EP2219984B1 - Lift drive and method for driving and detaining a lift car, a corresponding method and a braking device, and method for decelerating and detaining a lift car, and an associated method - Google Patents

Abstract

A lift drive (20) serves to drive and to detain a lift car, and it essentially contains a traction wheel (22) for transmitting a driving or detaining force to the lift car, a motor (21) for driving the traction wheel (22), and a braking arrangement for detaining the traction wheel (22). A drive shaft (2) connects the traction wheel, the motor and the braking arrangement to one another. The braking arrangement contains at least two braking devices (24.1, 24.2), wherein, according to the invention, the traction wheel (22) is arranged between the braking devices (24.1, 24.2). This is advantageous, since the braking torques (MB1,2) which are transmitted by the traction wheel (22) to the braking devices (24.1, 24.2) are divided. In the case of an advantageous, symmetrical division of the braking devices (24.1, 24.2), half on either side of the traction wheel, a torque which is to be transmitted is reduced by half in the drive shaft (2). A risk of failure or risk of breakage of the drive shaft (2) is thereby significantly reduced. In addition, during a possible failure of the drive shaft (2), there continues to be a braking function, since the braking devices (24.1, 24.2) are distributed on both sides of the traction wheel (22).

Description

The present invention relates to an elevator drive for driving and holding an elevator car according to claim 1.

An elevator drive of this kind is for example from the WO 2007/020325 known.

From the DE 197 37 485 C1 is an electromagnetically actuated braking device, as can be used in an elevator drive, known with a stationary housing and a rotating work shaft therein. With the working shaft, two brake discs rotatably, but axially displaceable connected. By a respective spring axially displaceable armature discs are biased with a normal force against the brake discs so that a first frictional contact between the brake discs and the housing and a second frictional contact between the rotatable relative to the housing armature discs and the brake disc is closed. The frictional forces acting in these contacts counteract a rotation between the brake disk rotatably fixed to the working shaft and the housing or the armature disks rotatably connected therewith, thus braking the working shaft. To release the brake, the armature discs are released electromagnetically against the springs. To reduce the noise that occurs when the brake is released, the armature discs are made in three parts.

If such a braking device, for example, due to wear in the brake discs, can only apply a reduced frictional force between the armature and brake discs, it can lead to slippage of the armature discs to the brake discs adjacent to them. This endangers safety.

An object of the present invention is therefore to provide an elevator drive with a braking device which increases the safety of the elevator drive.

To solve this problem, an elevator drive according to the preamble of claim 1 is further developed by the characterizing features. Claim 10 protects a corresponding method and with claim 11, a corresponding elevator system is protected. The solution further comprises a braking device according to the preamble of claim 12 further developed by its characterizing features, and a corresponding elevator system as in claim 22 characterized and further a method for detecting the function of the braking device according to claim 26.

A braking device is usually installed in an elevator drive. The drive is used for driving and holding an elevator car and it essentially comprises a traction sheave for transmitting a drive and / or holding force to the elevator car, a motor for driving the traction wheel and a brake assembly for holding the traction wheel. A drive shaft connects the traction wheel, the engine and the brake assembly together. The brake assembly includes at least two brake devices, wherein, according to one aspect of the invention, the traction wheel is disposed between the brake devices. This is advantageous because the braking moments which must be transmitted from the traction wheel to the brake devices divide. In an advantageous symmetrical distribution of the braking devices, each half on both sides of the traction wheel, reduces a torque to be transmitted in the drive shaft to half. A risk of failure, or risk of breakage of the drive shaft is thereby significantly reduced. In addition, given a possible failure of the drive shaft is still a braking function given that the braking devices are distributed on both sides of the traction wheel. The terms traction wheel and traction sheave are synonymous with respect to the present invention.

Advantageously, the braking devices are arranged substantially at the two-sided ends of the drive shaft. This provides easy maintenance and accessibility.

Advantageously, the brake devices arranged on both sides of the traction wheel can be controlled individually. Thus, in the case of requirement monitoring logic can specifically determine whether a braking device alone is able to hold the elevator car at a standstill. This is advantageously done by the fact that the control of the braking devices for closing the same takes place with a small time delay, or that alternately during a stop of the elevator car and when advantageously no transport requirement is logged, a braking device is opened briefly. The monitoring logic can, during the period when only one of the braking device is closed, determine whether a braking device alone is able to hold the elevator car at a standstill. This in turn is advantageous because it allows the overall function of the brake assembly to be tested.

The elevator drive according to the invention is usually arranged stationarily in a driving shaft and it drives the elevator car by means of a suspension element. The suspension elements are in this case wound up or unwound by the elevator drive or by the traction wheel or they are driven by the traction wheel or by the traction sheave via friction. When using the friction, a counterweight is usually attached to the elevator car opposite end of the support means, which ensures a sufficient reaction force. Of course, the elevator car and accordingly the counterweight can be hung directly or it can be hung several times by means of pulley.
However, the elevator drive can also be arranged to ride, be arranged directly on the elevator car, in which case the traction wheel acts on a stationary part, such as a rail with friction surface, a gear rod or a threaded rod or for example on a rope.

Advantageously, the braking device, or at least one of the braking devices of such an elevator drive, further generally includes a static element and a movable element or drive shaft which is movable relative to the static element in a first degree of freedom and is to be braked relative to the static element.

