Electric brake actuator of a motor vehicle

Abstract

Electric brake actuator (1) for a motor vehicle, comprising an actuator housing (2) closed by means of a housing cover (3), in which an electric motor (4) and a multi-stage transmission (7) as well as a carrier unit (6) are accommodated, which has a first bearing seat (21) for receiving a first bearing axis (9) of a gear (17) of a first transmission stage and a second bearing seat (10) for receiving a second bearing axis (10) of a gear (18) of a second transmission stage, which is coupled to a third transmission stage with an output gear (20), wherein the electric motor (4) has a motor shaft (23) with a shaft-fixed first pinion (24) which meshes with the gear (17) of the first transmission stage coupled to the gear (18) of the second transmission stage, characterized in that - that the first bearing axis (9) and / or the second bearing axis (10) is guided into a spacer bridge (8) which is arranged between the support unit (6) and the housing cover (3), and - that the distance bridge (8) has a bridge base body (8a) and an elastic damping component (8b) abutting the housing cover (3), and - that the distance bridge (8) has at least one receiving opening (11, 12) for the first bearing axis (9) or for the second bearing axis (10).

Description

[0001] The invention relates to an electric (electromotor) brake actuator for a motor vehicle, comprising an actuator housing in which an electric motor and a multi-stage transmission as well as a carrier unit are accommodated, according to the preamble of claim 1.

[0002] Such an electric or electromechanical brake actuator is typically used in motor vehicles. For example, an electric parking brake can be engaged and disengaged using such a brake actuator. Depending on the application, the brake actuator can either be manually operated by a user via a switch or automatically controlled or regulated by a control unit. For instance, automatically releasing the parking brake can simplify starting off, especially on an incline.

[0003] Furthermore, due to the electric control, both a handbrake lever and the associated cable are no longer necessary, thus saving costs and installation space. However, the use of such a brake actuator is not limited to a parking brake. For example, it is also conceivable to use such brake actuators for traction control and an electronic stability program (ESP), as well as in the vehicle's service brake.

[0004] The electric brake actuator typically comprises a low-voltage DC motor, often operating at high speeds, with a brush system that engages a commutator (hereinafter referred to as an electric motor or brush-commutated electric motor), and a gearbox driven by this motor. To achieve the highest possible torque transmission ratio, the gearbox conventionally incorporates multiple gear stages. This reduces noise generated by high speeds and provides the comparatively high torque necessary for braking the vehicle.

[0005] From DE 20 2017 104 469, a generic electric brake actuator is known, comprising an actuator housing with a first housing half-shell and a cover-like second housing half-shell, in which an electric motor, a support unit, and a multi-stage gearbox are housed. The support unit has a first bearing seat for receiving a first bearing axis of a gear of a first gearbox stage and a second bearing seat for receiving a second bearing axis of a gear of a second gearbox stage, which is coupled to a third gearbox stage with an output gear. A second bearing seat for the first and second bearing axes is provided in the cover-like second housing half-shell.

[0006] The electric motor has a motor shaft with a shaft-mounted first pinion that meshes with the gear (double gear) of the first gear stage, which in turn meshes with the gear (double gear) of the second gear stage. One or two intermediate gear stages can be arranged between the first and last gear stages, with each pinion driving a comparatively large gear, thus enabling a relatively high gear ratio for operating a brake.

[0007] From DE 10 2016 004 297 A1 it is known in an electromechanical actuating device for a vehicle brake to mount a gear of an intermediate gear driven by the output gear of the electric motor and a gear of an output gear unit coupled to it via an intermediate gear on a bearing element which extends in steps from the (axially) higher intermediate gear to the (axially) lower gear of the output gear unit.

[0008] From KR 101 592 825 B1, an electromechanical brake actuator with a multi-stage gearbox is known, which is arranged within a housing closed by a housing cover. To absorb vibrations, the gearbox is damped by means of annular damping elements in the housing and on the housing cover.

