Braking force generator for brake equipment, operating device for brake equipment

Abstract

The invention relates to a brake force generator (1) for a brake device, comprising: a drive shaft (3) rotatably supported in a housing (2) of the brake force generator (1); an electric motor (4) having a rotor and at least one motor winding, wherein the rotor is arranged on the drive shaft (3) in a rotationally fixed manner and can be rotated by energizing the motor winding; an operating element (53) which is supported displaceably; and a transmission device (6) which acts between the drive shaft (3) and the operating element (53) such that the operating element (53) is displaced when the drive shaft (3) rotates, wherein the transmission device (6) has a planetary transmission (7) having: a sun gear (11) connected to the drive shaft (3) in a rotationally fixed manner, a rotatably supported planetary carrier (8), and at least one planetary gear (9A) which is rotatably supported on the planetary carrier (8) by means of a planetary gear shaft (10A). The planetary gear carrier (8) has a hollow shaft section (13), wherein the circumferential side wall (15) of the hollow shaft section (13) has radial apertures (16A), the planetary gears (9A) are inserted into the radial apertures, and wherein the planetary gear shafts (10A) are supported in the hollow shaft section (13) on both sides of the planetary gears (9A).

Description

Technical Field

[0001] The present invention relates to a brake force generator for a brake device, comprising: a drive shaft, which is rotatably supported in a housing of the brake force generator; an electric motor, which has a rotor and at least one motor winding, wherein the rotor is arranged on the drive shaft in a rotationally fixed manner and can be rotated by energizing the motor winding; an operating element, which is supported so as to be displaceable; and a transmission mechanism device, which acts between the drive shaft and the operating element so that the operating element is displaced when the drive shaft rotates, wherein the transmission mechanism device has a planetary transmission mechanism, which has: a sun gear connected to the drive shaft in a rotationally fixed manner; a rotatably supported planetary wheel carrier; and at least one planetary wheel, which is rotatably supported on the planetary wheel carrier by means of a planetary wheel shaft.

[0002] The invention further relates to an actuating device having a brake force generator of the type mentioned in the introduction. Background Art

[0003] A hydraulic brake system of a motor vehicle usually has at least one friction brake device. To actuate the friction brake device, the brake system usually has an actuating device with a master brake cylinder, in which at least one hydraulic piston is displaceably mounted. The master brake cylinder is fluidically connected to a slave cylinder of the friction brake device. To actuate the friction brake device, the hydraulic cylinder is displaced in such a way that hydraulic fluid is displaced from the master brake cylinder into the slave cylinder.

[0004] An operating device with a brake force generator is increasingly frequently installed in the structure of a motor vehicle, by means of which an electric motor-type displacement of a hydraulic piston and thus an electric motor-type actuation of a friction brake device can be achieved. For example, an operating device of the applicant's intelligent booster (iBooster) type has such a brake force generator. Here, the brake force generator has a drive shaft, which is rotatably supported in the housing of the brake force generator. In addition, the brake force generator has an electric motor, which has a rotor and at least one, in particular multi-phase, motor winding. The rotor is arranged on the drive shaft in a rotationally fixed manner and can be rotated by suitable energization of the motor winding, wherein the drive shaft then rotates with the rotor. The motor winding is, for example, a stator winding fixed to the housing or a rotor winding that can rotate with the rotor.

[0005] The brake force generator also has a displaceably mounted actuating element. In addition, a gear mechanism device is provided, which acts between the drive shaft and the actuating element in such a way that the actuating element is displaced when the drive shaft rotates. The gear mechanism device is then designed to convert the rotational movement of the drive shaft into a translational movement of the actuating element. For this purpose, the gear mechanism device usually has a planetary gear, which has a sun gear connected to the drive shaft in a rotationally fixed manner, a rotatably mounted planet wheel carrier, and at least one planet wheel, which is rotatably mounted on the planet wheel carrier by means of a planet wheel shaft. Summary of the invention

[0006] The cam is a gear mounted on a rear portion of the chassis and is configured to mount the cam on a shaft mounted on the chassis cam and to provide a rotational support for the cam. The invention relates to a planetary gear carrier having a hollow shaft section, wherein the circumferential wall of the hollow shaft section has radial openings, the planetary gears are inserted into the radial openings, and wherein the planetary gear shafts are supported on both sides of the planetary gears in the hollow shaft section, wherein the brake force generator is provided with a first bearing for transmitting radial forces, wherein the hollow shaft section abuts against a first bearing ring of the first bearing radially from the inside or radially from the outside, wherein the brake force generator is provided with a bearing cover fixed to the housing, wherein the bearing cover abuts against a second bearing ring of the first bearing radially from the inside or radially from the outside, wherein the first bearing ring has a first axial protrusion, wherein the hollow shaft section abuts against the first axial protrusion radially from the outside, and / or the second bearing ring has a second axial protrusion, wherein the bearing cover abuts against the second axial protrusion radially from the outside.

