Electromechanical brake, braking method, and use thereof

Abstract

The invention relates to an electromechanical brake comprising an electric motor (1) which drives a spindle (3) that has a rotational profile (2) so as to advance the brake. The invention is characterized in that the brake is designed such that while the brake is being advanced, the spindle (3), which interacts with a pin element (5) under the effect of a spring force (F) that advances the brake, said pin element being connected via a force transmission element (4) and pressing against the rotational profile (2) of the spindle (3), and the rotational profile (2) of which has an incline (6), is rotated such that the pin element (5) is guided over the incline (6) such that an axial movement of the rotational element (4) is produced which interacts with a brake lining (7) such that the brake lining (7) is also axially moved so as to advance the brake.

Description

[0001] Electromechanical brake, braking method and use

[0002] The invention relates to an electromechanical brake, a braking method and a use.

[0003] A large number of electromechanical brakes are known from the state of the art. These often feature an electric motor that drives a rotating screw drive with a spindle featuring a rotational profile to apply the brake. A distinction is made between service brakes with controlled application force and emergency and holding brakes with a predetermined application force, for example, for the de-energized state.

[0004] For emergency and holding brakes, a preloaded spring assembly is often used for application in the de-energized state. The emergency brake is held open against the force of a spring assembly, for example, by electromagnets. For larger emergency brakes with high application forces, scaling limitations arise due to the holding forces to be handled. When such brakes, designed as service brakes, are applied in an emergency, the masses of the brake components involved must be moved over the usually gently rising rotation profile of the spindle, which, due to the system, requires a certain amount of time.

[0005] The problem at hand is that, in certain emergency situations, the required times may be too long to avoid major damage to the devices being braked. The present invention is based on the object of designing a brake that, on the one hand, enables the controlled braking and release of rotating masses in its service and holding brake functions, and, on the other hand, serves or can serve as a fast-reacting emergency brake when opened.

[0006] 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.

[0007] 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 to apply the brake, wherein the brake is designed in such a way that when the brake is applied, the spindle, whose rotational profile has a slope, is rotated, wherein the spindle interacts with at least one spring force of a

[0008] A force transmission element located on the spring element, which has a bolt element, so that the bolt element is guided over the slope, so that an axial movement of the force transmission element is achieved, which interacts with a brake pad, so that the brake pad is also moved axially to apply the brake; or b.)with an electric motor which drives a spindle having a bolt element to apply the brake, wherein the brake is designed such that when the brake is applied the spindle is rotated, wherein the spindle interacts with at least one force transmission element which is subject to a spring force of a spring element which applies the brake and has a rotational profile, 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 brought about, which interacts with a brake pad, so that the brake pad is also moved axially to apply the brake.

[0009] Due to the slope, which has a very high longitudinal axial component in the radial course - with continuous or non-continuous course - an axial feed of the brake can be realized via a small rotary movement of the spindle, with correspondingly very short and generally shorter feed closing times compared to conventional electromechanical brakes.

[0010] The electromechanical service brake according to the invention, with a rapid emergency brake closing function, can be used by moving the force-transmitting bolts against the spring force in the brake's spindle-forming contour, in the open state, to a starting point located immediately behind the maximum spindle pitch of the service brake function. This starting point is held there by the small, motor-side electromagnetic brake, which is then closed when power is applied. A second contour begins there in the spindle, which leads to a significantly greater pitch, the slope, of the rotary spindle contour. Upon power interruption, the forces of the thus maximally compressed brake spring immediately force the brake to be applied much more quickly.The stopping point is selected so that the high spring forces of the brake always utilize the second, much steeper profile of the spindle contour, the slope, while at the same time requiring low holding forces from the much smaller, also spring-loaded motor brake, which opens when the power is interrupted. A brake designed in this way is suitable wherever either both functions (service brake and safety brake) or only the safety brake n are required to decelerate masses from a movement or to hold them at a standstill. Even if the brake is only used as a safety brake, the guide contour 1, designed with a low gradient, serves to tension the usually strong spring assembly when commissioning the machine to be braked and is the prerequisite for optimizing the size and consumption data.The optimal area of ​​application includes, in particular, applications where it is used as a finely adjustable service brake where, for safety reasons, there is also a need to bring moving masses to a standstill within the shortest possible time in an emergency.