[0009] From DE 10 2016 221 162 A1, a geared motor drive for use in a parking brake is known, which has a support extending perpendicular to the longitudinal axis of the motor, in which a pinion arranged at the shaft end of the motor is received, and in which the shafts of a double gear meshing with the pinion and of another double gear meshing with it are mounted. A bearing bracket with cap-like damping elements, which can be integrally formed on the housing cover or on the bearing bracket, is arranged between the support and a housing cover.

[0010] The invention is based on the objective of providing a particularly quiet electric brake actuator with an actuator housing in which an electric motor and a multi-stage gearbox are accommodated. In particular, to improve the acoustic properties of the brake actuator, suitable damping is to be provided between a support of a bearing shaft of at least one gearbox stage and a housing cover of the actuator housing.

[0011] This problem is solved according to the invention by the features of claim 1. Advantageous further developments and embodiments are the subject of the dependent claims.

[0012] The electric (electromechanical) brake actuator has an actuator housing that is closed or closable with a housing cover, in particular a shell-like cover. An electric motor, a multi-stage gearbox, and a support unit are housed within the actuator housing. The support unit has a first bearing seat that serves to receive a first bearing axis of a gear, preferably a double gear, of a first gearbox stage. The support unit has a second bearing seat that serves to receive a second bearing axis of a gear, preferably also a double gear, of a second gearbox stage. The second gearbox stage is coupled to a third gearbox stage via an output gear. The electric motor has a motor shaft with a shaft-mounted first pinion that meshes with the gear, preferably a double gear, of the first gearbox stage.This gear of the first gear stage is coupled to the gear, in particular a double gear, of the second gear stage; in particular, these gears of the first two gear stages mesh with each other.

[0013] A "double gear" is understood to be a gear composed of two gears of different sizes, whereby the comparatively small gear, which is also referred to as pinion below, and the comparatively large gear are coaxial to each other and connected to each other.

[0014] A spacer bridge is arranged between the support unit and the housing cover. This spacer bridge comprises a bridge base and an elastic damping component that rests against the housing cover, i.e., against its inner surface facing the gearbox and the electric motor. The first bearing shaft and / or the second bearing shaft are guided into the spacer bridge. For this purpose, the spacer bridge, or its bridge base, has a receiving opening for the respective bearing shaft.

[0015] Preferably, the bridge base has a receiving opening for each of the two bearing axes. The two receiving openings are spaced apart from each other along the bridge span so that the two bearing axes are oriented parallel to each other. In a corresponding embodiment of the bridge span, it has two bearing receptacles spaced apart from each other and connected by a bridge web of the bridge base, namely one bearing receptacle each for the first bearing axis and for the second bearing axis.

[0016] In an advantageous embodiment, the damping component is positively and / or materially bonded to the bridge body of the spacer bridge. The spacer bridge can be designed as a two-component component with a hard component forming the bridge body and a soft, elastic component forming the damping component.

[0017] According to a practical embodiment, a receiving bushing is provided in the bridge body in the area of ​​the respective receiving opening, into which an axle end of the first or second bearing axle projects. A bearing seat for the first or second bearing axle, respectively, is then suitably integrated into the housing cover within the respective receiving bushing. Furthermore, in this embodiment, the damping component of the spacer bridge advantageously has a through-opening in the area of ​​the respective receiving bushing, the edge of which surrounds that of the corresponding receiving bushing.

[0018] In a particularly advantageous embodiment, the spacer bridge has a sealing lip, especially a circumferential one. This sealing lip is part of the damping component and is, in particular, integrally formed with it. The deformable sealing lip, with which the spacer bridge elastically rests against the housing cover (on the inside of the cover), surrounds the at least one receiving opening, preferably both receiving openings.