[0007] The brake force generator according to the invention has the advantage that a particularly stable mounting of the planetary wheels on the planetary wheel carrier is ensured. To this end, it is provided according to the invention that the planetary wheel carrier has a hollow shaft section, wherein the circumferential side wall of the hollow shaft section has radial openings, in which the planetary wheels are inserted, and wherein the planetary wheel shaft is supported on both sides of the planetary wheels in the hollow shaft section. In contrast to the solution according to the invention, which is known from the prior art, the planetary wheel shaft is supported on one side at the end side of the planetary wheel carrier. Preferably, the planetary transmission has a plurality of planetary wheels, which are rotatably supported on the planetary wheel carrier by means of each other planetary wheel shaft, wherein the circumferential side wall of the hollow shaft section has radial openings for each of the planetary wheels. Particularly preferably, the planetary wheels are rotatably supported on the planetary wheel carrier in a manner evenly distributed in the circumferential direction of the planetary wheel carrier. Preferably, the drive shaft and the planetary wheel carrier are rotatably supported about the same axis of rotation. If the terms "axially" or "radially" are used within the framework of the present disclosure, these terms relate to this axis of rotation, unless other references are explicitly mentioned. Preferably, the operating element is supported so that it can be displaced in the axial direction. The operating element can then be displaced along the axis of rotation or along an axis extending parallel to the axis of rotation and radially spaced apart from the axis of rotation. According to the invention, the planetary gears are inserted into radial openings in the circumferential side walls of the hollow shaft section. Accordingly, the planetary gear carrier protrudes axially on both sides beyond the planetary gears. Preferably, the planetary gears protrude radially outward beyond the circumferential side walls, wherein the toothing of the planetary gears meshes with the toothing of a ring gear of the planetary gear mechanism, in particular a housing-fixed ring gear.

[0008] The planetary carrier is preferably made of plastic. The planetary carrier can thus be manufactured cost-effectively. Since the planetary axles are supported on both sides of the planetary wheels, sufficient stability of the planetary gear is nevertheless ensured. A more expensive planetary carrier made of metal, as is known from the prior art, is not necessary. The planetary axles are preferably made of metal. The planetary carrier is particularly preferably manufactured as an injection molded part, i.e. manufactured by means of injection molding. This also makes it technically easy to manufacture complex geometries.

[0009] According to a preferred embodiment, it is provided that the planetary shaft is connected to the planetary carrier in a rotationally fixed manner, or the planetary shaft is connected to the planetary wheels in a rotationally fixed manner. If the planetary shaft is connected to the planetary carrier in a rotationally fixed manner, the wear of the planetary carrier and the planetary shaft in the contact area between the planetary shaft and the planetary carrier is small. "The planetary shaft is connected to the planetary carrier in a rotationally fixed manner" should also be understood as the planetary shaft being supported in the planetary carrier or in a hollow shaft section. The planetary shaft and the planetary wheels can then be rotated relative to each other in a suitable manner. If the planetary shaft is connected to the planetary wheels in a rotationally fixed manner, the wear of the planetary wheels and the planetary shaft in the contact area between the planetary wheels and the planetary shaft is small. The planetary shaft and the planetary carrier can in this case be rotated relative to each other in a suitable manner.

[0010] Preferably, the hollow shaft section has a first bearing section and a second bearing section, wherein a radial aperture is placed axially between the bearing sections, wherein the first bearing section has an axial aperture, wherein the second bearing section has an axial recess, and wherein the planetary gear shaft is supported not only in the axial aperture but also in the axial recess. The support of the planetary gear shaft in the axial aperture and the axial recess results in a particularly stable support of the planetary gear shaft in the hollow shaft section. In addition, a simple assembly of the planetary gear at the planetary gear carrier can be achieved. For this purpose, preferably, the planetary gear is first placed in the radial aperture. Subsequently, the planetary gear shaft is passed through the axial aperture and through the central recess of the planetary gear and inserted into the axial recess. Preferably, the inserted planetary gear shaft is connected to the planetary gear carrier in a rotationally fixed manner by an interference fit acting between the planetary gear shaft on the one hand and the axial recess on the other hand and / or by an interference fit acting between the planetary gear shaft on the one hand and the axial aperture on the other hand. Preferably, the axial aperture and the axial recess are aligned with each other. The axial aperture and the axial recess then form a blind hole bore which extends through the first bearing section and ends in the second bearing section.

