WO2023151740A1

WO2023151740A1 - Recoil brake for an actuator, and actuator comprising a recoil brake

Info

Publication number: WO2023151740A1
Application number: PCT/DE2023/100023
Authority: WO
Inventors: Maximilian Bossecker
Original assignee: Schaeffler Technologies AG & Co. KG
Priority date: 2022-02-11
Filing date: 2023-01-16
Publication date: 2023-08-17
Also published as: DE102022103250B4; DE102022103250A1

Abstract

The invention relates to a recoil brake (1) for an actuator (35), said recoil brake comprising: a coupling unit (2) which is designed, when closed, to couple an output unit (13) of the actuator (35) to a housing (38, 42) of the actuator (35) in a torque-resistant manner; a spring unit (3) which is designed to close the coupling unit (2) when the actuator (35) is in a drive-free state; and an actuating unit (4) which is designed to open the coupling unit (2) when the actuator (35) is in a driven state, the actuating unit (4) comprising a ramp pinion (19), that has a first ramp geometry (27), and a ramp sleeve (27), that has a second ramp geometry (31), the ramp pinion (19) being designed to be coupled to a drive unit (26) of the actuator (35) in a torque-transmitting manner and the ramp sleeve (20) being designed to be coupled to the output unit (13) of the actuator (35) in a rotationally fixed but axially displaceable manner, the first ramp geometry (27) and the second ramp geometry (31) each having ramp-like guide surfaces (28, 32) which cooperate directly or indirectly in such a way that a rotation of the ramp pinion (19) causes an axial displacement of the ramp sleeve (20) counter to a spring force of the spring unit (3). The invention also relates to an actuator (35) comprising a recoil brake (1) according to the invention.

Description

Return brake for actuator and actuator with return brake

The present invention relates to a reverse brake for an actuator, in particular an electromechanical actuator and an actuator with such a reverse brake.

State of the art

Reverse brakes or backstops are well known in the prior art. For example, such brakes can be activated in the rear axle steering of a vehicle to reduce the duty cycle, in the event of a fault or in the event of vibrations, as described in DE 10 2019 219 392 A1, for example. Furthermore, return brakes can be used in steering actuators or chassis actuators, where they act on the output side of the actuator. DE 10 2017214 284 B4, for example, discloses an electromagnetically actuated reverse brake, in which a frictional connection is achieved by a radially actuated pin. A considerable amount of force can be required to generate a braking effect. Other radially acting return brakes are disclosed, for example, in US Pat. No. 10,858,043 B2 and WO 2020/080832 A1.

Other reverse brakes are actuated electromagnetically, e.g. by pulling an armature in the axial direction onto a counter surface, thus generating a frictional torque proportional to the attraction force.

It has now been found that there is a further need to improve a known recoil brake for an actuator, in particular to provide a rotational recoil brake that can be actuated independently of the direction of rotation, is compact, low-noise and inexpensive, and allows universal use.

Against this background, it is an object of the present invention to provide an improved reverse brake for an actuator, in particular to provide a rotary reverse brake that can be actuated independently of the direction of rotation, is compact, low-noise and inexpensive, and allows universal use. Disclosure of Invention

These and other objects that may be mentioned or recognized by a person skilled in the art upon reading the following description are solved by the subject-matters of the independent claims. Advantageous embodiments and developments can be found in the dependent claims and the following description.

The reverse brake according to the invention for an actuator, in particular for an electromechanical actuator, has a clutch unit, a spring unit and an actuating unit. The clutch unit is set up to couple an output unit of the actuator to a housing of the actuator in a torque-proof manner in a closed state. The spring unit is set up to close the clutch unit when the actuator is in a non-driven state, and the actuating unit is set up to open or release the clutch unit when the actuator is in a driven state. The actuation unit has a ramp pinion with a first ramp geometry and a ramp sleeve with a second ramp geometry, wherein the ramp pinion is designed to be coupled in a torque-transmitting manner to a drive unit of the actuator and the ramp sleeve is designed to be non-rotatably and axially displaceable with the output side of the actuator to be coupled. The first ramp geometry and the second ramp geometry each have ramp-like guide surfaces that interact directly or indirectly in such a way that rotating the ramp pinion causes an axial displacement of the ramp sleeve against a spring force of the spring unit.

