Fixed-Caliper Brake Comprising Electromechanical-Hydraulic Force Transmission

Abstract

A fixed-caliper brake has a combined electromechanical/hydraulic force transmission, including a fixed caliper, a brake disc, a first brake piston device which is arranged on or in the brake caliper and is designed to directly or indirectly transmit a first pressure force to a first lateral face of the brake disc associated therewith by way of at least one brake piston, a second brake piston device which is arranged on or in the brake caliper and is designed to directly or indirectly transmit a second pressure force to a second lateral face of the brake disc associated therewith and opposite the first lateral face by way of at least one brake piston, and an electromechanical actuator which is arranged on or in the brake caliper and is configured to exert a force onto the first brake piston device and onto the second brake piston device, respectively, when actuated. The force is further transmitted by the particular brake piston device, at least proportionally, as the first or second pressure force, respectively, onto the particular associated lateral face of the brake disc. The electromechanical actuator and the second brake piston device are hydraulically coupled to one another to cause the exertion of force from the electromechanical actuator to the second brake piston device.

Claims

1.-12. (canceled)

13. A fixed-caliper brake, comprising: a brake caliper; a brake disk; a first brake piston device which is arranged on or in the brake caliper and is configured to use at least one brake piston to directly or indirectly transmit a first pressure force to an associated first side surface of the brake disk; a second brake piston device which is arranged on or in the brake caliper and is configured to use at least one brake piston to directly or indirectly transmit a second pressure force to an associated second side surface of the brake disk opposite the first side surface; and an electromechanical actuator which is arranged on or in the brake caliper and is configured, when actuated, to exert, both on the first brake piston device and on the second brake piston device, a respective force which is further transmitted by the respective brake piston device, at least proportionally, as a respective first or second pressure force to the respectively associated side surface of the brake disk; wherein the electromechanical actuator and the second brake piston device are hydraulically coupled to each other in order to bring about the exertion of force from the electromechanical actuator to the second brake piston device.

14. The fixed-caliper brake according to claim 13, wherein the electromechanical actuator is arranged relative to the brake disk on the same side of the fixed-caliper brake as the first brake piston device.

15. The fixed-caliper brake according to claim 13, wherein a hydraulic channel running at least in sections inside the brake caliper is provided for the hydraulic coupling of the electromechanical actuator to the second brake piston device.

16. The fixed-caliper brake according to claim 13, wherein the first brake piston device is also hydraulically coupled to the electromechanical actuator for bringing about the exertion of force from the electromechanical actuator to the first brake piston device.

17. The fixed-caliper brake according to claim 16, wherein the electromechanical actuator and the two brake piston devices are hydraulically coupled to a common hydraulic channel in order to bring about the exertion of force from the electromechanical actuator on the brake piston devices.

18. The fixed-caliper brake according to claim 13, wherein the first brake piston device is coupled in terms of force mechanically or electromechanically to the electromechanical actuator, in order to bring about the exertion of force from the electromechanical actuator on the first brake piston device, in such a manner that, during said exertion of force, at the same time the exertion of force from the electromechanical actuator on the second brake piston device is brought about via the hydraulic coupling thereof to the electromechanical actuator.

19. The fixed-caliper brake according to claim 18, wherein the electromechanical actuator is configured to generate force by way of a spindle drive or a piezo element.

20. The fixed-caliper brake according to claim 13, wherein the first brake piston device has two pistons which are hydraulically coupled to each other in terms of force by way of a fluid located between them.

21. The fixed-caliper brake according to claim 20, wherein: the first brake piston device has a telescopic brake piston which has a hollow piston which is arranged movably relative to the brake disk and has an internal piston arranged therein so as to be movable relative to the hollow piston; the interior of the hollow piston together with a head surface of the internal piston defines a fluid chamber, which is hydraulically coupled to the second brake piston device, inside the hollow piston; and the telescopic brake piston is coupled in terms of force to the electromechanical actuator in such a manner that, when the electromechanical actuator is actuated, a fluid located in the fluid chamber is pressurized via the internal piston, the pressurization firstly bringing about the first pressure force on the brake disk via the hollow piston and secondly bringing about the second pressure force on the brake disk via the hydraulically coupled second brake piston device.

22. The fixed-caliper brake according to claim 20, wherein: the two pistons are connected in series; an intermediate space between the two pistons defines a fluid chamber, which is hydraulically coupled to the second brake piston device, inside the first brake piston device for the fluid; and a first of the two pistons is coupled in terms of force to the electromechanical actuator in such a manner that, when the electromechanical actuator is actuated, the fluid located in the fluid chamber is pressurized via this first piston, the pressurization firstly bringing about the first pressure force on the brake disk via the second of the pistons and secondly bringing about the second pressure force on the brake disk via the hydraulically coupled second brake piston device.