[0011] The first bearing section having the axial aperture is preferably situated closer to the electric motor than the second bearing section.

[0012] Preferably, the planet shaft is fixed in the axial direction by heat caulking the first bearing section.A stable form-fitting connection is achieved between the planet shaft and the first bearing section by heat caulking.

[0013] Preferably, the brake force generator has a first bearing for transmitting radial forces, wherein the hollow shaft section bears against a first bearing ring of the first bearing radially from the inside or radially from the outside. This allows a stable support of the planetary carrier in the region of the hollow shaft section. Preferably, the hollow shaft section is firmly connected to the first bearing ring of the first bearing. If the hollow shaft section bears against the first bearing ring of the first bearing radially from the outside, the hollow shaft section or the circumferential side wall surrounds the first bearing. This results in the advantage that a small and therefore cost-effective bearing can be used as the first bearing.

[0014] According to a preferred embodiment, it is provided that the first bearing is arranged on the side of the planetary gear facing the electric motor. The first bearing is then located in the area between the electric motor and the planetary gear. This area is easily accessible in terms of assembly technology and is therefore particularly suitable for the arrangement of the first bearing.

[0015] Preferably, the brake force generator has a housing-fixed bearing cover, which radially abuts against the second bearing ring of the first bearing from the inside or from the outside. This achieves a stable support of the second bearing ring of the first bearing at the housing of the brake force generator. In an appropriate manner, the first bearing ring of the first bearing and the second bearing ring of the first bearing can be rotated relative to each other. In order to reduce the friction between the first bearing ring of the first bearing and the second bearing ring of the first bearing, a plurality of rolling bodies or sliding media are preferably arranged between the bearing rings. Preferably, the second bearing ring is firmly connected to the bearing cover. Preferably, when the hollow shaft section radially abuts against the first bearing ring of the first bearing from the inside, the bearing cover radially abuts against the second bearing ring of the first bearing from the outside. Preferably, when the hollow shaft section radially abuts against the first bearing ring of the first bearing from the outside, the bearing cover radially abuts against the second bearing ring of the first bearing from the inside.

[0016] According to a preferred embodiment, it is provided that the first bearing ring has a first axial projection, wherein the hollow shaft section bears against the first axial projection radially from the outside, and / or the second bearing ring has a second axial projection, wherein the bearing cover bears against the second axial projection radially from the outside. Here, an "axial projection" is to be understood as a part of the first bearing ring or the second bearing ring, which protrudes axially beyond one or more other bearing rings of the first bearing. If the first bearing ring has a first axial projection, the first bearing ring can be contacted radially from the outside through the hollow shaft section even when the first bearing ring does not form the outermost bearing ring of the first bearing. If the second bearing ring has a second axial projection, the second bearing ring can be contacted radially from the outside through the bearing cover even when the second bearing ring does not form the outermost bearing ring of the first bearing.

[0017] Preferably, the drive shaft is rotatably supported by means of the first bearing. Since the drive shaft is also rotatably supported by means of the first bearing, the number of bearings required for rotatably supporting the drive shaft and the planet carrier is small. This saves components and installation space.

[0018] According to a preferred embodiment, it is provided that the drive shaft abuts radially from the inside against the third bearing ring of the first bearing. Preferably, a sliding medium or a plurality of rolling bodies are also arranged between the third bearing ring of the first bearing and the adjacent bearing ring, i.e. the first bearing ring or the second bearing ring of the first bearing. Preferably, the third bearing ring is firmly connected to the drive shaft.

[0019] Alternatively, the drive shaft preferably abuts radially from the inside on the first bearing ring or the second bearing ring of the first bearing. The first bearing then has only two bearing rings, namely the first bearing ring and the second bearing ring. In order to enable the drive shaft, the planetary carrier and the bearing cap to rotate relative to each other, the drive shaft preferably abuts radially from the inside on the first bearing ring or the second bearing ring of the first bearing by means of a sliding medium or by means of a plurality of rolling bodies.

