Electromechanical brake device for a motor vehicle

Abstract

The invention relates to an electromechanical brake device (1) for a motor vehicle, comprising an actuator (5) and a brake element (32) connected thereto, which brake element (32) can be adjusted along an axis (A) by means of the actuator (5) and can be brought into braking engagement with a counter brake element (2); wherein the actuator (5) has a first actuator (6) and a second actuator (7) coupled in series therewith; wherein the first actuator (6) has a first rotationally drivable drive wheel (65) and the second actuator (7) has a second rotationally drivable drive wheel (75) coaxial with the first drive wheel; wherein a friction clutch is arranged between the first drive wheel (65) and the second drive wheel (75), which friction clutch comprises two friction elements (8, 9) having coaxial friction surfaces (81, 91), which friction elements can be connected to one another in a frictional fit manner to produce a clutching engagement. In order to reduce the manufacturing and assembly complexity under the conditions of smaller installation space requirements and lighter weight, the invention proposes that the at least one friction element (8, 9) is formed integrally with the first drive wheel (65) or the second drive wheel (75).

Description

Prior Art

[0001] The present invention relates to an electro-mechanical braking device for a motor vehicle, which includes an actuating device and a braking component connected thereto. The braking component is adjustable along an axis by the actuating device and is capable of achieving braking engagement with a mating braking component; wherein, the actuating device has a first actuator and a second actuator connected in series therewith; wherein, the first actuator has a first rotatably driven drive wheel, and the second actuator has a second rotatably driven drive wheel coaxial with the first drive wheel; wherein, a friction clutch is arranged between the first drive wheel and the second drive wheel, and the friction clutch includes two friction elements having coaxial friction surfaces, which can be connected to each other in a frictionally engaged manner to produce a clutch engagement.

[0002] The braking device for the motor vehicle adopts a friction braking structure, in which a braking component that is stationary relative to the wheel to be braked and supported on the chassis forms a braking engagement with a mating braking component that rotates synchronously with the wheel through an actuating device. In the braking engagement state, frictional contact is generated between the braking component and the mating braking component, and the greater the adjusting force applied by the actuating device along the adjusting direction, the greater the generated frictional braking torque.

[0003] A widely adopted structural form is a disc brake, the basic principle of which is well known. The mating braking component is constituted by a brake disc that rotates synchronously with the wheel, and the brake disc is surrounded by a brake caliper on both sides in the axial direction. The braking component, usually a brake lining, can be adjusted along the axial adjusting direction by at least one preferably linear actuator that is supported on the brake caliper in the axial direction and can thus make frictional contact with one axial side of the brake disc, so as to clamp the brake disc in a frictionally engaged manner between the adjusted braking component and another braking component to achieve braking engagement, wherein the other braking component is axially supported on the brake caliper relatively.

[0004] In order to achieve the normal operation and precise response of the brake, in the non-activated state, a defined spacing, i.e., the so-called "air gap", must be set in the adjusting direction between the braking component and the mating braking component. When the brake is activated, the braking component is moved by the actuating device perpendicular to the air gap direction towards the mating braking component until the air gap is overcome and frictional contact is achieved, thereby producing braking engagement.

[0005] To achieve repeatable and precise braking response during driving, it is crucial that in the unactivated state, the air gap must have a defined gap width in the axial adjustment direction. During use, the gap width may increase, for example, due to wear of the brake pads, and corresponding adjustment is required. To adjust the air gap, it is known from German Patent Publication DE10 2017 123 266 A1 that the actuating device has two actuators arranged in series along the adjustment direction. Each actuator has a drive element near the drive end and an output element near the output end, and the output element is linearly adjustable relative to the drive element in the axial adjustment direction. To achieve the adjustment movement, each drive element is provided with a drive wheel, preferably a gear, such as a gear or a similar structure, which is driven by an electric servo motor to rotate about its axis. The rotation of the drive wheel is converted in each actuator into a relative adjustment movement or actuating stroke of the output element relative to the drive element in the axial adjustment direction. In the general prior art, the two drive wheels of the first and second actuators are coaxially arranged on a common axis in the axial adjustment direction.

[0006] Each actuator respectively constitutes a lifting or adjusting device acting axially in the adjustment direction. For example, the actuator can have a lead screw drive device, where the drive element has a lead screw nut and the output element has a threaded lead screw meshing with the lead screw nut, and vice versa. Other structural forms of actuators can also be used, such as those that can include inclined plane bearings, flat cams or cam discs, inclined pin assemblies, etc., which can also convert the rotation of the drive element into a linear adjustment of the output element.