23. The fixed-caliper brake according to claim 13, wherein the electromechanical actuator is connected to an electric line which serves both for energy supply of the electromechanical actuator and activation thereof.

24. A vehicle comprising a fixed-caliper brake according to claim 13.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIG. 1 schematically shows a simplified operating principle of a conventional hydraulic fixed-caliper brake from the prior art;

[0030] FIG. 2 schematically shows the construction of a fixed-caliper brake according to a first preferred embodiment of the invention;

[0031] FIG. 3 schematically shows the construction of a fixed-caliper brake according to a second preferred embodiment of the invention; and

[0032] FIG. 4 schematically shows a motor vehicle, the chassis of which is equipped with fixed-caliper brakes according to FIG. 2 (or alternatively according to FIG. 3).

DETAILED DESCRIPTION OF THE DRAWINGS

[0033] The various fixed-caliper brakes explained below are each described, without this being understood as a limitation, using the example of a disk brake for a motor vehicle, since this is a particularly relevant application.

[0034] The conventional hydraulic fixed-caliper brake illustrated in FIG. 1 has a brake caliper 115 connected fixedly to a wheel suspension of the wheel to be braked, a brake disk 120 and a respective brake piston device on both sides thereof, i.e. both on an inner side 105 and on an outer side 110 of the fixed-caliper brake 100. The brake piston device has a brake piston 125a and 125b and a brake pad 130a and 130b fastened thereto, wherein the respective brake piston 125a and 125b is arranged so as to be movable in a cylindrical cavity formed by the brake caliper 125 and sealed by means of one or more seals 128.

[0035] In order to actuate the brake, a suitable fluid, e.g. a hydraulic fluid, for example a hydraulic oil suitable for the operation of a fixed-caliper brake, is pressed via a hydraulic line under a pressure p into a hydraulic channel 135 formed in the brake caliper 115. The pressure p can be generated in a known manner in particular by a brake pedal or a brake booster connected in between. In addition, the hydraulic channel 135 is designed as a connection between the two cylindrical cavities in which the brake pistons 125a and 125b are arranged. In each of these cavities, the respective volume region not taken up by the associated brake piston 125a or 125b itself is a fluid chamber 140a or 140b. By subjecting the fluid to the pressure p, the pressure propagates through the fluid in the hydraulic channel 135 on both sides of the fixed-caliper brake 100 into the corresponding fluid chamber 140a and 140b and is transmitted there to the rear side of the respective brake piston 125a and 125b. The respective brake piston 125a and 125b is thereby caused to press the brake pad 130a and 130b attached to the front side thereof with a drive force corresponding, at least substantially, to the pressure p against the brake disk 120 in order to brake the latter and therefore an axle which is coupled thereto and has the vehicle wheel fastened thereto.

[0036] In this known type of fixed-caliper brake, a substantially symmetrical construction is therefore provided, in which the activation and the energy supply of the fixed-caliper brake 100 as a whole take place solely hydraulically and accordingly an exclusively hydraulically actuated brake piston is provided in each case on both sides 105 and 110 of the fixed-caliper brake 100.

[0037] The embodiments 200 and 300 of a fixed-caliper brake according to the invention that are respectively illustrated in the two following FIGS. 2 and 3 are based, by contrast, on a hybrid operating concept in which the fixed-caliper brake is not activated hydraulically but rather via a signal which may be in particular an electric, optical or wireless signal. An electromechanical actuator provided as part of the fixed-caliper brake itself serves, controlled by this signal, as an actuating element for the fixed-caliper brake.

[0038] The construction of the fixed-caliper brake is no longer substantially symmetrical, but rather asymmetrical. On the one side, preferably the inner side, of the fixed-caliper brake, the actuator acts on a first piston element, which is hydraulically coupled to a second piston element, in order to transmit the action of the actuator thereto. The second piston element in turn bears a brake pad and, when the brake is actuated, owing to the action of force of the actuator transmitted to it as described, is pressed against the brake disk in order to brake the latter. By contrast, in order to actuate the brake piston on the other side of the fixed-caliper brake, i.e. preferably the outer side, the hydraulic pressure generated on the first side is transmitted similarly as in the conventional fixed-caliper brake according to FIG. 1 via a hydraulic channel.

[0039] In this way, the second side, i.e. in particular the outer side, of the fixed-caliper brake can furthermore be driven exclusively hydraulically, with space being optimized, while the fixed-caliper brake as a whole, instead of a hydraulic activation and energy supply, obtains a signal activation and has a dedicated, hydraulically independent energy supply for actuating the actuator.

