Electromechanical brake, braking method and use

Abstract

An electromechanical brake is presented, comprising an electric motor (1) which drives a spindle (3) having a rotational profile (2) in a manner that applies the brake, wherein the brake is designed such that when the brake is applied the spindle (3), whose rotational profile (2) has a slope (6), is rotated, wherein the spindle (3) interacts with at least one force transmission element (4) which is subject to a spring force of a spring element (F) that applies the brake and which has a bolt element (5), such that the bolt element (5) is guided over the slope (6), thus effecting an axial movement of the force transmission element (4), which interacts with a brake pad (7), so that the brake pad (7) is also axially moved in a manner that applies the brake;or with an electric motor (1) which drives a spindle (3) having a bolt element (5) in a manner that applies the brake, wherein the brake is designed such that when the brake is applied the spindle (3) is rotated, wherein the spindle (3) interacts with at least one force transmission element (4) which is subject to a spring force of a spring element (F) applying the brake and which has a rotation profile (2) and whose rotation profile (2) has a slope (6) so that the bolt element (5) is guided over the slope (6) so that an axial movement of the force transmission element (4) is effected, which interacts with a brake pad (7) so that the brake pad (7) is also moved axially in a manner that applies the brake.

Description

The invention relates to an electromechanical brake, a braking method and a use.A large number of electromechanical brakes are known from the prior art, which in many cases have an electric motor which drives a rotating threaded drive with a spindle having a rotational profile in an adjusting manner the brake. In this case, a distinction is made between service brakes with a controlled application force and emergency and holding brakes with a predefined application force, for example for the non-energized state.For emergency and holding brakes, a prestressed spring pack is often used for the delivery in the non-energized state. The emergency brake is kept open against the force of a feeding spring pack, for example by electromagnets. In the case of emergency brakes of a larger design with high application forces, there are restrictions on the scaling due to the holding forces to be managed. When such brakes designed as service brakes are closed in an emergency, the masses of the brake components involved must be moved via the usually flat increasing rotational profile of the spindle, which requires a certain time for system reasons.The present problem therefore exists in that, in certain cases of emergency, the required times can be too great to avoid major damage to the devices to be braked.The object of the present invention is to design a brake which, on the one hand, enables controlled braking and release of rotating masses in the function of the operating and holding brake and, on the other hand, serves or can serve as a rapidly reacting emergency brake in the open state.This object is achieved by an electromechanical brake according to the invention according to claim 1, a method according to claim 10 and a use according to claim 11.The electromechanical brake according to the invention is one which is characterized:a.) with an electric motor which drives a spindle having a rotational profile in a feeding manner the brake, wherein the brake is designed such that, when the brake is fed, the spindle whose rotational profile has a slope is rotated, wherein the spindle interacts with at least one force transmission element which is under a spring force of a spring element feeding the brake and has a bolt element, such that the bolt element is guided over the slope, such that an axial movement of the force transmission element is effected which interacts with a brake lining, such that the brake lining is also moved axially in a feeding manner the brake; orb.) with an electric motor which drives a spindle having a bolt element in a feeding manner the brake, wherein the brake is designed in such a way that when the brake is fed the spindle is rotated, wherein the spindle interacts with at least one force transmission element which is under a spring force of a spring element which feeds the brake and has a rotational profile and the rotational profile of which has a slope, so that the bolt element is guided over the slope, so that an axial movement of the force transmission element is effected which interacts with a brake lining, so that the brake lining is also moved axially in a feeding manner the brake.Due to the slope, which has a very high longitudinal axial component in the radial course--in the case of a continuous or even non-continuous course--an axial advance of the brake can be realized by means of a slight rotational movement of the spindle, with correspondingly very short advance closing times and generally shorter advance closing times compared to conventional electromechanical brakes.An employment of the electromechanical operating brake according to the invention with an emergency function that quickly closes the brake can be achieved in that the force-transmitting bolts are moved against the spring force in the contour of the brake forming the pitch of the spindle in the open state to a starting point which lies directly behind the maximum of the spindle pitch of the service brake function and is held there by the function of the small motor-side electromagnetic brake, which is then to be closed, when current is supplied. There, a second contour begins in the spindle, which contour leads into a substantially greater pitch, the slope, of