature occur more, which advantageously no longer wear occurs during normal braking can.

It is also advantageous if an additional spring is provided, which is compressed at the wear end of the brake lining by the thus extended brake piston in the brake caliper under or pulled apart. This force exerted by the brake piston on the mainspring force must be overcome for generating the air gap by means of the solenoid additionally, whereby the required coil current increases with increasing brake pad wear. By evaluating the current characteristic during the activation of the actuator for generating the air clearance, the wear limit can thus be evaluated or determined. In contrast to the previous contact wear, a region of the pad wear can be evaluated with steadily increasing spring force and corresponding jerk effect on the armature. This is useful for the driver as he receives information as to when to ultimately service. The additional spring can be advantageously arranged on the armature. About a likewise arranged on the armature pin, the brake piston compress the auxiliary spring. For this purpose, a stop ring can advantageously be arranged on the brake piston. The problem of degassing, ie air formation in the brake circuit at suppression, can be solved by the advantageous use of a storage chamber, which can be connected by means of a valve, which may advantageously be a 2/2-way valve, with the hydraulic brake line of the wheel brake. In the storage chamber, the hydraulic volume is stored, which is pressed out during the brake piston movement to produce the air clearance by means of the actuator from the brake cylinder. When the air clearance is deactivated, the stored volume can again be introduced or flowed back into the brake circuit by opening the valve in the brake cylinder synchronously with the brake piston pressure movement. The storage chamber can also be integrated in the caliper together with 2/2 solenoid valves. The function of the storage chamber described above can be taken in a brake system with an electric motor driven tandem master cylinder through the provided there Nachforderkammer.

It is also advantageous if at least one permanent magnet is used to reduce the required holding force of the actuator and / or kinetic energy. The at least one permanent magnet can be provided in Magnetj och and / or in the armature of the actuator. However, any other arrangement of the permanent magnet is possible. When providing a permanent magnet, it may be necessary to reverse the coil to turn off the air gap. The brake system according to the invention is advantageously characterized in that it is simple in design, diagnosable and also adaptive. The brake system according to the invention can be used in conventional and new hydraulic brake systems.

The possible embodiments of the invention and control concepts are explained in more detail with reference to drawings. Show it :

Fig. 1: A first embodiment of the invention, with a linear motor as an actuator, which is arranged in a wheel brake; 2 shows another embodiment of the invention, wherein the actuator is arranged as a spring element in an electric motor-driven parking brake.

3 shows a third embodiment of the invention, with a lifting magnet as an actuator, which is arranged in the brake piston of a wheel brake;

Fig. 3a: a section of the magnetic yoke with non-magnetic sheet metal;

Fig. 4: Further development of a brake system acc. of Figures 1 to 3 with an air game input by means of adjustment of the floating caliper of the wheel brake;

Fig. 5: Wheel brake with arranged in the brake piston solenoid with two levers in the armature for coupling to the piston;

Fig. 5a: alternative embodiment of a wheel brake with actuator and brake pad wear detection

Fig. 6: force-displacement curve;

Fig. 7: current-time course without and with reaching the wear limit;

Fig. 8: modified storage chamber with 2/2 solenoid valve in the hydraulic unit of the ESP; Fig. 9: Use of Nachforderkammer for volume compensation.

Fig. 1 shows an electrical adjustment of the brake piston 49 for generating an air gap BLS by means of a linear magnet with stator 50 and permanent magnets 51. The permanent magnets are arranged on the brake piston 49. In order to achieve a small construction, the brake piston to the working space hm is designed topfpfig, wherein the permanent magnets 51 are arranged on the cylindrical pot inside the stator 50 around. The stator 50 is isolated from the pressure space by a sheath 54 of non-magnetic material which is sealed to the caliper. The movement of the brake piston 49 is detected by preferably an inductive sensor with coil 48 and target 48a. The electrical connection is made via a plug 55 or cable tail. About the expansion element 47 of the brake piston 49 is coupled to the brake pad 52. After preferably end of braking, the air clearance BLS is generated by the electric piston adjustment, which can be switched off in the described control mode as required by electrical adjustment of the brake piston again. An application of the brake pad in rain and similar conditions can be done here electrically without hydraulic power. Again, with timely or rapid adjustment - as described above - no Pedalweg- prolongation. FIG. 2 shows the modified FIG. 1 from DE 10 2007 015 809 of an electric parking brake with pressure assistance. In this parking brake, an electric motor, after the end of parking braking, returns the spindle with pressure plate 56 via a defined path. The lower half of the figure is shown in FIG. 1 of the preceding drawing. In the upper Bildhalfte the modification is drawn, in which the pressure plate 56 has a flange 56a for supporting the compression spring 57. The compression spring 57 is supported at its other end on a stop ring 58 which is fixed to the brake piston. By this construction, it is possible that the brake piston can move freely when pressurized. By jerking - in the figure to the right - the spindle after braking, the air clearance BLS can be adjusted via a sensor, wherein the spring force is stronger than the frictional force of the seal 29 must be. In this solution can thus by electrically adjusting the spindle before or at the beginning of Braking electrically applied the brake pad and lifted the air clearance.

