EP3818279A1

EP3818279A1 - Brake having a wedge gear and mechanical energy store, and method for the operation thereof

Info

Publication number: EP3818279A1
Application number: EP19749575.7A
Authority: EP
Inventors: Alexander Müller; Norman Perner; Martin Reichle; Wolfgang TZSCHORN
Original assignee: Chr Mayr GmbH and Co KG
Current assignee: Chr Mayr GmbH and Co KG
Priority date: 2018-07-06
Filing date: 2019-07-03
Publication date: 2021-05-12
Also published as: CN112689717B; CN112689717A; WO2020007384A1; DE102018116437A1; DE102018116437B4

Abstract

The invention relates to a brake, comprising a brake housing; at least one clamping body for applying brake force to a linearly moving or rotating counter piece to be braked; a mechanical energy store having a spring arrangement, which during braking applies force to an actuating piston of a wedge gear, which actuating piston is in at least indirect drive connection with the clamping body until the braking position is reached; an actuator device for ventilating the brake; and a fixing device for controllably holding the brake ventilation position. The invention comprises an actuator device having a mechanical gearbox and a shape memory actuator, wherein in the brake ventilation position, the fixing device at least indirectly acts upon the spring arrangement or a separate brake release assembly in the mechanical gearbox via the mechanical gearbox, and the gearbox input side of the mechanical gearbox is in constant drive connection with the shape memory actuator, and the gearbox output side of the mechanical gearbox is in constant drive connection with the spring arrangement. The shape memory actuator is configured such that in an activated state, said shape memory actuator moves the spring arrangement into the brake ventilation position by means of the mechanical gearbox; and the gradient of the transmission ratio of the mechanical gearbox increases for the entire course of the transmission movement directed against the force of the spring arrangement in the direction of the brake ventilation position, wherein in the brake ventilation position, the magnitude of the transmission ratio of the mechanical gearbox is greater than one and corresponds to at least twice the transmission ratio in the braking position.

Description

Brake with wedge gear and mechanical energy storage

and procedures for their operation

The present application relates to a brake with a wedge gear and mechanical energy store according to the preamble features of claim 1 and a method for its operation.

Brakes, the clamping bodies of which are acted upon by the spring arrangement of a mechanical energy store via a wedge gear, are known and are used in particular for fixing linearly moving or rotating ones

Machine components. The clamping bodies typically engage in profile grooves of the counterpart to be braked, reference being made, for example, to the design as a linear brake to DE 101 27664 C I, one along one

Guide rail moved, generic brake disclosed with a wedge gear, the wedge-shaped actuating piston driving the clamping body by a spring arrangement of a mechanical energy store when braking

power application †. The brake is released by a

Electromagnet, which generates a force restoring the spring arrangement in overcurrent mode. The one to be moved is at the beginning of the brake release

Actuating piston of the wedge gear spaced from the armature of the electromagnet, so that the maximum resilient spring forces and thus the braking force of the

Arrangement are limited.

If a hydraulic or pneumatic actuator device is used to apply force to the spring arrangement of a mechanical energy store for releasing the brake, high actuating forces can be generated. In addition, there is the advantage of a simple brake release by removing the operating pressure.

Prerequisite for such an actuator design, as for example by

DE 1 0201 2025438 AI is described, is a sufficiently large space for the necessary fluid cylinder.

In addition, a closed-circuit brake that brakes without the supply of external energy is preferred for implementing a fail-save principle. To this end, how

confirmation copy in DE 1 025291 5 B3 or DE 1 0201 501 0495 A1, by means of one

Pneumatic, hydraulic, electromagnetic, electromechanical or piezoelectric drive, the spring arrangement of a mechanical energy store is biased and the brake release position achieved thereby by means of a

be locked electromagnetically or electromechanically operated locking mechanism. In this holding position there is the possibility of separating the actuator from the spring arrangement. If, for example, an electric motor is used for this purpose, the drive spindle used for the brake ventilation movement can be moved back to a zero position.

Actuators for preloading a spring arrangement that is designed for high braking forces are typically large. Therefore, for alternative

Actuators proposed shape memory materials, which are characterized by a high force density and which perform an actuating movement

Phase change effect.

For a component made of a thermally activated shape memory alloy,

For example, TiNi, TiNiCu, CuZnNi or CuAINi, plastic deformation occurs in a low-temperature phase, for which a martensite structure is present †. When heated to a temperature sufficient to convert the martensite structure to an austenite structure, the shape changes to the state before the plastic deformation. A subsequent cooling, for which again

Martensite structure does not return to the original deformation state with a one-way effect shape memory alloy without additional effort. However, it is possible to train the material through several matching plastic transformation and temperature change cycles so that a two-way effect occurs and an actuator component can be created that changes between two defined shape states depending on the temperature.

In addition to thermal activation of the shape memory effect, materials are known which carry out a phase change due to the action of an electric field or under the action of UV radiation, the

Structural changes lead to a shape memory effect. Examples of such Materials are NiMnGa with a high degree of deformation or

Shape memory polymers with a cinnamic acid group.

