ELECTROMECHANICAL BRAKE PRESSURE GENERATOR FOR A HYDRAULIC BRAKE SYSTEM OF A VEHICLE, AND VEHICLE HAVING AN ELECTROMECHANICAL BRAKE PRESSURE GENERATOR

Abstract

An electromechanical brake pressure generator for a hydraulic brake system of a vehicle. The electromechanical brake pressure generator includes a screw drive system for converting a drive-side rotary movement into a translation movement to generate brake pressure. The screw drive system includes a spindle which is rotatable via an electric motor, a spindle nut, which interacts with a thread of the spindle so that the spindle nut is axially displaceable by a rotation of the spindle, and a drive wheel, which is situated coaxially on the spindle in a torsionally fixed manner and via which the spindle is connected to the electric motor. The drive wheel is developed from at least two different materials. A first material forms at least a wheel hub of the drive wheel. A second material forms at least a drive ring enclosing the wheel hub. The first material has greater strength than the second material.

Claims

1-10. (canceled)

11. An electromechanical brake pressure generator for a hydraulic brake system of a vehicle, comprising: a screw drive system configured to convert a drive-side rotary movement into an output-side translation movement; and a piston/cylinder unit which is actuable by the screw drive system to generate brake pressure; wherein the screw drive system includes: a spindle which is rotatable via an electric motor as a drive, a spindle nut which interacts with a thread of the spindle so that the spindle nut is axially displaced by a rotation of the spindle, and a drive wheel which is situated coaxially on the spindle in a torsionally fixed manner and via which the spindle is connected to the electric motor, wherein the drive wheel is formed from at least two different materials, a first material forming at least a wheel hub of the drive wheel, and a second material forming at least a drive ring enclosing the wheel hub, and the first material has greater strength than the second material.

12. The electromechanical brake pressure generator as recited in claim 11, wherein the second material is a plastic material.

13. The electromechanical brake pressure generator as recited in claim 11, wherein the first material is a metal.

14. The electromechanical brake pressure generator as recited in claim 13, wherein the wheel hub made from metal is produced from sheet metal as a punched and bent part by stamping.

15. The electromechanical brake pressure generator as recited in claim 11, wherein the first material of the wheel hub is a plastic material.

16. The electromechanical brake pressure generator as recited in claim 11, wherein the first material of the wheel hub extends in a radial direction in a region of the second material of the drive ring.

17. The electromechanical brake pressure generator as recited in claim 12, wherein the wheel hub has a plurality of axial and/or radial passages, which are penetrated by the plastic of the second material of the drive ring so that a form-locked connection is established between the two materials.

18. The electromechanical brake pressure generator as recited in claim 11, wherein the drive wheel is fixed in place on the spindle in an axial direction.

19. The electromechanical brake pressure generator as recited in claim 11, wherein the first material of the wheel hub and/or the second material of the drive ring is made of plastic and injection-molded onto the spindle.

20. A vehicle comprising an electromechanical brake pressure generator for a hydraulic brake system of the vehicle, the electromechanical brake pressure generator including: a screw drive system configured to convert a drive-side rotary movement into an output-side translation movement; and a piston/cylinder unit which is actuable by the screw drive system to generate brake pressure; wherein the screw drive system includes: a spindle which is rotatable via an electric motor as a drive, a spindle nut which interacts with a thread of the spindle so that the spindle nut is axially displaced by a rotation of the spindle, and a drive wheel which is situated coaxially on the spindle in a torsionally fixed manner and via which the spindle is connected to the electric motor, wherein the drive wheel is formed from at least two different materials, a first material forming at least a wheel hub of the drive wheel, and a second material forming at least a drive ring enclosing the wheel hub, and the first material has greater strength than the second material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIG. 1 shows an illustration of an electromechanical brake booster from the related art;

[0030] FIG. 2 shows a simplified schematic illustration of a hydraulic brake system from the related art for a vehicle having an electromechanical brake pressure generator.

[0031] FIG. 3 shows a longitudinal sectional view of a first exemplary embodiment of a screw drive system for an electromechanical brake pressure generator according to an example embodiment of the present invention.

[0032] FIG. 4 shows a perspective view of the first material forming the wheel hub shown in FIG. 3.

[0033] FIG. 5 shows a perspective longitudinal sectional view of a second exemplary embodiment of a screw drive system for an electromechanical brake pressure generator.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0034] FIG. 2 shows a simplified schematic representation of a hydraulic brake system 10 from the related art for a vehicle having an electromechanical brake pressure generator 14. Hydraulic brake system 10 includes electromechanical brake pressure generator 14 and a piston/cylinder unit 18.