Fig. 3 also shows an electrical adjustment of the brake piston for generating an air gap BLS. During braking, the brake piston 49 is pressurized and exerts a corresponding force by means of the brake pad 52 on the brake disc 59. In this case, the brake piston 49 slides over the armature 60 with friction element 61. After completion of the braking occurs at zero pressure, a rest position of the brake piston, with a residual force remaining through the sealing ring 29. In this case, the piston 49 again slides over the magnet armature 60 with friction element 61, the friction force of which is greater than that of the sealing ring 29. In this case, the force of the restoring spring 66 is again greater than the frictional force of the friction element 61, so that no movement of the armature 60 takes place in the piston pressure position. After the end of the braking of the magnetic core 62 of the solenoid is energized and the armature 60 moves and pulls the brake piston, so that adjusts an air gap BLS.

By the sliding movement of the brake piston 49 relative to the armature 60, the wear of the lining is automatically compensated. As a result of the wear of the brake piston moves forward, in the drawing to the left, and the magnet armature with solenoid 60 remains in position.

As in the previous embodiment, the solenoid 62 is switched off again before or at the beginning of the next braking via a control signal and the brake pad 52 is printed by the spring force of the return spring 66 with high dynamics against the brake disc 59. This ensures that the pedal travel is not adversely affected. The free braking of the brake disk 59 can also take place without pressurization. Furthermore, there is no risk of vapor bubble formation under reduced pressure. The only drawback is the small additional power for holding the armature while traveling with set air clearance BLS and an increased residual braking effect when the solenoid fails. The anchor movement can by the Current change to be diagnosed at power up. In this embodiment, two return springs 66 are provided, which are arranged symmetrically to the axis of the piston, so that there is no tilting of the armature 60. Below the central axis an alternative form of the magnetic armature 60 is shown with storage. In the alternative embodiment, the friction element is designed so that the pressure force is smaller. For this purpose, the armature 60 is mounted on the guide pin 49 fixed in the brake piston 65a. In addition to the embodiment shown in the upper half of the figure, two further springs 69 are provided in the alternative embodiment, which are rotated by 90 ° relative to the compression springs 66 and arranged offset around the axis of the armature 60 around. These additional compression springs 69 print against the sliding pieces 68 and 68a. The spring force thus generates a friction force on the brake piston and the guide pin moved with the brake piston 65a. By appropriate choice of the spring force of the springs 69, the friction force can be set exactly. As a result, the spring force to generate the friction force is halved. Since the brake piston is now made of aluminum, a sliding ring 71 made of steel on the brake piston is introduced and thus achieved a lower wear. The anchor must be limited in the stroke or air clearance. For this purpose, the stop pin 70 is connected to the armature and fixed to the magnetic core 62 via the stop ring 64a. Preferably, a second arranged by 180 ° pin with stop ring is used. The two compression springs 66 act on the stop ring 64. The electrical connection is made by appropriate holes in the magnetic circuit to the plug 55 or cable tail. FIG. 3a shows a detail of the magnetic circuit 62 with coil and non-magnetic sheet-metal ring 54a. This is a simpler solution than the complete Uπunantelung. In addition, there is the advantage that the residual air gap is smaller than the thickness of the welded sheet metal ring. Thus, the required power for holding the armature is lower. 4 shows a detail of the floating caliper bearing with brake holder 33, brake caliper IIa and Fuhrungsbolzen 31. In Fuhrungsbolzen 31 is a magnet armature 32 is provided with journals and a spreader 34 whose friction is greater than the friction of the two Fuhrungszapfen the saddle. At the beginning of the braking, the coil of the magnet 46 is energized and attracts the armature 32 with brake caliper 11. On the opposite side is pressed by the reaction force of the brake piston, the brake caliper 11 on the brake pad 52 on the brake disc and thus generates the known braking effect. After the end of the braking of the magnet 46 is turned off, and the return bolt 35 with compression spring 36 generates a defined clearance BLS ₂ and thus the provision of the saddle. Characterized in that at the start of braking similar to Fig. 1 is activated by a distance sensor to the brake pedal of the magnet, this air game BLS _{2 has} no Pedalwegverlangerung result. With appropriate dynamic dimensioning of the actuator, the movement takes place so fast that the distance sensor is not necessary.