Shape memory actuators for direct application of force to brake pistons

Large-scale wind turbine brakes are known from EP 2597329 Al. Furthermore, DE 1 0200701 3421 A1 describes dry

Vehicle disc brakes are described for which a shape memory actuator acting via a wedge gear is used to generate the braking force. Furthermore, DE 1 02005055759 A1 discloses kinematics driven by a converter material with a toggle lever for executing an actuating element for a vehicle brake. The use of the toggle mechanism in the area of is not described

Dead center.

Furthermore, DE 1020050201 describes 26 Al shape memory plates for the

Safety locking of motor vehicle components in the event of an accident known to disclose shape memory actuators for biasing a spring element. In this case, the spring arrangement is acted upon by a

Toggle lever mechanism in a two-leg design, a wire-shaped shape memory element being fixed at the two outer joint ends and running over the central joint of the toggle lever. The when activating the

Traction forces in the wire resulting from shape memory material lead to a stretching of the toggle lever, the course of movement up to the fixing position not being carried out into an area in which the dead center of the transmission is present. In addition, there is a flat transmission characteristic for the wire guide disclosed.

For generic brakes with wedge gears and mechanical energy storage, DE 102009041 907 A1 specifies heatable or coolable shape memory elements as a possible configuration for an actuator. Furthermore is out

DE 1 020040601 09 Al discloses a plate spring arrangement made of a shape memory material in direct drive connection to a brake piston with wedge surfaces. A disadvantage of the disclosed embodiment is the active control of the

Shape memory material when braking, so that no closed-circuit brake is implemented. This also applies to the linear brake disclosed by DE 1 0201 6005003 A1, which has an outside space that is outside the brake housing and thus additional space claiming Bowden cable actuator, which is driven by a shape memory wire. A Bowden cable actuator allows the use of long wire lengths, so that due to the long travel range, a reduction gear with a constant transmission ratio is proposed for the direct application of force to a piston element acting on a clamping housing. In order to maintain the braking force, the shape memory wire in the Bowden cable must be continuously energized for permanent activation. As an alternative, the possibility is mentioned of fixing the braking position with an additional locking element †. Not disclosed is a constructive design for releasing the latching and for an additional actuator, which is necessary to release the brake due to the Bowden cable arrangement which only generates tensile forces.

Furthermore, DE 10201 61 1 8772 A1 describes a brake with a mechanical one

Known energy storage device, the spring arrangement of which is released by means of a shape memory wire. For this purpose, the shape memory wires are more direct

Drive connection to the spring arrangement. Accordingly, they have to

Maintain the ventilation position until the brakes are activated by energizing. When braking, the current flow through the shape memory wire is interrupted for a first embodiment, so that when the shape memory wire cools, a movement takes place in the direction of the braking position, which is driven by the force of the spring arrangement. In order to overcome the disadvantage of a brake release that is too slow, it is proposed for a second embodiment to provide a separation device between the shape memory wires and the spring arrangement which is triggered when braking is initiated and which is moved by an additional wire-shaped shape memory actuator. In addition to the disadvantage of braking activated by external energy, a further task is to reinsert the disclosed separating device when the brake is released

Bring coupling state. For this purpose, the additional shape memory belt † must perform an actuating movement against the triggering direction, a wire-shaped shape memory controller not being used for this purpose.

The invention has for its object a brake with a

Spring arrangement comprising mechanical energy storage

Force application of a wedge gear and a shape memory for the Specify brake ventilation, which leads to a compact size and high effective braking forces as well as a quick brake release. Furthermore, a method for operating such a brake is to be specified.

The task is solved by the features of the independent claims. Advantageous refinements result from the subclaims. The inventors assume a brake that includes a mechanical energy store with a spring arrangement within the brake housing, which the

Actuating piston of a wedge gear until the braking position is reached

kraftbeaufschlag †. The wedge gear serves to drive at least one clamping body, which engages in a groove of a guide rail or on a rotating counterpart to be braked during braking.

A spring assembly that prestresses the spring arrangement is used to release the brake

Actuator device. Furthermore, a fixing device is provided which controllably maintains the brake release position so that the actuator device can be deactivated. The fixing device preferably operates according to the

Quiescent current principle, so that the brake release position only remains as long as a control signal is pending † or a continuous power supply is available. A fixation device which is provided by a

Electric holding magnet is formed. Another preferred embodiment is a spring force actuator secured by means of an electro-holding magnet. For a structurally simple design, the fixing device can be replaced by a part of the

Actuator device for releasing the brake are formed so that the

Fixing device comprises a shape memory actuator, which is switched off when the brake is released and is therefore deactivated.

For a preferred further development, the fixing device has a

Spring-elastic support on the brake housing, which is designed so that an elastic stop for movement in the brake release direction or in

Braking direction present †.

The actuator device for releasing the brake comprises a mechanical transmission and a shape memory actuator, the transmission input side with the Shape memory plate is in constant drive connection. Accordingly, there is a permanent coupling of the transmission output side with the spring arrangement of the mechanical energy store, so that this is in constant drive connection to the shape memory actuator via the mechanical transmission.