[0040] The first embodiment 200 of the fixed-caliper brake according to the invention that is illustrated in FIG. 2 has a brake caliper 215 connected fixedly to a wheel suspension of the wheel to be braked (not illustrated), a brake disk 220 and a respective brake piston device on both sides thereof, i.e. both on an inner side 205 and on an outer side 210 of the fixed-caliper brake 200, the brake piston device in the simplest case having only one brake piston and one brake pad 230a or 230b fastened thereto. However, use may equally also be made of brake piston devices which in each case themselves have a plurality of brake pistons, and also the use of a plurality of brake pads per brake piston is possible.

[0041] The brake piston of the first side 205, which preferably forms the inner side of the vehicle brake, is designed as a telescopic brake piston which in particular has a hollow piston 227 and an internal piston 226 mounted in a coaxially movable manner therein. The hollow piston 227 in turn is arranged movably in a cylindrical recess of the brake caliper 215 and is sealed therein via sealing rings 228. By contrast, on the second side 210, which preferably forms the outer side of the vehicle brake, a conventional, hydraulically actuated brake piston 225 is provided in a cylindrical recess of the brake caliper 215, the construction of which brake piston substantially corresponds to that of the brake pistons 125a and 125b from FIG. 1. A seal (not illustrated) which can be designed in particular in the form of one or more sealing rings can also be provided for the brake piston 225 in a similar manner as for the hollow piston 227.

[0042] In addition, as part of the fixed-caliper brake 200, an electromechanical actuator 245 is provided which is fixed to the brake caliper 215 and is coupled in terms of force to the rear side of the internal piston 226 in order to be able to transmit an—in particular mechanical, electrical or magnetic—action of force to the internal piston. The electromechanical actuator 245 is activatable via a signal, which may be in particular electric or optical, and also has an, in particular, electric, energy supply which can be provided in particular via an electric line 250. In the case of an electric activation, this line 250 can serve at the same time as an activation line for the actuator 245, for which purpose, for example, an alternating voltage signal superimposed on an energy supply direct voltage can be used.

[0043] In addition, a hydraulic channel 235 filled with a hydraulic fluid is provided. It connects a first fluid chamber 240a, which is defined inside the hollow piston 227 by the inner wall thereof and the front side of the internal piston 226, to a second fluid chamber 240b, which is defined on the second side of the brake 200 in the cylindrical recess for the brake piston 225 by the inner wall of this recess and the rear side of the brake piston 225, and therefore provides a hydraulic coupling of the two fluid chambers 240a, b. In order to produce or improve the hydraulic coupling of the hydraulic channel 235 to the first fluid chamber 240a located in the interior of the hollow piston 227, one or more passages for the hydraulic fluid can be provided in the wall of the hollow piston 227.

[0044] If the actuator 245 is now activated and thus actuated, it exerts a force on the internal piston 226 causing the latter to move inside the hollow piston 227 in the direction of the brake disk 220 and, in the process, to exert an increased pressure on the hydraulic fluid present in the fluid chamber 240a. This pressure increase firstly causes the hollow piston 227 to likewise be moved in the direction of the brake disk 220 and, in the process, to press the brake pad 230a onto the brake disk. Secondly, the pressure increase propagates via the hydraulic fluid located in the hydraulic channel 235 to the second fluid chamber 240b and leads there in the same manner, as already described above for FIG. 1, to an action of force on the rear side of the brake piston 225. This action of force causes the brake piston 225 in turn to press the brake pad 230b in the opposite direction to the direction of movement of the brake pad 230a against the brake disk 220. Overall, the brake disk 220 is thus braked on both sides by the action of force of the brake pads 230a and 230b.

[0045] The second embodiment 300 of the fixed-caliper brake according to the invention that is illustrated in FIG. 3 has a brake caliper 315 connected fixedly to a wheel suspension of the wheel to be braked (not illustrated), a brake disk 320 and a respective brake piston device on both sides thereof, i.e. both on an inner side 305 and on an outer side 310 of the fixed-caliper brake 300. In the simplest case, this brake piston device has only one brake piston and one brake pad 330a or 330b fastened thereto. However, as in the case of the brake 200, use can equally also be made of brake piston devices which themselves have a plurality of brake pistons, and also the use of a plurality of brake pads per brake piston is possible.

[0046] The brake piston of the first side 305, which preferably forms the inner side of the vehicle brake, is designed here especially as a series connection of two individual pistons 326 and 327 which are hydraulically coupled via a first fluid chamber 340a located in between and which are arranged movably coaxially in a cylindrical recess of the brake caliper 315 and are sealed therein via sealing rings 328. By contrast, on the second side 310, which preferably forms the outer side of the vehicle brake, a conventional, hydraulically actuated brake piston 325 is provided in a cylindrical recess of the brake caliper 215, the construction of which brake piston substantially corresponds to that of the brake piston 225 from FIG. 1. A seal (not illustrated) which can be designed in particular in the form of one or more sealing rings can also be provided for the brake piston 325, as for the brake piston 225.

