Electromechanical braking mechanism for a motor vehicle

Abstract

The present invention relates to an electromechanical braking mechanism (1) for a motor vehicle, comprising a driver carrier (100) to which an electric motor (41, 42) and an adjustment device (5) are attached, wherein said adjustment device is connected transmission-wise to a motor shaft (411, 421) and by means of which a brake part (22) can be adjusted, wherein the motor (41, 42) has a motor housing (413, 423) in which the motor shaft (411, 421), which extends in an axial direction, is supported in an end-face bearing cover (414, 424) and projects axially herefrom, wherein the motor housing (413, 423) is fixed to the drive carrier (100). To enable improved production and assembly, and to keep the installation space and weight low, according to the invention the drive carrier (100) has a recess (101) in which the motor housing (413, 423) can be received in an interlocking manner in the axial and radial direction, wherein the machine housing (413, 423) can be braced against an axial support surface (104) of the recess (101) on the end face.

Description

[0001] Electromechanical braking device for a motor vehicle

[0002] State of the art

[0003] The invention relates to an electromechanical braking device for a motor vehicle, comprising a drive carrier to which an electric motor and an actuating device are mounted, which is gear-coupled to a motor shaft and by which a braking part is adjustable, wherein the motor has a motor housing in which the motor shaft extending in the axial direction is mounted in a front-side bearing cover and projects axially therefrom, wherein the motor housing is fixed to the drive carrier.

[0004] Such a braking device of a motor vehicle is designed as a friction brake, in which a braking element supported on the chassis and fixed relative to the rotation of the wheel to be braked can be brought into braking engagement by means of an adjusting device with a counter-braking element that rotates with the wheel. During braking engagement, frictional contact is created between the braking element and the counter-braking element, whereby the braking torque generated by friction increases the higher the adjusting force exerted by the adjusting device in the adjustment direction.

[0005] A common design is the well-known disc brake, in which the counter-braking component is formed by a brake disc rotating with the wheel and axially gripped on both sides by a brake caliper. By means of at least one, preferably linear, actuator axially supported on the brake caliper, a braking component, usually a brake pad, can be adjusted in an axial direction and thereby brought into frictional contact with an axial side of the brake disc. The brake disc is frictionally clamped in braking engagement between the adjusted braking component and another braking component supported axially opposite the brake caliper.

[0006] From DE 10 2017 123 266 A1, it is known that the adjusting device has two actuators arranged serially in the adjustment direction. Each of the actuators has a drive-side drive element and an output-side output element that is linearly adjustable relative to the drive element in the axial adjustment direction. To implement an adjustment movement, each drive element has a drive wheel, preferably a gear wheel such as a toothed wheel or the like, which can be driven to rotate about its axis by an electric motor, the actuator motor. The rotation of the drive wheel is converted in the actuator into a relative adjustment movement or an adjustment stroke of the output element relative to the drive element in the axial adjustment direction. In the generic prior art, the two drive wheels of the first and second actuators are arranged coaxially on a common axis lying in the axial adjustment direction.

[0007] An actuator forms a lifting or adjusting device that acts axially in the adjustment direction. For example, an actuator can have a spindle drive, in which the drive element has a spindle nut and the output element has a threaded spindle engaging therein, or vice versa. Other actuator designs can also be used, which can include, for example, ramp bearings, cam or cam discs, tilt pin arrangements, or the like, and also convert a rotation of the drive element into a linear adjustment of the output element.

[0008] The actuator and the motor(s) are mounted on a drive carrier such that a gear wheel, for example a toothed wheel, attached to a rotatably driven motor shaft of the motor is in gear engagement with the drive wheel of an actuator, as described in the aforementioned DE 10 2017 123 266 A1. The drive carrier is connected to the brake caliper. It has a plate-shaped mounting section that extends over a large area and to which the motor is secured such that the motor shaft and the axis of the actuator, which is parallel to it, are perpendicular to the drive carrier.

[0009] The motor has a motor housing in which the motor shaft and rotor are rotatably mounted and which is connected to the drive carrier. The motor housing includes a front-end bearing cover through which the motor shaft passes axially forward toward the drive carrier. The bearing cover is connected to the motor housing, which is connected to the drive carrier.

[0010] For smooth and low-wear operation, it is essential that the motor shaft is aligned parallel to the axis of the actuator at a defined distance to ensure optimal gear engagement. This requires that the motor is precisely positioned and securely fixed to the drive carrier relative to the actuator on the drive carrier. The effort required for manufacturing and assembly, as well as the installation space and weight, should be as low as possible. A disadvantage of the known designs, however, is that the installation and alignment of the motor housing on the drive carrier is complex. In view of the problems explained above, it is an object of the present invention to enable improved manufacturing and assembly and to keep installation space and weight to a minimum.

[0011] Description of the invention

[0012] This object is achieved according to the invention by the braking device having the features of claim 1. Advantageous further developments emerge from the subclaims.