[0019] The bridge body of the distance bridge is suitably rod- or strip-shaped. In other words, the distance bridge has two parallel longitudinal sides and two narrow sides, which are preferably semicircular. The damping component preferably covers the longitudinal sides completely and the narrow sides of the bridge body at least partially.

[0020] The bridge body of the spacer bridge can have a joining element, and the housing cover can have a corresponding joining contour in which the joining element is seated. Suitablely, such a joining element is provided on both narrow sides of the spacer bridge, preferably not covered by the damping component.

[0021] The advantages achieved with the invention consist in particular of the fact that, by means of such a spacer bridge, the position of the gear of the respective gear stage associated with the respective bearing axis is axially limited within the actuator housing, i.e., along the bearing axis. In other words, the corresponding gear of the respective gear stage is arranged within the actuator housing at a distance from the housing cover that corresponds at least to the axial dimension (thickness or height) of the spacer bridge. This already achieves a decoupling of the corresponding gear from the actuator housing. Furthermore, the damping component, being a comparatively soft component, provides additional noise decoupling of the gearbox or individual gearbox components from the housing cover.Thus, the spacer bridge reduces excitation of the housing cover and improves the acoustic properties of the electric (electromotive) brake actuator, which is intended especially for a motor vehicle.

[0022] An embodiment of the invention is explained in more detail below with reference to a drawing. The drawing shows: Fig. 1 and Fig. 2 in perspective view an electric (electromotive) brake actuator with an actuator housing in which a brushed electric motor (commutator motor) and a multi-stage gearbox mounted on a support unit are arranged, with or when the housing cover is removed, Fig. 3 the electric (electromotive) brake actuator according to Fig. 1 in a sectional view with a spacer bridge between the housing cover and motor-side stages of the gearbox, Fig. 4 in perspective sectional view that the actuator housing provided with the housing cover with the carrier unit, with a motor housing and with the spacer bridge, into which two bearing axes of the gearbox are guided, Fig. 5a and Fig. 5b in perspective view the distance bridge with embedded bearing axles, looking at the upper side of the bridge facing the housing cover or at the lower side of the bridge facing the gearbox, and Fig. 6 in a sectional view the distance bridge with a bridge body and with a damping component partially enclosing this bridge on the upper side.

[0023] Corresponding parts are marked with the same reference symbols in all figures.

[0024] The Fig. 1 and Fig. Figure 2 shows an electric brake actuator 1 for a motor vehicle (not shown). The brake actuator 1 has an actuator housing 2, which is closed with a housing cover 3, which is shown in Figure 2. Fig. 2 is removed. The actuator housing 2 has a substantially cylindrical (cup-shaped) housing area (housing section) 2a, which houses an electric motor 4 ( Fig. 3) with a motor housing 5 and a carrier unit 6 as well as a multi-stage gearbox 7 of the brake actuator 1.

[0025] Between the carrier unit 6 and the housing cover 3 there is a Fig. A spacer bridge 8 is arranged in two recognizable sections. This is located above the gearbox 7 and outside an area of ​​the actuator housing 2 covered by the housing cover 3. A first bearing shaft 9 and a second bearing shaft 10 are guided into the spacer bridge 8. For this purpose, the spacer bridge 8 has a first receiving opening 11 for the first bearing shaft 9 and a second receiving opening 12 for the second bearing shaft 10. In the area of ​​the respective receiving opening 11, 12, a first and a second receiving bushing 13, 14 are provided, into which a shaft end 9a, 10a of the first bearing shaft 9 and of the second bearing shaft 10 projects. In the respective receiving bushing 13, 14, a first and second bearing seat 15, 16 for the first and second bearing shaft 9 and 10, respectively, is integrally formed with the housing cover 3. Fig. 3).

[0026] The first bearing axis 9 supports a first gear (double gear) 17 of a first gear stage, which is coupled to the electric motor 4. The second bearing axis 10 supports a second gear (double gear) 18 of a second gear stage, which is coupled to the first and a last gear stage, from which in Fig. 2 a large gear 19 designed as a double gear is recognizable, which is connected to a comparatively small gear in the form of an output pinion 20 that is coaxial to it ( Fig. 3).