In the foregoing, many feasible solutions have been described which allow adaptive control of the air clearance with the aim of keeping the braking effect very low, resulting in a high level of performance

Reduction of CO ₂ and fuel consumption results. According to the

According to the invention not only brake piston side, but also on the saddle side, an air clearance with the inventive solutions can be set specifically, so that the residual braking effect is almost zero.

FIG. 5 shows a construction which is similar to the construction according to FIG.

The actuator, consisting of the magnet 105, 106 and the armature 111, purple, 112 and 112 a, is disposed within the hollow cylindrical brake piston 102 in the brake caliper 104. The armature consists of the main components Magnetjoch 105 and armature housing 111 with anchor plate, which together form a solenoid with coil 106, which with a connecting cable 107 with the corresponding control unit, preferably that of ESP or ABS, connected is. The control unit takes over the control of the actuators according to the described simple controls for switching on and off. The cable goes from the coil 6 through the yoke 105 and the mounting pin 124 to the outside and is sealed accordingly, z. B. overmoulded. The mounting pin 124 is sealed in the brake caliper 104 with the sealing ring 109 against the brake pressure and bolted by means of nut 8 to the brake caliper 104. The coil 106 is sealed by means of a welded to the yoke 105 preferably non-magnetic disk 110 against the hydraulic medium.

In the anchor housing two offset by 180 ° lever 113, 113a are preferably arranged, which are mounted on a bearing part 112 via bearing journals 115 between anchor plate 111 and anchor pressure plate purple. This bearing part 112 is mounted radially floating in the plane of the levers 113, 113a, so that both levers 113, 113a bear against the armature movement in the inner bore of the brake piston 102 with a corresponding introduction of force during the armature movement. This bearing part 112 can be made of plastic.

FIG. 5 shows two alternative embodiments of the levers 113, 113a. The upper half of the image shows a variant in which a spring part 114 is arranged on the bearing part, which acts on the lever 113 and its support, which is formed by the bearing bush 123. The spring member 114, in cooperation with the bushing 123, which is printed by the spring 122 to the left, causes the anchor housing 111 via the stop sleeve

117 is printed on the stop 118 in the magnetic yoke 105, unless the coil 106 is energized. The position of the armature shown in Figure 5 is referred to as the starting position, in which the

Clutch is not coupled, so that there is no frictional engagement between the lever 113, 113 a and the inner wall of the brake piston 102. The same effect is achieved alternatively, if the

Spring part 114a is part of the lever 113a.

The armature housing 111 is received on one side on the bearing shaft 116 connected to the brake piston 102 and on the on the other side mounted on the bushing 123. This bearing shaft 116 may also be mounted in the yoke 105, which facilitates assembly. If the coil 6 is energized, the magnetic force causes a movement of the armature to the right against the low spring force F _{0 of} the spring parts 114 and 114a. When the levers 113 and 113a are applied to the bushing 123, the biasing force of the strong compression spring 122 acts on the levers 113 and 113a, respectively, and generates a radial force on the inner wall of the brake piston 102 in accordance with the lever transposing ratio and thus the coupling. At the same time, the magnetic housing 111 moves up to the abutment on the cutting disk 110 and, by means of the friction coupling, takes the brake piston 102 along with it in accordance with the distance traveled, which then corresponds to the clearance of the air. When switching off the magnet 105, 106, the compression spring 122 drives the armature back. Their force acts at the same time on the levers 113, 113a, so that the friction coupling is also in the return movement of the armature 111 and the brake piston 102 is again moved to the left to cancel or reduce the air clearance.