[0013] In an electromechanical braking device for a motor vehicle, comprising a drive carrier to which an electric motor and an actuating device are mounted, which is gear-coupled to a motor shaft and by which a braking part is adjustable, wherein the motor has a motor housing in which the motor shaft extending in the axial direction is mounted in a front-side bearing cover and projects axially therefrom, wherein the motor housing is fixed to the drive carrier, it is provided according to the invention that the drive carrier has a recess in which the motor housing can be received in a form-fitting manner in the axial and radial directions, wherein the motor housing can be clamped at the front against an axial support surface of the recess.

[0014] The recess provides a receptacle for the motor, in which the motor housing can be accommodated in a defined axial and radial alignment relative to the drive carrier. The recess has an opening extending through the drive carrier, through which the motor shaft passes vertically through the drive carrier.

[0015] The support surface can be formed on a support projection projecting radially inward into the opening of the recess, for example, on a step or the like arranged at the edge of the opening. The open cross-section of the recess is matched to the outer cross-section of the motor housing such that the housing can be inserted axially into the recess with minimal radial play—by definition, forward in the direction of the motor axis defined by the motor shaft—until it axially abuts the support surface. The motor shaft protrudes on the side of the drive carrier facing away from the motor.

[0016] The bearing cap located on the front end of the motor housing can be supported against the support surface and clamped to the motor housing. One advantage is that the motor housing is held positively in the radial direction when inserted into the recess and is also positively supported in the axial direction when it comes into contact with the support surface. This ensures that the motor accommodated in the recess is spatially defined relative to the drive carrier. Clamping to fix the motor can be carried out after insertion into the recess. This advantageously simplifies assembly and makes it easy to provide a defined gear engagement with the actuating device, for example via meshing gear wheels on the motor shaft and the actuating device.

[0017] It is possible for the support surface to be formed on a projection projecting radially inward into the recess. The projection may preferably have a step or the like extending circumferentially inside the recess at least over part of its circumference, on which the support surface is formed parallel to the planar extension of a mounting portion of the drive carrier.

[0018] It is preferred that the bearing cap be attached to the front of the motor housing. The bearing cap can initially be provided as a separate part and then joined to the motor housing during assembly after the rotor has been inserted into the motor shaft. This enables efficient assembly of the motor.

[0019] It may be provided that the bearing cap is supported axially against the support surface.

[0020] The bearing cap, mounted axially at the front of the motor housing, can rest against the support surface with its front face, facing away from the motor housing. The bearing cap is connected to the motor housing on its rear face, facing away from the front face.

[0021] It is advantageous if the bearing cap can be clamped between the support surface and the motor housing. The bearing cap has at least one section that is arranged axially between the motor housing and the support surface. The bearing cap can therefore be clamped axially against the motor housing by clamping it against the support surface. In other words, the bearing cap is located at least partially in the force flow of the clamping of the motor housing to the drive carrier. This means that the fixing of the motor to the drive carrier and the fixing of the bearing cap to the motor housing during clamping can take place in a single assembly step, thus advantageously reducing the effort. For example, the bearing cap can have an axial shoulder that is inserted into an axial opening in the motor housing, and a circumferential collar that projects radially outwards beyond the cross-section of the opening.The collar can have essentially the same outer cross-section as the motor housing and is arranged axially between the support surface and the motor housing. When the motor housing is clamped against the support surface, the bearing cap can be supported on the support surface and secured to the motor housing at the same time. One advantage of this is that the bearing cap only needs to be temporarily connected to the motor housing before the motor is installed in the braking device, and the final fixing can take place in a single assembly step when the motor is clamped to the drive carrier. The clamping thus fulfills a dual function of fixing the motor to the drive carrier and fixing the bearing cap to the motor housing. For example, the bearing cap can be simply inserted into the motor housing with an axial shoulder to ensure a force fit, or it can be pushed onto the motor housing.This eliminates the need for complex screw, weld or other joining connections between the bearing cap and the motor housing, simplifying the construction of the motor and saving weight.

[0022] It can preferably be provided that the motor housing has a flange element which is axially spaced from the end face and projects radially beyond the recess.

[0023] The flange element projects radially outwards from the motor housing and protrudes beyond the recess. It can be connected to the drive carrier. For this purpose, fastening means can be provided which can be connected to the drive carrier outside the recess in order to axially clamp the motor housing against an outer side of the brake housing. For example, the flange element can preferably be provided with a plurality of axial flange bores distributed over the circumference, through which fastening elements such as screws or the like can be passed and screwed into corresponding threaded bores in the drive carrier. Because the flange element is at an axial distance from the front end of the bearing cap, the axial clamping of the flange element against the drive carrier can clamp the motor housing, which extends into the recess, with the bearing cap at the end against the support surface arranged in the recess.In this way, the flange element can fix the motor in the position defined by the recess on the drive carrier, and at the same time the bearing cover can be clamped and firmly connected to the motor housing.