The shape memory controller is designed so that, when activated, it moves the spring arrangement of the mechanical energy store into the brake release position via the mechanical transmission. This is under one

Shape memory plate in the activated state of the plate with one after one

Understand the phase change structure that shows a steeper stress-strain curve compared to the non-activated state. A can

Phase changes are triggered either thermally, magnetically or optically. For the preferred embodiment of a shape memory controller made of a thermally activatable shape memory alloy, a phase change takes place from the non-activated state with a martensite structure to an activated state with an austenite structure by energization or the connection to an external one

Heat source. A shape memory wire is advantageously used which has a higher spring hardness in the hot state than in the cold state, so that the activation generates tensile forces which act on the input side of the mechanical transmission when the brake is released.

According to the invention, the mechanical transmission is designed such that a non-linear transmission characteristic is present, the gradient of the translation of the mechanical transmission for the entire course of the transmission movement directed against the force of the spring arrangement increasing monotonically in the direction of the brake release position and the amount of the translation of the mechanical transmission in the

Brake release position is greater than one and corresponds to at least twice the ratio in the brake position. For a preferred embodiment, the amount of the translation of the mechanical transmission in the brake release position is at least five times the translation in the brake position.

The term translation here refers to the relationship between

Understand the drive speed and output speed on the mechanical transmission, with the transmission input side, regardless of the direction of force flow, which is assigned the drive speed, is in constant drive connection to the shape memory plate. Correspondingly, there is a constant drive connection to the spring arrangement on the transmission output side, through the transmission

driven movement the output speed is assigned. This

In the present case, the definition remains even if the force flow in the mechanical transmission is reversed during braking, that is to say during a transmission movement from the brake release position to the braking position.

The transmission design according to the invention leads to several advantages. On the one hand, the fixing device can be arranged in such a way that it acts at least indirectly on the spring arrangement via the mechanical transmission and in one

Reduction gear according to the reduced holding force requirement

small and can be designed to save energy in terms of control.

Another advantage of the increasing increasing characteristic curve for a gear movement in the ventilation direction is an improved utilization of the actuator capacity of the shape memory actuator and an advantageous one

Final approach to the ventilation position can be seen. The inventors have recognized that the non-linear stress expansion characteristic of the shape memory actuator in the activated state with an austenite phase with low elongation and a stress-induced mixing phase can be used particularly well for increasing elongation if the actuating forces to be applied to the mechanical transmission on the input side during the brake release during the course of movement up to

Decrease the brake release position the most for the final approach in the area of the brake release position. As a result, an improved use of material by the shape memory controller allows a compact actuator, which is preferably arranged entirely within the brake housing.

For an advantageous embodiment, a shape memory adjuster, in particular a shape memory wire, acts on a guide slide which is moved parallel to the direction of movement of the spring arrangement in the mechanical energy store. For another preferred embodiment, a shape memory wire is used use †, which runs from a fixed logger on the brake housing via deflection rollers to a loose bearing on the mechanical transmission.

The inventors have recognized that it is advantageous to move the final approach phase to the fixing device when the brake is released, in the steepest section of the

To set the transmission characteristic. This enables the final

To be able to carry out the approach phase to the fixing position against a greatly reduced counterforce. The monotonically increasing gradient therefore allows the

Translation for a gear movement from the braking position to

Brake release position against the force of the spring assembly a precise approach to the holding position, wherein a position sensor is used to detect the approach movement to the brake release position for an advantageous embodiment.

Furthermore, an advantageous further development consists in using a sensor to detect the temperature and / or the resistance of the shape memory controller, so that a position determination can be derived from the stress expansion characteristic.

It is also essential that the gear ratio selected according to the invention means that the brake is first released with a high degree of activation of the shape memory actuator, which can be reduced in the course of the ventilation movement. For a shape memory controller that can be activated thermally, the initial section of the ventilation movement is operated at a high temperature, so that large initial actuating forces result. Due to the monotonically increasing gradient of the translation for a transmission movement from the braking position to the brake release position and due to the additional requirement that the amount of the translation of the mechanical transmission in the brake release position is greater than one and corresponds to at least twice the translation in the brake position, the degree of activation of the shape memory element in the final phase of

Ventilation movement can be lowered. Accordingly, the shape memory element is held at the final approximation just above the threshold of a phase transition back to the unactivated state, a reduced voltage in the activated shape memory element meaning that the reverse transformation temperature is also lower. As a result, braking can be triggered within a very short time after reaching the brake ventilation position, the inventive method The arrangement † requires that the available brake

The spring force is sufficient not only to apply a braking force to the clamping body of the brake via the wedge gear, but there is an additional requirement due to the permanent coupling of the shape memory actuator to return it to the braking position. Will for the

Shape memory controller uses a wire-shaped element, this means that when braking, an elongation of the shape memory wire must be carried out. This presupposes that the shape memory controller is in the non-activated state. For a thermally activated shape memory material, a cooling phase must therefore be awaited after the brake is released, which is due to the

Gear characteristic selected according to the invention is shortened.

For a preferred further development, the actuator device for releasing the brake comprises a multiplicity of parallel-acting and individually controllable ones

Shape memory elements. As a result, the transmission characteristic according to the invention can be used to bring the final approach to the stop positions of the

Brake release position only with a part of the individually controllable

Execute shape memory elements in the activated state, so that the

Cooling phase is further shortened.