[0007] Since the drive element of the second actuator is coupled to the output element of the first actuator, and the braking element is connected to the output element of the second actuator, by activating the first actuator, the braking element and the second actuator can be linearly adjusted together to achieve braking engagement. By independently adjusting the second actuator, the air gap can be adjusted without relying on the activation of the first actuator. In this way, the first actuator can always operate within the optimal working range.

[0008] Another advantage of the two coupled actuators is that redundant design can be achieved. Therefore, braking engagement can also be generated by the second actuator in principle, even if the second actuator is only used to adjust the air gap during normal operation.

[0009] In order to achieve synchronous rotation of the first drive element and the second drive element during normal operation, so that the second actuator is driven as a whole without adjustment action, it is proposed in the above-mentioned German patent DE 10 2017 123 266 A1 to provide a locking coupling structure between the first drive wheel and the second drive wheel. Thus, the two drive wheels can be coupled at releasable locking positions independent of each other, and these positions can be engaged with each other in a form-fitting manner, so as to achieve reliable torque transmission for synchronization. However, in order to adjust the air gap, it is also necessary to overcome the preset discrete locking positions. The disadvantage in this case is that the air gap can only be adjusted step by step, and thus the continuous wear of the braking element cannot be compensated satisfactorily. In addition, a relatively high driving torque is required to overcome the locking position.

[0010] To overcome the disadvantages of the above-known coupling structure, it is proposed in the unpublished application BE 2022 / 5999 to use a friction clutch that acts continuously in terms of clutch engagement. The friction clutch has friction elements respectively connected to the two drive wheels, and these friction elements have friction surfaces facing each other coaxially for achieving frictional contact during clutch engagement. The friction elements adopt a split structure and are rotationally coupled with the drive wheels. This design results in relatively high manufacturing and assembly complexity, required installation space, and overall weight.

[0011] In view of the above series of problems, the object of the present invention is to reduce the manufacturing and assembly complexity while achieving smaller installation space requirements and lower weight. Summary of the Invention

[0013] This object is achieved according to the present invention by a braking device having the features described in claim 1. Preferred improvements are derived from the dependent claims.

[0014] The present invention relates to an electromechanical braking device for a motor vehicle, which includes an actuator and a braking component connected thereto. The braking component is adjustable along an axis by the actuator and can achieve braking engagement with a mating braking component. Among them, the actuator has a first actuator and a second actuator serially coupled thereto. The first actuator has a first rotatably drivable drive wheel, and the second actuator has a second rotatably drivable drive wheel coaxial with the first drive wheel. Among them, a friction clutch is provided between the first drive wheel and the second drive wheel. The friction clutch includes two friction elements having coaxial friction surfaces, and they can be connected to each other in a friction-fit manner to produce clutch engagement. According to the present invention, at least one friction element is integrally formed with the first drive wheel or the second drive wheel.

[0015] In the following text, the first and second drive wheels are also jointly referred to as two drive wheels, or simply as drive wheels for short. One drive wheel has a friction element, and the other drive wheel has a corresponding friction element that mates with it, which can also be referred to as a mating friction element. Therefore, the friction element and the mating friction element are jointly referred to as friction elements in the following text. In this definition, the friction element is the part of the friction clutch that has a friction surface.

[0016] The drive wheels can be designed as gears respectively, such as spur gears, or as pulleys, synchronous pulleys, or worm gears. Generally speaking, they can be referred to as gear elements for coupling the drive torque from an electric servo motor into the actuator.

[0017] According to the present invention, the friction element is structurally designed to be integrally formed with the drive wheel. Preferably, the drive wheels on both sides can be correspondingly designed as an integral structure. This integral structure form has the advantage of lower manufacturing costs, and the reduction in the number of components simplifies the assembly process. In addition, a more compact structure form can be achieved, thereby reducing the required installation space and weight.

[0018] A preferred improvement can integrate the friction element with the drive wheel. Thus, functional elements for coupling the drive torque, such as a toothed ring or a similar structure, can be integrally integrated with the friction element on a continuous integral component. This design is particularly beneficial for achieving a compact structure and lightweight. Since no connecting structure is required, the manufacturing process can be further simplified, and the load-bearing capacity is also improved.

[0019] It can be set that the drive wheel has a casting. The casting can be a component injection-molded from a thermoplastic material, which can be selectively fiber-reinforced to increase strength, or die-cast from a metal material such as aluminum, magnesium, or zinc alloy. The friction element can be integrally formed on the drive wheel during the casting process. Thus, an economical manufacturing method, as well as a weight-saving and assembly-friendly structure form, can be achieved.