[0024] The axial distance of the flange element from the end face of the bearing cap attached to the front of the motor housing is preferably greater than the depth of the recess, measured from the support surface to the outside of the drive carrier in the area of ​​the flange element. This allows the bearing cap to be clamped axially between the support surface and the motor housing by tightening the flange element. The advantage is that the bearing cap can be securely connected to the motor housing by connecting the motor housing to the drive housing without the need for additional fasteners. This allows the motor to be designed in a simpler and lighter manner.

[0025] It can be provided that the motor housing at least partially has a hollow cross-section to which the bearing cap can be secured in a form-fitting manner. The motor housing can, for example, be pot-shaped or cup-shaped and be axially closed at the front by the bearing cap attached thereto. The motor shaft comprising the rotor can be mounted internally in the motor housing at one end region and rotatably mounted with its other end region in the bearing cap and guided through it to the outside. The hollow cross-section can, for example, have a substantially cylindrical tube section, from whose open end the bearing cap can be secured by axial bracing.For example, a cylindrical extension of the bearing cover can be inserted into the opening of the hollow cross-section in a form-fitting manner, and a substantially annular collar can be clamped between the support surface and the end face of the pipe section in the manner described above.

[0026] It may be advantageous for the motor housing, the bearing cap, and / or the drive carrier to comprise a cast part. The cast part can be an injection-molded part made of a thermoplastic, which can optionally be fiber-reinforced to increase strength, or a die-cast part made of a metallic material, for example aluminum, magnesium, or zinc alloys. Complex shapes can be efficiently realized using the casting process. For example, the recess according to the invention and, if appropriate, further functional elements can be integrally formed on the drive carrier. Accordingly, the flange element and, if appropriate, further functional elements can be integrally formed on the motor housing. For example, a projection for connecting to the motor housing, a bearing holder for the motor shaft, or the like can be integrally formed on the bearing cap.

[0027] It is possible for an elastic holding element and / or sealing element to be arranged between the recess and the motor housing. For example, an elastically deformable O-ring made of a rubber or polymer material can be clamped radially between a circumferential inner surface of the recess and an outer surface of the motor housing. As a result, the motor housing can be temporarily held in position on the drive carrier in a force-fitting or friction-fitting manner by simply inserting it axially into the recess, which can simplify subsequent clamping. It can advantageously be provided for an O-ring to be received in a circumferential groove in the recess or the motor housing and thus held in a form-fitting manner in the axial direction.

[0028] In addition, an O-ring or other elastic sealing element can be used to effectively seal the motor housing in the recess against the ingress of moisture or contaminants.

[0029] Preferably, the drive carrier can have at least two recesses. A motor can be fixed in each of the recesses, each of which can drive an actuator of the actuating device. This makes it possible to mount two motors for driving two actuators of the actuating device on the drive carrier. It is advantageous that, according to the invention, both motors can be easily and securely positioned and mounted relative to the actuators.

[0030] An advantageous embodiment can provide that the braking device comprises an adjusting device and a braking part connected thereto, which can be adjusted along an axis by the adjusting device and brought into braking engagement with a counter-braking part, wherein the adjusting device has a first adjusting drive and a second adjusting drive coupled in series thereto, wherein the first adjusting drive has a first drive wheel that can be driven in rotation, and the second adjusting drive has a second drive wheel that can be driven in rotation and is coaxial with the first drive wheel, wherein a coupling device is arranged between the first drive wheel and the second drive wheel.

[0031] The actuating device can be driven by at least one electric actuator. This actuator is preferably in gear engagement with at least one drive wheel. Preferably, one actuator can be provided for each of the first and second drive wheels. According to the invention, the actuator(s) can be controlled by a wheel brake control unit assigned to the braking device. The clutch device can be designed as a friction clutch with a friction element that, when engaged, can be frictionally connected to a counter-friction element.

[0032] In the following, the first and second drive wheels are referred to together as the two drive wheels or simply as the drive wheels.

[0033] The drive wheels can each be designed as a gear, for example as a spur gear, or as a belt or toothed belt wheel or worm wheel, so that generally a gear wheel is provided via which a drive torque from an electric actuator can be coupled into the actuator.

[0034] A friction clutch is implemented between the drive wheels. This comprises a friction element, which is torque-locked to one of the drive wheels, and a corresponding counter-friction element, which is torque-locked to the other drive wheel. The friction element can be brought into frictional engagement with the counter-friction element in any relative angular position. This creates a purely force-locking coupling, as opposed to a positive locking connection. This allows the relative position of the drive wheels to be continuously specified, in contrast to the discrete locking steps of a locking connection. Accordingly, a uniform, continuous adjustment of the second actuator relative to the first actuator is possible, and a continuous adjustment of the air gap can be achieved.This is particularly advantageous with regard to the consistent adjustment of the optimal operating point of the braking system to the continuous wear of the braking component during operation, i.e., the continuous wear of the brake pad. Compared to a purely incremental adjustment option, a consistently improved response of the braking system can be achieved, thus increasing operational reliability and greater ease of use.