In addition, the axial displacement of the ramp sleeve, in particular in the direction of the spring force of the spring unit, can cause the ramp pinion to rotate. If the first ramp geometry and the second ramp geometry interact directly, the respective ramp-like guide surfaces are in contact with one another, in particular in sliding and/or frictional contact. Alternatively, if the respective ramped guide surfaces of the first ramp geometry and the second ramp geometry cooperate indirectly, the respective ramped guide surfaces are in operative contact via at least one further element arranged between them. In particular, the ramp pinion can also be set up to be coupled in an axially fixed manner to the drive unit of the actuator. The advantage of the solution according to the invention lies in particular in the fact that the reverse brake is opened solely by the drive side of the actuator and is released independently of a drive direction of rotation, ie in both directions of rotation of the ramp pinion. The actuation of the reverse brake by the drive side of the actuator makes it possible to dispense with a separate control unit for the reverse brake. As a result, the number of components and the required installation space of the reverse brake can be reduced, as a result of which the reverse brake has a particularly compact design.

Furthermore, the return brake can also be closed independently of a so-called reverse direction of load rotation on the output side, ie in both directions of rotation of the ramp pinion. In addition, the return brake is inexpensive and/or versatile or universally applicable.

In other words, one can say that the actuation unit has a drivable or driven ramp pinion with an essentially complementary ramp sleeve that is assigned to the output side. The ramp pinion is in particular set up to be driven in rotation by a drive torque, as a result of which the ramp pinion and the ramp sleeve rotate relative to one another, which leads to an axial displacement of the ramp sleeve. This axial displacement, which is caused in particular by driving the ramp pinion, serves to open or release the clutch unit. Furthermore, the spring unit is designed and/or arranged in such a way that it causes a spring force that closes the clutch unit. It can therefore be said that the spring force of the spring unit counteracts the axial displacement of the ramp sleeve to release the clutch unit.

According to one embodiment, the ramp-like guide surfaces extend from an inner diameter to an outer diameter of the respective ramp geometry. In particular, the ramp-like guide surfaces are arranged in a circumferential direction of the ramp geometry, more particularly distributed substantially equally, the ramp-like guide surfaces of the first and second ramp geometry arranged parallel to one another being set up to be in direct or indirect operative contact in the axial direction. In the case of direct operative contact, the ramp-like guide surfaces of the first ramp geometry and the ramp-like guide surfaces of the second ramp geometry are in direct contact with one another, in particular in sliding contact. In the case of an indirect active contact, there is between the ramp-like guide surfaces of the first ramp geometry and the ramp-like guide surfaces of the second ramp geometry at least one rolling body is arranged, wherein the ramp-like guide surfaces of the first ramp geometry are at least partially in rolling contact with the at least one rolling body, and the ramp-like guide surfaces of the second ramp geometry are also at least partially in rolling contact with the at least one rolling body. Furthermore, the ramp pinion and/or the ramp sleeve can each have a connection geometry that is set up to couple the ramp pinion to the drive side or the ramp sleeve to the output side, at least in a torque-transmitting manner.

According to one embodiment, the ramp-like guide surfaces are essentially in the form of screw threads. As a result, the ramp-like guide surfaces have a gradient that can be specified in an axial travel per revolution, e.g. in mm/rev. A ramp angle thus becomes flatter as the reaming diameter increases, i.e. from the inner diameter to the outer diameter. In other words, one can say that the slope, and the resulting ramp angle, of the ramp-like guide surfaces, which are designed essentially in the form of a screw thread, is greater on the inner diameter than on the outer diameter. Therefore, the gradient of the ramp-like guide surfaces is determined in particular as a mean value. In particular, this average slope can be determined using an average friction diameter, which is calculated as follows:

2 (outer diameter ³ - inner diameter ³ ) mean reaming diameter = - x

3 (outer diameter ^{2 -} inner diameter ² ) (1)

According to one embodiment, the first ramp geometry and/or the second ramp geometry have at least one cambered, ramp-like guide surface. In particular, at least one ramp-like guide surface is convex or crowned when viewed in cross section. The crowning has its so-called high point in the calculated mean friction diameter. Thus, the crowning makes it possible to compensate for tolerance-related shape deviations of the ramp-like guide surfaces, especially when new, which lead to a deviation from the calculated average friction diameter, and thus ensure proper functioning of the actuating unit.

According to one embodiment, the ramp pinion and/or the ramp sleeve has at least one end stop which is set up to limit relative twisting between the ramp pinion and the ramp sleeve. The end stop ensures that the ramp pinion and the ramp sleeve are always in active contact and the operating unit is therefore always functional. According to a further embodiment, the at least one end stop is designed as a rotary limiter for the relative twisting between the ramp pinion and the ramp sleeve, or as an axial limiter for the axial displacement (of a disengagement path) of the ramp sleeve. The rotary limitation can be designed in particular as at least one, in particular several, end stop fingers. The end stop finger(s) can preferably be formed integrally in one piece with the respective ramp geometry. The axial limitation can in particular be designed as a stop which extends in the radial direction and in particular essentially runs all the way around, which is positioned in such a way that it limits the axial displacement of the ramp sleeve in the axial direction.