[0011] It is advantageous and proven if, according to variant a.), the spindle has at least two rotation profiles spaced apart from one another 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 along its longitudinal axial extent in order to reduce the mechanical load on the individual bolt element in the respective rotation profile.

[0012] Furthermore, it is advantageous and proven if the force transmission element interacts with the brake pad by means of an automatic adjustment device. For example, and in particular, the automatic adjustment device is one in which a spring presses against a tappet plate which is rotatably connected to a pressure nut and the tappet, which transfers the force to the brake lever. The tappet stroke depends on the adjustment state of the brake and increases with increasing brake pad wear. The task of the automatic adjustment device is to unscrew the tappet by turning the pressure nut so that a constant stroke, spring pressure and constant braking time can be achieved. The automatic adjustment device has a ratchet wheel which is mounted in the pressure nut, and a counter wheel which is axially freely movable but is equipped with several pins which run in helical grooves in a housing block.A spring presses the ratchet wheels against each other. When the plunger unit is moved forward during braking, the counter gear also rotates, but is forced into relative movement to the ratchet wheel by the helical grooves. As the counter gear rotates, the teeth of the counter gear run onto the back of the teeth of the ratchet wheel, compressing the spring slightly until the ratchet has shifted one tooth, provided the stroke is large enough. When the brake is released and the plunger unit returns to the housing, the pins of the counter gear press against the walls of the helical grooves and hold the ratchet wheels together. This allows the counter gear to turn the thrust nut as it returns to its original position, unscrewing the plunger and reducing its stroke.The tappet is equipped with a hexagonal end that fits into a groove in the brake lever, thus preventing the tappet and pressure nut from rotating together. This adjustment process occurs with each braking action until the design stroke is reached and the wheel can no longer rotate one tooth further during the forward stroke.

[0013] In this context, it is advantageous and proven if the brake is designed in such a way 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 power transmission element and the rotational profile of the power transmission element is maintained by means of position detection during operation in order to realize reproducible operating processes.

[0014] In this context, it is advantageous and proven if the position detection is accomplished by moving the bolt element against the slope via the electric motor, so that at the point on the slope at which the bolt element has moved against the slope, the position of the bolt element in relation to the slope is detected by the resulting increased current consumption of the electric motor.

[0015] Alternatively, it is advantageous and proven if the position detection is carried out by means of a rotary encoder in that the rotary encoder mounted on the electric motor clearly determines the angular position of the electric motor in any position and by fixing the force transmission element in its rotational movement and by the rigid connection of the electric motor to the spindle, the position of the spindle relative to the bolt element is clearly determined.

[0016] Furthermore, it is advantageous and proven if the brake according to the invention is designed in such a way that, according to variant a.), in a first operating mode when the spindle rotates at a certain rotational speed in one direction, an axial relative movement of the bolt element along the rotational profile of the spindle is realized by means of the rotational profile of the spindle, wherein the speed of the axial advance of the brake pad interacting with the bolt element is lower compared to the speed of the axial advance of the brake pad interacting with the bolt element when the spindle rotates in the opposite direction with the same rotational speed of the spindle in a second operating mode, so that when the spindle rotates in the opposite direction, the bolt element is guided over the slope at a correspondingly higher speed of the axial advance of the brake pad interacting with the bolt element, or according to variant b.) in a first operating mode when the spindle rotates at a specific rotational speed in one direction by means of the rotational profile of the force transmission element an axial relative movement of the bolt element along the rotational profile of the force transmission element is realized, wherein the speed of the axial advance of the brake pad interacting with the bolt element is lower compared to the speed of the axial advance of the brake pad interacting with the bolt element when the spindle rotates in the opposite direction with the same rotational speed of the spindle in a second operating mode, so that when the spindle rotates in the opposite direction the bolt element is guided over the slope at a correspondingly higher speed of the axial advance of the brake pad interacting with the bolt element.