[0020] The brake force generator preferably has a second bearing for transmitting radial forces, wherein the drive shaft bears radially from the inside against a first bearing ring of the second bearing. The drive shaft is then rotatably supported by means of a bearing different from that of the planetary carrier. This results in the advantage that the second bearing supporting the drive shaft can be arranged in a targeted manner at a position that is particularly advantageous for supporting the drive shaft.

[0021] According to a preferred embodiment, the bearing cap is provided to abut radially from the outside on the second bearing ring of the second bearing on the one hand and radially from the inside on the other hand. Thus, only a single bearing cap is required for contacting the housing-fixed bearing rings of the first bearing and the second bearing.

[0022] The operating device according to the invention for a brake system has a master brake cylinder in which a hydraulic piston is displaceably supported and also has a brake force generator according to the invention, wherein the hydraulic piston can be displaced by displacing an operating element. This also results in the advantages already mentioned. Other preferred features and feature combinations are obtained from the previous description and from the preferred technical solution. Preferably, the hydraulic piston can be displaced axially. The hydraulic piston can then be displaced along the axis of rotation or along an axis extending parallel to the axis of rotation and radially spaced from the axis of rotation. Preferably, when the hydraulic piston is displaced, the operating element indirectly abuts against the hydraulic piston. Then there is at least one other displaceable element between the operating element and the hydraulic piston. Alternatively, when the hydraulic piston is displaced, the operating element abuts against the hydraulic piston in close proximity, i.e. directly. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The invention is explained in more detail below with reference to the accompanying drawings. For this purpose, it is shown:

[0024] Figure 1 A first embodiment of a brake force generator of an operating device of a brake equipment is shown;

[0025] Figure 2 A second embodiment of a braking force generator is shown;

[0026] Figure 3 A third embodiment of a braking force generator is shown;

[0027] Figure 4 A fourth embodiment of a braking force generator is shown;

[0028] Figure 5 A fifth embodiment of a braking force generator is shown;

[0029] Figure 6 A sixth embodiment of a braking force generator is shown;

[0030] Figure 7 A seventh embodiment of a braking force generator is shown; and

[0031] Figure 8 An eighth exemplary embodiment of a brake force generator is shown. DETAILED DESCRIPTION

[0032] Figure 1 A first embodiment of a brake force generator 1 of an actuating device (not shown) of a hydraulic brake system is shown. The hydraulic brake system has a plurality of friction brake devices. The actuating device is designed to actuate the friction brake devices so as to generate a friction braking torque by means of the friction brake devices. For this purpose, the actuating device has a master brake cylinder in which at least one hydraulic piston is displaceably supported. Usually, the master brake cylinder is a tandem master brake cylinder, so that two hydraulic pistons are usually displaceably supported in the master brake cylinder. Here, the master brake cylinder is connected to the slave cylinder of the friction brake device in terms of fluid technology. If the hydraulic piston is displaced in the actuating direction, the hydraulic fluid is displaced from the master brake cylinder into the slave cylinder and a friction braking torque is generated.

[0033] The actuating device 1 is designed to displace a hydraulic piston by electric motor and thus actuate a friction brake device by electric motor. Such principles are known in principle from an actuating device of the applicant's iBooster type.

[0034] The operating device 1 has a housing 2 in which a drive shaft 3 is rotatably mounted. The drive shaft 3 is rotatably mounted about an axis of rotation 5. The operating device 1 also has an electric motor 4, which is only schematically shown. The electric motor 4 has a rotor and a multi-phase motor winding. The rotor is arranged on the drive shaft 3 in a rotationally fixed manner and can be rotated by energizing the motor winding, wherein the drive shaft 3 then rotates together with the rotor. The motor winding is, for example, a housing-fixed stator winding which is arranged distributed around the rotor.

[0035] The operating device 1 furthermore has at least Figure 1 An actuating element, not shown, is mounted so as to be displaceable in the axial direction, ie along the rotation axis 5 or along an axis extending parallel to the rotation axis 5 and spaced apart radially from the rotation axis 5 .

[0036] The operating device 1 also has a transmission device 6, which acts between the drive shaft 3 and the operating element in such a way that the operating element is displaced axially when the drive shaft 3 rotates. The operating element is coupled to a hydraulic piston in such a way that the hydraulic piston is displaced together with the operating element when the operating element is displaced in the operating direction.

