Drive for electromechanical brake device, brake device

Abstract

The present invention relates to a drive device (2) for an electromechanical brake device (1), in particular a brake booster, comprising an electric motor having a housing (4) and a rotor shaft (3) rotatably supported in the housing (4) coupled to a transmission device, in particular a planetary gear device (10), having an internal gear (9), the rotor shaft (3) being rotatably supported in the housing (4) by at least one rolling bearing (7), the rolling bearing (7) being held in a bearing receptacle (6) of a bearing cover (5) arranged in the housing (4). The bearing cover (5) has an internal gear section (8) at a distance from the bearing receptacle (6), and an internal gear (9) is arranged on the internal gear section.

Description

[Technical field]

[0001] The present invention relates to a drive device for an electromechanical brake device, in particular a brake booster, which comprises an electric motor having a housing and a rotor shaft coupled to a transmission with an internal gear and rotatably supported in the housing, the rotor shaft being supported in the housing by at least one rolling bearing, the rolling bearing being held in a bearing receptacle of a bearing cover arranged in the housing. [Background technology]

[0002] Furthermore, the invention relates in particular to a braking system for a vehicle, in particular a motor vehicle, comprising a hydraulic pressure generator fluidically connected to at least one brake circuit having at least one hydraulically operable brake device, and a drive device for driving the hydraulic pressure generator.

[0003] Drives of the type mentioned at the outset are already known from the prior art. In particular with the increasing electrification of motor vehicles, there is also an increasing demand for an individual brake boost, for example in autonomous driving, and for the brake process to be carried out independently of the brake pedal actuation. For this reason, vehicles are increasingly using brake systems in which the brake pressure is generated with the help of an electrically drivable actuator or an electrically drivable drive, not only or not by the brake force applied by the user on the brake pedal, but separately therefrom. In addition, it is known to provide a hydraulic pressure generator in the brake system that can be driven by the drive, which generates hydraulic pressure that can be used, if necessary, in the brake circuit or brake system for carrying out one or more brake processes, independently of the brake pedal actuation by the user. In particular, brake systems are known that use a drivable drive instead of a conventional vacuum brake booster. Summary of the Invention

[0004] The drive according to the invention with the features of claim 1 has the advantage that it is particularly space-saving, the assembly is simplified and the assembly and manufacturing costs are reduced. According to the invention, it is provided for this purpose that the bearing cover of the drive has an internal gear section at a distance from the bearing receptacle for the rolling bearing, on which the internal gear is arranged. With the drive according to the invention, it is thus achieved that both the rolling bearing and the internal gear are held by the bearing cover on the housing of the drive, in particular of the electric motor. Whereas up to now a separate bearing was provided for the internal gear, which was welded in particular to the outer ring of the rolling bearing, according to the invention, a simplified assembly is achieved, in particular without cost-intensive welding processes.

[0005] In a preferred development of the invention, the bearing cover has at least one, in particular several, radial projections and / or recesses formed at a distance from one another in the circumferential direction on the internal gear segment, which cooperate as a rotation prevention with the radial recesses and / or radial projections of the internal gear engaged in the internal gear segment. Thus, a rotation prevention or rotation prevention is formed between the bearing cover and the internal gear, which prevents the internal gear from rotating together. This ensures that the internal gear is held fixed in the housing. A simple form-locking connection in the circumferential direction is ensured by the radial projections and / or radial recesses of the internal gear on the one hand and the radial recesses or radial projections of the internal gear segment on the other hand. In particular, there is at least one radial recess per radial projection, into which the respective radial projection can engage.

[0006] It is further provided that the radial projections and / or recesses are preferably arranged with an even distribution over the circumference of the internal gear segment, which ensures an even force transmission from the internal gear to the internal gear segment, which ensures an even load and therefore a long service life of the drive.

[0007] In a preferred development of the invention, the internal gear segment forms the internal gear, whereby the internal gear is formed integrally with the bearing cover, i.e. in this case the internal gear is an integral component of the bearing cover, whereby the number of parts of the drive is reduced and the manufacturing costs are reduced, in particular by the integral formation an additional anti-rotation feature is omitted, whereby the manufacturing costs are further reduced compared to the above-mentioned embodiment.

[0008] In a preferred embodiment of the invention, the internal gear forms a planetary gear set together with a number of planetary gears and a sun gear which is arranged non-rotatably on a rotor shaft, in particular of an electric motor, by means of which the rotational speed of the electric motor is reduced and the torque is increased, in particular in which the planetary gears are rotatably supported on a planetary gear carrier, the planetary gear carrier forming the output shaft of the planetary gear set.