For a preferred embodiment, the mechanical gear is designed as a toggle lever gear. The gradient of the gear ratio, which increases monotonically according to the invention, is realized by a transmission kinematics, which leads to the

Brake release position is arranged within a range around a gear dead center position. In the present case, the area of a gear dead center position means a position of the toggle lever gear for which the amount of the translation is at least 5 or at least 10. There are two different ones

Designs possible. For a first variant, the movement to

Brake release position to the gearbox dead center position without being fully reached. This leads to a simple design if the force of the spring arrangement is sufficient even in the brake release position † to cause the non-activated shape memory plate to elongate when braking. Correspondingly, a fixing device with an electromagnet is used for the first variant use † to absorb the force of the spring assembly in the brake release position via at least part of the mechanical transmission.

For an advantageous further development of the first variant, the force acting via the mechanical transmission can be used for faster brake release

Spring arrangement in the ventilation position are reinforced by an additional brake spring system, which acts on the transmission over a limited distance. This auxiliary brake spring system can also be operated by the closed-circuit principle

Fixation device can be assigned.

For the second variant with a toggle lever mechanism, the

Gearbox movement when the brake is released beyond the gearbox dead center position up to a stopping point which lies within the range defined above with an amount of the translation of at least 5 and preferably at least 10 around the gearbox dead center position. The amount of the translation is considered, since after the gearbox dead center position has been passed, the direction of movement changes

Gearbox output reverses and the gear ratio takes a negative value.

Accordingly follows the one directed against the force of the spring arrangement

Gearbox movement when venting to dead center with increasing gradient of the gear ratio a limited section with a falling gear ratio characteristic for which the spring arrangement has a driving effect.

For the brake release position of the second embodiment, according to

Triggering the fixing device the spring arrangement of the mechanical

Energy storage itself do not move backwards over the gearbox dead center position. A separate brake release arrangement is therefore provided, which is preferably designed as a further spring force element, the force introduction point and / or force direction on the toggle lever mechanism of which differs from that of the spring arrangement, which is in drive connection to the clamping body of the brake. The

Brake release arrangement is used to move the toggle lever back over the gear dead center. Accordingly, it is preferred to limit the force effect of the separate brake release arrangement to a section of the transmission brake movement, which particularly preferably comprises only the area of the transmission dead center position. The gear movement of the second variant, which is carried out beyond the gear dead center position when the brake is released, requires a configuration of the

Fixing device for controllably holding the brake release position, which exerts a retaining force on the separate brake release arrangement. An electric holding magnet is preferably used which, in the brake release position, acts either directly on the brake release arrangement or via at least part of the mechanical transmission, and preferably keeps it energized for the brake release position. For an alternative embodiment, which works according to the open-circuit principle, an electric lifting magnet is used to form the fixing device and the brake release arrangement of the second variant.

Advantageous embodiments of the invention are described below with reference to the

Figure representations explained, which represent the following in detail:

1 shows a slide with a shape memory plate

Linear brake on a guide rail in a perspective view.

Fig. 2 shows a first embodiment of a brake according to the invention in the

Braking position as a side sectional view.

3 shows the linear brake from FIG. 2 in the brake release position.

4 shows the cross-sectional view B-B from FIG. 2.

5 shows the phase change characteristic of a thermally activate

Shape memory material.

6 shows the temperature profile of the phase transition temperatures

Figure 5.

Fig. 7 shows expansion stress characteristics of a thermally activated

Shape memory material.

Fig. 8 shows the transmission characteristic of the mechanical transmission for the in the

Figures 2-4 shown first embodiment. FIG. 9 represents † for the transmission according to FIG. 8 the course of movement and the forces acting on the transmission input side during a brake ventilation movement.

Fig. 1 0 shows a second embodiment of a brake according to the invention in the

Braking position as a side sectional view.

Fig. 1 1 shows the second embodiment of Figure 10 in the brake release position.

Fig. 1 2 shows a third embodiment of a brake according to the invention in the

Braking position as a side sectional view.

Fig. 1 3 shows the third embodiment of Figure 1 2 in the

Brake release position.

Fig. 1 4 shows a fourth embodiment of a brake according to the invention in the

Braking position as a side sectional view.

Fig. 1 5 shows the linear brake from Figure 1 4 in the brake release position.

Fig. 1 6 shows a fifth embodiment of a brake according to the invention in the

Braking position as a side sectional view.

Fig. 1 7 shows the brake of Figure 1 6 in the brake release position.

Figure 1 shows a schematic simplification of a perspective view of a carriage 1 on a guide rail 2 with a double prismatic profile. The carriage 1 has a brake housing 4, in which a shape memory adjuster 1 7 with individually controllable shape memory elements 1 8.1 - 1 8.5 is arranged. The brake housing 4 comprises a housing middle part 5, which is one

Housing cover 6 and a housing base 7 is covered. The carriage 1 engages around the profile rail 2 in a U-shape, a double arrangement with a first linear brake in the first housing side part 26 and a second linear brake in the second housing part 27 †. Both housing side parts 26, 27 are connected by an upper housing part 28. FIGS. 2 and 3 show longitudinal sections AA for a first embodiment of the invention in a schematic simplification, an associated cross-sectional view BB through the center plane of the wedge gear 9 being shown in FIG. 4. A is shown

mechanical energy storage 1 2 with a spring arrangement 1 3, which on the

Push rod 34 is in direct drive connection to the actuating piston 1 0.1 of a wedge gear 9. It can be seen from FIG. 4 that actuating pistons 10.1-10.4 with inclined surfaces, to which roller bearings 11.1-1.1.4 are assigned, exert a force effect on the clamping bodies 3, 3.1 when braking.