[0020] It is also feasible that the drive wheel is composed of interconnected castings, for example, made by a two-component injection molding process, where the friction element can be made of a material different from other functional components of the drive wheel, such as a hub or a rotating toothed ring. It is also conceivable and achievable that different functional elements of the drive wheel can also be integrally connected by material integration, so as to form an integral component in the injection molding process. For example, a plastic toothed ring can be overmolded on the friction element, or a hub component made of plastic material can be injection-molded into the toothed ring, and the hub component is connected to the friction element.

[0021] As an alternative, it can also be set that the drive wheel is integrally or monolithically manufactured by a subtractive machining method, such as machined from steel. A combined machining method can also be used; for example, subsequent subtractive machining can be performed on a casting or a stamping.

[0022] It can be set that the drive wheel has a sintered part. Through the sintering method, complex geometric structures and shapes can be manufactured economically in mass production.

[0023] It can be set that the drive wheel has a gear, such as a spur gear. The gear can have a tooth ring that coaxially surrounds the hub component on the outside. According to the present invention, the friction element can be integrally formed or molded with the tooth ring and the hub component. The manufacturing method can be a casting method, such as a plastic injection molded part, or a metal casting, and additionally or alternatively a subtractive machining method can be used.

[0024] In order to optimize the surface performance of the functions required by the drive wheel, the drive wheel that is integrally structured or integrally molded according to the present invention can have a surface coating and / or a surface structure in at least some regions. For example, a surface coating, such as an antifriction plastic coating, can be applied to the tooth region of the gear to optimize the rolling and wear performance and reduce the noise emission. By performing targeted modification treatment in the friction surface region - such as setting a specific roughness and / or coating a coating with an adapted friction coefficient and wear resistance (such as surface modification means such as hard coatings or local heat treatment), an ideal friction pair with predetermined adhesion-friction characteristics can be formed.

[0025] Preferably, it can be set that the friction element has a conical structure. At least some regions of one of the friction elements have a conical outer surface that tapers in the axial adjustment direction to form a friction surface. The other friction element, that is, the corresponding mating friction element, has a conical opening that has a conical inner surface adapted to the above outer surface and forms another friction surface. These friction surfaces have the same cone angle and are matched in terms of diameter and axial length so that frictional surface contact can be generated when the activation force of the clutch is applied in the axial adjustment direction. The advantage of the conical friction surface is that: by setting the cone angle, a definite force transmission ratio can be generated between the axial activation force or preloading force applied between the friction elements and the normal force generated between the conical friction surfaces. This force transmission ratio determines the circumferential frictional force, and the circumferential frictional force is directly related to the transmission efficiency of the coupling torque. In this process, a relatively high force transmission ratio can be achieved through a relatively small cone angle, so that a relatively high frictional pressing force is generated between the conical friction surfaces, and a correspondingly high coupling torque can be achieved with a relatively small activation force or preloading force.

[0026] The cone angle is preferably set such that self-locking does not occur between the friction surfaces. This can ensure reliable separation of the clutch. Half of the cone angle α / 2 should be greater than the arctangent value of the static friction coefficient μ acting between the friction surfaces. That is: α / 2 > arctan(μ). Particularly preferably, half of the cone angle α / 2 should be greater than 7°, and more particularly preferably greater than 10°.

[0027] In the above-described embodiment, it can be set that the friction element has a truncated cone structure. The friction element has a truncated cone that axially protrudes in the adjustment direction, and its annularly surrounded conical outer surface constitutes a friction surface. Another friction element is provided with an axially limited conical opening that is adapted to the truncated cone in a form-fitting manner and has an annular conical inner surface that constitutes another friction surface. For frictional coupling engagement, the truncated cone is axially inserted into the conical opening until the conical friction surfaces come into contact with each other, i.e., they are in frictional contact with each other. The friction surface can have the shape of a coaxial annular cone surface, which is integrally formed or integrally molded with the drive wheel according to the present invention. Thus, the lead screw drive of one of the actuators can pass through the drive wheel coaxially with the friction surface, enabling a particularly compact structural form to be achieved.

[0028] Advantageously, the friction element has end faces that are axially spaced apart from each other. The truncated cone has an axial end face at the front end of its conical contraction end. The conical opening also has an axial end face at its inner end, which axially defines the conical inner surface, in other words, constitutes the axial bottom surface of the conical opening, and this bottom surface is axially located on the side opposite to the front end face of the truncated cone. The design and sizing of the conical friction surface are such that: in the frictional engagement of the clutch, there is an axial spacing between the two axial end faces.