[0035] A further advantage over a locking clutch is that, to engage and disengage the clutch device, essentially no axial relative movement is required between the clutch elements engaged in the clutch, for example, between the drive gears or the locking elements, which must necessarily be movable relative to one another to create and release the lockable positive locking. In contrast, the pure frictional connection between the friction and counter-friction elements according to the invention can be simply determined by the applied axial actuation force, whereby the friction and counter-friction elements do not need to be moved axially relative to one another. This enables a simpler and more reliable design of the clutch device.

[0036] It is preferably provided that the friction clutch has a defined, predeterminable clutch torque. The clutch torque indicates the maximum differential torque that can be transmitted force-lockingly between the friction element and the counter-friction element due to the frictional engagement during clutch engagement. If the clutch torque is exceeded, the clutch device slips, causing the two drive wheels to rotate relative to each other. One advantage of this is that the friction clutch according to the invention slips continuously in a sliding manner, enabling improved, uniform readjustment of the air gap. Furthermore, there is no need to design for axial evasive movements of locking elements, as is the case with the known locking clutch, and thus compensate for these.

[0037] It is advantageous for the friction element and the counter-friction element to be arranged coaxially. This coaxial arrangement corresponds to the coaxial arrangement of the drive wheels. The friction element and the counter-friction element can be arranged in a simple and compact design near the axially opposing end faces of the drive wheels. Due to the above-described generation of the pure frictional connection of the clutch, no moving parts are required.

[0038] In an advantageous embodiment, it can be provided that the friction element and the counter-friction element are conical. The friction element can have a conical section that converges at least partially in the axial adjustment direction and has a conical friction surface, which can be designed as an outer cone or inner cone, and which has a corresponding conical section on the counter-friction element, which is designed in the opposite direction as an inner cone or outer cone and has a conical counter-friction surface. To generate the clutch engagement, the outer cone dips into the inner cone, with the conical friction and counter-friction surfaces being frictionally loaded against one another by an axial actuating force of the clutch. One advantage of this is that the cone can convert the axially acting actuating force of the clutch into the normal force acting between the conical friction surfaces in frictional contact.Thus, a flatter pitch allows a relatively small axial actuating force to be converted into a larger normal force in the frictional contact, whereby a high clutch torque can be achieved even with a relatively small axial actuating force of the clutch.

[0039] Alternatively or in addition to the aforementioned embodiment, the friction element and the counter friction element can be designed as planar surfaces. The corresponding friction surfaces are designed, at least in sections, as flat axial surfaces, similar to a disc clutch. This enables a space-saving arrangement, especially when only a relatively small clutch torque is to be achieved.

[0040] It can preferably be provided that the friction element and the counter-friction element are preloaded against each other. Preferably, the friction element and the counter-friction element are elastically or resiliently preloaded against each other. The friction and counter-friction surfaces are pressed against each other in frictional engagement with a predetermined axial preload force. To generate the preload force, an elastic preload element, for example a spring element or the like, can preferably be provided. The clutch torque of the friction clutch is determined by the actuating force acting perpendicular to the frictional contact, i.e. the force applied axially between the friction and counter-friction elements, whereby the clutch torque is greater the greater the preload force. This opens up the advantageous possibility of simply specifying the clutch torque through the preload force exerted by the preload element.For example, in the case of a spring element that is elastic in the axial direction, such as a compression spring, the applied preload force can be simply specified and adjusted by the spring constant and the compression of the spring.

[0041] The aforementioned embodiment can advantageously be realized in that the friction element and / or the counter-friction element is axially displaceable and supported against the first drive wheel or the second drive wheel via an axially acting spring element. The friction element or the counter-friction element is connected to one of the drive wheels in a torque-locking and axially displaceable manner, for example via radially projecting drivers that create a positive connection effective in the circumferential direction. The spring element axially clamped between the friction element or the counter-friction element and one of the drive wheels, which spring is preferably designed as an axially acting compression spring, ensures that the friction or counter-friction element is axially preloaded against the corresponding counter-friction or friction element axially supported on the other drive wheel, i.e. is pressed axially against it in frictional contact.The corresponding counter-friction or friction element is rotationally connected to the other drive wheel. It is also possible, alternatively or additionally, for the counter-friction element to be supported on one of the drive wheels via a spring element. An advantage of this arrangement is that this friction clutch can be integrated between the drive wheels in a structurally simple and space-saving manner. In an advantageous development, it is possible for the friction element and / or the counter-friction element to be arranged in the first drive wheel or the second drive wheel. For example, it is possible to design one drive wheel essentially drum-shaped so that the friction or counter-friction element can be arranged in an interior space enclosed by the rotating gear or gear ring. This enables a compact design that is protected against external influences.For example, the drive wheel of the first actuator can have a conical friction element which engages axially in a counter friction element designed as an inner cone which is arranged at least partially within the second drive wheel.

[0042] A particularly compact design can be achieved - especially in the last-mentioned embodiment - by arranging the drive wheels within the axial extension of the actuators, i.e. by not being mounted axially protruding on one side.