For tensioning the spring arrangement 1 3 when the brake is released, FIG. 2 shows an actuator arrangement 14 with a mechanical transmission 1 6 and one

Shape memory plate 1 7 in the form of a shape memory wire 20. The

Shape memory wire 20 forms several windings between a fixed bearing 32 on the housing middle part 5 and a loose bearing 33 within a guide carriage 21, which is in a sliding bearing 30 between the housing middle part 5 and the

Housing cover 6 moves. The guide carriage 21 is in direct drive connection with the input side of the mechanical transmission 1 6 via the rigid member 35.3. On the transmission output side there is a further permanent drive connection between the mechanical transmission 1 6 via the rigid member 35.1 and the push rod 34 to the spring arrangement 1 3.

For the preferred embodiment shown, the shape memory wire 20 is cohesively connected to the fixed bearing 32 or the loose bearing 33 at the respective deflection sections by an adhesive connection, so that individually controllable ones

Shape memory elements 1 8.1, 1 8.2 arise. The associated separate electrical contacts of the individually controllable shape memory elements 1 8.1, 1 8.2 are not shown in FIGS. 2 and 3.

To implement the transmission characteristic according to the invention with a monotonically increasing gradient of the translation for a against the force of the

Spring arrangement 1 3 directional gear movement in the direction of

Brake release position LS is a toggle lever gear with rigid links 35.1, 35.2 and 35.3. The fixed bearing is formed by the pivot bearing 36.3 on the middle rigid member 35.2, on which there are also loose bearings with the pivot bearings 36.2 and 36.4. The coupling on the transmission input side to the guide slide 21 takes place via the rotary bearing 36.5 designed as a floating bearing. Between the first rigid part 35.1 and the push rod 34 there is another loose bearing with the pivot bearing 36.1.

Due to the housing-side guidance of the push rod 34, the spring arrangement 1 3 is moved parallel to the movement of the guide slide 21 with the

Shape memory plate 1 7. This parallel guidance results in a compact design that covers the entire longitudinal extent of the middle part 5 of the housing

Accommodation of sufficiently long, individually controllable shape memory elements 1 8.1, 1 8.2 exploitable †.

Figure 2 shows the mechanical transmission 1 6 in the braking position BS. To release the linear brake, the individually controllable shape memory elements 1 8.1, 1 8.2 are energized and activated by heating to the phase transition temperature. This results in an increased voltage of the individually controllable

Shape memory elements 1 8.1, 1 8.2, which move the guide carriage 21 until it rests on the fixing device 15. For the embodiment shown, the fixing device 15 is formed by an electromagnet. This preferably has a rear elastic support 29, which is designed in such a way that deflection in the brake ventilation direction is possible and a stop for

There is a movement limit in the braking direction. In this position, which is shown in FIG. 3 as ventilation position LS, the position of the guide carriage 21 is determined by

Current supply to the electro-holding magnet of the fixing device 1 5 is fixed, so that the heating current at the shape memory plate 1 7 can be switched off and this can be returned to the cooled state, in which a brake release is possible.

For the embodiment shown in FIGS. 2 and 3, the movement from the braking position BS into the brake ventilation position LS leads to the dead center of the transmission without the dead center being reached. In this position, the force of the

Spring arrangement 1 2 provided that it has cooled sufficiently

Shape memory controller 1 7 without additional actuation, the braking can be effected by triggering the electromagnet on the fixing device 1 5. For clarification of the actuating movement of the shape memory actuator 17 and the consequent requirement for the gear design, reference is made to FIGS. 5-7. Figure 5 shows the martensite content in the structure of a thermally activated

Shape memory material when going through a temperature cycle. A complete martensite structure is available for the cooled shape memory setter 1 7, whereby heating from an initial austenite temperature threshold As leads to a successive conversion of martensite into austenite, which occurs when the final one

Austenite temperature threshold Af has been completed. There is a hysteresis effect for the renewed cooling, an initial one lying below Af

Martensite temperature threshold Ms marks the beginning of the regression to martensite and the regression is completely completed at a final martensite temperature threshold Mf, which in turn lies below As. As shown in Figure 6, the temperature thresholds Mf, Ms, As and Af are from the stress state of the

Shape memory material dependent.