[0037] The gear mechanism device 6 has a planetary gear 7. The planetary gear 7 has a sun gear 11, which is connected to the drive shaft 3 in a rotationally fixed manner. In addition, the planetary gear 7 has a planetary carrier 8, which is rotatably supported about the rotation axis 5. In addition, the planetary gear 7 has a plurality of planetary gears, which are rotatably supported on the planetary carrier 8 and whose toothing meshes with the toothing of the sun gear 11. There are a first planetary gear 9A, a second planetary gear 9B and a third planetary gear, of which only the first planetary gear 9A and the second planetary gear 9B are visible. The first planetary gear 9A is rotatably supported on the planetary carrier 8 by means of a metallic first planetary gear shaft 10A. The second planetary gear 9B is rotatably supported on the planetary carrier 8 by means of a metallic second planetary gear shaft 10B. The invisible third planetary gear is rotatably supported on the planetary carrier 8 by means of an invisible metallic third planetary gear shaft. If the structural design of one of the planetary wheels or the structural design of one of the planetary axles is described below, this structural design is also implemented in the other planetary wheels or other planetary axles. The toothed ring gear 12 of the planetary gear also meshes with the toothed ring gear 12.

[0038] The planet carrier 8 is produced as an injection-molded part, ie, by means of injection molding, from plastic. The planet carrier 8 has a first end region 13 facing the electric motor 4 and a second end region 14 facing away from the electric motor 4 .

[0039] The first end region 13 is designed as a hollow shaft section 13. In this regard, the end region 13 is cylindrical. The circumferential side wall 15 of the hollow shaft section 13 has a number of radial openings corresponding to the number of planetary gears. Each of the planetary gears is assigned one of the radial openings, and the planetary gears are inserted into the radial openings. For example, the first planetary gear 9A is inserted into the first radial opening 16A. The second planetary gear 9B is inserted into the second radial opening 16B.

[0040] The planetary shaft is supported on both sides of the planetary gear in the hollow shaft section 13. This is explained in more detail below with reference to the first planetary shaft 10A. The hollow shaft section 13 has a first bearing section 17 and a second bearing section 18. The first bearing section 17 has an axial aperture 19. The second bearing section 18 has an axial recess 20, which is aligned with the axial aperture 19. The first planetary shaft 10A is supported not only in the axial aperture 19 but also in the axial recess 20. Here, the first planetary shaft 10A is firmly connected to the planetary carrier 8 in the area of ​​the axial aperture 19 and in the area of ​​the axial recess 20, preferably by means of an interference fit. In order to assemble the first planetary gear 9A, the first planetary gear 9A is first inserted into the radial aperture 16A. The planetary shaft 10A is then inserted through the axial aperture 19 and the central recess of the first planetary gear 9A and into the axial recess 20 until the end of the planetary shaft 10A located at the front in the insertion direction abuts axially against the bottom of the axial recess 20. The planetary shaft 10A is dimensioned in such a way that the region of the axial aperture 19 located at the rear in the insertion direction does not contain the planetary shaft 10A in the inserted state of the planetary shaft 10A. In order to fix the planetary shaft 10A in the axial direction, this region of the axial aperture 19 is deformed by means of heat caulking. In this case, the first bearing section 17 is placed closer to the electric motor 4 than the second bearing section 18.

[0041] The second end region 14 of the planetary carrier 8 facing away from the electric motor 4 has a circumferential side wall 21 in which an output gear 22, ie, the gear output of the planetary gear 7, is formed. The planetary carrier 8 made of plastic then has an output gear 22. Figure 1 In the exemplary embodiment shown in FIG. 8 , the lateral wall 21 is a lateral outer wall 51 of the second end region 14 of the planet carrier 8 .

[0042] According to Figure 1 In the embodiment shown in the figure, the transmission device 6 has another transmission element 23, namely a gear 23, whose toothing meshes with the driven toothing 22. Therefore, at least one other transmission element of the transmission device 6 acts between the driven toothing 22 and the operating element not shown. If the operating element is shown, the toothing of the operating element will mesh with the toothing of the gear 23, for example. Alternatively, there will be at least one other transmission element, such as a threaded nut, between the gear 23 and the operating element. In addition, the operating element will be assigned an anti-rotation device to avoid rotation of the operating element.

[0043] according to Figure 1In the embodiment shown in FIG, the planet carrier 8 is injection molded onto a metal support rod 24 in order to increase the stability of the planet carrier 8. The support rod 24 extends through the second end region 14 of the planet carrier 8. The end 25 of the support rod 24 facing away from the electric motor 4 is free of the planet carrier 8 made of plastic.