[0017] Furthermore, it is advantageous if the brake according to the invention is designed in such a way that when the electric motor is disconnected from the power supply, the brake is in the second operating mode if the bolt element is in the predefined position at the time the electric motor is disconnected from the power supply, in order to enable the fastest possible axial delivery of the brake in such a state.

[0018] 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.

[0019] Advantageously, the initial pitch has a higher radial than axial component, so that the axial, for example and in particular initial, pitch is sufficient to safely accelerate the brake to the delivery, but on the other hand to keep the holding forces for the smaller motor brake as low as possible.

[0020] In this context, it is advantageous and proven if the axial gradient of the slope is at least 50, 55, 60, 65, 70, 75, 80, 85, or 90 degrees. The higher the degree, the higher the axial component; at 90 degrees, only the axial component is present.

[0021] Due to the slope, which has a higher longitudinal axial component in the radial course compared to the radial component, thus more than 45 degrees, and according to the invention with regard to the axial movability of the bolt element - with continuous or discontinuous course - an axial feed of the brake can be realized via a slight rotary movement of the spindle, with correspondingly very short and generally shorter feed closing times compared to conventional electromechanical brakes.

[0022] Finally, it is advantageous and proven if the electric motor has a magnetic brake to relieve the load on the electric motor when the brake is open.

[0023] After triggering a safety brake along the contour of the spindle profile, the force-absorbing bolts can be guided to the starting point of the spindle contour by further turning without applying force. This enables the starting point for releasing the brake while simultaneously tensioning the brake spring assembly.

[0024] Furthermore, both a braking method in which a brake according to the invention is used and a use of an indicated slope in a rotation profile of a spindle of a brake according to the invention are claimed.

[0025] The geometry of the individual components can be such that the spindle is located inside or outside the power transmission element, and thus also arranged around the power transmission element.

[0026] The invention is explained in more detail below in a non-limiting manner, whereby

[0027] Figure 1 is a sketchy 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;

[0028] Figure 2 - is a comparison of the time course of the axial feed of the bolt element in a first (normal) (a.) and in a second (emergency) (b.) operating state;

[0029] Figure 3 - a perspective cross-sectional view of a

[0030] embodiment of the electromechanical brake according to the invention;

[0031] Figure 4 is a representation of two axially spaced rotation profiles of a spindle of a screw drive of an electromechanical brake;

[0032] Figure 5 - a functional sketch of the device shown in Figure 3

[0033] embodiment.

[0034] Figure 3 shows a perspective view of an embodiment of the electromechanical brake according to the invention, with an electric motor 1 which drives a spindle 3 having a rotational profile 2 to apply the brake, the brake being designed such that when the brake is applied the spindle 3, the rotational profile 2 of which has a slope 6, is rotated, the spindle 3 interacting with at least one force transmission element 4 which is subject to a spring force of a spring element F which applies the brake and which has a bolt element 5, so that the bolt element 5 is guided over the slope 6, so that an axial movement of the force transmission element 4 is achieved, which interacts with a brake pad 7, so that the brake pad 7 is also moved axially to apply the brake;

[0035] The spindle 3 has at least two rotation profiles 2 spaced apart from one another along its longitudinal axial extent.

[0036] The force transmission element 4 interacts with the brake pad 7 by means of an automatic adjustment device 8 (not shown in detail) via a pressure piece 9.

[0037] The brake is designed in such a way that, by means of a position detection during operation, a predefined position P is maintained between a bolt element 5 pressing on the rotation profile 2 of the spindle 3 and the rotation profile 2 of the spindle 3.