It can be seen from the expansion stress characteristic curves schematically sketched in FIG. 7 that there is a pseudoplastic region for the martensite phase, which is followed by curves that resemble those of a steel spring element. In the pseudoplastic area there is a plateau in which the shape memory material with martensite structure has an almost horizontal strain curve. If the transformation from martensite to austenite takes place through the heating illustrated in FIGS. 5 and 6, the shape memory controller 17 shows a significantly steeper stress-strain curve which, from a certain degree of elongation, has a kink to a pseudo-elastic behavior, which is due to a mixed phase of austenite and stress in the Structure formed martensite is marked. As shown in the schematic representation, the shape memory material has a pronounced hysteresis behavior in the pseudoelastic range. Furthermore, the stress-strain curve for the austenite phase can be determined by a

Temperature setting can be adjusted. The dashed curve is at a higher temperature compared to the solid curve for the austenite phase. Accordingly, when the brake is released by a

sufficient heating of the shape memory plate 1 7 initially with an initially existing stretch of the activated material in the range of 3-4% by the Temperature control adjustable, sufficiently large force on the mechanical

Gearboxes are exercised so that a gearbox movement is also possible for smaller ones

Translations against the action of the spring assembly 1 3 can be performed. To use a short wire length for the individually controllable

To be able to work shape memory elements 1 8.1, 1 8.2 of the shape memory controller 1 7, which allows a compact size, the area of a steeply falling expansion stress characteristic curve can be used in the austenite phase if the intermediate mechanical transmission 1 6 has the characteristics required according to the invention with a monotonically increasing gradient Gear ratio as long as the movement takes place against the force of the spring arrangement.

FIG. 8 shows the kinematics of the mechanical transmission 1 6 for the first embodiment according to FIGS. 2 and 3. GE denotes the distance of the transmission input for a movement from the braking position BS into the ventilation position LS, against which the distance of the transmission output GA is plotted in FIG. 9 which flattens with increasing movement to the ventilation position LS †. Correspondingly, the transmission ratio I increases as shown in FIG. 8, which theoretically assumes an infinite value at gearbox dead center TP †. The negative transmission characteristic for a movement beyond the gear dead center TP is not shown in detail.

According to the invention, the brake position BS and the brake release position LS are determined so that in the final approximation phase of the ventilation movement there is a high gear ratio I † as long as the spring arrangement 1 6 is being worked on, i.e. At gearbox output A there is a force directed against GA †. In the brake release position LS, an amount of the ratio I greater than one is required, which is at least twice and preferably five times the ratio I for the

Braking position BS corresponds. An approximation to the gear dead center position TP, for which the toggle lever gear has an amount of the transmission ratio I of at least 5 and preferably at least 10, is particularly preferred.

The translation threshold with a doubling of the amount of the translation, which characterizes the area which allows an approach without great opposing forces to the fixing device 15, is shown as a dash-dotted horizontal line in FIG. The preferred quintuple translation threshold is in FIG. 8 dash-dotted lines. The selected transmission characteristic enables the degree of activation initially set when the brake is applied to the

Shape memory plate 1 7 in the last section of the brake ventilation movement can be reduced. Accordingly, it is preferred to work for the final approach phase in a temperature range which is only slightly above that in FIG. 5

initial martensite threshold temperature Ms shown or it becomes a

Operating point set in the mixed phase range within the temperature interval between Ms and Mf. This leads to an advantageously quick release of the brake after reaching the brake release position LS, since the cooling time of the

Shape memory plate 1 7 can be shortened.

To illustrate the decreasing force requirement in the course of

Ventilation movement is referred to the dash-dotted curve in Figure 9, which represents the necessary force at the transmission input E to compress the spring assembly 1 3 at the transmission output A. This force curve is available when the brake is released in order to lengthen the shape memory plate 1 7. The force necessary for this, provided that a cold, not activated

Shape memory plate 1 7 here †, is shown by the dash-and-dot curve in Figure 9. It can be seen that the driving force available from the spring arrangement 1 3 when braking is also sufficiently large at the beginning of the actuating movement, the shape memory controller 1 7 preferably being designed such that with increasing elongation the pseudoplastic region of the martensite phase shown in FIG. 7 is achieved, so that a successively increasing proportion of force is available for the application of the clamping body 3 in the course of the braking movement.

For the configuration for which the shape memory controller 1 comprises 7 individually controllable shape memory elements 1 8.1, 1 8.2, preference is given already in the phase of the final approach to the brake ventilation position LS due to the reduced

Requirements for the positioning force are a part of the individually controllable

Shape memory elements 1 8.1, 1 8.2 deactivated. The mean temperature of the shape memory plate 17 is thus reduced, so that the activated ones remain

Shape memory elements 1 8.1, 1 8.2 after reaching the brake release position LS can cool down more quickly, thus further reducing the time for which braking is not carried out again after ventilation.

For a second, structurally simplified embodiment of the invention, the lateral sectional views shown in FIGS. 10 and 11 represent the braking position BS and the ventilation position LS. The components that correspond to the first exemplary embodiment are provided with the same reference numerals.

For the second embodiment, the fixation device is formed by the individually controllable shape memory element 1 8.1 of the shape memory actuator.

This remains permanently activated in the brake release position LS and generates a counterforce to the compressed spring arrangement 1 3 of the mechanical energy store 1 2 via the mechanical transmission 1 6. In order to ensure that the mechanical transmission 1 6 for the brake release position LS does not reach the dead center of the transmission

exceeds, the movement of the guide carriage 21 when the brake is released is limited by an adjustable stop 38. To initiate braking, the shape memory element 1 8.1 is also switched current-free and yields to the

Cool down below the reconversion temperature, the compressed spring assembly 1 3 free. Due to the delayed brake release, the second embodiment is suitable as a parking brake.