The term "braking" may equally include the braking of the movable relative to the static element, ie the reduction of its relative speed, as well as the complete stopping or holding the movable element. In the present case, the distinction between static and movable element serves only to distinguish between two elements which are movable relative to one another in one degree of freedom. In particular, for example, one of the static and movable elements can be arranged inertially fixed in order to brake the other from the static and movable element with respect to the environment. The braking device can be designed in particular as a parking brake for holding the cabin.
This is the normal case in today's elevator systems, since the elevator car or the drive associated with the car drive parts, counterweight and suspension means are controlled by electromotive force to a standstill and therefore the braking device must hold only the already stationary car. Of course, however, such a braking device must be able to assume a braking function in addition to the locking function, if, for example, in a fault, such as a power failure, a quick shutdown of the elevator car must be done.

The first degree of freedom may be, for example, a rotational degree of freedom. For this purpose, the movable element can be rotatably mounted in the static element. In this sense, the term "force" encompasses in general terms the forces or torques acting in the respective degree of freedom in order to present the present invention, which can be applied to different braking devices acting in different degrees of freedom, together, ie when a "frictional force" is mentioned , including at rotational degrees of freedom equally the acting friction torque can be included.

The first degree of freedom can also be a translational degree of freedom. For this purpose, the movable element can be displaceably mounted in the static element, as for example from the DE 41 06 595 A1 is known, in which a static element in the form of a measuring brake slides linearly along a movable element in the form of a brake application rail.

A first frictional contact in a first contact surface can optionally be closed by a controllable normal force acting in a second degree of freedom between the static element and the movable element. In the first frictional contact, a first frictional force counteracts a movement of the movable element relative to the static element. In the DE 197 37 485 C1 For this example, the brake discs are pressed in a first contact surface against the housing. The first frictional forces occurring in these frictional engagements counteract a rotation of the working shaft rotatably connected to the brake discs. As explained above, the term "frictional force" in this case includes the frictional torque acting thereon due to the rotational freedom of the working shaft.

Furthermore, one or more relative elements are provided such that a second frictional contact in a second contact surface is closed between the movable element and each of the relative elements by the normal force and in the second frictional contact a second frictional force counteracts a movement of the movable element relative to the relative element. In the DE 197 37 485 C1 For example, presses a first part of each disc three-piece armature disc against the associated brake disc when the normal force biases the brake disc against the housing. The second frictional forces occurring in these frictional engagements counteract a rotation of the working shaft, which is non-rotatably connected to the brake disks, relative to the first partial disks which are connected to the housing in a rotationally fixed manner.

Furthermore, one, preferably each relative element is associated with an actuating element, which is fixed in the first degree of freedom with respect to the static element, wherein between the actuating element and the relative element is closed by the normal force a third frictional contact in a third contact surface and in the third frictional contact a third frictional force counteracts a movement of the relative element relative to the actuating element. In the DE 197 37 485 C1 For example, pushes a second part of the disc three-piece armature disc on the first part of the disc when the normal force biases the brake disc against the housing. The third frictional forces occurring in these frictional engagements counteract rotation of the first dividing discs relative to the second dividing discs. Preferably, the first, second and / or third contact surface is acted upon by the same normal force.

In a frictional contact, the frictional force FR, which is opposite in principle to the sum of the other forces, always assumes the maximum value FRmax = μ × FN, FN designating the normal force acting on the contact surface and μ a coefficient of friction. If static friction (index H) is present, a maximum friction force FR ^H = μ ^H × FN can thus be set. If the sum of the other attacking forces exceeds this value, the frictional contact changes from static friction to sliding friction (index G) and the coefficient of friction FR ^G = μ ^G × FN is established. The term "sliding friction" also includes rolling friction, as occurs for example when rolling bearings.

According to a variant embodiment of the elevator drive according to the invention, a relative element of the braking device in the first degree of freedom relative to the static element between a normal position and a braking position is biased elastically and elastically into the normal position, wherein the second and third contact surfaces are designed such that a maximum second frictional force, especially when adhering in the second and third frictional contact, greater than a maximum third frictional force. A movement of the relative element in the first degree of freedom beyond the brake position is, for example, positive and / or non-positive, prevented. For this purpose, stops preferably limit the movement of the relative element between the normal position and the braking position.

This mechanically causes the following: If the movable element is held, the normal force FN acts in the second degree of freedom, all three friction contacts are closed and there is static friction. Since the third frictional force FR3 ^H acting between the relative element and the actuating element, which is fixed in the first degree of freedom relative to the static element, is always smaller than the second frictional force FR2max ^H , which can act maximally between the relative element and the movable element , This smaller third frictional force FR3 ^H limits the frictional force which exists over the actuating and the relative element between transmitted to the static and the mobile element. Together with the first frictional force FR1 ^H , which can be transmitted directly, ie without interposition of the actuator and the relative element in the first contact surface, this results in the entire, acting on the movable element friction force FR ^H as the sum of these two frictional forces: $$\mathrm{F}{\mathrm{R}}^{\mathrm{H}}\mathrm{=}\mathrm{FR}{\mathrm{1}}^{\mathrm{H}}\mathrm{+}\mathrm{FR}{\mathrm{3}}^{\mathrm{H}}$$

If this frictional force no longer suffices during operation for holding the movable element, which may result in particular from wear or contamination which leads to a decreasing normal force and / or a reduced coefficient of friction in the contact surfaces, slipping occurs of the movable element relative to the static element in the first degree of freedom.