[0043] It is preferred that the friction element and / or the counter-friction element have a friction lining. The friction and counter-friction elements preferably have a metallic base body, for example, made of steel. To prevent metal-to-metal contact, a coating or lining can preferably be applied to create a friction pairing with a defined friction force, for example, made of sintered, metal and / or ceramic friction materials, composite materials, or the like. This ensures a defined, reproducible clutch torque.

[0044] An actuator can be provided with a spindle drive. In this case, a threaded spindle engages a spindle nut in a conventional manner, and a relative rotating drive is provided via a drive wheel connected to the threaded spindle or the spindle nut. It is possible for the spindle nut to form the drive-side drive element of the actuator, and the threaded spindle to form the output-side output element, which is linearly adjustable relative to it, or vice versa.

[0045] It is possible for an actuator to have a ball ramp arrangement, a wedge disk arrangement, or a tilt pin arrangement. In a ball ramp arrangement, also known as a ramp bearing, the drive and output elements preferably have cam disks with raceways or ramps inclined relative to the axis, between which balls that can roll in the circumferential direction are arranged. A relative rotation leads to the output element being axially displaced relative to the drive element due to the ball rolling on the ramps. In a tilt pin arrangement known per se, tilt pins are arranged between the drive and output elements and each supported in the circumferential direction in such a way that, depending on the direction of rotation, they are inclined more or less towards the axis during relative rotation, whereby the distance between the drive and output elements can also be adjusted.

[0046] In the actuating device, two similarly acting actuators can be combined as first and second actuators, for example, two spindle drives. It is also possible to combine two different designs, for example, a ball ramp arrangement as the first actuator and a spindle drive as the second actuator for adjusting the air gap. The respective characteristic properties of each design can be optimally utilized. For example, with a ball ramp arrangement, a non-linear adjustment characteristic can be realized with little effort, and / or self-locking properties at least in sections, and / or a defined dead center or extended position that enables a defined adjustment path. The realization of the aforementioned positive properties can at least partially require a precise specification of the air gap, which can be easily achieved with the friction clutch according to the invention.

[0047] A braking device according to the invention can comprise an actuating device and a braking part connected thereto, which can be adjusted along an axis by the actuating device and brought into braking engagement with a counter-braking part, wherein the actuating device has a first actuating drive and a second actuating drive coupled in series therewith, wherein the first actuating drive has a first drive wheel that can be driven in rotation, and the second actuating drive has a second drive wheel that can be driven in rotation and is coaxial with the first drive wheel, wherein a coupling device is arranged between the first drive wheel and the second drive wheel.

[0048] The actuating device can be driven by at least one electric actuator. This actuator is preferably in gear engagement with at least one drive wheel. Preferably, one actuator can be provided for each of the first and second drive wheels. According to the invention, the actuator(s) can be controlled by a wheel brake control unit assigned to the braking device.

[0049] In the latter embodiment of the braking device, it can preferably be provided that the clutch device is designed as a friction clutch with a friction element that can be frictionally connected to a counter friction element during clutch engagement. This makes it possible to realize the advantages previously explained in connection with the braking system.

[0050] To implement the method according to the invention, it can be provided that the braking device has an actuating device which can be coupled to a servomotor and comprises a first actuating drive and a second actuating drive coupled in series therewith, and which acts on a braking part which can be brought into braking engagement with a counter-braking part in the direction of an axis, wherein the first actuating drive has a rotatably drivable first drive wheel to which a first drive torque can be applied for actuation, and the second actuating drive has a rotatably drivable second drive wheel which is coaxial with the first drive wheel and to which a second drive torque can be applied for actuation, wherein a clutch device is arranged between the first drive wheel and the second drive wheel, wherein it is provided according to the invention that the clutch device is designed as a friction clutch and has a predeterminable clutch torque,when this value is exceeded, the first drive wheel slips relative to the second drive wheel, whereby to actuate the first actuator, the first drive wheel and the second drive wheel are driven synchronously, so that the second actuator remains unactuated, and to actuate the second actuator, the second drive wheel is driven, and the first drive wheel is stopped relative to it, so that the friction clutch slips and the first actuator remains unactuated.

[0051] The features mentioned above in connection with the braking device according to the invention can be used individually and in combinations to implement the method according to the invention.

[0052] To adjust the first actuator, an actuating torque can be coupled into the first drive wheel by means of a first electric actuator motor, and accordingly the second actuator can be driven by a second electric actuator motor.

[0053] During normal braking operation, the first and second drive wheels rotate synchronously. This can be achieved, on the one hand, by driving the first and second drive wheels with synchronized drive torques by the first and second actuators. On the other hand, the second drive wheel can be driven synchronously by the clutch device when the first drive wheel is driven, as long as the transmitted drive torque remains below the clutch torque. In this operating mode, the second actuator remains unactuated and rotates idly as a whole together with the braking element. In this method, the clutch device can slip continuously and smoothly when the clutch torque is exceeded to adjust the air gap.This can be achieved, for example, by immobilizing the drive wheel of the first actuator, for example, by a brake or a corresponding control of the first drive motor, while the second drive motor applies a second drive torque to the second drive wheel that is greater than the clutch torque. This causes the second drive wheel to rotate relative to the first drive wheel, and by actuating the second actuator, the air gap can be continuously and sensitively adjusted, allowing for the optimal compensation of continuously advancing wear of the brake element or brake pad.