[0009] It is furthermore preferably provided that the transmission is a spindle drive or spindle gear having an axially slidably supported spindle and a rotatably supported spindle wheel which engages with the spindle by means of helical teeth. In particular, the internal gear is centered in the spindle drive or spindle gear in a bearing cover which is arranged fixedly, for example with respect to the housing, of the transmission or spindle drive. For this, the internal gear has, in particular, an axially projecting centering section which can be or is axially pressed into a cylindrical outer casing wall section of the spindle drive, in particular the bearing cover. For better connection, the centering section has a number of crushing ribs which, in particular, project radially inwards or in the direction of the spindle drive. Optionally, the internal gear also has a number of crushing ribs arranged evenly distributed on its outer casing wall, which in particular cooperate with the bearing cover of the drive. By advantageous centering, it is achieved that the internal gear and the spindle wheel or the transmission and the spindle gear are always optimally aligned with one another. In an alternative embodiment, it is preferably provided for a further rolling bearing to be arranged between the spindle wheel and the internal gear.

[0010] The braking device according to the invention having the features of claim 8 is characterized by the design of the drive device according to the invention, which results in the abovementioned advantages. [Brief description of the drawings]

[0011] [Figure 1] 1 is a simplified longitudinal cross-sectional view of an exemplary braking device; [Diagram 2] FIG. [Diagram 3] FIG. 2 is an enlarged perspective view of the area of ​​the centering section of the internal gear; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The present invention will now be described in detail with reference to the drawings.

[0013] FIG. 1 shows in a simplified cross-section a braking device 1 which is suitable for a motor vehicle not shown in detail here. The braking device 1 has a drive device 2 which includes an electric motor, of which only a rotor shaft 3 and a housing 4 are shown in FIG. 1. The rotor shaft 3 carries a rotor which is rotatably supported in the housing 4 and which cooperates in particular with a stator which is fixed relative to the housing, so that when the stator or the drive coil of the stator is energized, a torque is applied to the rotor and thus to the rotor shaft 3 which is intended to drive the braking device 1. The braking device 1 here is in particular an electromechanical brake booster which is intended to convert the rotational energy of the rotor shaft 3 into translational energy for sliding a hydraulic piston. In particular, the drive device 2 is designed to drive a master brake cylinder of the braking system.

[0014] A bearing cover 5 is arranged on the housing 4, which extends substantially across the housing 4 and rests at least locally against the inner surface of the housing 4, for example welded, clamped, screwed or glued to the housing 4. The bearing cover 5 is cup-shaped, the bearing cover having a number of sections in the axial direction with different inner diameters.

[0015] The bearing cover 5 therefore has a first section forming a bearing receptacle 6 for a rolling bearing 7 which rotatably supports the rotor shaft 3 in the bearing cover 5 and thus in the housing 4. The bearing receptacle 6 therefore has an inner diameter which is in particular slightly smaller than the outer diameter of the outer ring of the rolling bearing 7, so that in the bearing receptacle 6 there is a press fit between the rolling bearing 7 and the bearing cover 5.

[0016] The bearing receptacle 6 is followed by an internal gear segment 8, which has an inner diameter that is much larger than the inner diameter of the bearing receptacle 6. An internal gear 9 of a planetary gear set 10 is arranged in the internal gear segment 8. The internal gear 9 is then non-rotatably connected to the bearing cover 5 by an anti-rotation block 11, so that the internal gear 9 cannot rotate therewith.

[0017] 1, the planetary gear set 10 further comprises a number of planetary gears 14 rotatably supported on a planetary gear carrier 15, which is itself likewise rotatably supported, in particular about the axis of rotation of the rotor shaft. The planetary gears 14 then engage with the internal gear 9 and with a sun gear 20 which is non-rotatably arranged on the rotor shaft 3.

[0018] 2 shows the drive 2 in the region of the planetary gear 10 in an axial top view. The internal gear 9 has a number of, here four, equally spaced radial projections 12 on its outer periphery, which fit positively, in particular at least substantially without play, particularly preferably by press-fitting, into correspondingly shaped and arranged radial recesses 13 of the bearing cover 5. The radial projections 12 which fit into the radial recesses 13 ensure that the internal gear 9 is arranged non-rotatably with the bearing cover 5 and thus fixed relative to the housing. As a result, when the planetary gear 14 is driven by the sun gear 20, only the planetary gear 14 together with the planetary gear carrier 15 can rotate in the internal gear 9.

[0019] In another embodiment, instead of or in addition to a positively-fitting torque support in the circumferential direction, it is provided that a torque support or torque entrainment is provided in the axial direction, for example by heat staking.

[0020] In this embodiment, the planetary gear carrier 15 is formed by a spindle wheel 16 of a spindle gear 17 which further has a spindle 18 operatively connected to the spindle wheel 16 and supported so as to be axially slidable as indicated by the double-headed arrow in FIG. 1, the spindle being in particular connected to a piston of a master brake cylinder for moving the same.