According to one embodiment, the ramp sleeve and the clutch unit are integrally formed in one piece. As a result, the installation space of the reverse brake can be further reduced. For example, an outer circumference of the second ramp geometry of the ramp sleeve can be designed in the manner of a cone, with the cone-like outer surface being set up to form a frictionally engaged clutch unit with a complementarily designed conical surface, for example on the housing.

According to one embodiment, the clutch unit is embodied as a friction-locking clutch unit, e.g. Frictional clutch units have a lower hysteresis between releasing and closing the reverse brake than positive clutch units. Positive-locking coupling units are either released (no positive locking) or closed (positive locking).

Frictionally engaged clutch units have a transition area, ie when the clutch is released, an area in which the frictional force decreases essentially continuously, and when the clutch is engaged, an area in which the frictional force increases essentially continuously. As a result, the return brake can be particularly robust with regard to impacts and/or possible overtorques, so-called torque peaks, and can absorb them, in particular compensate for slipping of the clutch unit, and thus protect other components of the actuator. The multi-plate clutch is particularly suitable for use at high torques, for example for transmissions with a high level of efficiency, in particular an efficiency of more than 70%, more particularly of more than 80%. The conical friction surface clutch is a friction clutch in which two complementary cone-like surfaces interact in a friction-locked manner. The conical friction surface clutch is cheaper to manufacture than the multi-plate clutch and is suitable, for example, for transmissions with an efficiency of around 70%. In particular, the conical friction surface clutch is suitable for use in gears with self-locking, e.g. a worm gear.

According to one embodiment, the actuation unit also has rolling bodies, which are arranged between the first ramp geometry and the second ramp geometry. As a result, sliding friction, which occurs when there is direct contact between the ramp-like guide surfaces of the respective ramp geometries, can be reduced to rolling friction. As a result, the efficiency of the reverse brake can be improved. In particular, the rolling bodies can be arranged in a so-called rolling cage.

According to one embodiment, the spring unit is designed as a cup spring that is arranged in such a way that the spring force acts in the closing direction of the clutch unit. The plate spring has a small width, particularly in the axial direction, as a result of which the recoil brake can be made compact, particularly in the axial direction. In particular, the spring unit has a spring force which is set up to return the actuating unit to its initial position, a so-called neutral position, when the actuator is in a non-driven state. For this purpose, the spring force is preferably selected in such a way that it can move the actuating unit into the starting position, ie the neutral position, via the ramp gradient against a drag torque acting on the drive side.

Alternatively, it is conceivable to support the return of the actuating unit to the neutral position, and thus the closing of the clutch, on the drive side by applying a corresponding restoring torque to the ramp pinion, which, in combination with the spring force of the spring unit, brings the actuating unit back to the neutral position. As a result, a closing of the reverse brake can be ensured even with small inclines of the ramp-like guide surfaces.

According to one embodiment, the ramp pinion is made of a metal or a metal alloy, and the ramp sleeve is made of a plastic or a plastic mixture. The combination of steel and plastic makes it possible to reduce friction in the direct To reduce active contact of the ramp-like guide surfaces. Furthermore, other material pairings or combinations for the ramp pinion and the ramp sleeve are also conceivable, especially in the case of dry, ie not greased, running operating units, such as a bronze-steel pairing, or a steel-steel pairing, with at least the ramp-like guide surfaces of the ramp pinion or ramp sleeve have a coating. If the actuation unit is greased, there is no need to coat the steel-steel combination.

According to one embodiment, the reverse brake has position determination means that are set up to determine the angular position on the output side. For example, the clutch assembly and/or the ramp sleeve may have multiple material passages or bores that are sensed by a drive-side sensor. Alternatively, a magnetic code can also be applied to the coupling unit and/or the ramp sleeve.

According to one embodiment, the reverse brake also has a tolerance disc which is set up to compensate for axial tolerance fluctuations that occur, in particular manufacturing tolerances. For example, the tolerance disc can be arranged between the ramp pinion and the drive unit. Exact positioning of the ramp pinion makes it possible to use a characteristic curve range of the spring unit in which the spring force, in particular the axial spring force, is essentially constant, i.e. essentially unchanged, over a release path of the spring unit and/or the service life of the reverse brake.