[0054] It is possible for the first drive wheel and the second drive wheel to be torque-locked by the friction clutch to generate a synchronous drive.

[0055] This eliminates the need for synchronous drive of the two drive wheels by the servomotors. Any torque differences can be compensated within specified tolerances.

[0056] It can advantageously be provided that a higher clutch torque is specified when the first actuator is actuated than when the second actuator is actuated. The first actuator is actuated by synchronous drive of the first and second drive wheels. The friction element and the counter-friction element are preloaded against each other by the spring force of the spring element, and in addition, the adjusting force of the first actuator acts opposite to the spring force. This results in a relatively high clutch torque. If, on the other hand, only the second drive wheel is rotated to adjust the air gap, the spring force alone acts, so that a lower clutch torque is set. This facilitates the adjustment of the air gap.

[0057] Description of the drawings

[0058] Advantageous embodiments of the invention are explained in more detail below with reference to the drawings. In detail:

[0059] Figure 1 shows a braking device according to the invention in a schematic perspective view, Figure 2 shows a side view of the braking device according to Figure 1,

[0060] Figure 3 shows the adjusting device according to the invention of the braking device according to Figure 1 in a schematic perspective view,

[0061] Figure 4 shows a section QQ through the braking device according to Figure 1,

[0062] Figure 5 shows the first actuator of the braking device according to Figure 1 in a schematic perspective view,

[0063] Figure 6 is an enlarged detailed view of the adjusting device from Figure 4,

[0064] Figure 7 shows a longitudinal section through a motor mounted on the drive carrier of the braking device.

[0065] Embodiments of the invention

[0066] In the various figures, identical parts are always provided with the same reference symbols and are therefore usually named or mentioned only once.

[0067] Fig. 1 shows a braking device according to the invention as a whole, designed as a disc brake. This comprises a brake disc 2, which forms a counter-brake part and is connected to a vehicle wheel (not shown here) that is rotatable about a wheel axis R. A brake caliper 3 engages the two axial end faces of the brake disc 2.

[0068] Brake disc 2 is designed as a non-ventilated brake disc made of solid material. Alternatively, it can also be designed as an internally ventilated brake disc.

[0069] An electric brake actuator 4 according to the invention is attached to the brake caliper 3. This actuator is shown in Figure 3 in a separate, isolated schematic perspective view and is explained in detail in Figures 4 to 6. The brake actuator 4 comprises an adjusting device 5 that extends axially in the direction of an axis A, which is parallel to the wheel axis R and indicates the adjustment direction V of the adjusting device 5.

[0070] As can be seen in the sectional view of Figure 4 along axis A, the brake disc 2 is arranged axially between two brake pads 31 and 32. One brake pad 31 is firmly supported on the brake caliper 3 on the side facing away from the brake actuator 4. The other brake pad 32, which forms a braking part within the meaning of the invention, is attached to the adjusting device 5 and can be adjusted by it in the axial adjustment direction V defined by the axis A to generate the braking engagement on the brake disc 2, as indicated by the arrow in Figure 4.

[0071] In the unactuated state of the braking device 1, there is an axial air gap L between the brake disc 2 and the adjustable brake pad 32, which is shown schematically in Figure 4 as exaggeratedly wide.

[0072] The structure of the adjusting device 5 is shown in Figure 4 and in the enlarged section thereof in Figure 6.

[0073] The actuating device 5 comprises a first actuating drive 6, which has a ball ramp arrangement, also referred to as a ramp bearing, and a second actuating drive 7, which is axially (with respect to the axis A) serially coupled thereto and has a spindle drive.

[0074] The first actuator 6, which in the example shown is designed as a ball ramp arrangement or ramp bearing, comprises a drive-side cam disk 61 and an output-side cam disk 62, which are axially and rotationally fixedly supported on the brake actuator 4. Balls 63 are arranged between the cam disks 61 and 62. As can be seen in the schematically isolated view in Figure 5, the cam disks 61 and 62 have axially opposite, ramp-like raceways 64 arranged obliquely to the axis A, between which balls 63 can roll. A rotation of the output-side cam disk 62, at the top in Figure 5, relative to the stationary drive-side cam disk 61 - as schematically indicated by the curved arrows - leads to a linear adjustment of the output-side cam disk 62 in the adjustment direction V parallel to the axis A.As a result, the brake pad 32 can be brought into braking engagement, as shown in Figure 4, by actuating the first actuator 6. The cam disc 62 is connected to a coaxial gear 65, which is designed as a spur gear and forms a drive gear in the sense of the invention.