In this case, the movable element also moves under effective normal force FN in the first degree of freedom. Since the maximum second frictional force between the relative element and the movable element according to the invention is greater than the maximum third frictional force between relative element and aktuierendem element, is in the second frictional contact before static friction, while the third frictional contact comes into sliding (or rolling). In this case, the movable element takes the relative element in the first degree of freedom, until it passes from its normal in the braking position and there, for example, positively stopped by a stop or the like. The relative element thus becomes self-acting, i. Without control influence from the outside, switched from the normal position to the braking position and this change takes place in both traversing directions, ie backwards and forwards.

Once the relative element is stopped in the braking position and fixed in the first degree of freedom relative to the static element, the second friction force FR2 is transmitted from the static to the movable element via the second contact surface between the relative and movable element. The total frictional force FR acting on the movable element thus results as the sum of these two frictional forces: $$\begin{array}{lll}\mathrm{FR}& =\mathrm{FR}1+\mathrm{FR}2\left(1\text{'}\right)& \\ & \begin{array}{c}>\mathrm{FR}1+\mathrm{FR}3\end{array}& \left(1"\right)\end{array}$$

Thus, in a braking device according to the present invention, if the total frictional force FR = FR1 + FR3, which is normally designed to hold the movable element, no longer suffices for holding the movable element, then it moves in the first degree of freedom and displaces, As described above, the relative element in his Brake position where it is set relative to the static element and the second, larger frictional force FR2 transmits to the movable member, so that the total, acting on this frictional force of FR1 + FR3 increased to FR1 + FR2. Advantageously, a safety margin S = (FR1 + FR2) / (FR1 + FR3) can thus be made available in the event that the normal total frictional force is no longer sufficient, since, for example, the first and / or third contact surface has wear, is oiled or the normal force subsides.
This staggered build-up of the entire force required for braking further has a favorable effect in that a force pulse is reduced to the entire moving system, since the braking force is built up over two stages.
Alternatively, instead of the third contact surface and the actuating element, for example, a pressure spring can be used, which on the one hand can cause pressing of the relative element in the second degree of freedom and on the other hand allows a relative displacement of the relative element in the first degree of freedom between normal and braking position. The relative element can be performed in this embodiment, for example, at the same time as an anchor plate. In this embodiment, the value of the frictional force of the third contact surface (FR23) is reduced to virtually zero. In the following explanations, the third contact surface is always used. The content of this also means that this third contact surface is omitted as described and the associated friction force (FR3) assumes the value zero.

In a brake device, it may be difficult to easily and reliably detect a malfunction. Such a malfunction may be present, for example, if the braking device does not open during driving, or if, as described above, it only applies a reduced braking force. For this purpose, it is internally known, for example, to manually check the braking force and the wear in maintenance intervals, which is time-consuming, labor-intensive and error-prone.

In a preferred embodiment of the present invention, the braking device therefore comprises a sensor device for detecting the normal and / or braking position of the relative element. Such a sensor device may for example be a contact which is closed when the relative element comes into the braking position, and / or is opened as soon as it leaves the normal position. Equally, for example, optical sensors can monitor the position of the relative element or position sensors detect the position of the relative element.

Now moves, as described above, the movable member also under effective normal force FN in the first degree of freedom, the movable member takes the relative element in the first degree of freedom, until it passes from its normal to the braking position.

This movement of the relative element is detected by the sensor device for detecting the normal and / or braking position. Since the relative element is biased into the normal position and at a sufficient to hold sufficient total frictional FR ^H = FR1 ^H + FR3 ^H , so in normal, error-free operation remains in this, so can reliably from a shift of the relative element from the normal to the braking position the malfunction of the braking device and the corresponding elevator drive is closed and, for example, a warning is issued to an elevator control.

An advantage of the invention results from the use of a suitable monitoring logic which monitors the correct functioning of the braking device. This monitoring logic comprises the sensor device for detecting the normal and / or braking position of the relative element, a speed and / or path measuring device and the control signal to the braking device. In some cases, the brake device can be repealed with another sensor to determine the state contact play, or brake closed or contact play available or brake released be provided. A "control signal brake" signals in the following the instruction state which gives a control device as a control signal ("to" or "open") to the braking device. The "speed" corresponds to the state of the movable element or of the car or the elevator car and indicates whether the mobile element is at a standstill (o) or in motion (# 0).
A diagnosis of the condition can follow, for example, the following scheme: Control signal brake speed Position relative element statement to open 0 ≠ 0 normal brake F1 X X X okay F2 X X X Brake fault / overload F3 X X X okay F4 X X X okay F5 X X X Lüftfehler This diagnostic scheme allows an almost continuous monitoring of the function of the braking device, in particular because at each stop (F1, F2), the target state can be detected and appropriate measures can be taken in case of deviation. There is no danger since, when the braking position is reached, an increased braking force, as a rule a braking force increased by approximately 2 times, is available. This ensures a secure hold.

Equally, if a faulty position is detected (F5), the system can be stopped and the function verified. Due to an error history, which is stored in the monitoring logic, a service can be carried out purposefully.

A freewheeling of the relative element can be kept low. It can only be chosen so large that a reliable determination of the position of the relative element by the sensor device is easily possible and on the other hand by the resulting displacement of the movable element or the driving body no dangerous holding deviation, such as a step formation in an elevator car arises. Typically, the selected freewheeling path is approximately 3 to 10 mm in both directions of movement corresponding to the first degree of freedom.