A further aspect of the invention relates to an actuator, in particular an electromechanical actuator. The actuator has a drive unit, an output unit and a reverse brake according to the invention. The drive unit, for example an electric motor, is set up to generate a drive torque. The output unit, for example a gear unit, is set up to pass on the drive torque of the drive unit. For example, the output unit, designed as a gear unit, can convert the drive torque of the drive unit into an actuating torque of the actuator. The reverse brake is arranged between the drive unit and the output unit, the clutch unit being coupled to the output unit in a torque-proof manner. Furthermore, the ramp pinion is coupled to the drive unit in a rotationally fixed manner, and the ramp sleeve is coupled directly or indirectly to the output unit in a rotationally fixed and axially displaceable manner. When the ramp sleeve is coupled directly to the output unit, the ramp sleeve is at least partially in direct contact with the output unit. For example, the ramp sleeve can be arranged on an output shaft in a rotationally fixed but axially displaceable manner, in particular, for example, via a spline. If the ramp sleeve is indirectly coupled to the output unit, the ramp sleeve is coupled to the output unit in a rotationally fixed manner, for example, via the coupling unit, but is coupled in an axially displaceable manner.

The clutch unit is also set up to couple the driven unit of the actuator to a housing of the actuator in a torque-proof manner when the clutch unit is in a closed state. One can also say that a torque acting on the output unit is supported on the housing of the actuator via the closed clutch unit. This prevents rotation, in particular of an output shaft, of the output unit when the clutch unit is engaged, and thus when the reverse brake is engaged.

For example, the reverse brake actuator can be operated as follows: In a non-driven state of the actuator, i.e., in a state where the drive unit does not generate torque, the clutch unit is held in the closed state by the spring force of the spring unit. This means that the output unit, in particular an output shaft of the output unit, is coupled to the housing of the actuator in a torque-proof manner, in particular via a form fit or a friction fit.

In a driven state of the actuator, i.e. in a state in which the drive unit generates a torque, the ramp pinion is rotated relative to the ramp sleeve by the torque generated by the drive unit, with the ramp-like guide surfaces sliding on one another. An axial force resulting from this increases with increasing axial displacement of the ramp sleeve and counteracts the spring force of the spring unit. This releases the clutch unit and thus the reverse brake. The axial displacement of the ramp sleeve is limited by the end stop, thus preventing further relative rotation between the ramp pinion and the ramp sleeve.

With the clutch unit released or with the reverse brake released, the full torque of the drive unit, in particular with a synchronous speed, is now transmitted to the output unit, and a desired setting position of the actuator is thus approached. After the actuator has reached the set position, the torque is generated in of the drive unit ended. As a result, the spring force of the spring unit no longer counteracts any force and the spring force brings the clutch unit, and thus the reverse brake, back into the closed state. In the process, the ramp sleeve and ramp pinion rotate again relative to each other until they are back in their starting position or neutral position. In particular, the spring force should be selected in such a way that it is sufficiently large in the axial direction to ensure that the actuating unit, ie the ramp pinion and the ramp sleeve, is reset into the neutral position.

In particular, the actuator can be set up to be used in a vehicle, more particularly in a chassis of a vehicle.

Detailed description based on drawing

Further measures improving the invention are presented in more detail below together with the description of preferred exemplary embodiments of the invention with reference to the figures. It shows:

Fig. 1 is a schematic sectional view of a reverse brake according to a

embodiment of the invention,

2A and 2B schematic representations of a ramp pinion according to an embodiment of the invention in a perspective view,

3A and 3B schematic representations of a ramp sleeve according to an embodiment of the invention in a perspective view,

Fig. 4A and 4B schematic representations of a ramp pinion according to a

Embodiment of the invention in perspective view

5A to 5C schematic perspective representations of an actuating unit according to an embodiment of the invention in a neutral position (FIG. 5A), in an intermediate position (FIG. 5B) and in an end position (FIG. 5C), Fig. 6 is a schematic, perspective sectional view of a

operating unit according to an embodiment of the invention,

7A and 7B schematic representations of a disk carrier of a clutch unit according to an embodiment of the invention in a perspective view,

Fig. 8 is a schematic representation of a disk carrier with disks of a

Coupling unit according to an embodiment of the invention in a perspective view,

Fig. 9 is a schematic representation of an actuator according to a

Embodiment of the invention in a perspective view,

10A and 10B are schematic representations of a driven-side sub-assembly of an actuator according to an embodiment of the invention in a perspective view (FIG. 10A) and in an exploded view (FIG. 10B),

11A and 11B are schematic representations of a drive-side subassembly of an actuator according to an embodiment of the invention in a perspective view (FIG. 11A) and in an exploded view (FIG. 11B);

12A to 12C are schematic sectional views of an actuator with reverse brake according to an embodiment of the invention, wherein the reverse brake is in a closed state (FIG. 12A), in an intermediate state (FIG. 12B), and in an opened state (12C),

13 is a schematic sectional view of an actuator with a floating reverse brake according to an embodiment of the invention, and

14 shows a schematic sectional view of an actuator with an independently mounted reverse brake according to an embodiment of the invention. The figures are only of a schematic nature and serve only to understand the invention. The same elements are provided with the same reference numbers.