the rotary spindle contour and, in the event of a current interruption, force the forces of the spring of the brake thus maximally compressed directly into a substantially faster delivery of the brake. The holding point is selected such that the high spring forces of the brake in each case use the second, substantially steeper profile of the spindle contour, the slope, while on the other hand requiring low holding forces of the substantially smaller, likewise spring-loaded motor brake which opens upon interruption of the current. A brake designed in this way is appropriate wherever either both functions (service brake and safety brake) or only safety brake n are required in order to brake masses from a movement or to keep them stationary. Even if the brake is used only as a safety brake, the guide contour 1, designed with a low gradient, serves for tensioning the normally strong spring assembly when the machine to be braked is put into operation and is the prerequisite for optimizing the overall size and the consumption data. The optimum field of application includes in particular application purposes in which the use as a finely meterable service brake, where it is likewise necessary from a safety standpoint to bring masses moved in an emergency to a standstill within a very short time.It is advantageous, since it is proven to be useful if, according to variant a.), the spindle has at least two rotation profiles spaced apart from one another in a longitudinal axial direction along its longitudinal axial extent, or, according to variant b.), the force transmission element has at least two rotation profiles spaced apart from one another in a longitudinal axial direction along its longitudinal axial extent, in order to reduce the mechanical load of the individual bolt element in the respective rotation profile.It is furthermore advantageous, since it is proven to be useful if the force transmission element interacts with the brake pad by means of an automatic adjusting device, wherein, for example and in particular, the automatic adjusting device is one in which a spring presses against a plunger plate, which is rotatably connected to a pressure nut and the plunger, which transmits the force to the brake lever. The tappet stroke is dependent on the setting state of the brake and increases with increasing brake lining wear. The task of the adjusting mechanism is to screw out the plunger by rotating the pressure nut, so that a constant stroke, spring pressure and a constant braking time can be realized. The adjusting mechanism has a ratchet wheel which is mounted in the pressure nut and a counter wheel, wherein this is freely movable axially, but is equipped with a plurality of pins which run in helical grooves of a housing block. A spring urges the ratchet wheels against each other. When the plunger unit is moved forwards during the braking process, the counterwheel also travels along, but is forced to move relative to the ratchet wheel by the helical grooves. With the rotation of the counterwheel, the teeth of the counterwheel ride on the rear side of the teeth of the ratchetwheel, slightly pushing the spring together until the ratchet, provided the stroke is large enough, has offset one tooth. When the brake is released and the plunger unit retracts into the housing, the pins of the mating wheel press against the walls of the helical grooves and hold the ratchet wheels compressed. As a result, the counter wheel can also rotate the pressure nut when it is rotated back into the starting position, as a result of which the plunger is unscrewed and its stroke is reduced. The plunger is provided with a hexagonal end which runs in a groove in the brake lever and thus prevents the plunger and the pressure nut from rotating together. This readjustment process takes place during each braking until the structurally provided stroke is reached and during the forward stroke a rotation of the wheel by one tooth is no longer possible.In this context, it is advantageous, since it is proven, if the brake is designed such that, according to variant a.), a predefined position between a bolt element pressing on the rotational profile of the spindle and the rotational profile of the spindle is maintained by means of position detection during operation, or, according to variant b.), a predefined position between a bolt element pressing on the rotational profile of the force transmission element and the rotational profile of the force transmission element is maintained by means of position detection during operation, in order to realize reproducible operating processes.In this context, it is advantageous, since it is proven to be useful if the position detection is accomplished by driving the bolt element against the slope via the electric motor, so that at the point of the slope at which the bolt element has driven against the slope, the position of the bolt element with respect to the slope is detected by the increased current consumption of the electric motor as a result.Alternatively, it is advantageous, since it is proven to be effective if the position detection is accomplished by means of a rotary encoder to the effect that the rotary encoder mounted on the electric motor unambiguously determines the angular position of the electric motor in each position and the position of the spindle relative to the bolt element is unambiguously determined by fixing the force transmission element in its rotational movement and by the rigid connection of the electric motor to the spindle.Furthermore, it is advantageous, since it is proven, if the brake according to the invention is designed in such a way that, according to variant a.), in a first operating mode, an axial relative movement of the