[0044] The brake force generator 1 further comprises a first bearing 26 for transmitting radial forces. The first bearing 26 is arranged between the planetary gears on the one hand and the electric motor 4 on the other hand. The hollow shaft section 13 abuts radially from the inside against a first bearing ring 27 of the first bearing 26. A first bearing cover 28 fixed to the housing abuts radially from the outside against a second bearing ring 29 of the first bearing 26. A plurality of rolling bodies 30 are arranged between the first bearing ring 27 and the second bearing ring 29. In this regard, the first bearing 26 is arranged according to Figure 1 The exemplary embodiment shown in FIG. 2 is designed as a rolling element bearing 26 . In this case, a first bearing ring 27 forms an inner bearing ring of the first bearing 26 , and a second bearing ring 29 forms an outer bearing ring of the first bearing 26 .

[0045] The brake force generator 1 also has a second bearing 31 for transmitting radial forces. The second bearing 31 is arranged between the first bearing 26 on the one hand and the electric motor 4 on the other hand. The drive shaft 3 abuts radially from the inside against a first bearing ring 32 of the second bearing 31. A second bearing cover 33 fixed to the housing abuts radially from the outside against a second bearing ring 34 of the second bearing 31. A plurality of rolling bodies 40 are arranged between the first bearing ring 32 and the second bearing ring 34. In this regard, the second bearing 31 is arranged according to Figure 1 The exemplary embodiment shown in FIG. 3 is also designed as a rolling element bearing 31 .

[0046] The brake force generator 1 further has a third bearing 35 for transmitting radial forces. The end 25 of the support rod 24 abuts radially from the inside against a first bearing ring 36 of the third bearing 35. The first bearing cover 28 abuts radially from the outside against a second bearing ring 37 of the third bearing 35. A plurality of rolling bodies 38 are arranged between the first bearing ring 36 and the second bearing ring 37. In this regard, the third bearing 36 is arranged according to Figure 1 The exemplary embodiment shown in FIG. 3 is also designed as a rolling element bearing 36 .

[0047] Figure 2 A brake force generator 1 according to a second exemplary embodiment is shown. Figure 2 The brake force generator 1 shown in FIG. Figure 1 The brake force generator 1 shown in FIG. 1 differs in particular with regard to the design of the first bearing 26 . Figure 2In the embodiment shown in , the hollow shaft section 13 abuts radially from the outside on the first bearing ring 27 of the first bearing 26. The second bearing cover 33 abuts radially from the inside on the second bearing ring 29 of the first bearing 26. The second bearing cover 33 then abuts radially from the outside on the first bearing 31 second bearing ring 34 and radially from the inside on the second bearing ring 29 of the first bearing 26. For this purpose, the free end section 39 of the second bearing cover 33 has a step-forming course in the region of the bearings 26 and 31. According to Figure 2 In the exemplary embodiment shown in , the first bearing ring 27 forms an outer bearing ring of the first bearing 26 , and the second bearing ring 29 forms an inner bearing ring of the first bearing 26 .

[0048] Figure 3 A brake force generator 1 according to a third exemplary embodiment is shown. Figure 3 The brake force generator 1 shown in FIG. Figure 2 The brake force generator 1 shown in FIG. 1 differs in particular with regard to the design of the second end region 14 of the planet carrier 8 . Figure 3 In the embodiment shown in the figure, the transmission device 6 has a second planetary transmission 41. The second sun gear 42 of the second planetary transmission 41 is formed by the driven toothing 22 of the circumferential side wall 21 of the second end region 14 of the planetary carrier 8. The second planetary transmission 41 has a rotatably supported second planetary carrier 43. Preferably, the second planetary carrier 43 is also made of plastic, preferably by means of injection molding. Three planetary gears are rotatably supported on the second planetary carrier 43, wherein the second sun gear 42 is formed by the driven toothing 22 of the circumferential side wall 21 of the second end region 14 of the planetary carrier 8. Figure 3 Only the fourth planet gear 44A and the fifth planet gear 44B are visible. Figure 3 In the embodiment shown in the figure, the second planetary carrier 43 abuts radially from the inside against the first bearing ring 36 of the third bearing 35. Another housing-fixed bearing cover 45 abuts radially from the outside against the second bearing ring 37 of the third bearing 35. If an operating element is shown, the toothing of the operating element will, for example, mesh with the driven toothing of the second planetary carrier 43. Alternatively, there will be at least one further transmission element between the driven toothing of the second planetary carrier and the operating element. The operating element will also be assigned an anti-rotation device to prevent rotation of the operating element.