1 shows, schematically and by way of example, a reverse brake 1 according to an embodiment of the invention in a sectional view. The reverse brake 1 has a clutch unit 2 , a spring unit 3 and an actuation unit 4 .

The clutch unit 2 is designed here, for example, as a multi-plate clutch 5, which has a disk set 6 with three inner plate disks 7 and three outer plate disks 8, which are arranged alternating in the axial direction A. The three inner disks 7 are arranged in a disk carrier 9 in a rotationally fixed but axially displaceable manner (see also FIG. 8), and the three outer disks 8 are arranged in a disk cage 10 in a rotationally fixed but axially displaceable manner. The lamellar cage 10 is arranged in a housing 11 of the reverse brake 1 in a rotationally and axially fixed manner. The disk carrier 9 (see also Figs. 7A and 7B) is set up to be coupled to an output shaft 12 (see e.g. Fig. 10B) of an output unit 13 (see also Figs. 12A-C) in a rotationally fixed but axially displaceable manner.

Furthermore, the multi-plate clutch 5 has a pressure pot 14 and an axially fixed counter-pressure plate 15, the pressure pot 14 being arranged in the axial direction A on an output side 16 of the disk set 6 and the axial counter-pressure plate 15 being arranged in the axial direction A on an output side 17 of the disk set 6. The pressure pot 14 is pressed by the spring unit 3, which is designed here as a plate spring 18, in the direction of the disk set 6 in such a way that the clutch unit 2 is in a load-free state, i.e. in a state in which no external forces are acting on the clutch unit 2 work, is closed. Therefore, the clutch unit 2 can also be referred to as a “normally closed” clutch unit.

The actuating unit 4 has a ramp pinion 19 (see also FIGS. 3A and 3B) and a ramp sleeve 20 (see also FIGS. 2A and 2B). The ramp sleeve 20 is here, for example, non-rotatably via a spline 21, but is axially displaceably connected to the disk carrier 9. In addition, the ramp sleeve 20 has actuation fingers 22 which are arranged substantially evenly distributed over its circumference, which extend through corresponding openings 23 in the disk carrier 9 and are in contact with the pressure pot 14 . The ramp pinion 19 and the ramp sleeve 20 interact in such a way that rotation of the ramp pinion 19 causes an axial displacement of the ramp sleeve 20 against the spring force of the plate spring 18, ie towards the output side 16, causes what is described in more detail with reference to FIGS. 5A to 5C.

The ramp pinion 19 is described in more detail below with reference to FIGS. 2A and 2B. The ramp pinion 19 has a spline 24 on an inner diameter, via which it can be coupled in a rotationally and axially fixed manner to a drive shaft 25 of a drive unit 26 (see also FIGS. 11A and 11B). On an outer diameter, the ramp pinion 19 has a first ramp geometry 27 with a ramp-like guide surface 28 which is arranged circumferentially and extends in the axial direction A like a pinnacle. The “pinnacles” of the first ramp geometry 27 are so-called end stop fingers 29. Furthermore, the ramp pinion 19 has, for example, a plurality of recesses 30, which are arranged essentially equally distributed along the outer circumference of the ramp pinion 19 and are set up for this purpose, e.g. in contact with so-called sensor wheels to be, and thus serve to detect the angle of rotation of the ramp pinion 19 .

The first ramp geometry 27 of the ramp pinion 19 is configured or set up to interact with a second ramp geometry 31 that is configured on the ramp sleeve 20 (see FIGS. 3A and 3B). As shown in FIGS. 3A and 3B, the ramp sleeve 20 has the splines 21 on its outer diameter, via which it is coupled to the disk carrier 9 of the disk clutch 5 at least in a torque-proof manner. Alternatively, it is also conceivable that the ramp sleeve 20 is coupled directly to the output shaft 12 of the output unit 13 in a rotationally fixed but axially displaceable manner. The actuating fingers 22 extend axially from an inner diameter. Furthermore, the ramp socket 20 has the second ramp geometry 31 which is designed to be essentially complementary to the first ramp geometry 27 . The second ramp geometry 31 also has ramp-like guide surfaces 32 which interact with the ramp-like guide surfaces 28 of the first ramp geometry 27, as described below with reference to FIGS. 5A to 5C.