[0075] The gear 65 is in gear engagement with a first electric actuator 41, which is also referred to as motor 41 for short. This enables the rotating drive of the cam disk 62 and thus the actuation of the first actuator 6.

[0076] The second actuator 7, which in the example shown is designed as a spindle drive, has a threaded spindle 71 on the output side, which engages the internal thread of a drive-side spindle nut 72. This internal thread is formed in the output-side cam disc 62 of the first actuator 6, so that the functions of the output-side cam disc 62 and the drive-side spindle nut 72 are combined in one component.

[0077] The threaded spindle 71 is connected via a hub part 74 to a coaxial gear 75, which is axially fixed and rotatably mounted in the brake actuator 4. The threaded spindle is coupled to the gear 75 in a torque-locking but axially displaceable manner via drivers 73, which may, for example, have radially projecting projections or teeth that engage axially displaceably in axial slots of the hub part 74.

[0078] Like gear 65, gear 75 can be designed as a spur gear and is arranged coaxially adjacent to it. This gear 75 is in gear engagement with a second electric actuator 42, which is also referred to as motor 42 for short. This enables the rotating drive of the threaded spindle 71 and thus the actuation of the second actuator 7.

[0079] The threaded spindle 71 is axially connected via a thrust bearing 43, for example, an axial roller bearing as shown, to a thrust piece 44, to which the movable brake pad 32 is attached, as can be seen in Figure 4. The thrust piece 44 can also be referred to as a piston.

[0080] The clutch device has a friction element 8, which is directed as a coaxial, conical extension from the cam disk 62 toward the second actuator 7. The conical extension has a conical friction surface 81 arranged externally on an outer cone. The friction element 81 can preferably be formed integrally with the cam disk 62 / spindle nut 72. In clutch engagement, the friction element 8 is frictionally coupled to a counter friction element 9. The conical extension axially extends into a corresponding conical opening of the counter friction element 9, which opening has a conical friction surface 91 arranged in an inner cone. In clutch engagement, the friction surface 81 and the counter friction surface 91 bear against one another in a frictionally engaged manner, as can be clearly seen in Figure 6.

[0081] The counter friction element 9 is coupled to the gear 75 in a torque-locking but axially displaceable manner via drivers 92 which engage axially displaceably in corresponding slots 76 in the hub part 74 or the gear 75.

[0082] A spring element 93 is arranged between the gear 75 or the hub part 74 connected thereto and the counter friction element 9. Its axially acting spring force elastically braces the counter friction element 9 against the friction element 8. This generates a defined clutch torque of the friction clutch according to the invention formed by the friction element 8 and the counter friction element 9.

[0083] Figure 3 shows how the two motors 41, 42 and the actuating device 5 are arranged relative to the brake caliper 3. The drive carrier 100 is omitted in this illustration for clarity.

[0084] Each of the motors 41, 42 has a motor shaft 411, 421 which can be driven to rotate about a motor axis M and which lies parallel to the axis A. On this shaft, a gear 412 or 422 is mounted, which is in gear engagement with the gear 65 or 75 of the adjusting device 5.

[0085] Each motor 41, 42 has a motor housing 413, 423, which in the example shown has a cylindrical basic shape. It is cup-shaped and closed on its axial end face facing the viewer in Figure 3 by a bearing cover 414, 424. The motor shaft 411, 412, which carries a rotor of the motor 41, is mounted in the bearing cover 414, 424 and protrudes axially therefrom.

[0086] Figure 7 shows a longitudinal section along the motor axis M through the motor 41 or 42, wherein for better clarity only the reference numerals for the motor 41 are shown, which are also present in the other motor 42. The drive carrier 100 has a recess 101 which comprises an opening 102 extending through the drive carrier 100. A projection 103 which projects radially inwards into the opening cross-section in a stepped manner has an axial support surface 104 which is directed towards the motor 41. The recess 101 is delimited radially outwards by an inner surface 105 which runs coaxially to the motor axis M.

[0087] The inner surface 105 is adapted to the outer diameter of the motor housing 413 in such a way that the latter can be inserted axially therein and is held and supported in a form-fitting manner radially, ie transversely to the motor axis M.

[0088] The bearing cap 414 is inserted axially from the front into the motor housing 413 with an axial projection 415. With its front end face—which, by definition, faces forward and to the left in Figure 7—the bearing cap 414 rests axially against the support surface 104 of the recess 101.

[0089] The bearing cover 414 further comprises a circumferential, radially projecting collar 416 which is arranged axially between the motor housing 413 and the support surface 104.

[0090] The motor housing 413 has flange elements 416 projecting radially outward beyond the recess 101 with axially continuous flange bores through which screws 417 serving as fastening elements are passed and screwed into corresponding threaded bores in the drive carrier 100.