[0029] As an alternative or supplement to the above-described embodiment, it can be set that the friction surface has a planar structure. Here, the friction element and its corresponding mating friction element have flat friction surfaces that form an axial plane similar to a disc clutch at least in part.

[0030] In the present invention, a friction clutch is arranged between the drive wheels. The friction clutch includes a friction element that is torque-coupled to one of the drive wheels and a corresponding mating friction element that is torque-coupled to the other drive wheel. The friction element can achieve frictional engagement with the mating friction element at any relative angular position. In this process, a force-fit connection is formed, rather than the form-fit locking connection in the prior art described at the beginning. Therefore, the relative position between the two drive wheels can be continuously adjusted. Thus, uniform and continuous adjustment of the second actuator relative to the first actuator can be achieved, and the air gap can be continuously adjusted. This is particularly advantageous for uniformly tracking the optimal operating point of the braking device, thereby following the continuous wear of the braking components during operation, i.e., the continuous wear of the brake linings. Therefore, improved response performance, higher operating reliability, and higher operating comfort can be achieved.

[0031] Compared with the locking coupling mentioned at the beginning, a further advantage is that when activating and releasing the clutch device, there is basically no need for axial relative movement between the clutch elements in engagement. For example, in a conventional solution, in order to achieve and release the lockable form-fit, relative movement between the drive wheels or between the locking elements must occur. In contrast, according to the present invention, through the applied axial activation force, the pure force transmission between the friction element and its mating friction element can be simply set, and there is no need for axial relative movement between the friction element and the mating friction element. Therefore, a clutch device with a simpler structure and more reliable operation can be achieved.

[0032] It can be set that the friction clutch has a definable engagement torque. This engagement torque represents the maximum differential torque that can be transmitted in a force transmission manner through frictional engagement between the friction elements during engagement. When this engagement torque is exceeded, the clutch device slips, causing relative torsion between the two drive wheels. An advantage here is that the friction clutch according to the present invention slips continuously in a sliding manner, thereby achieving an improved and uniform readjustment of the air gap. In addition, there is no need to consider and absorb the axial compensation movement of the locking elements as in the existing locking coupling structures.

[0033] Advantageously, the friction elements are arranged coaxially. This coaxial arrangement corresponds to the coaxial arrangement of the drive wheels. The friction elements can be arranged in the end regions of the two drive wheels facing each other, and this structural form is simple and provides a compact structure.

[0034] Preferably, it can be set that the friction elements are pre-compressed against each other. During engagement, the friction elements are preferably pre-compressed against each other in an elastic or flexible manner. During this process, the friction surfaces in the frictional engagement are pressed against each other by a preset axial preloading force. This preloading force can also be referred to as the activation force of the clutch. Preferably, elastic preloading elements, such as spring elements or similar structures, can be provided to generate this preloading force. The engagement torque of the friction clutch is determined by the activation force applied perpendicular to the frictional contact surface, that is, the force in the axial direction acting between the friction elements, and this engagement torque increases with the increase of the preloading force (activation force). The advantage of this solution is that the engagement torque can be simply set by the preloading force applied by the preloading element. For example, in the case of using an axially compressible elastic spring element such as a compression spring, the applied preloading force can be simply set and adjusted by the spring stiffness and the spring compression amount.

[0035] It can be set that the one or two friction elements are arranged in the first drive wheel or the second drive wheel. In this way, for example, one drive wheel can be designed to be substantially drum-shaped, so that the friction element or the mating friction element can be arranged in the internal space surrounded by the rotating gear or the toothed ring. Thereby, a structurally compact and externally impact-protected structure can be achieved. For example, the drive wheel of the first actuator can have a conical friction element that axially engages in a mating friction element formed as an inner conical structure, and the mating friction element is at least partially arranged within the second drive wheel.

[0036] Particularly in the last-mentioned embodiment above, a particularly compact structure can be achieved, that is, the drive wheel is arranged within the axial extension of the actuator without being connected in a uniaxial extension manner.

[0037] Preferably, the one or two friction elements have friction linings. The friction element can, for example, have a metal matrix, such as being made of steel or metal casting. To avoid metal-to-metal contact, a coating or lining (such as using sintered metal, ceramic friction material, composite material, etc.) can preferably be applied to form a friction pair with a defined frictional force. Thereby, a defined and reproducible coupling torque can be ensured.

[0038] It can be set that the actuator has a lead screw drive. In this structure, the threaded lead screw engages with the lead screw nut in a known manner, and relative rotational drive is achieved through a drive wheel connected to the threaded lead screw or the lead screw nut. The lead screw nut can form the drive element of the actuator near the drive end, and the threaded lead screw can form the output element near the output end, and this output element can be linearly adjusted relative to the drive element; vice versa.