[0049] Figure 4 A brake force generator 1 according to a fourth exemplary embodiment is shown. Figure 4 The brake force generator 1 shown in FIG. Figure 3 The brake force generator 1 shown in FIG. 1 differs in particular in the design of the mounting of the drive shaft 3 and in the design of the mounting of the planet carrier 8 . Figure 4In the embodiment shown in , the second bearing 31 is abandoned. In other words, not only the planetary carrier 8 but also the drive shaft 3 is rotatably supported by means of the first bearing 26. Here, the first bearing ring 27 forms the outer bearing ring of the first bearing 26. The hollow shaft section 13 abuts against the first bearing ring 27 radially from the outside. The second bearing ring 29 forms the inner bearing ring of the first bearing 26. In order to enable the second bearing cover 33 to abut against the second bearing ring 29 radially from the outside, the second bearing ring 29 has a second axial protrusion 45, which protrudes axially from the first bearing 26 in the direction of the electric motor 4. The second bearing cover 33 abuts against the second axial protrusion 45 radially from the outside. The drive shaft 3 abuts against the second bearing ring 29 radially from the inside by means of a needle ring (Nadelkranz) 46. Instead, the drive shaft 3 rests radially from the inside against the third bearing ring, which then forms the inner bearing ring of the first bearing 26, so that the second bearing ring 29 forms the central bearing ring of the first bearing 26. In an appropriate manner, a plurality of rolling bodies or sliding media are then arranged between the second bearing ring 29 and the third bearing ring.

[0050] Figure 5 A brake force generator 1 according to a fifth exemplary embodiment is shown. Figure 5 The brake force generator 1 shown in FIG. Figure 4 The brake force generator 1 shown in FIG. 1 differs in particular with regard to the design of the first bearing 26 . Figure 5 In the embodiment shown in , the second bearing ring 29 forms the outer bearing ring of the first bearing 26. The second bearing cover 33 abuts radially from the outside on the second bearing ring 29. The first bearing ring 27 forms the inner bearing ring of the first bearing 26. In order that the hollow shaft section 13 can nevertheless abut radially from the outside on the first bearing ring 27, the first bearing ring 27 has a first axial projection 47, which protrudes axially from the first bearing 26 in the direction of the planetary gear 9. The hollow shaft section 13 abuts radially from the outside on the first axial projection 47. The drive shaft 3 abuts radially from the inside on the first bearing ring 27 by means of a needle ring 46. As an alternative to this, the drive shaft 3 abuts radially from the inside on the third bearing ring, which then forms the inner bearing ring of the first bearing 26, so that the first bearing ring 27 forms the central bearing ring of the first bearing 26. In an appropriate manner, a plurality of rolling bodies or sliding media are then arranged between the first bearing ring 27 and the third bearing ring.

[0051] Figure 6 A brake force generator 1 according to a sixth exemplary embodiment is shown. Figure 6 The brake force generator 1 shown in FIG. Figure 5The brake force generator 1 shown in FIG. 1 differs in that a plurality of balls 48 are provided as rolling bodies between the drive shaft 3 and the first bearing ring 27 instead of the needle ring 46. The drive shaft 3 has a peripheral groove 49. The first bearing ring 27 has a peripheral groove 50 which is radially opposite to the peripheral groove 49. The balls 48 engage radially both in the peripheral groove 49 and in the peripheral groove 50.

[0052] Figure 7 A brake force generator 1 according to a seventh exemplary embodiment is shown. Figure 7 The embodiments shown in Figure 1 The exemplary embodiments shown in FIG. 1 differ in particular in the design of the second end region 14 of the planet carrier 8 . Figure 7 In the embodiment shown in FIG. 1 , the second end region 14 is configured in the shape of a hollow shaft. The driven toothing 22 is configured in the circumferential inner wall 52 of the hollow shaft-shaped end region 14. Figure 7 , an actuating element 53 is shown. Here, the actuating element 53 is a threaded spindle 54, which is screwed into the driven toothing 22. The threaded spindle 54 is assigned a non-illustrated anti-rotation device, so that the threaded spindle 54 does not rotate with the planetary carrier 8 when the planetary carrier 8 rotates, but is displaced axially.

