ELECTROMECHANICALLY DRIVEABLE BRAKE PRESSURE GENERATOR FOR A HYDRAULIC BRAKING SYSTEM OF A VEHICLE, AND VEHICLE INCLUDING AN ELECTROMECHANICAL BRAKE PRESSURE GENERATOR

Abstract

The invention relates to an electromechanical brake pressure generator (14) for a hydraulic braking system (10) of a vehicle. The electromechanical brake pressure generator (14) includes at least one threaded drive assembly (40) for converting a drive-side rotation into a translation for brake pressure generation. The threaded drive assembly (40) includes a spindle (68), which is rotatable via an electric motor (38), and a spindle nut (80), which is situated on a thread (76) of the spindle (68) in such a way that the spindle nut (80) and a hydraulic piston (92) formed thereon are axially displaceable upon rotation of the spindle (68). In addition, the threaded drive assembly (40) includes a housing (64), which forms a hydraulic cylinder (66) corresponding to the hydraulic piston (92), in which the spindle (68) and the spindle nut (80) are accommodated, and a rotation lock (84, 88), via which the spindle nut (80) is secured against rotation upon rotation of the spindle (68).

Claims

1-10. (canceled)

11. An electromechanically driveable brake pressure generator for a hydraulic braking system of a vehicle, comprising: at least one threaded drive assembly configured to convert a drive-side rotation into a translation; and a piston/cylinder unit actuatable by the threaded drive assembly for hydraulic brake pressure generation; wherein the threaded drive assembly includes: a spindle which is rotatable via an electric motor, a spindle nut which is situated on a thread of the spindle in such a way that, upon rotation of the spindle, the spindle nut and a hydraulic piston of the piston/cylinder unit formed thereon nut are axially displaceable, a housing which forms a hydraulic cylinder of the piston/cylinder unit corresponding to the hydraulic piston in which the spindle and the spindle nut are accommodated, and a rotation lock via which the spindle nut is secured against rotation upon rotation of the spindle.

12. The electromechanical brake pressure generator as recited in claim 11, wherein the spindle nut and the hydraulic piston are made of different materials and are situated lying coaxially next to one another.

13. The electromechanical brake pressure generator as recited in claim 11, wherein the rotation lock is formed by the housing and the hydraulic piston and/or the spindle nut.

14. The electromechanical brake pressure generator as recited in claim 11, wherein the rotation lock is formed by a tongue and groove connection.

15. The electromechanical brake pressure generator as recited in claim 11, wherein the rotation lock of the spindle nut forms two diametrically opposed, radially outwardly extending blades, which engage into corresponding grooves of the housing.

16. The electromechanical brake pressure generator as recited in claim 11, wherein at least a portion of the spindle nut is made of plastic.

17. The electromechanical brake pressure generator as recited in claim 16, wherein the portion of the spindle nut made of plastic is a plastic injection-molded part.

18. The electromechanical brake pressure generator as recited in claim 11, wherein the housing is made of an aluminum or steel alloy.

19. The electromechanical brake pressure generator as recited in claim 11, wherein at least the rotation lock at the spindle nut and/or the hydraulic piston is made of plastic to improve slide properties with respect to the housing made of metal.

20. A vehicle, comprising: an electromechanical brake pressure generator for a hydraulic braking system, the electromechanical brake pressure generator including: at least one threaded drive assembly configured to convert a drive-side rotation into a translation; and a piston/cylinder unit actuatable by the threaded drive assembly for hydraulic brake pressure generation; wherein the threaded drive assembly includes: a spindle which is rotatable via an electric motor, a spindle nut which is situated on a thread of the spindle in such a way that, upon rotation of the spindle, the spindle nut and a hydraulic piston of the piston/cylinder unit formed thereon nut are axially displaceable, a housing which forms a hydraulic cylinder of the piston/cylinder unit corresponding to the hydraulic piston in which the spindle and the spindle nut are accommodated, and a rotation lock via which the spindle nut is secured against rotation upon rotation of the spindle.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] FIG. 1 shows a representation of an electromechanical brake booster from the related art.

[0029] FIG. 2 shows a schematic representation of a hydraulic braking system for a vehicle including an electromechanical brake pressure generator.