The relative element is held by means of a bias voltage in its normal position or returned to the normal position after a successful relative displacement. This bias can be generated for example by means of an elastic spring, such as a simple spring bar, a mechanical rotary or coil spring or a hydraulic spring. A bias by means of magnetic force is possible by magnetic poles are arranged accordingly. Especially when using a pressure spring instead of the actuator element as previously explained, the biasing device can be combined with a magnetic air unit.

was bei vernachlässigbar kleiner Kraft KV für $$\mathrm{FR}\mathrm{2}{\max }^{\mathrm{H}}\mathrm{>}\mathrm{FR}\mathrm{3}{\max }^{\mathrm{H}}$$

erfüllt ist, insbesondere, wenn die zweite Reibkraft erheblich größer als die dritte Reibkraft ist: $$\mathrm{FR}\mathrm{2}{\max }^{\mathrm{H}}>\mathrm{>}\mathrm{FR}\mathrm{3}{\max }^{\mathrm{H}}$$

In the foregoing, the preload to be overcome by the relative element during the movement from the normal position to the braking position, which attempts to bias the relative element into the normal position, has been neglected. Advantageously, however, the second and third contact surface are formed such that the maximum second friction force, in particular in the case of adhesion in the second and third friction contact, is also greater than the sum of the maximum third friction force and the force KV biasing the relative element into its normal position: $$\mathrm{FR}\mathrm{2}{\mathrm{Max}}^{\mathrm{H}}\mathrm{>}\mathrm{FR}\mathrm{3}{\mathrm{Max}}^{\mathrm{H}}\mathrm{+}\mathrm{KV}$$

what with negligible force KV for $$\mathrm{FR}\mathrm{2}{\mathrm{Max}}^{\mathrm{H}}\mathrm{>}\mathrm{FR}\mathrm{3}{\mathrm{Max}}^{\mathrm{H}}$$

is satisfied, in particular, when the second friction force is significantly greater than the third friction force: $$\mathrm{FR}\mathrm{2}{\mathrm{Max}}^{\mathrm{H}}>\mathrm{>}\mathrm{FR}\mathrm{3}{\mathrm{Max}}^{\mathrm{H}}$$

Moreover, since relatively large frictional forces FR2 ^H , FR3 ^H occur regularly in braking devices, in particular for elevator systems, Equation (2 ') or (2 ") also applies Equation (2) to a good approximation.

In the above, the case of holding the movable member has been explained in which there is static friction in the first, second and third frictional contact, respectively. If the brake device is provided as a parking brake for holding, only this case occurs.

However, if the braking device is used in addition to braking the movable element, the movable element moves during deceleration even under the normal force in the first degree of freedom and seeks due to the principle described above to take along the relative element and from its normal to its braking position pull. In this case, there is sliding friction in the first and at least in the second or third friction contact.

For this case, the force KV, which biases the relative element in the normal position, be designed so that it sufficiently compensates for the second friction force in a normal deceleration together with the third friction force and so holds the relative element in its normal position. The bias voltage can generally be generated, for example, by means of an elastic spring, such as a mechanical rotary or coil spring or a hydraulic spring. If the movable element is finally decelerated to a standstill and then held, the contact states change from sliding to static friction in the first, second or third frictional contact. The occurring static friction forces are generally significantly greater than the friction forces prevailing during braking during sliding friction (or rolling friction).

Then, when the total static frictional force FR ^H = FR1 ^H + FR3 ^{H is} no longer sufficient to hold the movable element, the relative element is, as described above, finally displaced and set in its braking position, which is detected in the preferred embodiment of the sensor device. Since the sliding friction is generally much lower than the static friction, so the relative element during braking, in which sliding friction occurs in at least some of the contact surfaces, can be held by a slight bias in its normal position, while holding, in the static friction and thus a higher second and third frictional force is present, the mechanism described above for securing a sufficient total frictional force or for detecting an incorrectly low total frictional frictional force FR ^H = FR1 ^H + FR3 ^H comes into force.

$$\mathrm{FR}\mathrm{2}{\max }^{\mathrm{H}}\mathrm{>}\mathrm{KV}\mathrm{+}\mathrm{FR}\mathrm{3}{\max }^{\mathrm{H}}$$

In a preferred embodiment, the second and third contact surfaces are therefore designed such that the second friction force FR2 ^G , which occurs when sliding in the second friction contact, is less than the sum of the force KV, which biases the relative element in its normal position, and the third Friction force FR3 ^G and / or FR3 ", which is established during sliding or adhering in the third frictional contact, thereby holding the relative element in its normal position during deceleration At the same time, in this preferred embodiment, the second and third contact surfaces are designed such that the maximum second frictional force FR2max ^H , which can be maximally set when adhered in the second frictional contact, is greater than the sum of the force KV, which biases the relative element in its normal position, and the third frictional force FR3max ^H , which can occur when adhering in the third frictional contact. This is, as explained above, easy to implement, since the Haftreibkräfte in general NEN significantly larger than the Gleitreibkräfte are. In the preferred embodiment, then: $$\mathrm{FR}{\mathrm{2}}^{\mathrm{G}}\mathrm{<}\mathrm{KV}\mathrm{+}\mathrm{FR}{\mathrm{3}}^{\mathrm{G}}$$

$$\mathrm{FR}\mathrm{2}{\mathrm{Max}}^{\mathrm{H}}\mathrm{>}\mathrm{KV}\mathrm{+}\mathrm{FR}\mathrm{3}{\mathrm{Max}}^{\mathrm{H}}$$

so dass das Relativelement sich gegenüber dem aktuierenden Element nicht bewegt, sondern in seiner Normallage verbleibt, während im zweiten Reibkontakt Gleitreibung vorliegt.
Sobald das bewegliche Element stillsteht, wechselt auch der zweite Reibkontakt von Gleit- zu Haftreibung und es gilt $$\mathrm{FR}\mathrm{2}{\max }^{\mathrm{H}}\mathrm{>}\mathrm{KV}\mathrm{+}\mathrm{FR}\mathrm{3}{\max }^{\mathrm{H}}$$