[0053] Figure 8 A brake force generator 1 according to an eighth exemplary embodiment is shown. Figure 8 In the embodiment shown in the figure, the second end region 14 is also configured in the shape of a hollow shaft, and the driven toothing 22 is configured in the circumferential inner wall of the hollow shaft-shaped end region 14. The threaded screw 55 is screwed into the driven toothing 22. As an alternative to this, the planetary carrier 8 is injection molded onto the threaded screw 55. The actuating element 53 is formed by a threaded nut 56, which is screwed onto the threaded screw 55. The threaded nut 56 is assigned a non-illustrated anti-rotation device, so that the threaded nut 56 does not rotate with the planetary carrier 8 when the planetary carrier 8 rotates, but is displaced axially.

Claims

1. A brake force generator for a brake device, comprising: a drive shaft (3) which is rotatably supported in a housing (2) of the brake force generator (1); An electric motor (4) having a rotor and at least one motor winding, wherein: The rotor is arranged on the drive shaft (3) in a rotationally fixed manner and can be rotated by energizing the motor winding; an operating element (53) which is supported displaceably; and a transmission device (6) which acts between the drive shaft (3) and the actuating element (53) in such a way that the actuating element (53) is displaced when the drive shaft (3) rotates, The transmission mechanism device (6) has a planetary transmission mechanism (7), and the planetary transmission mechanism has: a sun gear (11) connected to the drive shaft (3) in a rotationally fixed manner, a planetary wheel carrier (8) rotatably supported, and at least one planetary gear (9A) which is rotatably supported on the planetary gear carrier (8) by means of a planetary gear shaft (10A); The invention is characterized in that the planetary wheel carrier (8) has a hollow shaft section (13), wherein the circumferential side wall (15) of the hollow shaft section (13) has a radial opening (16A), the planetary wheels (9A) are inserted into the radial opening, and The planetary gear shaft (10A) is supported on both sides of the planetary gear (9A) in the hollow shaft section (13). The brake force generator is provided with a first bearing (26) for transmitting radial forces, wherein the hollow shaft section (13) abuts radially from the inside or radially from the outside against a first bearing ring (27) of the first bearing (26), The brake force generator is provided with a housing-fixed bearing cover (33), the bearing cover abutting against a second bearing ring (29) of the first bearing (26) radially from the inside or radially from the outside. The first bearing ring (27) has a first axial projection (47), wherein the hollow shaft section (13) abuts against the first axial projection (47) radially from the outside, and / or the second bearing ring (29) has a second axial projection (45), wherein the bearing cover (33) abuts against the second axial projection (45) radially from the outside.

2. The brake force generator according to claim 1, characterized in that: The planetary wheel carrier (8) is made of plastic.

3. The braking force generator according to claim 1 or 2, characterized in that: The planetary shaft (10A) is connected to the planetary carrier (8) in a rotationally fixed manner, or the planetary shaft (10A) is connected to the planetary gear (9A) in a rotationally fixed manner.

4. The braking force generator according to claim 1 or 2, characterized in that: The hollow shaft section (13) has a first bearing section (17) and a second bearing section (18), wherein the radial aperture (16A) is arranged axially between the bearing sections (17, 18), wherein the first bearing section (17) has an axial aperture (19), wherein the second bearing section (18) has an axial recess (20), and wherein the planetary gear shaft (10A) is supported both in the axial aperture (19) and in the axial recess (20).

5. The braking force generator according to claim 4, characterized in that: The planetary shaft (10A) is fixed in the axial direction by heat caulking the first bearing section (17).

6. The braking force generator according to claim 1 or 2, characterized in that: The first bearing (26) is arranged on the side of the planetary gear (9A) facing the electric motor (4).

7. The braking force generator according to claim 1 or 2, characterized in that: The drive shaft (3) is rotatably supported by means of the first bearing (26).

8. The brake force generator according to claim 7, characterized in that: The drive shaft (3) rests radially from the inside against a third bearing ring of the first bearing (26).

9. The brake force generator according to claim 7, characterized in that: The drive shaft (3) rests radially from the inside against a first bearing ring or a second bearing ring (27, 29) of the first bearing (26).

10. The brake force generator according to claim 1 or 2, characterized in that A second bearing (31) for transmitting radial forces, wherein the drive shaft (3) bears radially from the inside against a first bearing ring (32) of the second bearing (31).

11. The brake force generator according to claim 10, characterized in that: The bearing cover (33) abuts radially from the outside on the one hand against a second bearing ring (34) of the second bearing (31) and radially from the inside on the other hand against a second bearing ring (29) of the first bearing (26).

12. An actuating device for a brake system, comprising: a master brake cylinder, in which a hydraulic piston is displaceably supported; and a brake force generator according to any one of claims 1 to 11, wherein: The hydraulic piston can be displaced by displacing the actuating element (53).

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