4A and 4B show another exemplary embodiment of the ramp pinion 19, in which the first ramp geometry 27 has four ramp designs 33, each with two ramp-like guide surfaces 28. The associated ramp sleeve 20 (not shown) is correspondingly designed to complement the ramp pinion 19 with four ramp designs. It can be seen that the exemplary ramp pinion 19 shown in Figures 4A and 4B compares favorably to that shown in Figures 2A and 2B exemplary ramp pinion 19, in particular due to the non-existent

End stop finger, in the axial direction A has a reduced space.

The interaction of the first ramp geometry 27 of the ramp pinion 19 and the second ramp geometry 31 of the ramp sleeve 20 is explained in more detail below with reference to FIGS. 5A to 5C. 5A shows the ramp pinion 19 and the ramp sleeve 20 in an assembled state in a neutral position. It can be seen that the end stop fingers 29 of the first ramp geometry 27 engage in corresponding recesses 34 or depressions 34 of the second ramp geometry 31, the end stop fingers 29 being arranged essentially centrally in the depression 34 in the neutral position. The ramp-like guide surfaces 28, 32 are designed in the form of a screw thread, which means that they have a pitch which is specified by an axial travel per revolution. Thus, the guide surfaces 28, 32 have a pitch angle that changes from an inner diameter to an outer diameter, ie, a pitch angle that changes from radially inside to radially outside.

By rotating the ramp pinion 19 in the direction of arrow P1 (see Fig. 5B), the ramp-like guide surfaces 28, 32 slide off one another, whereby the ramp sleeve 20 is moved in the axial direction A in the direction of arrow P2, since the ramp pinion 19 is axially fixed and the Ramp sleeve 20 rotatably, but are arranged axially displaceable. In Fig. 5C, the ramp pinion 19 and ramp sleeve 20 are in an end position in which the end stop fingers 29 of the second ramp geometry 27, in the direction of rotation, come into abutting contact with end stop fingers 46 of the second ramp geometry 21, and so further relative rotation between the ramp pinion 19 and the ramp sleeve 20, and thus the displacement of the ramp sleeve 20 in the axial direction A is limited.

FIG. 6 shows a schematic perspective sectional view of the actuation unit 4, ie the ramp pinion 19 and the ramp sleeve 20 in an assembled state. It can be seen in FIG. 6 that at least one ramp-like guide surface 28 and the associated complementary ramp-like guide surface 32, in particular all ramp-like guide surfaces 28, 32, have a crowning along the ramp contour. This means that the ramp-like guide surfaces 28, 32 are at least slightly convex, with the convex shape or crowning (see arrows P3, P4) having a diameter at its highest point that ensures that the ramp-like guide surfaces 28, 32 are independent of possible tolerances, such as Manufacturing tolerances, etc., are in contact with each other, and so a proper function of the actuating unit 4 is guaranteed.

9 to 14 show exemplary embodiments of an actuator 35 according to the invention. The actuator 35 is designed as an electromechanical actuator, such as is used in vehicles, for example. Referring to Figs. 9 to 12C, the actuator 35 is separable into a driven side sub-assembly 36 (see Figs. 10A and 10B) and a driving side sub-assembly 37 (see Figs. 11A and 11B) with respect to assembly of the actuator 35.

As shown in FIGS. 10A and 10B, the output-side subassembly 36 has a first housing part 38, the output shaft 12, the spring unit 3 designed as a plate spring 18, the clutch unit 4 designed as a multi-plate clutch 5 and the ramp sleeve 20. The lamellar basket 10 is here formed integrally in one piece in the first housing part 38 . The output shaft 12 is here, for example, as a worm shaft 39 which is mounted in the first housing part 38 via roller bearings 40, 41 (see also FIGS. 12A to 12C).

The drive-side sub-assembly 37, as shown in FIGS. 11A and 11B by way of example, comprises a second housing part 42, the drive unit 26 with the drive shaft 25 and a position-sensing unit 43. As shown in FIG. The input-side sub-assembly 37 is connectable to the output-side sub-assembly 36 via bolts 44 . The drive unit 26 can be designed, for example, as an electric motor 45 (see also FIGS. 13 and 14).

A positioning process of the actuator 35 will be described in more detail below with reference to FIGS. 12A to 12C. In Fig. 12A, the electric motor 45 is not energized. The plate spring 18 thus presses the disk pack 6 together via the pressure pot 14 . There is thus a frictional connection between the worm shaft 39 and the first housing part 38 . This means that reverse brake 1 is closed and twisting of worm shaft 39 is prevented.