[0021] At its end face facing the spindle wheel 16, the internal gear 9 has an axially projecting centering section 19, the inside diameter of which corresponds at least substantially to the outside diameter of a cylindrical casing wall section of a bearing cover 21 of the spindle gear 17. The spindle gear 17 has a bearing cover 21 that is substantially cup-shaped, which is arranged fixedly relative to the housing and carries a rolling bearing 22 for rotatably supporting the spindle wheel 16. The outer ring of the rolling bearing 22 is pressed into the bearing cover 21, and the inner ring of the rolling bearing 22 rests on the outer surface of the casing of the spindle wheel 16, so that the spindle wheel 16 is rotatably supported with advantageously little wear. The centering section 19 abuts, in particular radially, in a casing outer wall section of the bearing cover 21 with a radial bias, so that the internal gear 9 is advantageously centered or aligned and held in the bearing cover 21 and thus in the spindle gear 17. This improves the robustness and functionality of the brake device 1 or the drive device 2.

[0022] 3 shows the region of the centering section 19 of the internal gear 9 in an enlarged perspective view. The centering section 19 has, in particular, a number of crushing ribs 23, which are distributed around the circumference and project radially inwards. The crushing ribs 23 project only slightly from the inner surface of the centering section 19 and are designed so as to be plastically and / or elastically deformed when pressed into the bearing cover 21, thereby ensuring a particularly secure fixation and centering of the internal gear 9 in the bearing cover 21. Optionally, the outer wall of the casing of the internal gear 9 is also formed with a number of crushing ribs arranged evenly distributed therein, in particular formed integrally with the internal gear 9, which cooperate accordingly with the bearing cover 5 for centering and supporting the internal gear 9 in the bearing cover 5. This advantageously enables centering of the electric motor or rotor shaft 3 and the sun gear 20.

[0023] In an alternative embodiment, the internal gear 9 can be formed integrally with the bearing cover 5, whereby the additional anti-rotation feature 10 can be omitted, thereby further reducing the number of parts and simplifying assembly. [Explanation of symbols]

[0024] 1 Brake device 2. Drive unit 3 Rotor shaft 4. Housing 5 Drive bearing cover 6 Bearing housing 7. Rolling bearing of rotor shaft 8 Internal Gear Segment 9 Internal Gear 10 Planetary gear unit 11 Anti-rotation part 12 Radial protrusion 13 Radial recess 14 Planetary Gear 15 Planetary gear carrier 16 Spindle Wheel 17 Spindle gear 18 Spindle 19 Centering Section 20 Sun Gear 21 Spindle gear bearing cover 22 Spindle wheel rolling bearing 23 Crushed rib

Claims

1. A drive (2) for an electromechanical brake device (1), in particular a brake booster, comprising an electric motor having a housing (4) and a rotor shaft (3) coupled to a transmission, in particular a planetary gear (10), having an internal gear (9) and rotatably supported in the housing (4), the rotor shaft (3) being rotatably supported in the housing (4) by at least one rolling bearing (7), the rolling bearing (7) being held in a bearing receptacle (6) of a bearing cover (5) arranged in the housing (4), the bearing cover (5) having an internal gear section (8) at a distance from the bearing receptacle (6), the internal gear (9) being arranged in the internal gear section, 1. A drive device, characterized in that the bearing cover (5) has at least one radial protrusion (12) and / or radial recess (13) formed at a distance from one another in the circumferential direction on the internal gear section (8) which cooperates as a rotation prevention portion with a radial recess (13) and / or a radial protrusion (12) of the internal gear (9) fitted into the internal gear section (8).

2. A drive device as described in claim 1, characterized in that the radial convex portions (12) and / or the radial concave portions (13) are evenly distributed and arranged around the circumference of the internal gear segment (8).

3. A drive device as described in claim 1 or 2, characterized in that the internal gear segment (8) forms the internal gear (9), whereby the internal gear (9) is formed integrally with the bearing cover (5).

4. A drive device described in any one of claims 1 to 3, characterized in that the internal gear (9) forms a planetary gear device (10) together with a plurality of planetary gears (14) and a sun gear (20) non-rotatably arranged on the rotor shaft (3).

5. The drive unit described in claim 4, characterized in that the transmission device is a spindle gear (17) having a spindle (18) supported so as to be axially displaceable and a spindle wheel (16) supported so as to be rotatable and engaging with the spindle (18) by helical teeth, the spindle wheel (16) forming a planetary gear carrier (15) for the planetary gear (14).

6. A drive device as described in claim 5, characterized in that the internal gear (9) is mounted by a centering section (19) on the spindle gear (17), in particular on a bearing cover (21) of the spindle gear (17).

7. A brake device (1) for a vehicle comprising a hydraulic generator and a drive device (2) described in any one of claims 1 to 6 for driving the hydraulic generator.

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