After hitting the bearing bushing 113 on the stop 105a in the yoke 105, the force on the levers 113, 113a and thus also the coupling to the brake piston, so that no more frictional engagement between the levers 113, 113a and the brake piston 102 consists more - what the The goal of the design is.

In this sequence, a lining wear detection can be easily integrated, which is an essential Sicherheitsmerkmai, as a worn friction lining leads to a reduction in the braking effect. The wear of the brake pad is expressed by the fact that the piston 102 accordingly moves to the left out of the brake caliper 104. However, yoke 105 with armature 111 is fixedly connected to caliper 104. In the brake piston 102, a stop disc 119 is resiliently mounted, ie this is based on a compression spring 120 which bears against the brake piston 102. With progressive wear and corresponding piston position, this stop disk 119 hits the magnet armature 111. The additional movement thus takes effect during the lifting movement Force of the compression spring 120 against the magnetic force of the solenoid, which is detected by the activation of the magnet 105, 106 via a resulting increase in current.

As shown in Figure 5a, the movable stop member 119 'with spring 120' of course also be secured to the anchor housing 111, which on a fixed stop 119 'on

Brake piston 102 impinges. In this form from fuhrungs the spring element supports 114 ^Λ on the anchor plate purple jerk and acts on

End of the lever arm of the lever 113, in which also the force of the spring 22 is introduced by means of the bearing bush 123.

In Figure 5a, a possible arrangement of a permanent magnet 134 is additionally shown to reduce the required holding force of the actuator. Through the use of the optional permanent magnet 134, moreover, the energy required to move the armature 111, purple can be reduced. A reversal of the coil 106 for switching off the air clearance may be required.

In FIG. 6, the forces occurring at the magnet are plotted against the stroke s. In the starting position or basic position S _0, the weak restoring force F _{0 of} the spring parts 114, 114a acts. After contact of the levers 113, 113a at S _1, the biasing force F _{v of} the compression spring 122 acts, which stands out sharply. Now hits the brake piston 102 in wear on the armature 111 with the described resilient compensation, so there is a significant increase in force on F ₁ at the beginning of the wear limit and F ₂ at higher wear, which highest warning level is given.

FIG. 7 shows the current-time profile under the above-mentioned conditions. The lower fully drawn curve is the course without additional forces on the anchor. The current increase causes the increase in force. When the armature moves, the typical current change occurs as a result of the counter-armature induction. This current profile can be measured with i ₀ . Now, if the additional force described F ₁ , F ₂ acts on reaching the wear limit, the current level is corresponding to i _{l 7} i ₂ higher and can from the electrical Circuit via a corresponding shunt can be easily evaluated. The same can be recognized by the force jump F _v when the compression spring force 122 is acted upon with corresponding current measurement i ₀ i, in ii ₂ . Both current levels or preferably the first i ₀ , ii, i ₂ can be evaluated, with corresponding evaluation for the vehicle diagnosis and display.

This concept fulfills all currently known requirements for the wheel brake with a simple construction:

- control of the air play;

- no additional friction;

- Brake pad wear indicator.

As a result, no additional electrical wiring to the caliper are necessary because the lines of conventional wear contact omitted. Due to the floating support of the levers 113, 113a, the function is not sensitive to tolerance.

It is also conceivable that for controlling the solenoid at least one connecting cable of Drehfuhlers is used with, since the speed sensor signal is required only when braking for ABS and here the magnet 105, 106 is turned off.

FIG. 8 shows the known valve circuit of the ESP with pump and vacuum brake booster for a brake circuit, the description of which is omitted. Only the modification is discussed. Integrated in the caliper is the air play actuator (LSA) described in FIG. At the beginning of braking, the LSA should be turned off, possibly creating a vacuum in the lines by the rapid piston pushing movement until the liquid is sucked out of the reservoir. During brake actuation, the volume corresponding to the piston movement is missing, which leads to pedal extension in brake systems without a travel simulator. To prevent this is stored the corresponding volume for a brake circuit for two LSA in the storage chambers 126. For this purpose, the normally usual non-return valve must be replaced by a 2/2-way solenoid valve 128, so that the memory remains filled. If now the LSA is switched off, the valve 122 opens for a short time and thus compensates the volume of the brake piston, the so-called refilling. Alternatively, the valve 122 can be switched off when a certain pressure is measured by the pressure sensor in the brake circuit. If, after braking, the brake pressure is reduced, opening of the valve 132 takes place until the storage chamber 126 has a specific filling at low pressure via the position transmitter 127 on the piston. If the ABS or ESP function, the 2/2-solenoid valve 128 is opened.