If the electric motor 45 is energized, it builds up a torque that is transmitted to the ramp pinion 19 via the drive shaft 25 (see FIG. 12B). This means that the ramp pinion 19 rotates relative to the ramp sleeve 20, with the respective ramp-like guide surfaces sliding on one another. The resulting axial force, which counteracts the axial displacement of the ramp sleeve 20 against the axial spring force causes the plate spring 18 increases increasingly. As a result, the contact pressure force acting on the disk set 6 is increasingly reduced and causes a decreasing braking torque and thus a release of the reverse brake 1. In the further course of the process, the pressure pot 14 is lifted from the disk set 6 by the axial displacement of the ramp sleeve 20, with the ramp pinion 19 and the Ramp sleeve 20 reach its end position in which further relative rotation between the ramp pinion 19 and the ramp sleeve 20 is prevented by the end stop fingers 29, 46 (see Fig. 12C).

With the reverse brake 1 released, the engagement of the first ramp geometry 27 and the second ramp geometry 31 serves to transmit the full torque of the electric motor 45 to the worm shaft 39 at synchronous speed and thus to achieve the desired setting position of the actuator. After the actuator has reached the desired setting position, the energization of the electric motor 45 is deactivated, and thus no more torque is transmitted to the ramp pinion 19 . The spring force of the disk spring 18 thus only counteracts a comparatively axial force, which essentially results from the friction between the first ramp geometry 27 and the second ramp geometry 31 . Thus, the plate spring 18 now presses the disk pack 6 together again via the pressure pot 14 and thus closes the return brake 1. The actuating unit 4 is then moved back into the neutral position (see FIG. 12A).

In particular, the spring force of the spring unit 3 (plate spring 18) is sufficiently large to turn the electric motor 45 back against an engine drag torque via the slope of the ramp geometries 27, 31 until the neutral position of the actuating unit 4 is reached and the full braking torque is thus achieved. When the electric motor 45 is turned back, the restoring torque is generated, so to speak, from the “slope downhill force” resulting from the gradient and/or the shape of the ramp. A small ramp gradient, ie a flat gradient angle, in combination with high friction values of the ramp-like guide surfaces 28, 32 is counterproductive for this. Therefore, material pairings with low coefficients of friction, such as a steel-plastic pairing, are to be used for the actuating unit 4 in particular.

In general, it can be said that a large gradient is beneficial for turning the actuating unit back into the neutral position, but a rather small gradient is suitable for opening reverse brake 1, since the axial force resulting from the drive torque increases with increasing gradient of the guide surfaces. Thus, in the design of the reverse brake 1 in particular an intersection between the largest permissible slope for opening and a required minimum slope for closing reverse brake 1 is determined and a slope from this intersection is used. The intersection can be influenced, in particular increased, by reducing the engine drag torque, reducing the coefficients of friction of the guide surfaces 28, 32, a characteristic curve of the spring unit 3, a number of friction plates and/or increasing the coefficients of friction of the plates.

If no intersection can be determined, the slope must be chosen in such a way that a safe release of reverse brake 1 is guaranteed. It is then necessary for the closing of the reverse brake 1 to energize the electric motor 45 at least for a short time in such a way that it actively turns the actuating unit 4 back into the neutral position. In particular, this requires the angular position of the ramp socket 20 to be detected or the position of the neutral position to be known in a corresponding control unit. For this purpose, for example, the current intensity over time can be recorded during the energization for the execution of the actuating movement. In addition or as an alternative, position-determining elements can be provided, e.g. on disk carrier 9 or on ramp sleeve 20, which are suitable for determining the angular position on the output side. For example, this can be in the form of a pattern or a large number of material openings or bores on the disk carrier 9, which are then detected by the position detection unit 43, such as a sensor, arranged in particular on the drive side.

The use of the multi-plate clutch 5 as the clutch unit 2 is particularly advantageous since the multi-plate clutch 5 is particularly quiet. In addition, an adjustment of the braking or holding torque through the use of more or fewer friction surfaces, ie disks 7, 8 is possible. Furthermore, the multi-plate clutch 5 enables a compact design of the reverse brake 1. In addition, the frictional functional principle of the multi-plate clutch 5 offers the advantage of a “soft” closing process of the reverse brake 1, due to a particularly steadily increasing braking torque. In addition, the multi-plate clutch 5 can act as a slipping clutch in the event of excess torque, such as torque peaks at the electric motor 45, and thus protect the other components of the actuator 35 from being overloaded by such excess torque.

13 and 14 show the actuator 35 in which the reverse brake 1 has been retrofitted as a so-called “add-on”. The reverse brake designed as an "add-on" forms an independent assembly with its own housing 11, which can also be integrated into the actuator 35 at a later date. 13 and 14 differed only in the 13 shows a floating reverse brake 1 and FIG. 14 shows a fully supported reverse brake 1.