Übersteigen nun die übrigen am beweglichen Element angreifenden Kräfte die von der Bremseinrichtung maximal zur Verfügung gestellten Reibkräfte $$\mathrm{FR}{\max }^{\mathrm{H}}=\mathrm{FR}\mathrm{1}{\max }^{\mathrm{H}}+\mathrm{FR}3{\max }^{\mathrm{H}}$$

wird das Relativelement aus seiner Normallage in die Bremslage verlagert und dort festgelegt, wobei vorteilhafterweise eine Fehlfunktion erkannt werden kann. Wie erläutert, reicht also die Erfüllung der Bedingung (2) bzw. unter Vernachlässigung der Kraft KV der Bedingung (2') aus, um die Sicherheit der Bremseinrichtung zu erhöhen und eine Fehlfunktion bei einer nur haltenden Bremseinrichtung zu erfassen. Wird mit der Bremseinrichtung das bewegliche Element auch abgebremst, reicht darüber hinaus die Erfüllung der Bedingung (3) oder (3') aus, um sicherzustellen, dass das Relativelement beim normalen Abbremsvorgang in seiner Normallage verbleibt , so dass anschließend die vorstehend beschriebene Sicherheitsreserve zur Verfügung steht und vorteilhafterweise eine Fehlfunktion beim Halten festgestellt werden kann.As a rule, however, the fulfillment of condition (2) is already sufficient for the following reason: If the braking device begins the braking process, the first, second and third frictional contact are closed. In this case, there is instantaneous sliding friction in the second frictional contact between the movable element, which initially moves relative to the static element, and the relative element, which is prestressed into its normal position resting relative to the static element. In the third frictional contact between the relative element and the actuating element is initially, as long as the relative element is not accelerated, static friction before. Now, as stated above, in general, the sliding friction is significantly lower than the maximum static friction. Thus, the second frictional force FR2 ^G acting in the second frictional contact is generally lower than the third frictional force FR3max ^H , which can be maximally set in the third frictional contact. Thus, as a rule (if the relative element and the actuating element do not move relative to one another), the second frictional force in the second frictional contact, in which sliding friction prevails, will be permanently smaller during braking than the third frictional force in the third frictional contact in which static friction prevails. Thus, the relative element is held in its normal position until the movable element has come to a complete halt. At the beginning of deceleration applies $$\mathrm{FR}{\mathrm{2}}^{\mathrm{G}}\mathrm{<}\mathrm{FR}{\mathrm{3}\mathrm{Max}}^{\mathrm{H}}\mathrm{+}\mathrm{KV}$$

so that the relative element does not move with respect to the actuating element, but remains in its normal position, while there is sliding friction in the second friction contact.
As soon as the moving element stops, the second frictional contact also changes from sliding to static friction and it applies $$\mathrm{FR}\mathrm{2}{\mathrm{Max}}^{\mathrm{H}}\mathrm{>}\mathrm{KV}\mathrm{+}\mathrm{FR}\mathrm{3}{\mathrm{Max}}^{\mathrm{H}}$$

Now the remaining forces acting on the movable element exceed the maximum frictional forces provided by the braking device $$\mathrm{FR}{\mathrm{Max}}^{\mathrm{H}}=\mathrm{FR}\mathrm{1}{\mathrm{Max}}^{\mathrm{H}}+\mathrm{FR}3{\mathrm{Max}}^{\mathrm{H}}$$

the relative element is displaced from its normal position in the braking position and fixed there, advantageously a malfunction can be detected. As explained, the fulfillment of condition (2) or neglecting the force KV of the condition (2 ') is sufficient to increase the safety of the braking device and to detect a malfunction in a braking device that only holds it. If the movable element is also braked with the braking device, fulfillment of condition (3) or (3 ') is sufficient to ensure that the relative element remains in its normal position during the normal braking operation, so that subsequently the safety reserve described above is available stands and advantageously a malfunction in holding can be determined.

Condition (3 ') is usually satisfied simultaneously with condition (2) or (2'), since the sliding friction (or rolling friction) is usually much lower than the static friction. According to the invention, therefore, it is generally only necessary that the maximum frictional force FR2max, which is present in the second frictional contact and is as a rule defined by the maximum frictional friction force FR2max ^H , be greater than the maximum frictional force FR3max present in the third frictional contact and, as a rule, by the maximum static frictional force FR3max ^{H is} determined (condition (2 ')). Thus, in general, condition (3 ') is fulfilled, so that even when braking, the relative element is held in its normal position until the holding state is reached.
Advantageously, however, dispense with this fine tuning of the bias voltage when the brake device is primarily used as a holding or parking brake and is used only in case of need for dynamic braking of the drive body. A requirement is, for example, a response of a speed monitoring circuit or a power failure, etc. In such a case of need, it is quite desirable that the relative element is taken immediately to the braking position (B) and then inevitably generates a higher braking force. The requirement for the bias voltage are then correspondingly low, it is only designed to move the unloaded relative element (3) again in the normal position and to keep loose there with little force.