[0027] As in the Fig. 3 and Fig. As can be seen in Figure 4, the support unit 6 has a first bearing seat 21 for the first bearing axis 9 of the gear 17, designed as a double gear, of the first gear stage, and a second bearing seat 22 for receiving the second bearing axis 10 of the gear 18, also designed as a double gear, of the second gear stage. The electric motor 4 has a motor shaft 23 with a shaft-mounted, helical pinion 24, which meshes with a ring gear 17a with internal teeth (helical teeth) of the gear 17, designed as a double gear, and together they form the first gear stage. The gear 17, designed as a double gear, has a comparatively small gear in the form of a pinion 17b, which is coaxial with the comparatively large ring gear 17a and mounted with it on the first bearing axis 9. This pinion meshes with the gear (double gear) 18, and together they form the second gear stage.The double gear 18, composed of the comparatively large outer gear 18a and a comparatively small gear in the form of a pinion 18b, is coupled via its pinion 18b to further gears 25, 26 of at least one further gear stage, which in turn are coupled to the gear (double gear) 19 of the last gear stage.

[0028] The electric motor 4 has a stator 27 formed from housing-mounted permanent magnets and a shaft-mounted rotor 28 surrounded by it, the coil windings of which are connected in a manner not shown to a shaft-mounted commutator 29. This is energized via a brush system (not shown) which is energized by means of connection contacts 30 in a connection socket 31 integrally formed with the actuator housing 2.

[0029] Fig. Figure 4 shows the electric (electromotive) brake actuator 1 in a perspective sectional view looking into the actuator housing 2 without gearbox 7 and without electric motor 4. Visible are the support unit 6, the motor housing 5, the motor shaft 23, the first bearing axis 9 and the second bearing axis 10. The bearing axes 9, 10 are located in the support unit 6 and there in the associated bearing seats 21, 22 ( Fig. 3) fixed to the support. The opposite axle ends 9a, 10a are guided into the spacer bridge 8 and there into the corresponding receiving openings 11, 12.

[0030] The spacer bridge 8 comprises a bridge body 8a and a damping component 8b. The damping component 8b is soft and, in particular, elastic compared to the bridge body 8a. The damping component 8b is positively and preferably materially bonded to the bridge body 8a of the spacer bridge 8. The spacer bridge 8 is suitably designed as a two-component component with the comparatively hard bridge body 8a and the comparatively soft damping component 8b.

[0031] The Fig. 5a and Fig. Figure 5b shows the spacer bridge 8 in a perspective top view and a perspective rear view. The spacer bridge 8 is shown with the bearing axles 9 and 10 inserted. On the upper side facing the housing cover 3 ( Fig. 5a) A circumferential sealing lip 32 is integrally formed with the damping component 8a. This sealing lip is circumferential, extending over the opposing longitudinal sides 33a, 33b and the two narrow sides 33c, 33d of the spacer bridge 8. The sealing lip 32 thus encloses the two receiving bushings 13, 14 and the receiving openings 11, 12 on the bottom side of these bushings. Fig. 5b) for the two bearing axes 9 and 10.

[0032] The narrow sides 33c, 33d of the spacer bridge 8 – and thus its bridge base 8a as well as the damping component 8b – are rounded, in particular semicircular. The radius of this semicircular shape is suitably adapted to the radius of the receiving bushings 13, 14. Joining elements 34 project from the narrow sides (end faces) 33c, 33d of the spacer bridge 8. These joining elements are integrally formed with the bridge base 8a or are monolithic with it. These joining elements 34 are not covered or enclosed by the damping component 8b. The joining elements 34 correspond to joining contours 35 in the housing cover 3, i.e., on its inner surface. The joining elements 34 of the spacer bridge 8 are engaged in these inner-cover joining contours 35, in particular in a form-fitting manner, as shown in Fig. 4 is recognizable.