In the case of the floating mounting as in FIG. 13, the reverse brake 1 is mounted indirectly via the output shaft 12 and the drive shaft 25 through the bearings of the output shaft 12 and the drive shaft 25. In the complete storage as in Fig. 14, the reverse brake 1 has its own bearing 47, via which it is mounted in the housing 11.

Reference List

1 reverse brake

2 clutch unit

3 spring unit

4 operating unit

5 multi-plate clutch

6 disk pack

7 inner flap disc

8 outer flap disc

9 slat carriers

10 slat basket

11 housing

12 output shaft

13 output unit

14 pressure pot

15 backing plate

16 driven side

17 drive side

18 disc spring

19 ramp sprockets

20 ramp sleeve

21 spline

22 actuation fingers

23 opening

24 splines

25 drive shaft

26 drive unit

27 first ramp geometry

28 ramped guide surface

29 end stop fingers

30 recess

31 second ramp geometry

32 ramped guide surface

33 Ramp Execution

34 recess/indentation

35 actuator 36 PTO subassembly

37 drive side subassembly

38 first housing part

39 worm shaft 40 roller bearing

41 rolling bearings

42 second housing part

43 position detection unit

44 screw 45 electric motor

46 end stop fingers

47 storage

A axial direction P1 arrow

P2 arrow

P3 arrow

P4 arrow

Claims

Expectations

1. reverse brake (1) for an actuator (35), comprising: a clutch unit (2) which is designed to, in a closed state, an output unit (13) of the actuator (35) with a housing (38, 42) of the actuator (35) in a torque-proof manner, a spring unit (3) which is set up to close the clutch unit (2) when the actuator (35) is in a non-driven state, and an actuating unit (4) which is set up to close the clutch unit ( 2) to open the actuator (35) in a driven state, wherein the actuating unit (4) has a ramp pinion (19) with a first ramp geometry (27) and a ramp sleeve (20) with a second ramp geometry (31), with the Ramp pinion (19) is set up to be coupled in a torque-transmitting manner to a drive unit (26) of the actuator (35) and the ramp sleeve (20) is set up to be non-rotatably and axially displaceably coupled to the output unit (13) of the actuator (35). wherein the first ramp geometry (27) and the second ramp geometry (31) each have ramp-like guide surfaces (28, 32) which interact directly or indirectly in such a way that rotation of the ramp pinion (19) counteracts axial displacement of the ramp sleeve (20). a spring force of the spring unit (3).

2. reverse brake (1) according to claim 1, wherein the ramp-like guide surfaces (28, 32) extend from an inner diameter to an outer diameter of the respective ramp geometry (27, 31).

3. reverse brake (1) according to claim 1 or 2, wherein the ramp-like guide surfaces (28, 32) are formed in the shape of a screw thread.

4. reverse brake (1) according to any one of claims 1 to 3, wherein the first ramp geometry (27) and / or the second ramp geometry (31) have at least one cambered ramp-like guide surface (28, 32).

5. reverse brake (1) according to any one of claims 1 to 4, wherein the ramp pinion (19) and / or the ramp sleeve (20) have at least one end stop, the is set up to limit relative twisting between the ramp pinion (19) and the ramp sleeve (20).

6. reverse brake (1) according to claim 5, wherein the at least one end stop is designed as a rotary limitation (29, 46) of the relative rotation between the ramp pinion (19) and the ramp sleeve (20), or as an axial limitation of the axial displacement the ramp sleeve (20) is formed.

7. reverse brake (1) according to any one of claims 1 to 6, wherein the ramp sleeve (20) and the clutch unit (2) are integrally formed in one piece.

8. reverse brake (1) according to any one of claims 1 to 7, wherein the clutch unit (2) is designed as a frictional clutch unit (5) or as a positive clutch.

9. reverse brake (1) according to claim one of claims 1 to 8, wherein the actuating unit (4) further comprises rolling elements which are arranged between the first ramp geometry (27) and the second ramp geometry (31).

10. Actuator (35), comprising: a drive unit (26), which is set up to generate a drive torque, an output unit (13), which is set up to pass on the drive torque of the drive unit (26), and a reverse brake (1st ) according to one of claims 1 to 9, which is arranged between the drive unit (26) and the output unit (13), wherein the clutch unit (2) is non-rotatably coupled to the output unit (13), and wherein the ramp pinion (19) with the The drive unit (26) is coupled in a torque-transmitting manner, and the ramp sleeve (20) is directly or indirectly non-rotatably coupled to the output unit (13), but is coupled in an axially displaceable manner.