The maximum second frictional force can be predetermined, for example, greater than the maximum third frictional force, that the second contact surface has a higher coefficient of friction than the third contact surface. This allows the conditions (2) or (2 ') and (3) or (3') fulfill. If relative and actuating elements are subjected to the same normal force FN, this results in a maximum second frictional force FR2 = μ2 × FN, which is greater than the maximum third frictional force FR3 = μ3 × FN. For this purpose, the second and third contact surface, for example, consist of different materials. For this purpose, the relative element on the second contact surface may have a coating for increasing the coefficient of friction μ 2 and / or the actuating element may have a coating for reducing the coefficient of friction μ 3 on the third contact surface. In the third contact surface and rolling bearings, in particular needle roller bearings can be arranged to represent certain coefficients of friction.

In a preferred embodiment, the coefficients of friction of the first and second contact surfaces are substantially the same, so that substantially identical frictional forces are set in the first and second frictional contact, which can advantageously distribute the loads more uniformly. The term "coefficient of friction" may in the present case comprise both the adhesion and the sliding or rolling friction value of a frictional contact, wherein in practical application the first and the second frictional contact are designed in a proven manner as friction brake lining.

The maximum second friction force can alternatively or additionally be greater than the maximum third friction force predetermined that the third contact surface is inclined relative to the normal force. Thus acts on the oblique third contact surface a correspondingly lower normal force and thus a correspondingly lower third frictional force. Advantageously, the normal force acting in the first, second and third frictional contact splits at an inclined third contact surface into a component normal to the third contact surface inducing the third frictional force and a component tangential to the third contact surface impinging upon movement into one Direction added in the first degree of freedom to the third frictional force to a third Gesamtreibkraft, subtracted in the opposite movement of this. Thus, it would be advantageous for different movements in the first degree of freedom different third Gesamtreibkräfte be displayed. Advantageously, the use of the inclined third contact surface results in a relative movement between the relative and aktuierendem element, a change in the normal force, for example, springs, which are used to generate this normal force, be relaxed or relaxed. This is advantageously used, for example, when used in elevator systems with partially balanced counterweights, since different braking effects can thus be generated depending on a possible sliding direction.

As stated above, the term "force" in the present application is understood to mean translational forces and torques acting in the respective degree of freedom. Different friction forces can therefore also be represented by different lever arms. Thus, for example, a larger second frictional force (in this case, a torque) can be represented by the fact that the second frictional contact is radially further spaced from a rotational axis of the movable element as the third frictional contact. For the same normal force thus resulting in different frictional forces, in this case torques.

Preferably, the relative element and the actuating element can be moved by the normal force in the second degree of freedom so that the first, second and third frictional contact is closed. This allows a simple mechanical realization of the friction contacts. In particular, a braking element may be provided, which is fixed in the first degree of freedom relative to the movable element and is moved by the normal force in the second degree of freedom so that the first, second and third frictional contact is closed. Likewise, the movable member may be so moved relative to the static member by the normal force in the second degree of freedom, in particular elastically deformed, that the first, second and third frictional contact is closed.

In for example from the DE 197 37 485 C1 or the DE 41 06 595 A1 In known manner, the actuating element, in particular by an elastic means to be biased with the normal force and electromagnetic and / or hydraulic optionally be ventilated. In the event of failure of a voltage applied to an electromagnet, a pressure drop in a hydraulic line or a fault in the control of the braking device, the actuating element is no longer released, so that the normal force closes the friction contacts and thus the braking device. In the case of a defect, the braking device thus closes automatically and automatically.

The elevator drive according to the invention accordingly includes a braking device which is designed in such a way that the braking device can be switched into a normal position in which normal position the braking device generates a first holding force when the traveling body or stationary mobile element is stationary. This holding force is designed to keep the movable element at a standstill. Further, the brake device automatically changes in a possible movement of the movable element, regardless of a direction of movement of the normal position in a braking position. In the braking position, the braking device generates a substantially doubled or multiplied holding force or braking force.
Advantageously, this automatic change from the normal position to the braking position is monitored by means of a sensor device.
The advantage of this part of the invention is that a first slippage of the movable element can be detected by means of sensor device and that there is an automatic reinforcement of the holding force, whereby further slippage is prevented.
Advantageously, the elevator drive is used in an elevator, which accelerates the vehicle body, for example, electric motor or hydraulically controlled from standstill away and in turn retarded to a standstill, whereby the braking device is usually used only for holding the vehicle body at a standstill.

An elevator drive according to the invention with a braking device can comprise a plurality of relative elements and actuation elements associated therewith, as is the case in principle, for example, from US Pat DE 197 37 485 C1 is known. The above-explained total frictional forces then result from the sums of the first and third or second frictional forces.

As explained above, one of the possible malfunctions of a braking device may be that a total frictional force, which is composed of the first and the third friction force, is too small to hold the movable element at a standstill. This malfunction can be detected when the sensor device detects that the relative element is not in its normal position. Preferably, a movement of the relative element is limited by stops. As a result, upon reaching these stops, the second frictional force, which is higher in comparison with the third frictional force, is used and holds the movable element. This malfunction can thus be detected without endangering the function of holding the movable element as a whole. It is only an indication that the safety reserve S is used. The safety of the braking device is increased and a service can be initialized.

Another possible malfunction is that the brake device is incorrectly not solved, ie the first, second and third friction contact remain closed while driving. This malfunction may result, for example, from a defect of brake control units. This malfunction can also be detected if the sensor device detects that the relative element is not in its normal position. Because, as described above, takes in such a case, the movable element, the relative element in the first degree of freedom, whereby this is displaced from its normal to its braking position. A driving operation can be stopped, for example, when such a malfunction occurs, before the corresponding contact surfaces have overheated, worn or otherwise damaged.