[0033] Fig.Figure 6 shows the spacer bridge 8 in a perspective sectional view. The sealing component 8b of the spacer bridge 8, with corresponding component sections 8b', can be seen projecting at least slightly into the respective receiving bushing 11, 12 of the spacer bridge 8. In the area of ​​the circumferential sealing lip 2 of the damping component 8b, it can be connected to the bridge base body 8a of the spacer bridge 8, forming a cavity 37. This further increases the elasticity of the damping component 8b in the area of ​​its sealing lip 32 and the damping effect of the spacer bridge 8.

[0034] In the area of ​​the respective receiving bushings 13, 14 of the spacer bridge 8, the sealing component 8b with receiving openings 11, 12 for the two bearing axes 9 and 10 respectively, and with the receiving bushings 15, 16, has aligned through-openings 37. The sections 8b' of the damping component 8b are practically drawn into the receiving bushings 13, 14 in this area of ​​the through-openings 37. In this area, the cover-side bearing seats 15, 16 bear against the wall of the receiving bushings 13, 14 within this area. This improves the damping effect of the spacer bridge 8.

[0035] In summary, the invention relates to an electric (electromotive) brake actuator 1 for a motor vehicle, comprising an actuator housing 2 which is closed or can be closed by means of a housing cover 3, in which an electric motor 4 and a multi-stage transmission 7 as well as a support unit 6 are accommodated, wherein a first bearing axis 9 of a gear 17 of a first transmission stage and / or a second bearing axis 10 of a gear 18 of a second transmission stage is guided into a spacer bridge 8 which is arranged between the support unit 6 and the housing cover 3, wherein the spacer bridge 8 has a bridge base body 8a and an elastic damping component 8b abutting the housing cover 3, and wherein the spacer bridge 8 has at least one receiving opening 11, 12 for the first bearing axis 9 or for the second bearing axis 10.

[0036] The spacer bridge 8 forms an axial limit for the gears 17, 18, at least of the first and / or a second (motor-side) gear stage of the gearbox 7, so that a corresponding distance is established between these gears and the housing cover 3. Together with the damping effect of the spacer bridge 8, this achieves a targeted decoupling of these gearbox components (17, 18), which has been shown to have a significant influence on the acoustic excitation of the housing cover 3 that causes noise.

[0037] The claimed invention is not limited to the embodiments described above. Rather, other variants of the invention can also be derived by a person skilled in the art within the scope of the disclosed claims without departing from the subject matter of the claimed invention. In particular, all individual features described in connection with the various embodiments can also be combined in other ways within the scope of the disclosed claims without departing from the subject matter of the claimed invention. Reference symbol list 1 brake actuator 2 actuator housings 2a Housing area / section 3 Housing covers 4 electric motor 5 Motor housing 6 carrier unit 7 gearboxes 8 Distance bridge 8a Bridge base structure 8b Damping component 8b' Component section 9 first bearing axle 9a Axle end 10 second bearing axle 10a Axle end 11 first recording opening 12 second recording opening 13 first recording socket 14 second recording socket 15 first warehouse location 16 second warehouse location 17 first double / gear 17a Ring gear 17b Pinion 18 second double / gear 18a Outer gear 18b sprocket 19 Double / gear 20 output pinions 21 first warehouse location 22 second warehouse location 23 Motor shaft 24 sprockets 25 gear 26 gear 27 Stator 28 Rotor 29 Commutator 30 connection contacts 31 Connection socket 32 Sealing lip 33a,b Long side 33c,d narrow side 34 Joining element 35 Joining contour 36 cavity 37 Passage opening