bolt element along the rotational profile of the spindle is realized during rotation of the spindle at a specific rotational speed in one direction by means of the rotational profile of the spindle, wherein the speed of the axial delivery of the brake pad interacting with the bolt element is lower compared to the speed of the axial delivery of the brake pad interacting with the bolt element during opposite rotation of the spindle at the same rotational speed of the spindle in a second operating mode, so that during opposite rotation the bolt element is guided over the slope at a correspondingly higher speed of the axial delivery of the brake pad interacting with the bolt element, or according to variant b.), in a first operating mode, an axial relative movement of the bolt element along the rotational profile of the force transmission element is realized when the spindle is rotated at a specific rotational speed in one direction by means of the rotational profile of the force transmission element, wherein the speed of the axial delivery of the brake pad interacting with the bolt element is lower compared to the speed of the axial delivery of the brake pad interacting with the bolt element when the spindle is rotated in the opposite direction at the same rotational speed of the spindle in a second operating mode, so that, when the rotation is opposite, the bolt element is guided over the slope at a correspondingly higher speed of the axial delivery of the brake pad interacting with the bolt element.Furthermore, it is advantageous, since it is proven, if the brake according to the invention is designed in such a way that, when the electric motor is disconnected from the current, the brake is in the second operating mode, when the bolt element is at the predefined position at the time of the disconnection of the electric motor from the current, in order to enable the fastest possible axial delivery of the brake in such a state.According to the invention, the slope has at least partially a higher axial component than a radial component, so that the axial gradient of the slope is at least partially at least 45 degrees.Advantageously, the initial gradient has a higher radial than axial component, so that the axial, for example and in particular initial, gradient is sufficient to reliably accelerate the brake for delivery, but on the other hand to keep the holding forces for the smaller engine brake as low as possible.In this context, it is advantageous, since it is proven advantageous if the axial slope of the slope is at least 50, 55, 60, 65, 70, 75, 80, 85 or 90 degrees. The higher the number of degrees, the higher the axial component; at 90 degrees, only the axial component is present.Due to the slope, which has a higher longitudinally axial component in the radial course compared to the radial component, thus more than 45 degrees, and according to the invention with respect to the axial movability of the bolt element--with a continuous or non-continuous course--an axial advance of the brake can be realized via a slight rotational movement of the spindle with correspondingly very short and generally shorter advance closing times compared to conventional electromechanical brakes.Finally, it is advantageous, since it is proven, if the electric motor has a magnetic brake, in order to relieve the electric motor in the open state of the brake.After triggering a safety brake along the contour of the spindle profile, the force-absorbing bolts can be guided in the contour thus applied by further rotation without the action of force to the starting point of the contour of the spindle. This enables the starting point for releasing the brake while simultaneously tensioning the spring assembly of the brake.Furthermore, both a braking method in which a brake according to the invention is used and a use of a indicated slope in a rotational profile of a spindle of a brake according to the invention are claimed.The geometry of the individual components can be such that the spindle is located inside or outside the force transmission element, and is therefore also arranged around the force transmission element.The invention will be explained in more detail below in a non-limiting manner, in which FIG. 1 is a schematic functional diagram of different kinematic phases in both a first and a second operating mode of an embodiment of the electromechanical brake according to the invention; FIG. 2 shows a comparison of the time profile of the axial delivery of the bolt element in a first (normal) (a.) and in a second (emergency) (b.) operating state; FIG. 3 is a cross-sectional perspective view of an embodiment of the electromechanical brake according to the invention; FIG. 4 is a view of two axially spaced rotational profiles of a spindle of a threaded drive of an electromechanical brake; FIG. 5 is a functional diagram of the embodiment shown in FIG. 3.FIG. 3 shows a perspective view of an embodiment of the electromechanical brake according to the invention, having an electric motor 1 which drives a spindle 3 having a rotational profile 2 in an adjusting manner the brake, wherein the brake is designed in such a way that, when the brake is adjusted, the spindle 3 whose rotational profile 2 has a slope 6 is rotated, wherein the spindle 3 interacts with at least one force transmission element 4 which is under a spring force of a spring element F which adjusts the brake and has a bolt element 5, such that the bolt element 5 is guided over the slope 6, such that an axial movement of the force transmission element 4 is effected, which interacts with a brake lining 7, such that the brake lining 7 is also moved axially in an adjusting manner the brake;The spindle 3 has along its longitudinal axial extension