[0038] The position detection is accomplished by moving the bolt element 5 against the slope 6 via the electric motor 1, so that at the point on the slope 6 at which the bolt element 5 has moved against the slope 6, the position of the bolt element 5 with respect to the slope 6 is detected by the resulting increased current consumption of the electric motor 1.

[0039] The brake is designed such that in a first (normal) operating mode (see Figures 1 and 2) when the spindle 3 rotates at a certain rotational speed in one direction by means of the rotational profile 2, here a bevel 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 advance of the brake pad 7 interacting with the bolt element 5 is lower compared to the speed of the axial advance of the brake pad 7 interacting with the bolt element 5 when the spindle 3 rotates in the opposite direction with the same rotational speed of the spindle 3 in a second operating mode,so that in the opposite direction, the bolt element 5 is guided over the slope 6 at a correspondingly higher speed of the axial feed of the brake pad 7 interacting with the bolt element 5.

[0040] Furthermore, the brake is designed such that when the electric motor 1 is disconnected from the power supply, the brake is in the second operating mode if the bolt element 5 is in the predefined position P at the time the electric motor 1 is disconnected from the power supply.

[0041] The axial gradient of slope 6 is at least partially at least approximately 80 degrees.

[0042] Figure 1 shows various kinematic phases of the brake according to the invention: Initially, the brake is open (initial position) (A); in the first operating mode (normal operating mode), the brake begins to close (B) and is then closed (C); the bolt element 5, driven by a spring force of a spring element F, runs along a slope 10 of the rotation profile 2 of the spindle 3 with an axial travel speed of the bolt element 5 and thus of the brake pad 7 shown in Figure 3 defined by the rotation speed of the spindle 3 and the angle of inclination of the slope 10 of the rotation profile 2 of the spindle 3. The rotation profile 2 moves to the left in relation to the bolt element 5 (arrow pointing left).

[0043] In the second operating mode (emergency operating mode), the brake begins to close (D) and then remains closed (E); the bolt element 5, driven by the spring force of the spring element F, runs along the slope 6 of the rotation profile 2 of the spindle 3 at a maximum possible axial travel speed, namely approximately zero degrees with respect to the actual axial movement direction of the bolt element 5 and thus of the brake pad 7 shown in Figure 3. The rotation profile 2 moves to the right in relation to the bolt element 5 (arrow pointing to the right).

[0044] The automatic adjuster is one in which a spring presses against a tappet plate, which is rotatably connected to a pressure nut and the tappet, which transfers the force to the brake lever. The tappet stroke depends on the adjustment state of the brake and increases with increasing brake pad wear. The task of the automatic adjuster is to unscrew the tappet by turning the pressure nut so that a constant stroke, spring pressure and constant braking time can be achieved. The automatic adjuster has a ratchet wheel, which is mounted in the pressure nut, and a counter wheel, which is axially freely movable but is equipped with several pins that run in helical grooves in a housing block. A spring presses the ratchet wheels against each other.When the plunger unit is moved forward during braking, the counter gear also rotates but is forced into relative movement to the ratchet wheel by the helical grooves. As the counter gear rotates, the teeth of the counter gear run onto the back of the teeth of the ratchet wheel, compressing the spring slightly until the ratchet has shifted one tooth, provided the stroke is large enough. When the brake is released and the plunger unit returns to the housing, the pins of the counter gear press against the walls of the helical grooves and hold the ratchet wheels compressed. This allows the counter gear to turn the thrust nut as it returns to its original position, unscrewing the plunger and reducing its stroke. The plunger has a hexagonal end that runs into a groove in the brake lever and thus prevents the plunger and thrust nut from rotating together.This adjustment process takes place with each braking action until the design stroke is reached and the wheel can no longer be turned one tooth further during the forward stroke.

[0045] The electric motor has a magnetic brake (not shown) to relieve the load on the electric motor when the brake is open.

[0046] Another variant (not shown) is one in which the force transmission element 4 has the rotation profile 2, while the spindle 3 has the bolt element 5. The interaction between the rotation profile 2 and the bolt element 5 remains and corresponds to the interaction of the variant shown.