[0091] By screwing in and tightening the screws 417, the motor housing 413 is secured to the drive carrier 100 and clamped thereto. The bearing cover 414, together with the motor housing 413, is clamped axially against the support surface 104 (to the left in Figure 7, as indicated by the arrow) and simultaneously pressed axially into the motor housing 413 (to the right in Figure 7) and fixed. The screws 417 thus serve a dual function: securing the motor 41 to the drive carrier 100 and connecting the bearing cover 414 to the motor housing 413. The support surface 104 and the inner surface 105 ensure a defined alignment of the motor 41 relative to the drive carrier 100.

[0092] An O-ring 106 made of an elastic elastomer or rubber material can also be arranged between the motor housing 413 and the inner surface 105, for example, as shown, in a groove running circumferentially inside the inner surface 105. This O-ring is elastically clamped there in the radial direction and ensures that the motor housing 413 is held frictionally in place by simply axially inserting it – in Figure 7 in the direction of the arrow to the left – into the recess 101. Furthermore, it can be used to seal the motor 41 against the drive carrier 100. The bearing cover 414 has a receiving opening 418 through which the motor shaft 411 extends. A bearing 419 for rotatably supporting the motor shaft 411 relative to the bearing cover 414 is arranged between the motor shaft 411 and the receiving opening 418. This bearing is designed as a rolling bearing, more precisely as a radial deep groove ball bearing.The receiving opening 418 has an inwardly projecting shoulder portion 418a against which the bearing 419 rests in the direction of the motor axis M and is supported thereon.

[0093] List of reference symbols

[0094] 1 braking device

[0095] 100 drive carriers

[0096] 101 recess

[0097] 102 Opening

[0098] 103 lead

[0099] 104 support surface

[0100] 105 interior surface

[0101] 106 O-ring

[0102] 2 brake discs

[0103] 3 brake caliper

[0104] 31, 32 brake pad

[0105] 33 fastening bolts

[0106] 4 Brake actuator

[0107] 41, 42 Motor (actuator)

[0108] 411. 421 Motor shaft

[0109] 412. 422 gear

[0110] 413. 423 Engine housing

[0111] 414. 424 Bearing cap

[0112] 415. 425 approach

[0113] 416. 426 Flange element

[0114] 417. 427 Screw

[0115] 418 Receiving opening

[0116] 418a shoulder section

[0117] 419 warehouses

[0118] 43 thrust bearings

[0119] 44 Pressure piece

[0120] 5 Adjusting device

[0121] 6 first actuator

[0122] 61 cam disc

[0123] 62 cam disc (integrated with spindle nut 72)

[0124] 63 ball

[0125] 64 Career

[0126] 65 gear

[0127] 66 ball cage

[0128] 67 recess 7 second actuator

[0129] 71 threaded spindle

[0130] 72 spindle nut (integrated with cam disc 62)

[0131] 73 Driver 74 Hub part

[0132] 75 gear

[0133] 76 slot

[0134] 8 Friction element

[0135] 81 Friction surface 9 Counter friction element

[0136] 91 Counter friction surface

[0137] 92 drivers

[0138] 93 spring element

[0139] A Axle R Wheel axle

[0140] V Adjustment direction

[0141] L Air gap

[0142] M motor axle

Claims

PATENT CLAIMS 1. An electromechanical braking device (1) for a motor vehicle, comprising a drive support (100) to which an electric motor (41, 42) and an actuating device (5) are mounted, which is gear-coupled to a motor shaft (411, 421) and by which a braking part (22) is adjustable, wherein the motor (41, 42) has a motor housing (413, 423) in which the axially extending motor shaft (411, 421) is mounted in a front-end bearing cover (414, 424) and projects axially therefrom, wherein the motor housing (413, 423) is fixed to the drive support (100), characterized in that the drive support (100) has a recess (101) in which the motor housing (413, 423) can be received in a form-fitting manner in the axial and radial directions, wherein the motor housing (413, 423) can be clamped at the front against an axial support surface (104) of the recess (101).

2. Braking device according to claim 1, characterized in that the support surface (104) is formed on a projection (103) projecting radially inwards in the recess (101).

3. Braking device according to one of the preceding claims, characterized in that the bearing cover (414, 424) is attached to the end face of the motor housing (413, 423).

4. Braking device according to one of the preceding claims, characterized in that the bearing cover (414, 424) is supported axially against the support surface (104).

5. Braking device according to one of the preceding claims, characterized in that the bearing cover (414, 424) can be clamped between the support surface (104) and the motor housing (413, 423).

6. Braking device according to one of the preceding claims, characterized in that the motor housing (413, 423) has a flange element (417) which is axially spaced from the end face and projects radially beyond the recess (101).

7. Braking device according to one of the preceding claims, characterized in that the motor housing (413) at least partially has a hollow cross-section to which the bearing cover (414) can be positively secured.

8. Braking device according to one of the preceding claims, characterized in that the motor housing (413), the bearing cover (414), and / or the drive carrier (100) comprise a cast part.

9. Braking device according to one of the preceding claims, characterized in that between the recess (101) and the motor housing (413) an elastic Holding element (106) and / or sealing element (106) is arranged.

10. Braking device according to one of the preceding claims, characterized in that the drive carrier (100) has at least two recesses (101).

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