It is particularly advantageous in this case that a functionality of the braking device and a sufficient safety margin can be determined at each normal working cycle of the braking device. This significantly increases the reliability of the braking device.

In general, such a braking device is delivered in new systems, advantageously directly together with a corresponding drive unit. Likewise, a corresponding braking device can also be used in existing systems and elevator systems as a replacement for an existing braking device. This can be achieved especially in connection with a possible modernization of a drive control increased security. A corresponding modernization set can be prepared in tune with known elevator systems.

Fig. 1a

eine Bremseinrichtung nach einer ersten Ausführung der vorliegenden Erfindung im gelüfteten Zustand in einem Schnitt I-I in Fig. 1b;

Fig. 1b

die Bremseinrichtung nach Fig. 1a in einem seitlichen Schnitt;

Fig. 2a, 2b

die Bremseinrichtung nach Fig. 1 in einem normalen Haltezustand;

Fig. 3a, 3b

die Bremseinrichtung nach Fig. 1 bei einer Fehlfunktion mit Überwachungslogik;

Fig. 4

eine Bremseinrichtung nach einer zweiten Ausführung der vorliegenden Erfindung im gelüfteten Zustand in einem seitlichen Schnitt;

Fig. 5

die Bremseinrichtung nach Fig. 4 in einem normalen Haltezustand;

Fig. 6

die Bremseinrichtung nach Fig. 4 bei einer Fehlfunktion;

Fig. 7

eine Prinzipskizze einer dritten Ausführung der vorliegenden Erfindung;

Fig. 8a, 8b

die Bremseinrichtung nach Fig. 1 mit seriellen Bremsscheiben;

Fig. 9

ein Aufzugsantrieb welche nicht zur Erfindung gehört, mit angebauter Bremseinrichtung;

Fig. 10

ein Aufzugsantrieb mit beidseitig eines Traktionsrades angebauter Bremseinrichtung;

Fig. 11

eine alternative Ausführung eines Aufzugsantriebes die nicht zur Erfindung gehört und

Fig. 12

ein Detail einer Bremsanordnung bei einem Antrieb nach Fig. 11.

Fig. 13

ein Beispiel einer Aufzugsanlage

In den Figuren sind für gleichwertige Funktionen die gleichen Bezugszeichen verwendet.Other objects, features and advantages of the present invention will become apparent from the dependent claims and the embodiments described below. This shows, partially schematized:

Fig. 1a

a braking device according to a first embodiment of the present invention in the released state in a section II in Fig. 1b ;

Fig. 1b

the braking device after Fig. 1a in a lateral section;

Fig. 2a, 2b

the braking device after Fig. 1 in a normal holding state;

Fig. 3a, 3b

the braking device after Fig. 1 in case of malfunction with monitoring logic;

Fig. 4

a braking device according to a second embodiment of the present invention in the released state in a lateral section;

Fig. 5

the braking device after Fig. 4 in a normal holding state;

Fig. 6

the braking device after Fig. 4 in case of malfunction

Fig. 7

a schematic diagram of a third embodiment of the present invention;

Fig. 8a, 8b

the braking device after Fig. 1 with serial brake discs;

Fig. 9

an elevator drive which does not belong to the invention, with attached braking device;

Fig. 10

an elevator drive with braking device mounted on both sides of a traction wheel;

Fig. 11

an alternative embodiment of an elevator drive which does not belong to the invention and

Fig. 12

a detail of a brake assembly in a drive to Fig. 11 ,

Fig. 13

an example of an elevator installation

In the figures, the same reference numerals are used for equivalent functions.

Fig. 1a, 1b show a braking device as it is used for an elevator drive, according to an embodiment of the present invention in the released, non-braking state in a side or frontal view. The braking device comprises a static element in the form of a multi-part housing 1 which is inertially fixed. In the housing 1, a movable element in the form of a working shaft 2 is rotatably mounted and has with respect to the housing 1 to the rotational degree of freedom φ. On the shaft are two brake elements in the form of brake discs 5 axially displaceable, but rotationally fixed, for example by means of a spline or a key (not shown).

Two actuator elements in the form of armature discs 4 are axially displaceable, but rotatably mounted in the housing 1. For this purpose, three bolts 9 are distributed over the circumference, pass through the passage or blind holes in the housing 1 and the armature discs 4 and on which the armature discs 4 slide.

Between each of a brake disc 5 and an armature disc 4, a relative element in the form of a disc 3 is mounted axially displaceable. The discs 3 each have three groove-like recesses 10 with a groove bottom, which pass through the bolts 9 in such a way that they rest on the respective groove base and thus rotatably support the discs 3. A rotation of the discs 3 is positively limited by the flanks of the grooves 10, wherein the discs can be rotated by a certain angle before the bolts 9 abut the respective flanks. By two springs which are accommodated in the housing 1 and at the extended thereto flanks 10 (in Fig. 1a Supported inside, the discs are 3 in their in Fig. 1, 2 shown normal position A biased, which is detected by a sensor device 8.

Fig. 1a, 1b show the braking device in the released state. For this purpose, electromagnets pull the armature disks 4 against the tension of a compression spring 7 away from the brake disks 5, which thereby can rotate freely with the working shaft 2. In this state, the Relative elements 3 held by the above-mentioned springs in their normal position, indicating a fault-free operation.

Fig. 2a, 2b show the braking device in the closed state. For this purpose, the electromagnets are no longer supplied with energy, so that the armature discs 4 are acted upon by the springs 7 with a normal force FN in the direction of a second, axial degree of freedom y. With the same normal force, the armature discs 4 press the relative elements 3 against the brake discs 5, which are thereby axially displaced and pressed against the housing 1 with the same normal force.