A filling of the storage chamber 126 can also be done while driving on the pump P by this similar to the ESP function

Volume from the Vorratsbehalter in the wheel brake calls and the open valve 122, the storage chamber with low pressure about

2 bar fills until the sensor 127 filling by closing the

Valve 122 and switching off the pump P stops. The refilling can also be made larger to prefill the brake, resulting in

Beginning of braking means smaller pedal travel and a braking distance shorting.

FIG. 9 shows a system with an electromotive drive 131 of the tandem master cylinder. Here Nachforderkammern 130 are provided with 2/2-way valves 129 to demand additional volume in the brake circuits / wheel brakes, if necessary. These request chambers 130 can assume the function of the storage chamber 126 described in FIG. 8 in order to avoid a vacuum when the air play actuator is switched off. Alternatively, the Nachforderkammern can be provided with position sensor on the piston. Also, in addition to the refilling for the air game actuator also an additional prefilling done by at the beginning of the braking when the Schnuffeiloch is closed in the THZ, a certain volume in the brake circuits is fed. The re-filling of the Nachforderkammer is known to be at the end of braking at pressure reduction.

Thus, the problems of possible degassing under negative pressure and additional Bremswegverkurzung are solved by prefilling the brakes at the beginning of braking.

List of reference numbers:

11 caliper

31 Guide pins 32 Magnetic anchor with bearing pin

33 brake holder

34 expansion element

35 return bolts

36 Return spring 37 Brake piston sensor

48 sensor coil

48 ° sensor target

49 brake pistons

50 stator 51 permanent magnets

52 brake pad

53 caliper

54 non-magnetic sleeve

54a non-magnetic metal ring 55 plug

56 pressure plate 56a flange

57 compression spring

58 stop ring 59 brake disc

60 magnetic armature

61 friction element

62 magnetic core with coil

63 Housing seal 64 Stop ring

65 guide bolts

65a alternative guide pin

66 return spring

67 Housing 68 Slider

68a slider

69 compression springs

70 stop pin

71 Slide ring 101 Brake lining

102 brake piston

103 sealing ring

104 caliper

105 magnetic yoke 106 coil

107 connection cable

108 fixing nut

109 sealing ring

110 Cutting disc 111 Anchor housing purple Anchor back plate

112 bearing part

113 lever 113a lever Continuation of the reference list:

114, 114 ^λ spring on the bearing part

114a Spring on the lever

115 bearing pin 116 bearing shaft

117 stop pulses

118 stop

119, 119 'stop disc

119a * Mounting ring 120, 120 ^x compression spring

120a ^λ stop pin

121 Stop on compression spring

122 compression spring

123 Bearing bush 124 Fastening pin

125 air game actuator LSA

126 Speyer Chambers

127 position transmitter

128 2/2 solenoid valve 129 2/2 Solenoid valve in front of the prechamber

130 demand chamber

131 electronic drive for THZ

132 A valve

133 Pressure transducer 134 Permanent magnet

BLS ₁ air game

Egg electric drive as lifting magnet acc. Fig. 1

E ₂ Electric drive as linear motor acc. Fig. 3

E ₃ actuator for floating caliper adjustment

EP Electric Parking Brake

Claims

Patent claims

1. A hydraulically acting brake system with a master cylinder whose at least one working space is connected via at least one hydraulic line with at least one wheel brake or parking brake of the vehicle, characterized in that an actuator at least one brake pad (52) of a wheel brake to achieve an air clearance (BLS ₁ ) adjusted ,

2. Hydraulically acting brake system according to claim 1, characterized - characterized in that the actuator is a spring (57) which is biased in particular by the actuator, or the actuator is an electrical, in particular electromagnetic, drive (E ₁ , E ₂ ).

3. Hydraulically acting brake system according to claim 1 or 2, characterized in that the

Brake system is an electro-hydraulic brake system, in which the master cylinder is adjustable by means of an electric drive or a pneumatic-hydraulic brake system, in which the master cylinder is pneumatically adjustable.