[0039] According to the present invention, it can preferably be set that the lead screw thread is integrally formed with the drive wheel, and particularly preferably, it is a one-piece structure. In this way, in addition to the function of the friction element, the function of the lead screw nut in the lead screw drive can also be integrally designed with the drive wheel. Thereby, the complexity of manufacturing and assembly can be further reduced, and a more space-saving and weight-saving structural manner can be achieved.

[0040] It can be set that the actuator has a ball ramp assembly, a V-belt pulley assembly, or an inclined pin assembly. In the ball ramp assembly, also known as a ramp bearing, the drive element and the output element preferably have inclined slots or ramp cam disks inclined towards the axis, and rolling balls are arranged therebetween. When the balls roll on the ramp, relative rotation causes the output element to axially displace relative to the drive element. In a known inclined pin assembly, the inclined pins are arranged between the drive element and the output element and are supported in the circumferential direction, so that during relative rotation, the inclined pins tilt towards the axis to different degrees according to the direction of movement, and thereby the distance between the drive element and the output element can also be adjusted.

[0041] It can be set that the drive wheel has at least one functional element of the actuator. Thus, the functional elements of one or two actuators can be integrally structured into the drive wheel of the present invention. For example, the drive wheel can integrally or integrally molded include: the internal thread of the lead screw nut, the raceway of the ball ramp assembly, the V-shaped part of the V-belt pulley assembly, the support element of the tilt pin assembly, and additionally or alternatively include the thread of the lead screw nut, etc. Thus, according to the present invention, the integrally formed or preferably integrally molded drive wheel can advantageously realize multiple functions. This not only saves installation space and weight, but also significantly reduces the manufacturing complexity.

[0042] Two actuators with the same function, for example, two lead screw drives, can be combined as the first and second actuators in the actuating device. It is also possible to combine two different structural forms with each other, for example, using the ball ramp assembly as the first actuator and the lead screw drive as the second actuator for adjusting the air gap. Here, the characteristic performance of each structural form can be optimally utilized. For example, a non-linear adjustment characteristic can be achieved with lower complexity through the ball ramp assembly, and / or at least partially has a self-locking performance, and / or realizes a defined dead point position or extended position, thereby obtaining a defined adjustment stroke. To achieve these performances, the air gap needs to be precisely set to a certain extent, which cannot be achieved by the locking coupling in the prior art, but can be easily achieved by the friction clutch according to the present invention.

[0043] In a method for operating an electromechanical braking device, the braking device has an actuating device that includes a first actuator and an actuator coupled in series therewith, and acts on a braking part that can achieve braking engagement with a mating braking part along the axial direction; wherein, the first actuator has a first drive wheel that can be rotationally driven, and a first drive torque can be applied thereto for activation; the second actuator has a second drive wheel that can be rotationally driven, the second drive wheel is coaxial with the first drive wheel, and a second drive torque can be applied thereto for activation; a clutch device is arranged between the first drive wheel and the second drive wheel, the clutch device can be designed as a friction clutch, and has a settable coupling torque; when the coupling torque is exceeded, the first drive wheel slips relative to the second drive wheel in a sliding manner; wherein, when the first actuator needs to be activated, the first drive wheel and the second drive wheel are driven synchronously, so that the second actuator remains in an inactive state; when the second actuator needs to be activated, the second drive wheel is driven while the first drive wheel remains stationary, so that the friction clutch slips and the first actuator remains in an inactive state.

[0044] The above-mentioned features mentioned in the context of the braking device of the present invention can be used alone or in combination to implement the operation method.

[0045] To adjust the first actuator, a drive torque can be coupled to the first drive wheel by a first electric servo motor, while the second actuator is correspondingly driven by a second electric servo motor.

[0046] During normal braking operation, the first drive wheel and the second drive wheel rotate synchronously. This can be achieved in one of two ways: On the one hand, the first and second drive wheels can be driven by the first and second servo motors with a synchronous drive torque; on the other hand, when driving the first drive wheel, as long as the transmitted drive torque is lower than the coupling torque, the second drive wheel can be synchronously driven by the clutch device. In this operating mode, the second actuator remains deactivated and rotates together with the braking element as a non-activated unit.

[0047] During operation, to adjust the air gap, the clutch device can slip in a continuous and uniform sliding manner when the coupling torque is exceeded. For example, the drive wheel of the first actuator can be stopped by a brake or corresponding braking of the first drive motor; at the same time, a second drive torque greater than the coupling torque is applied to the second drive wheel by the second drive motor. Thereby, the second drive wheel twists relative to the first drive wheel, and the second actuator is activated to achieve continuous fine adjustment of the air gap, so as to be able to optimize the compensation for the continuous wear of the braking components or brake linings during operation.