at least two rotation profiles 2 spaced apart from one another longitudinally.The force transmission element 4 interacts with the brake lining 7 by means of an adjusting automatic system 8 (not shown in more detail) via a pressure piece 9.The brake is designed in such a way that a predefined position P is maintained between a bolt element 5 pressing on the rotational profile 2 of the spindle 3 and the rotational profile 2 of the spindle 3 by means of position detection during operation.The position detection is accomplished by driving the bolt element 5 against the slope 6 via the electric motor 1, so that at the point of the slope 6 at which the bolt element 5 has driven against the slope 6, the position of the bolt element 5 with respect to the slope 6 is detected by the thus increased current consumption of the electric motor 1.The brake is configured such that in a first (normal) operating mode (see FIGS. 1 and 2 ), upon rotation of the spindle 3 at a specific rotational speed in one direction by means of the rotational profile 2, here an inclination 10, of the spindle 3, an axial relative movement of the bolt element 5 along the rotational profile 2 of the spindle 3 is realized, wherein the speed of the axial delivery of the brake pad 7 interacting with the bolt element 5 is lower compared to the speed of the axial delivery of the brake pad 7 interacting with the bolt element 5 is lower compared to the speed of the axial delivery of the brake pad 7 interacting with the bolt element 5 upon opposite rotation of the spindle 3 at the same rotational speed of the spindle 3 in a second operating mode, so that, in the case of opposite rotation, the bolt element 5 is guided over the slope 6 at a correspondingly higher speed of the axial advancement of the brake lining 7 interacting with the bolt element 5.Furthermore, the brake is configured such that, when the electric motor 1 is disconnected from the current, the brake is in the second operating mode when the bolt element 5 is at the predefined position P at the time of disconnection of the electric motor 1 from the current.The axial pitch of the slope 6 is at least partially at least about 80 degrees.In FIG. 1, various kinematic phases of the brake according to the invention can be seen: First, the brake is opened (initial position) (A); in the first operating mode (normal operating mode), the brake starts to be closed (B) and then to be closed (C); in this case, the bolt element 5, driven by a spring force of a spring element F, runs along an incline 10 of the rotational profile 2 of the spindle 3 at an axial process speed of the bolt element 5 defined by the rotational speed of the spindle 3 and the inclination angles of the inclines 10 of the rotational profile 2 of the spindle 3, and thus of the brake lining 7 shown in FIG. 3.In the second operating mode (emergency operating mode), the brake starts to close (D) and then to be closed (E); in this case, the bolt element 5, driven by the spring force of the spring element F, runs along the slope 6 of the rotational profile 2 of the spindle 3 virtually at a maximum possible axial method speed, namely approximately zero degrees with respect to the actual axial direction of movement of the bolt element 5 and therefore of the brake lining 7 shown in FIG. 3. In this case, the rotational profile 2 moves to the right (arrow to the right) in relation to the bolt element 5.The adjusting mechanism is one in which a spring presses against a follower plate which is rotatably connected to a pressing nut and the follower which transmits the force to the brake lever. The tappet stroke is dependent on the setting state of the brake and increases with increasing brake lining wear. The task of the adjusting mechanism is to screw out the plunger by rotating the pressure nut, so that a constant stroke, spring pressure and a constant braking time can be realized. The adjusting mechanism has a ratchet wheel which is mounted in the pressure nut and a counter wheel, wherein this is freely movable axially, but is equipped with a plurality of pins which run in helical grooves of a housing block. A spring urges the ratchet wheels against each other. When the plunger unit is moved forwards during the braking process, the counterwheel also travels along, but is forced to move relative to the ratchet wheel by the helical grooves. With the rotation of the counterwheel, the teeth of the counterwheel ride on the rear side of the teeth of the ratchetwheel, slightly pushing the spring together until the ratchet, provided the stroke is large enough, has offset one tooth. When the brake is released and the plunger unit retracts into the housing, the pins of the mating wheel press against the walls of the helical grooves and hold the ratchet wheels compressed. As a result, the counter wheel can also rotate the pressure nut when it is rotated back into the starting position, as a result of which the plunger is unscrewed and its stroke is reduced. The plunger is provided with a hexagonal end which runs in a groove in the brake lever and thus prevents the plunger and the pressure nut from rotating together. This readjustment process takes place during each braking until the structurally provided stroke is reached and during the forward stroke a rotation of the wheel by one tooth is no longer possible.The electric motor has a magnetic brake (not shown) in order to relieve the electric motor in the open state of the brake.A further variant (not shown) is that in which the force transmission element 4 has the rotational profile 2, while the spindle 3 has the bolt element 5. The interaction between the rotational profile 2 and the bolt element 5 remains and corresponds to the interaction of the shown variant.