4. Hydraulically acting brake system according to one of claims 1 to 3, d a d u r c h e c e n e z e c h e in that the actuator acts on a force transmission member to the brake disc.

5. Hydraulically acting brake system according to one of claims 1 to 4, characterized in that the actuator acts directly on the brake piston of the wheel brake.

6. Hydraulically acting brake system according to claim 5, characterized in that the actuator is at least partially disposed within the brake piston (49) of the wheel brake.

7. A hydraulically-acting brake system according to claim 5 or 6, d a d e r c h e c e n e c e s in that the actuator is arranged within the working space of the piston-cylinder system of the wheel brake.

8. Hydraulically acting brake system according to claim 6 or 7, d a d e r c h e c e n e c e s in that the

Brake piston (49) on its side facing away from the brake pad (52) has a recess (49a) in which the actuator rests at least partially.

9. Hydraulically acting brake system according to one of the preceding claims, characterized in that the actuator (E ₁ ) is a linear motor.

10. Hydraulically acting brake system according to claim 9, characterized in that the brake piston

(49) forms the rotor of the linear motor (Ei).

11. Hydraulically acting brake system according to claim 10, characterized in that on the brake piston (49), in particular in a recess (49a) of the brake piston, permanent magnets (51) are arranged, which generate a adjusting force for generating a clearance (BLS) with a stator.

12. Hydraulically acting brake system according to one of claims 7 to 11, characterized in that a separating element (54) made of non-magnetic material, the electrical components, in particular the coils, stator or the magnetic circuit separated from the pressure chamber or the brake fluid.

13. Hydraulically acting brake system according to one of claims 1 to 8, characterized in that the actuator (E ₂ ) is a solenoid, which is arranged in particular within the brake piston (49).

14. Hydraulically acting brake system according to claim 13, characterized in that the armature (60) of the lifting magnet is connected to the brake piston (49) via frictional engagement, in particular by means of a friction element (61).

15. Hydraulically acting brake system according to one of claims 7 to 14, d a d e r c h e c e n e s in that there is at least one restoring spring (66) pressurizing the brake piston (49) in the direction of the brake pad (52) and displacing it in the direction of the brake pad when the actuator is deactivated.

16. Hydraulically acting brake system according to claim 15, characterized in that the force of the return spring (66) is greater than the frictional force of the piston seal (29).

17. Hydraulically acting brake system according to claim 15 or 16, characterized in that two additional compression springs (69) in the armature (60) are arranged, whose force is perpendicular to the force of the return springs (66), wherein the compression springs (69) with their respective ends in each case two sliding pieces (68, 68 a) against the piston (49) and Fuhrungs tap (65 a) to pressurize a friction force.

18. Hydraulically acting brake system according to claim 17, characterized in that the two restoring springs (66) and the two additional compression springs

(69) are each distributed around the axis of the armature (60) around.

19. Hydraulically acting brake system according to claim 17 or 18, characterized in that stop pins (70) are arranged on the magnet housing (62) which limit the stroke of the magnet armature (60).

20. Hydraulically acting brake system according to claim 17, wherein a sheet-metal ring (54a), in particular made of non-magnetic material, which is in particular welded or soldered in, sealingly seals the coil of the actuator from the hydraulic medium.

21. Hydraulically acting brake system according to claim 20, characterized in that the thickness (s) of the sheet-metal ring (54a) is greater than the distance (a) from the magnetic yoke to the magnet armature (60).

22. A hydraulically-acting brake system according to one of claims 1 to 4, in which a supplementary actuator acts on the brake caliper (11).

23. Hydraulically acting brake system according to claim 22, characterized in that the actuator is a linear motor or a lifting magnet (E ₃ ).

24. Hydraulically acting brake system according to claim 22 or 23, d a d e r c h e c e n e c e in that the additional actuator is arranged in a housing (67) on the brake calliper support (33).

25. Hydraulically acting brake system according to one of the preceding claims, characterized in that a displacement sensor detects the lifting height or the displacement of the brake piston (49), the actuator or its movable parts for adjusting the air clearance (BLS ₁ ).

26. Hydraulically acting brake system according to claim 25, characterized in that the brake pad wear can be determined by means of the displacement sensor.