[0048] It can be set that the first drive wheel and the second drive wheel are synchronously driven by friction coupling in a torque-matching manner. In this case, it is not necessary to synchronously drive the two drive wheels by the servo motors. And the potential differential torque can be balanced within the specified tolerance range.

[0049] Preferably, it can be set that a higher coupling torque is set when the first actuator is activated, while a lower coupling torque is set when the second actuator is activated. The first actuator is activated by the synchronous drive of the first and second drive wheels. The friction element and the mating friction element are preloaded with each other by the elastic force of the spring element, and the adjusting force of the first actuator additionally acts in the opposite direction of this elastic force. Thereby, a relatively high coupling torque is achieved. And if only the second drive wheel is rotated to adjust the air gap, only the spring force acts, so a lower coupling torque is set. This makes the air gap adjustment more convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Advantageous embodiments of the present invention will be described in more detail below with reference to the accompanying drawings, in which:

[0051] Figure 1 shows a schematic perspective view of a braking device according to the present invention;

[0052] Figure 2 shows Figure 1 a side view of the shown braking device;

[0053] Figure 3 is shown separately Figure 1 a schematic perspective view of an actuator of a braking device according to the present invention;

[0054] Figure 4 shows along Figure 1 a Q-Q cross-sectional view of the braking device shown;

[0055] Figure 5 is shown separately Figure 1 a schematic perspective view of a first actuator of the braking device shown;

[0056] Figure 6 shows a schematic sectional perspective view of the corresponding Figure 4 actuator according to the present invention;

[0057] Figure 7 shows Figure 6 a locally enlarged view in DETAILED DESCRIPTION

[0058] In the figures, the same parts are always denoted by the same reference signs and are thus usually only discussed or mentioned once when they first appear.

[0059] Figure 1 shows a braking device as a whole according to the present invention, which is configured as a disc brake. The latter includes a brake disc 2, which forms a mating braking part in the present invention and is connected to a vehicle wheel not shown in this figure and is rotatable about a wheel axis R. A brake caliper 3 surrounds two axial end faces of the brake disc 2.

[0060] The brake disc 2 is herein a non-ventilated brake disc made of solid material. As an alternative, the brake disc 2 can also be configured as an internally ventilated brake disc.

[0061] An electric braking actuator 4 according to the present invention is connected to the brake caliper 3, Figure 3 is shown in a separate schematic perspective view in Figures 4 to 7 and is described in detail therein.

[0062] The braking actuator 4 includes an actuator 5, which extends axially along an axis A parallel to the wheel axis R, and this axis A also indicates the adjustment direction V of the actuator 5.

[0063] As shown in Figure 4As seen in the sectional view along axis A shown, the brake disc 2 is axially arranged between two brake linings 31 and 32. One of the brake linings 31 is fixedly supported on the brake caliper 3 on the side away from the brake actuator 4. The other brake lining 32, which constitutes the braking component in the present invention, is mounted on the actuating device 5. The brake lining 32 can be adjusted by the actuating device in the axial adjustment direction V defined by the axis A towards the brake disc 2 to achieve braking engagement.

[0064] In the non-activated state of the braking device 1, there is an axial air gap L between the brake disc 2 and the adjustable brake lining 32, and this air gap is schematically drawn in Figure 4 at an enlarged scale.

[0065] The structure of the actuating device 5 is shown in Figure 4 and is schematically illustrated in a partially sectional perspective view along axis A in Figure 6 . Figure 7 Shows Figure 6 an enlarged partial view in

[0066] The actuating device 5 includes a first actuator 6 having an inclined plane bearing and a second actuator 7 serially coupled thereto in the direction of axis A. The second actuator has a lead screw drive device.

[0067] The first actuator 6 in the illustrated embodiment is configured as an inclined plane bearing, which includes a cam disc 61 near the drive end and a cam disc 62 near the output end. The cam disc 61 is axially supported in the brake actuator 4 and rotates together with it. There are balls 63 arranged between the cam discs 61 and 62. As shown in the schematic single view of Figure 5 , the cam discs 61 and 62 have ramp-shaped raceways 64, which are oppositely arranged in the direction of axis A and are inclined with respect to axis A, and the balls 63 can roll therebetween. Figure 5 Rotation of the upper output end cam disc 62 relative to the stationary drive end cam disc 61 (as shown by the curved arrow) in Figure 4 will cause a linear movement of the output end cam disc 62 in the adjustment direction V parallel to axis A. Thus, by activating the first actuator 6, the brake lining 32 can be brought into the braking engagement state, as shown in

[0068] The cam disc 62 is connected to a coaxial gear 65, which has a spur gear structure with an externally coaxially rotating tooth ring 650 and constitutes a driving wheel in the present invention. In the illustrated embodiment, the cam disc 62 and the gear 65 are integrally formed. The gear 65 is configured according to the present invention, and its details will be further explained later.