[0030] FIG. 3 shows a cross-sectional and longitudinal section of an exemplary embodiment of a threaded drive assembly according to the present invention of the electromechanical brake pressure generator, in accordance with the present invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0031] In FIG. 2, a schematic representation of a hydraulic braking system 10 for a vehicle including an electromechanical brake pressure generator 14 is shown. Hydraulic braking system 10 includes electromechanical brake pressure generator 14. This brake pressure generator 14 includes a piston/cylinder unit 18, which is supplied with brake fluid via a brake fluid reservoir 22.

[0032] Piston/cylinder unit 18 may be activated via a brake pedal 26 actuated by the driver and the resultant brake pedal travel is measured by a pedal travel sensor 30 and forwarded to a control unit 34.

[0033] Although FIG. 2 shows, in principle, a brake booster; here the brake pedal travel is measured via pedal travel sensor 30. A brake pressure generation without a brake pedal travel is also possible, so that the vehicle is deceleratable also in the autonomous driving condition.

[0034] Control unit 34 generates, on the basis of the measured brake pedal travel, a control signal for an electric motor 38 of brake pressure generator 14. Electric motor 38, which is connected to a transmission (not shown) of brake pressure generator 14, boosts the braking force introduced by brake pedal 26 according to the control signal. For this purpose, according to the actuation of brake pedal 26, a threaded drive assembly 40 situated in brake pressure generator 14 is activated by electric motor 38, so that the rotation of electric motor 38 is converted into a translation.

[0035] Due to the actuation of brake pedal 26, the brake fluid present in piston/cylinder unit 18 is pressurized with the aid of brake pressure generator 14. This brake pressure is forwarded to a brake hydraulics system 46 via brake lines 42. Brake hydraulics system 46, which is represented here only as a box, is formed by various valves and further components for forming, for example, an electronic stability program (ESP). Brake hydraulics system 46 is additionally connected to at least one wheel brake unit 50, so that a braking force is able to be applied at wheel brake unit 50 due to an appropriate switching of valves.

[0036] FIG. 3 shows a cross-sectional and longitudinal section of one exemplary embodiment of threaded drive assembly 40 according to the present invention of electromechanical brake pressure generator 14. Threaded drive assembly 40 includes a housing 64, which forms a cup-shaped hydraulic cylinder 66. In this exemplary embodiment, housing 64 is made of metal. Additionally, threaded drive assembly 40 includes a spindle 68, which is drivable via electric motor 38 shown in FIG. 2, so that spindle 68 carries out a rotary motion about its longitudinal axis 72.

[0037] A spindle nut 80 is situated on a thread 76 of spindle 68 and is engaged with thread 76 of spindle 68. Spindle nut 80 essentially forms a hollow cylindrical body. Radially outwardly extending blades 84 are located at two diametrically opposed sides of the hollow cylindrical body, which engage into grooves 88 of housing 64 and form the rotation lock of spindle nut 80. Grooves 88 in housing 64 are formed as longitudinal grooves.

[0038] A width of blades 84 of spindle nut 80 in the circumferential direction is slightly less than a groove width of housing 64 formed in the circumferential direction. A length of blades 84 in the axial direction is considerably less than a length of grooves 88 of housing 64. Due to a rotation of spindle 68, spindle nut 80 is held by rotation lock 84, 88, so that spindle nut 80, including blades 84, is movable in the axial direction in housing 64 in the range across the length of grooves 88 of housing 64.

[0039] A hydraulic piston 92 is situated at spindle nut 80, which is connected to spindle nut 80. In contrast to spindle nut 80, hydraulic piston 92 is not in engagement with thread 76 of spindle 68. Hydraulic piston 92 is designed essentially in the shape of a cup. A seal 96 is situated between hydraulic piston 92 and hydraulic cylinder 66 of housing 64, so that a pressure is generatable in a working chamber 98 of hydraulic cylinder 66. Due to the rotation of spindle 68, hydraulic piston 92 may be axially displaced, via spindle nut 80, in the direction of working chamber 98, so that a brake fluid present in working chamber 98 may be pressurized.