27. Hydraulically acting brake system according to claim 1, characterized - in that the brake piston via at least one spring element (57) is coupled to the drive of an electric parking brake (EP), wherein by returning the drive of the parking brake, the spring element (57) has a force for lifting the brake pad from the brake disc to the brake piston (49) initiates, wherein the introduced spring force is greater than the frictional force of the brake piston seal (29).

28. Hydraulically acting brake system according to one of the preceding claims, dadurchgekenn - characterized in that a controller adjusts the air play (BLS ₁ ) in dependence on the driving situation or regulates.

29. A hydraulic braking system according to claim 28, wherein a control system does not generate an air clearance in the wheel brakes in the case of rain and / or wet road conditions.

30. Hydraulically acting brake system according to claim 28 or 29, characterized in that when the road is dry after a certain time and / or driving the air game generation is interrupted, and for a predetermined time the brake pads of the wheel brakes are pressurized against the brake discs to achieve a braking effect ,

31. Hydraulically acting brake system according to one of claims 28 to 30, characterized in that during normal driving without actuation of the brake by the person driving an air clearance is set by the controller.

32. Method using a hydraulically acting brake system according to one of the preceding claims, characterized in that the air clearance (BLS) is canceled in the individual wheel brakes as soon as the brake system recognizes from the driving situation that a braking process is imminent.

33. The method of claim 32, d a a c e c e c e n e c e s. in that the actuators are designed such that they quickly apply the brake pad of the respective wheel brake at the start of braking.

34. The method according to claim 32 or 33, characterized in that based on the movement of the accelerator pedal, in particular its speed, the speed of the brake foot, the distance of the brake pedal actuating foot relative to the brake pedal and / or the signal of a distance warning system, the brake system recognizes the imminent initiation of a braking process.

35. The method according to claim 32, wherein at least one distance sensor determines the distance of the foot from the brake pedal in at least one direction, preferably in three directions.

36. Wheel brake with actuator for generating an air gap, wherein by means of the actuator parallel to the direction Bremsbewegbewbewungsrichtung slidably mounted armature (111, purple, 112) is adjustable, wherein by means of the armature (111, purple, 112) of the brake piston (102) drivable is, characterized in that between armature (111, purple, 112) and brake piston (102) is arranged a coupling.

37. Wheel brake according to claim 36, characterized in that by means of the coupling, a compound, in particular a friction and / or adhesion, between anchor 111, purple, 112) and brake piston (102) can be produced.

38. Wheel brake according to claim 36 or 37, characterized in that when adjusting the armature 111, purple, 112) parallel to the direction of movement of the brake piston (102) closes the coupling and the connection, in particular the force, shape and / or frictional engagement between Anchor and brake piston generated.

39. Wheel brake according to one of claims 36 to 38, characterized in that, upon activation of the actuator, the clutch closes and establishes the connection, in particular the force, shape and / or frictional connection, between armature and brake piston.

40. The wheel brake according to claim 36, wherein a permanent magnet is arranged in the magnet yoke or armature for reducing the required holding force of the actuator when the clearance is generated and / or for moving the armature.

41. Wheel brake according to one of claims 36 to 40, characterized in that the switching off of the generated clearance of the actuator, a reversal of the coil of an electromagnet is carried out.

42. Wheel brake according to one of claims 36 to 41, characterized in that the coupling has at least one, in particular two, levers (113, 113a), each with at least two lever arms or legs, and the lever (113, 113a) on the armature (111 , purple, 112) are pivotably mounted, and that a lever arm of a lever (113, 113a) for producing a connection, in particular a friction, force or positive connection, with the brake piston (102), in particular its cylindrical inner wall, cooperates ,

43. Wheel brake according to claim 42, characterized in that the respective other lever arm of each lever (113, 113 ^y ) with a direction parallel to the direction of movement the first stop (123) interacts displaceably with the brake piston (102), the first stop (123) being subjected to force in the direction of the brake pad by means of a compression spring (122), and in particular as a bearing bush.

44. Wheel brake according to claim 43, characterized in that the movement of the first stop (123) is limited by a second stop (118) which is fixed relative to the actuator drive and which is arranged or formed in particular on the magnetic yoke (105).