[0069] The gear 65 is in driving engagement with the first electric servo motor 41 through the gear ring 650. This motor can rotationally drive the drive cam disk 62, thereby activating the first actuator 6.

[0070] In the illustrated embodiment, the second actuator 7 is configured as a lead screw drive device, and its output end has a lead screw 71, which engages with the internal thread of a lead screw nut 72 near the drive end. This internal thread is provided in the output end cam disk 62 of the first actuator 6, and this cam disk 62 is integrally formed with the gear 65. Therefore, the functions of the output end cam disk 62 and the drive end lead screw nut 72 are structurally integrated into the gear 65.

[0071] The gear 65 is rotatably mounted in the brake actuator 4 and is axially supported (fixed) at the same time.

[0072] The gear 75 can be configured as a spur gear similar to the gear 65, with an encircling gear ring 750 on its outside and is coaxially arranged with the former. The gear 75 is in driving engagement with the second electric servo motor 42. This motor rotationally drives the drive lead screw 71, thereby activating the second actuator 7.

[0073] The lead screw 71 is axially connected to a thrust member 44 through a thrust bearing 43, such as an axial roller bearing shown in the figure. The movable brake lining 32 is mounted on this thrust member 44, as Figure 4 shown. The thrust member 44 can also be referred to as a piston.

[0074] The clutch device according to the present invention includes a friction element 8, which extends from the cam disk 62 in the form of a coaxial conical projection towards the second actuator 7. This conical projection is provided with a conical friction surface 81 on its outside. According to the present invention, the friction element 8 is integrally formed with the gear 65 and is integrally molded in the illustrated embodiment. As described above, the cam disk 62 and the lead screw nut 72 can also be integrally molded with this structure.

[0075] In the clutch engaged state, the friction element 8 is coupled with the mating friction element 9 in a friction fit manner. During this process, the conical projection is axially inserted into the corresponding conical opening in the mating friction element 9, and a conical friction surface 91 is provided on the inner conical surface of this opening. In the clutch engaged state, the friction surface 81 and the mating friction surface 91 are in mutual contact in a friction fit manner, as Figure 6 clearly shown in.

[0076] According to the present invention, the mating friction element 9 is integrally formed with the gear 75 and is integrally molded in the illustrated embodiment.

[0077] A spring element 93 is provided between the gear 75 and the fixed part of the brake caliper 3. The axial elastic force exerted by the spring element 93 elastically preloads the mating friction element 9 relative to the friction element 8, as Figure 6 shown by the downward-pointing arrow in. In other words, the spring element 93 generates the activation force of the friction clutch. This activation force is converted into an increased normal force through a structure with a gently converging taper angle, and this normal force is the force that preloads between the friction surfaces 81 and 91 in the clutch engaged state. Thus, a defined clutch torque is generated by the friction clutch composed of the friction element 8 and the mating friction element 9 according to the present invention.

[0078] The friction element 8 is designed as a frustum of a cone and has a flat axial end face 82, which defines the frustum in the adjustment direction, and this end face is Figure 6 at the top in. The tapered opening of the mating friction element 9 also has a flat axial end face 94, which forms the bottom of the tapered opening and is also located Figure 6 above. In the clutch engaged state, that is, when the friction surfaces 81 and 91 are in force-fit contact with each other, these two axially opposed end faces 82 and 94 maintain a certain axial distance.

[0079] To activate the brake device 1, the gears 65 and 75 rotate synchronously, causing the first actuator 6 to perform a working stroke in the adjustment direction V, so that the brake lining 32 crosses the air gap L and engages with the brake disc 2 for braking. The synchronous drive of the gears 65 and 75 can be achieved by the drive speeds of the synchronous servo motors 41 and 42, or by driving only one of the servo motors 41 or 42 while allowing the other servo motor 42 or 41 to rotate in a follow-up manner in an inactive state. In this case, the clutch engagement achieved by the friction fit between the friction element 8 and the mating friction element 9 can ensure the synchronous rotation of the gears 65 and 75.