[0038] The invention relates to an electric brake actuator (1) for a motor vehicle, comprising an actuator housing (2) closed by means of a housing cover (3), in which an electric motor (4) and a multi-stage transmission (7) as well as a carrier unit (6) are accommodated, wherein a first bearing axis (9) of a gear (17) of a first transmission stage and / or a second bearing axis (10) of a gear (18) of a second transmission stage is guided into a spacer bridge (8) which is arranged between the carrier unit (6) and the housing cover (3), wherein the spacer bridge (8) has a bridge base body (8a) and an elastic damping component (8b) abutting the housing cover (3), and wherein the spacer bridge (8) has at least one receiving opening (11, 12) for the first bearing axis (9) or for the second bearing axis (10). QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 20 2017 104 469

[0005] DE 10 2016 004 297 A1

[0007] KR 101 592 825 B1

[0008] DE 10 2016 221 162 A1

[0009]

Claims

Electric brake actuator (1) for a motor vehicle, comprising an actuator housing (2) closed by means of a housing cover (3), in which an electric motor (4) and a multi-stage transmission (7) as well as a support unit (6) are accommodated, the support unit having a first bearing seat (21) for receiving a first bearing axis (9) of a gear (17) of a first transmission stage and a second bearing seat (10) for receiving a second bearing axis (10) of a gear (18) of a second transmission stage, which is coupled to a third transmission stage with an output gear (20), wherein the electric motor (4) has a motor shaft (23) with a shaft-fixed first pinion (24) which meshes with the gear (17) of the first transmission stage coupled to the gear (18) of the second transmission stage, characterized in that the first bearing axis (9) and / or the second bearing axis (10) is guided in a spacer bridge (8) which is located between the support unit (6) and the housing cover (3) is arranged,and- that the spacer bridge (8) has a bridge base body (8a) and an elastic damping component (8b) abutting the housing cover (3), and- that the spacer bridge (8) has at least one receiving opening (11, 12) for the first bearing axis (9) or for the second bearing axis (10). Electric brake actuator (1) according to claim 1 , characterized in that the damping component (8b) is positively connected and / or materially connected to the bridge base body (8a) of the distance bridge (8), in particular designed as a two-component injection molded part. Electric brake actuator (1) according to claim 1 or 2, characterized in that a receiving bushing (13, 14) is provided in the bridge base body (8a) in the area of ​​the respective receiving opening (11, 12), into which an axle end (9a, 10a) of the first or second bearing axle (9, 10) projects. Electric brake actuator (1) according to claim 3, characterized in that a bearing seat (15, 16) for the first or second bearing axis (9, 10) is molded onto the housing cover (3) in the respective receiving bushing (13, 14). Electric brake actuator (1) according to claim 3 or 4, characterized in that the damping component (8b) of the spacer bridge (8) in the area of ​​the respective receiving socket (13, 14) has a through opening (36) aligned with the receiving opening (11, 12). Electric brake actuator (1) according to one of claims 1 to 5, characterized in that the spacer bridge (8) has a first receiving opening (11) for the first bearing axis (9) and a second receiving opening (12) spaced apart from the first receiving opening (11) for the second bearing axis (10). Electric brake actuator (1) according to one of claims 1 to 6, characterized in that the damping component (8b) has a sealing lip (32) facing the housing cover (3). Electric brake actuator (1) according to claim 7, characterized in that the sealing lip (32) surrounds the at least one receiving opening (11, 12), preferably both receiving openings (11, 12). Electric brake actuator (1) according to one of claims 1 to 8, characterized in that the bridge base body (8a) of the distance bridge (8) has two longitudinal sides (33a, 33b) parallel to each other and two semicircular narrow sides (33c, 33d), and that the damping component (8b) covers the longitudinal sides (33a, 33b), in particular completely, and the narrow sides (33c, 33d), in particular partially. Electric brake actuator (1) according to one of claims 1 to 9, characterized in that the spacer bridge (8) has at least one joining element (34) and the housing cover (3) has a corresponding joining contour (35) in which the joining element (34) is seated.

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