For a third embodiment of the invention, the side sectional views shown in FIGS. 1 2 and 1 3 represent the braking position BS and the ventilation position LS. Those corresponding to the first and second exemplary embodiments

Components are provided with the same reference symbols.

In contrast to the first and second exemplary embodiment, the third

Embodiment led the gear movement when releasing the brake in a narrowly limited section beyond the gear dead center position TP by the spring forces are still so small that the activation of the shape memory actuator 1 7 can be carried out in accordance with the above embodiments.

It is preferred to set the brake release position BS in the area of the gearbox dead center position TP, for which the toggle lever gear has a gear ratio of at least 5 and preferably at least 10. For the third exemplary embodiment, the requirement of a monotonically increasing gradient of the translation applies only up to the transmission dead center TP, ie for the course of the ventilation movement, which is directed against the force of the spring arrangement 13.

Due to the force of the spring arrangement 1 3 acting after the transmission dead center in the direction of the brake ventilation movement, the compressed spring arrangement 1 3 cannot bring about a brake release from the brake release position and an additional brake release arrangement 1 9 is required, the point of force introduction and / or the direction of force on the mechanical transmission 1 6 differs from that of the spring arrangement 1 3 in order to shift the toggle lever again over the gear dead center when braking. The brake release arrangement 1 9 can be designed as a spring belt †. It is preferred to use the spatial scope

Brake release arrangement 1 9 to an area to limit the transmission dead center position TP. This advantageously relates to a section in which an amount of translation of at least 5 and preferably at least 10 is present †. Furthermore, for the embodiment of the invention shown in FIGS. 2 and 3 with a brake release position BL in front of the gearbox dead center TP

Brake release accelerating auxiliary brake spring system with action on the toggle lever can be used to support the initiation of the braking phase.

FIGS. 14 and 15 illustrate a fourth embodiment according to the invention, which, like the third embodiment, is based on a gear movement when the brake is released, which in a narrowly limited section extends beyond the gear dead center position TP †. In contrast to the previous embodiment, the fixing device 1 5 acts in the form of an electromagnet on the brake release arrangement 1 9.

FIGS. 1 6 and 1 7 show a fifth embodiment according to the invention, the components which correspond to the previous exemplary embodiments being provided with the same reference symbols. Unlike the previous ones

Exemplary embodiments include the mechanical transmission 1 6 a toggle lever with a double leg arrangement which is formed by the rigid bodies 35.1 and 35.2, the rotary bearing 36.3 as a fixed bearing and the rotary bearings 36.1 and 36.2 as a loose bearing. A shape memory adjuster 1 7 is a loose bearing 33 which is meandered around deflection rollers 22.1-22.5 and is arranged between a fixed bearing 32 on the housing side and a loose bearing 33 arranged in the region of the central joint on the first rigid member 35.1 stretched shape memory wire 20 used. This arrangement allows a sufficiently long shape memory wire 20 for a flat brake

to accommodate and to implement a force application point and a force application on the knee lever, which effect the translation characteristic according to the invention.

In addition, a position sensor 24 for controlling the final approach to the brake release position BL is provided for the fifth exemplary embodiment. The control electronics used for this is not shown in detail. Alternatively or additionally, a sensor device 23 on the shape memory wire 20 can be used for a regulated or controlled approach movement, which performs a temperature and / or resistance measurement † in order to be able to determine the gear position from the wire elongation. Furthermore, there is an adjustable stop 37 for the toggle lever mechanism on the housing base 7.

Further refinements of the invention result within the scope of the following protection claims.

LIST OF REFERENCE NUMBERS

carriage

guide rail

, 3.1 sprags

brake housing

Housing body

housing cover

caseback

, 9.1 Wedge gear

0.1 - 10.4 actuating piston

1 .1 - 1 1 .4 rolling bearings

2, 1 2.1 mechanical energy storage

3, 13.1 spring arrangement

4 actuator device

5 fixation device

6, 16.2 mechanical transmission

7 shape memory plates

8.1 - 18.5 individually controllable shape memory belt † 9 brake release arrangement

0 shape memory wire

1 guide carriage

2.1 - 22.5 pulley

3 sensor device

4 position sensor

5 profile groove

6 first housing side part

7 second housing side part

8 upper housing part

9 resilient support 30 plain bearings

31 plain bearings

32 fixed bearings

33 loose bearings

34, 34.1 push rod

35.1, 35.2,

35.3 Rigid link

36.1 - 36.8 pivot bearing

37 stop

38 stop

LS brake release position

BS braking position

E Transmission input side

A transmission output side

GE distance of the gearbox input

GA distance of the gearbox output

Claims

claims

1 . Brake, comprehensive

a brake housing (4);

at least one clamping body (3) for applying braking force to a counterpart to be braked, moved or rotating linearly;

a mechanical energy store (1 2) with a spring arrangement (1 3), which, when braking, has an at least indirect drive connection to the