[0080] To adjust the width of the air gap L, the gear 65 can be stopped or locked, for example, by correspondingly activating the first servo motor 41. Then, the gear 75 is twisted relative to the gear 65 by the second servo motor 42, so that the friction clutch continuously slips in a sliding manner. Correspondingly, the second actuator 7 will perform uniform adjustment, so that the width of the air gap L can also be continuously set and adjusted, for example, to compensate for the wear of the brake lining 32.

[0081] Since the friction element 8 and the mating friction element 9 are arranged completely or at least partially inside the gears 65 and 75, a particularly compact structural form can be achieved.

[0082] Figures 1 to 7The braking device shown is configured as a floating caliper brake, also known as a sliding caliper brake. Here, the brake lining 32 is pressed against the brake disc 2 by the thrust member 44, while the brake lining 31 is pressed against the brake disc 2 by the brake caliper 3 that is movable along the axis A direction relative to the brake disc 2. As an alternative, the solution of the present invention can also be used in a fixed caliper brake.

[0083] List of reference numerals:

[0084] 1 Braking device

[0085] 2 Brake disc

[0086] 3 Brake caliper

[0087] 31, 32 Brake linings

[0088] 4 Brake actuator

[0089] 41, 42 Servo motors

[0090] 43 Thrust bearing

[0091] 44 Thrust member

[0092] 5 Actuating device

[0093] 6 First actuator

[0094] 61 Cam disc

[0095] 62 Cam disc (integrally formed with the lead screw nut 72)

[0096] 63 Ball

[0097] 64 Raceway

[0098] 65 Gear

[0099] 650 Tooth ring

[0100] 7 Second actuator

[0101] 71 Threaded lead screw

[0102] 72 Lead screw nut (integrally formed with the cam disc 62)

[0103] 74 Hub component

[0104] 75 Gear

[0105] 750 Tooth ring

[0106] 8 Friction element

[0107] 81 Friction surface

[0108] 82 End face

[0109] 9 Pairing friction elements

[0110] 91 mating friction surfaces

[0111] 92 Ratchet teeth

[0112] 93 Spring elements

[0113] 94 End faces

[0114] A Axis

[0115] R Wheel axis

[0116] V Adjustment direction

[0117] L Air gap

Claims

1. An electro-mechanical braking device (1) for a motor vehicle, comprising an actuating device (5) and a braking component (32) connected thereto, the braking component (32) being adjustable along an axis (A) by means of the actuating device (5) and being capable of effecting a braking engagement with a mating braking component (2); Among them, The actuating device (5) has a first actuator (6) and a second actuator (7) coupled in series therewith; wherein the first actuator (6) has a first rotatably driven drive wheel (65), and the second actuator (7) has a second rotatably driven drive wheel (75) coaxial with the first drive wheel; wherein a friction clutch is arranged between the first drive wheel (65) and the second drive wheel (75), the friction clutch comprising two friction elements (8, 9) having coaxial friction surfaces (81, 91), which are capable of being connected to one another in a frictionally engaged manner to effect a clutch engagement, characterized in that: At least one friction element (8, 9) is integrally formed with the first drive wheel (65) or the second drive wheel (75).

2. The braking device according to claim 1, characterized in that, The friction element (8, 9) is integrally formed with the drive wheel (65, 75).

3. The braking device according to any one of the preceding claims, characterized in that, The drive wheel (65, 75) has a cast component or a sintered component.

4. The braking device according to any one of the preceding claims, characterized in that, The drive wheel (65, 75) has a gear (65, 75).

5. The braking device according to any one of the preceding claims, characterized in that, The drive wheel (65, 75) has a surface coating and / or a surface structure at least in part of the area.

6. The braking device according to any one of the preceding claims, characterized in that, The friction element (8, 9) has a conical structure.

7. The braking device according to any one of the preceding claims, characterized in that, The friction element (8, 9) has a frustoconical structure.

8. The braking device according to any one of the preceding claims, characterized in that, The friction element (8, 9) has end faces (82, 94) spaced apart from one another axially.

9. The braking device according to any one of the preceding claims, characterized in that, The drive wheel (65, 75) has at least one functional element of the actuator (6, 7).

10. The braking device according to any one of the preceding claims, characterized in that, The friction surface has a planar structure.

11. The braking device according to any one of the preceding claims, characterized in that, The friction elements (8, 9) are pre-compressed against one another.

12. The braking device according to any one of the preceding claims, characterized in that, At least one friction element (8, 9) has a friction lining.

13. The braking device according to any one of the preceding claims, characterized in that, The actuator (7) has a spindle drive device.

14. The braking device according to any one of the preceding claims, characterized in that, The actuator (6) has a V-belt pulley assembly, a ball ramp assembly or an inclined pin assembly.

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