Claims

Electromechanical brake, characterized: a.) with an electric motor (1) which drives a spindle (3) having a rotational profile (2) in a feeding manner the brake, wherein the brake is designed such that, when the brake is fed, the spindle (3) whose rotational profile (2) has a slope (6) is rotated, wherein the spindle (3) interacts with at least one force transmission element (4) which is under a spring force of a spring element (F) feeding the brake and has a bolt element (5), such that the bolt element (5) is guided over the slope (6), such that an axial movement of the force transmission element (4) is effected, which interacts with a brake lining (7), such that the brake lining (7) is also moved axially in a feeding manner the brake; or b.) with an electric motor (1) which drives a spindle (3) having a bolt element (5) in a feeding manner the brake, wherein the brake is designed in such a way that, when the brake is in a feeding manner, the spindle (3) is rotated, wherein the spindle (3) interacts with at least one force transmission element (4) which is under a spring force of a spring element (F) in a feeding manner the brake and has a rotational profile (2), the rotational profile (2) of which has a slope (6), such that the bolt element (5) is guided over the slope (6), such that an axial movement of the force transmission element (4) is effected, which interacts with a brake lining (7), such that the brake lining (7) is also moved axially in a feeding manner the brake.Brake according to claim 1, characterised in that according to variant a.) the spindle (3) has along its longitudinal axial extension at least two rotation profiles (2) spaced apart from one another longitudinally or according to variant b.) the force transmission element (4) has along its longitudinal axial extension at least two rotation profiles (2) spaced apart from one another longitudinally.Brake according to one of Claims 1 to 2, characterized in that the force transmission element (4) interacts with the brake lining (7) by means of an automatic adjusting mechanism (8).Brake according to claim 3, characterised in that the brake is designed in such a way that according to variant a.) a predefined position (P) between a bolt element (5) pressing on the rotational profile (2) of the spindle (3) and the rotational profile (2) of the spindle (3) is maintained by means of position detection during operation or according to variant b.) a predefined position (P) between a bolt element (5) pressing on the rotational profile (2) of the force transmission element (4) and the rotational profile (2) of the force transmission element (4) is maintained by means of position detection during operation.Brake according to claim 4, characterised in that the position detection is achieved by driving the bolt element (5) via the electric motor (1) against the slope (6) of the rotational profile (2), so that at the point of the slope (6) at which the bolt element (5) has driven against the slope (6), the position of the bolt element (5) with respect to the slope (6) is detected by the current consumption of the electric motor (1) increased as a result.Brake according to claim 4, characterised in that the position detection is effected by means of a rotary encoder in such a way that the rotary encoder mounted on the electric motor (1) unambiguously determines the angular position of the electric motor (1) in each position and by fixing the force transmission element (4) in its rotational movement and by the rigid connection of the electric motor (1) to the spindle (3) the position of the spindle (3) relative to the bolt element (5) is unambiguously determined.Brake according to one of Claims 1 to 6, characterized in that it is designed in such a way that, according to variant a.), in a first operating mode, on rotation of the spindle (3) at a specific rotational speed in one direction, an axial relative movement of the bolt element (5) along the rotational profile (2) of the spindle (3) is realized by means of the rotational profile (2) of the spindle (3), wherein the speed of the axial delivery of the brake lining (7) interacting with the bolt element (5) is lower in comparison with the speed of the axial delivery of the brake lining (7) interacting with the bolt element (5) on opposite rotation of the spindle (3) at the same rotational speed of the spindle (3) in a second operating mode, such that, in the case of opposite rotation, the bolt element (5) is guided over the slope (6) at a correspondingly higher speed of the axial feed of the brake lining (7) interacting with the bolt element (5), or, according to variant b.), in a first operating mode, an axial relative movement of the bolt element (5) along the rotation profile (2) of the force transmission element (4) is realized in the case of rotation of the spindle (3) at a specific rotational speed in one direction, wherein the speed of the axial feed of the brake lining (7) interacting with the bolt element (5) is lower in comparison with the speed of the axial feed of the brake lining (7) interacting with the bolt element (5) in the case of opposite rotation of the spindle (3) at the same rotational speed of the spindle (3) in a second operating mode, so that, in the case of opposite rotation, the bolt element (5) is guided over the slope (6) at a correspondingly higher speed of the axial feeding of the brake lining (7) interacting with the bolt element (5).Brake according to claim 7, characterised in that it is designed in such a way that, when the electric motor (1) is disconnected from the current, the brake is in the second operating mode when the bolt element (5) is at the predefined position (P) at the time of disconnection of the electric motor (1) from the current.Brake according to one of Claims 1 to 8, characterized in that the axial gradient of the slope (6) is at least partially at least 50, 55, 60, 65, 70, 75, 80, 85 or 90 degrees.Braking method, characterized in that a brake according to one of Claims 1 to 9 is used.Use of a slope (6) as defined in any one of claims 1 to 9 in a rotational profile (2) of a brake according to any one of claims 1 to 9.

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