45. Wheel brake according to one of claims 36 to 44, characterized in that a spring element (114, 114 ^Λ ), in particular a compression spring, the lever (113, 113 a) to a starting position in which the clutch is opened or no connection, in particular no friction, form and / or adhesion, exists.

46. Wheel brake according to claim 45, characterized in that the spring element (114) is arranged on the armature (111, IIIa) or is part of the armature and pressurizes the lever arm (113).

47. The wheel brake as claimed in claim 36, wherein the spring element is arranged on the lever arm of the lever, in particular formed on the lever arm, and that the spring element braces against the armature (111, 101a).

48. Wheel brake according to one of claims 42 to 47, d a d u c h e c e n e c e in that the armature is an anchor plate

(111), which cooperates with an electromagnet (105, 106) and forms the actuator.

49. Wheel brake according to claim 48, characterized in that on the anchor plate or on a bearing plate secured to the anchor plate or at an intermediate the armature plate and an anchor plate (purple) connected to the anchor plate, arranged, in particular radially floating bearing plate (112) of the at least one lever (113, 113a) is pivotally mounted or are.

50. The wheel brake as claimed in claim 36, wherein the brake piston is configured as a hollow cylinder or has a hollow cylindrical part in which the actuator is arranged at least in regions together with the armature.

51. Wheel brake according to claim 50, characterized in that in the hohlzylmdrischen part of the brake piston (102) a shaft (115) is arranged, which is in particular arranged centrally, wherein on the shaft (115) of the armature is displaceably mounted and the shaft on the brake piston ( 102) is formed or attached to this.

52. Wheel brake according to claim 51, characterized in that the first stop (123), which is designed in particular as a bearing bush, rests on the shaft

(115) and / or is displaceably mounted in the magnet yoke (105) of the actuator.

53. Wheel brake according to one of claims 36 to 52, characterized in that the actuator via an electrical Verbmdungskabel (107) is connected to a control unit, which forms the connection cable for the ABS-speed sensor, wherein at least one line is used for the control of the actuator ,

54. Wheel brake according to the preamble of claim 36 or any one of claims 36 to 53, characterized in that the brake piston (102) via at least one additional spring element (120, 120 ^λ ) exerts a force on the armature (111, purple) of the actuator ,

55. Wheel brake according to claim 54, characterized in that the brake pad wear can be determined by means of a control device on the basis of the current consumption characteristic of the actuator.

56. The wheel brake as claimed in claim 54 or 55, wherein the brake piston (102) exerts a force on the armature of the actuator only after a certain brake pad wear, in particular only in the end region of the brake pad wear, which increases with increasing brake pad wear.

57. Wheel brake according to one of claims 54 to 56, characterized in that the additional spring element (120M is mounted on the armature, wherein the brake piston (102) via a stop element (119 '), in particular a stop disc, the spring element (120 ^y ) in worn Brake pad pretensions.

58. Hydraulically acting brake system according to one of claims 1 to 3 using a wheel brake according to one of claims 36 to Sψ.

59. Brake system with a wheel brake according to the preamble of claim 36 or one of claims 36 to 57, characterized in that the brake system comprises at least one storage device (126, 130) for hydraulic medium, in particular a storage chamber, whose working chamber via a valve ( 128, 129, 132), in particular a 2/2-way valve, by means of hydraulic lines to the brake cylinder at least one wheel brake is connectable.

60. Brake system according to claim 59, characterized in that hydraulic medium, which is in particular under pressure, from the storage device (126, 130) flows when switching off the actuator and associated brake piston pressure movement in the brake cylinder.

61. Brake system according to claim 59 or 60, in which a pumping device (P) fills the storage device (26) upon appropriate actuation of the valve (128).

62. A braking system according to any of claims 59 to 61, wherein the storage device is the demand chamber (130) of the brake system.

63. Brake system according to one of claims 59 to 62, characterized in that the storage device (126, 130) is dimensioned for large hydraulic volumes, such that a sufficiently large pressurized hydraulic volume at the beginning of a braking from the storage device in the respective brake circuit by means of appropriate Actuation of the valve to support the brake booster is supplied.

64. Brake system according to one of claims 59 to 63, characterized in that the piston storage device (126, 130) has a position sensor for detecting the piston position.

65. Braking system according to claim 59, wherein the filling of the piston accumulator device is carried out on the basis of the signal of the position transmitter.