Claims

Patent claims Electromechanical brake, characterized: a.) with an electric motor (1) which drives a spindle (3) having a rotational profile (2) to apply 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) which applies the brake and which has a bolt element (5), so that the bolt element (5) is guided over the slope (6), so that an axial movement of the force transmission element (4) is brought about, which interacts with a brake pad (7) so that the brake pad (7) is also moved axially to apply the brake; or b.)with an electric motor (1) which drives a spindle (3) having a bolt element (5) to apply 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) which applies the brake and has a rotation profile (2), the rotation profile (2) of which 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 brought about, which interacts with a brake pad (7) so that the brake pad (7) is also moved axially to apply the brake. Brake according to claim 1, characterized in that according to Variant a.) the spindle (3) has at least two longitudinally spaced-apart rotation profiles (2) along its longitudinal axial extent, or according to variant b.) the force transmission element (4) has at least two longitudinally spaced-apart rotation profiles (2) along its longitudinal axial extent. Brake according to one of claims 1 to 2, characterized in that the force transmission element (4) interacts with the brake pad (7) by means of an automatic adjustment device (8). Brake according to claim 3, characterized in that the Brake is designed such that, according to variant a.), by means of a position detection during operation, a predefined position (P) between a bolt element (5) pressing on the rotation profile (2) of the spindle (3) and the rotation profile (2) of the spindle (3) is maintained, or according to variant b.), by means of a position detection during operation, a predefined position (P) between a bolt element (5) pressing on the rotation profile (2) of the force transmission element (4) and the rotation profile (2) of the force transmission element (4) is maintained. Brake according to claim 4, characterized in that the Position detection is accomplished in that the bolt element (5) is moved against the slope (6) of the rotary profile (2) via the electric motor (1), so that at the point on the slope (6) at which the bolt element (5) has moved against the slope (6), the position of the bolt element (5) in relation to the slope (6) is detected by the resulting increased current consumption of the electric motor (1). Brake according to claim 4, characterized in that the Position detection is achieved by means of a rotary encoder in such a way that the rotary encoder mounted on the electric motor (1) clearly determines the angular position of the electric motor (1) in any 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 clearly determined. Brake according to one of claims 1 to 6, characterized in that it is designed such that according to variant a.) in a first operating mode when the spindle (3) rotates 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 advance of the brake pad (7) interacting with the bolt element (5) is lower compared to the speed of the axial advance of the brake pad (7) interacting with the bolt element (5) when the spindle (3) rotates in the opposite direction with the same rotational speed of the spindle (3) in a second operating mode, so that when the spindle (3) rotates in the opposite direction, the bolt element (5) is guided over the slope (6) at a correspondingly higher speed of the axial advance of the brake pad (7) interacting with the bolt element (5), or according to variant b.) in a first operating mode when the spindle (3) rotates at a certain rotational speed in one direction by means of the rotation profile (2) of the force transmission element (4) an axial relative movement of the bolt element (5) along the. Rotation profile (2) of the force transmission element (4) is realized, wherein the speed of the axial advance of the brake pad (7) interacting with the bolt element (5) is lower compared to the speed of the axial advance of the brake pad (7) interacting with the bolt element (5) during opposite rotation of the spindle (3) with the same rotation speed of the spindle (3) in a second operating mode, so that during opposite rotation the bolt element (5) is guided over the slope (6) at a correspondingly higher speed of the axial advance of the brake pad (7) interacting with the bolt element (5). Brake according to claim 7, characterized in that it is designed such that when the electric motor (1) is disconnected from the power supply, the brake is in the second operating mode if the bolt element (5) is in the predefined position (P) at the time the electric motor (1) is disconnected from the power supply.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. Brake according to one of claims 1 to 9 is used. .) Use of a slope (6) shown in one of claims 1 to 9 in a rotation profile (2) of a brake according to one of claims 1 to 9.

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