[0047] In addition, as part of the fixed-caliper brake 300, an electromechanical actuator 345 is provided which is fixed to the brake caliper 315 and is coupled in terms of force to the rear side of a first piston 226 of the series-connected pistons in order to be able to transmit an—in particular mechanical, electrical or magnetic—action of force thereto. The electromechanical actuator 345 is activatable via a signal, which can be in particular electrical or optical, and also has an, in particular electrical, energy supply which can be provided, for example, via an electric line 350. In the event of an electrical activation, this line 350 can serve at the same time as an activation line for the actuator 345, for which purpose, for example, an alternating voltage signal superimposed on an energy supply direct voltage can be used.

[0048] In addition, a hydraulic channel 335 filled with a hydraulic fluid is provided. It connects the first fluid chamber 340a to a second fluid chamber 340b, which is defined on the second side of the brake 300 in the cylindrical recess for the brake piston 325 by the inner wall of the recess and the rear side of the brake piston 325, and therefore provides a hydraulic coupling of the two fluid chambers 340a, b.

[0049] If the actuator 345 is now activated and therefore actuated, it exerts a force on the first piston 326 causing the latter to move inside the cylinder in the direction of the brake disk 320 and, in the process, to exert an increased pressure on the hydraulic fluid present in the fluid chamber 340a. This pressure increase firstly causes the second piston 327 to likewise move in the direction of the brake disk 320 and, in the process, to press the brake pad 330a against the latter. Secondly, the pressure increase propagates via the hydraulic fluid located in the hydraulic channel 335 to the second fluid chamber 340b and leads there in the same manner, as already described above for FIGS. 1 and 2, to an action of force on the rear side of the brake piston 325. This action of force causes the brake piston 325 in turn to press the brake pad 330b in the opposite direction to the direction of movement of the brake pad 330a against the brake disk 320. Overall, the brake disk 320 is thus braked on both sides by the action of force of the brake pads 330a and 330b.

[0050] As illustrated in FIG. 4, the fixed-caliper brakes according to the invention, in particular according to the embodiments illustrated in FIG. 2 or FIG. 3, can be provided, for example, as vehicle brakes for a motor vehicle on wheel suspensions thereof, in order to brake the wheels of the vehicle. It is in particular also conceivable for different types of brake to be used, for example the brakes from FIG. 2 for the front wheels and the brakes from FIG. 3 for the rear wheels.

[0051] While at least one exemplary embodiment has been described previously, it should be noted that a large number of variations thereof exist. It should also be remembered that the exemplary embodiments described are only none-limiting examples, and the intention is not to thereby restrict the scope, applicability or configuration of the devices and methods described here. On the contrary, the preceding description will provide a person skilled in the art with guidance to implement at least one exemplary embodiment, and it goes without saying that various changes to the manner of operation and the arrangement of the elements described in an exemplary embodiment can be made without thereby departing from the subject matter respectively defined in the accompanying claims and from legal equivalents of the subject matter.

LIST OF REFERENCE SIGNS

[0052] 100 Conventional hydraulic fixed-caliper brake [0053] 105 First side of the fixed-caliper brake 100, on the inner side of the vehicle [0054] 110 Second side of the fixed-caliper brake 100, on the outer side of the vehicle [0055] 115 Brake caliper [0056] 120 Brake disk [0057] 125a,b, Brake pistons [0058] 128 Seals, in particular sealing rings [0059] 130a,b Brake pads [0060] 135 Hydraulic channel [0061] 140a,b Fluid chambers [0062] 200 Fixed-caliper brake according to a first embodiment [0063] 205 First side of the fixed-caliper brake 200, on the inner side of the vehicle [0064] 210 Second side of the fixed-caliper brake 200, on the outer side of the vehicle [0065] 215 Brake caliper [0066] 220 Brake disk [0067] 225 Brake piston [0068] 226 Internal piston [0069] 227 Hollow piston [0070] 228 Seals, in particular sealing rings [0071] 230a,b Brake pads [0072] 235 Hydraulic channel [0073] 240a,b Fluid chambers [0074] 245 Electromechanical actuator [0075] 250 Electric line for energy supply/activation of the actuator 245 [0076] 300 Fixed-caliper brake according to a second embodiment [0077] 305 First side of the fixed-caliper brake 300, on the inner side of the vehicle [0078] 310 Second side of the fixed-caliper brake 300, on the outer side of the vehicle [0079] 315 Brake caliper [0080] 320 Brake disk [0081] 325 Brake piston [0082] 326 First piston [0083] 327 Second piston [0084] 328 Seals, in particular sealing rings [0085] 330a,b Brake pads [0086] 335 Hydraulic channel [0087] 340a,b Fluid chambers [0088] 345 Electromechanical actuator [0089] 350 Electric line for energy supply/activation of the actuator 345 [0090] 400 Vehicle, here by way of example a motor vehicle