[0035] Piston/cylinder unit 18 and electromechanical brake pressure generator 14 are both hydraulically connected to a brake hydraulics system 22, which is depicted here only as a box.

[0036] Brake hydraulics system 22 is formed by various valves and further components in order to form an electronic stability program (ESP), for example. To be able to decelerate the vehicle, brake hydraulics system 22 is additionally connected to at least one wheel brake device 26 so that a brake force can be applied at wheel brake device 26 by switching the valves appropriately.

[0037] Piston/cylinder unit 18 is operated by muscle power via a brake pedal 30. The braking force of electromechanical brake pressure generator 14, on the other hand, is generated via an electric motor 34. To this end, electric motor 34 is connected to a gear unit 38 via which a screw drive system 42 is driven. Screw drive system 42 is connected to a hydraulic piston 46 situated in a hydraulic cylinder 44 so that a brake pressure is able to be generated.

[0038] FIG. 3 shows a longitudinal sectional view of a first exemplary embodiment of a screw drive system 42 for an electromechanical brake pressure generator 14 according to the present invention. Electromechanical brake pressure generator 14 according to the present invention is able to be used in hydraulic brake system 10 shown in FIG. 2. Screw drive system 42 includes a drive wheel 50, which is situated coaxially in a torsionally fixed manner on an axial end region 54 of a spindle 58. In this exemplary embodiment, spindle 58 is made of metal. Drive wheel 50 is connected to electric motor 34 as a drive so that spindle 58 together with drive wheel 50 is rotatable via electric motor 34. Screw drive system 42 additionally includes a spindle nut 62, which surrounds a section of spindle 58 and meshes with a thread 66 of spindle 58. Spindle nut 62 is protected against twisting so that it is axially displaceable by rotating spindle 58.

[0039] Moreover, screw drive system 42 includes a bearing 70 via which spindle 58 is rotatably mounted. This bearing 70 in this particular exemplary embodiment is disposed in a recess 74 in the region of drive wheel 50 so that axial space for bearing 70 is able to be reduced.

[0040] Drive wheel 50, which is embodied as a spur gear having an external tooth system in this exemplary embodiment, includes a first material which forms wheel hub 78 in this exemplary embodiment, and a second material, which forms a drive ring 82 having an external tooth system. The material forming wheel hub 78 is made from sheet metal in this exemplary embodiment, extends in a radial direction and forms an edge piece 86 that extends in the axial direction. Edge piece 86 is situated at an outer radial end of the region extending in the radial direction.

[0041] In this exemplary embodiment, plastic is used as the material for drive ring 82. This plastic material encloses the part of the material of wheel hub 78 that extends in the radial and axial directions. The plastic material is thereby reinforced by the stronger material of wheel hub 78.

[0042] FIG. 4 shows a perspective view of the first material depicted in FIG. 3 that forms wheel hub 78. The second material, which forms drive ring 82, thus has been emitted in this figure. In addition, spindle nut 62 from FIG. 3 is not shown in this figure for the sake of clarity. It may be gathered from FIG. 4 that spindle 58 has an external spindle tooth system 90 in the region to which drive wheel 50 is fastened in order to establish a form-locked connection between drive wheel 50 and spindle 58.

[0043] Wheel hub 78 forms a corresponding internal wheel hub tooth system 94, which interacts with external spindle tooth system 90 in a form-locked manner so that drive wheel 50 is connected to spindle 58 in a torsionally fixed manner. In this exemplary embodiment, external spindle tooth system 90 is developed up to an axial end of spindle 58. This makes it possible to slip drive wheel 50 from this end onto spindle 58.

[0044] FIG. 4 additionally shows that the part of wheel hub 78 extending in the radial direction and edge piece 86 have a plurality of axial and/or radial passages 98, which are developed in the form of bores. The plastic material enclosing wheel hub 78 penetrates these passages and is thereby connected to wheel hub 78 in a form-locked manner.

[0045] FIG. 5 shows a perspective longitudinal sectional view of a second exemplary embodiment of a screw drive system 42 for an electromechanical brake pressure generator 14. For the sake of simplicity, spindle nut 62 has been omitted in this figure. This second exemplary embodiment differs from the first exemplary embodiment in that in addition to drive ring 82, plastic material is also used for the first material that forms wheel hub 78. The plastic forming wheel hub 78 has greater strength than the plastic of drive ring 82.

[0046] Similar to the first exemplary embodiment, the material of wheel hub 78 extends in the radial direction in order to reinforce the material of drive ring 82. This drive wheel 50 is produced as a two-component injection cast. For instance, this means that wheel hub 78 is developed first and drive ring 82 is injection-molded subsequently.