Clamping body (3) standing actuating piston (10.1, 1 0.2) of a wedge gear (9) until the braking position (BS) is reached;

an actuator device (1 4) for releasing the brake; and

a fixing device (1 5) for controllably holding the

Brake release position (LS);

characterized in that

the actuator device (1 4) a mechanical gear (1 6) and one

Shape memory plate (1 7), the fixing device (1 5) in the brake release position (LS) at least indirectly via the mechanical transmission (1 6) on the spring arrangement (1 3) or on a separate one

Brake release arrangement in the mechanical transmission (1 6) acts; and

the transmission input side (E) of the mechanical transmission (1 6) with the

Shape memory plate (1 7) is in constant drive connection; and

the transmission output side (A) of the mechanical transmission (1 6) with the

Spring arrangement (1 3) is in constant drive connection;

wherein the shape memory actuator (1 7) is designed such that in the activated state it moves the spring arrangement (1 3) into the brake release position (LS) by means of the mechanical gear (1 6); and

the gradient of the translation of the mechanical transmission (1 6) for the entire course of the gear movement directed against the force of the spring arrangement (1 3) increases in the direction of the brake release position (LS), the amount of the translation of the mechanical transmission (1 6) in the

Brake release position (LS) is greater than one and at least twice the Gear ratio in the braking position (BS) corresponds.

2. Brake according to claim 1, wherein the amount of the translation of the mechanical transmission (1 6) in the brake release position (LS) corresponds to at least five times the translation of the mechanical transmission (1 6) in the braking position (BS).

3. Brake according to one of claims 1 or 2, wherein the mechanical gear (1 6) is designed as a toggle lever gear.

4. Brake according to claim 3, wherein the toggle gear for

Brake release position (LS) is within a range around a gearbox dead center position (TP), in which the amount of the translation corresponds to at least 5 and preferably at least 1 0.

5. Brake according to one of the preceding claims, the brake so

It is designed that after the fixing device (15) has been triggered, the clamping body (3) and the non-activated shape memory plate (17) are moved into the braking position (BS) by a spring force effect.

6. Brake according to one of the preceding claims, wherein the

Fixing device (1 5) works on the closed-circuit principle.

7. Brake according to claim 6, wherein the fixing device (1 5) one

Electric holding magnet or a spring force actuator secured by means of an electric holding magnet or a shape memory actuator.

8. Brake according to one of claims 3 to 7, wherein the toggle mechanism

it is arranged that the transmission movement when the brake is released starting from the braking position (BS) to the brake ventilation position (LS) does not pass through a dead center position (TP).

9. Brake according to claim 8, wherein the transmission movement during braking is driven by a combined force effect of the spring arrangement (1 3) of the mechanical energy store (1 2) and an additional brake spring system and the additional brake spring system has a force effect on the toggle lever mechanism over a limited portion of the transmission movement when braking † exercisable.

1 0. Brake according to one of claims 3 to 7, wherein the toggle mechanism

it is arranged that the transmission movement when the brake is released starting from the brake position (BS) to the brake release position (LS) passes through a dead center position (TP) and a brake release arrangement (1 9) is present †, which is designed so that the brake release arrangement ( 1 9) generates a force when braking, which moves the toggle lever mechanism over the dead center position (TP).

1 1. Brake according to claim 1 0, wherein the force effect of the brake release arrangement (1 9) is limited to a portion of the transmission movement when braking.

1 2. Brake according to one of the preceding claims, wherein the

Shape memory plate (1 7) is arranged within the brake housing (4).

1 3. Brake according to claim 1 2, wherein the shape memory plate (1 7) comprises at least one shape memory wire (20) which is parallel to the

Direction of movement of the spring arrangement (1 3) movable guide carriage (21) is acted upon by force and / or is guided via deflection rollers (22.1, ..., 22.5).

1 4. Brake according to one of the preceding claims, wherein the

Shape memory plate (1 7) an element from a thermally activated

Includes shape memory alloy, for which a sensor device (23)

Determination of the temperature and / or the resistance in the activated state is assigned.

1 5. Brake according to one of the preceding claims with a position sensor (24) for detecting the approach to the brake release position (LS).

1 6. Brake according to one of the preceding claims with a spring-elastic support (29) of the fixing device (1 5) on the brake housing (4), which is designed so that a deflection in the brake ventilation direction is possible and a stop to limit movement in the braking direction is present.

1 7. Brake according to one of the preceding claims, wherein the brake is a linear brake for braking a carriage (2) moved along a guide rail (1).

1 8. Method for operating a brake according to one of claims 1-3, wherein when the brake is released, the mechanical transmission (1 6) is guided into an area around a transmission dead center position (TP) in which the amount of the translation is at least 5 and preferably corresponds to at least 1 0, and the mechanical gear (1 6) is held in the brake release position (LS) by the fixing device (1 5).

1 9. The method of claim 1 8, wherein the shape memory plate (1 7) individually

controllable shape memory elements (1 8.1, ..., 1 8.n) and part of the individually controllable shape memory elements when the brake is released

(1 8.1, ..., 1 8.n) is deactivated before the brake release position (LS) is reached.