In a first contact surface 6.1 between the housing 1 and the brake disk 5, in a second contact surface 6.2 between the brake disk 5 and the relative element 3 or in a third contact surface 6.3 between the relative element 3 and the armature disk 4, a first, second or third frictional contact closes under this normal force FN , In this case, due to the rotating working shaft 2 in the first and second frictional contact from the beginning of sliding friction prevails, so that a first or second friction force (or a friction torque) FRi ^G = μi ^G × FN (i = 1, 2) sets. In this case, μi ^G denotes the Gleitreibwert in the first and second frictional contact.

$$\Rightarrow \mathrm{\mu }{\mathrm{3}}^{\mathrm{H}}\times \mathrm{FN}>\mathrm{\mu }{\mathrm{2}}^{\mathrm{G}}\times \mathrm{FN}$$

$$\Rightarrow \mathrm{FR}3{\max }^{\mathrm{H}}\mathrm{>}{\mathrm{FR}2}^{\mathrm{G}}$$

In the third frictional contact, static friction prevails at first, since relative element 3 and armature disk 4 rest relative to one another. The maximum acting third frictional force FR3max is thus given by FR3max ^H = μ3 ^H × FN, where μ3 ^H indicates the static frictional value in the third frictional contact. This is chosen such that the maximum third static friction force is greater than the second Gleitreibkraft: $$\mathrm{\mu }{\mathrm{3}}^{\mathrm{H}}\mathrm{>}\mathrm{\mu }{\mathrm{2}}^{\mathrm{G}}$$

$$\Rightarrow \mathrm{\mu }{\mathrm{3}}^{\mathrm{H}}\times \mathrm{FN}>\mathrm{\mu }{\mathrm{2}}^{\mathrm{G}}\times \mathrm{FN}$$

$$\Rightarrow \mathrm{FR}3{\mathrm{Max}}^{\mathrm{H}}\mathrm{>}{\mathrm{FR}2}^{\mathrm{G}}$$

By the adhesive force reserve (FR3max ^H - FR2 ^G ), the relative element 3 is held in its normal position A, while the brake disc 5 slides on it. Finally, the working wave 2 stops ( Fig. 2 ), the first and second frictional contact also change from sliding to static friction. Since the static friction values μ1 ^H = μ2 ^H >> μ3 ^H are selected, the maximum second friction force FR2max is now greater than the maximum third friction force FR3max. It should be noted that for the sake of simplicity only one coefficient of friction μi ^H , μi ^G is used. In reality, each of these coefficients of friction is subject to a scattering range or tolerance. For example, the definition μ3 ^H > μ2 ^G is to be understood such that the value of μ3 ^H , irrespective of its tolerance position, is greater than the value of μ2 ^G , irrespective of its tolerance position. Preference is given to Tolerance limits therefore chosen so that the described relationships also apply to frictional forces or coefficients of friction, which are at the tolerance limits, in order to ensure the functionality of the invention even in the case of variations occurring within the tolerances in practice.

A possible malfunction of the braking device is that the braking device does not solve faulty when the working shaft is put back into operation. In this case, the working shaft 2 exerts over the brake disk 5, starting from that described above with reference to FIG Fig. 2 described holding position, a force on the still closed first, second and third frictional contact. Since the maximum third frictional force is the lowest due to the choice of the coefficients of friction μ1 ^H = μ2 ^H >> μ3 ^H , first the third frictional contact changes from static friction to sliding friction, the relative element 3 begins to rotate relative to the armature disk 4. The relative element turns into the in Fig. 3 shown brake position B, which is detected by the sensor device 8. This then outputs a state information to a monitoring logic 11. The monitoring logic 11 evaluates the signal of the sensor device 8 using other signals, such as movement or speed state of the driving body or the movable element 2 and / or a brake signal indicating whether the brake to or is open, and outputs any error information to an elevator control (not shown), which stops the drive of the working shaft 2 and thus prevents annealing of the brake discs 5 and triggers a corresponding service message.

A further possible malfunction of the braking device is that the holding force applied by the braking device is insufficient. Again, starting from with reference to Fig. 2 described holding position is in the normal position A maximum of the braking device applied braking force FRmax due to the design with two brake discs $$\mathrm{FRmax}\mathrm{=}2\times \left(\mathrm{\mu }{1}^{\mathrm{H}}+\mathrm{\mu }{3}^{\mathrm{H}}\right)\times \mathrm{FN}$$

As stated above, due to the rotational degree of freedom (φ in the equations, instead of translational forces, torques can also be used.) If the frictional forces are not sufficient, the working shaft 2 begins to rotate ^H = μ2 ^H >> μ3 ^H the third frictional contact changes from static friction to sliding friction, while static friction still exists in the second frictional contact The relative element 3 begins to rotate relative to the armature disk 4. The relative element in turn rotates in in the Fig. 3 shown brake position B, which is detected by the sensor device 8. This then gives a malfunction message as before described for example via a monitoring logic to an elevator control (not shown).

In the braking position B ( Fig. 3 ) prevents the positive connection between the pin 9 and the flanks of the recess 10 further rotation of the relative element 3, this is characterized in the first degree of freedom φ relative to the housing 1 fixed. Thus now transmits the relative element 3, the larger second Haftreibkraft on the brake disc 5, the total braking force increases accordingly $$\mathrm{FR}\mathrm{=}2\times \left(\mathrm{\mu }{1}^{\mathrm{H}}+\mathrm{\mu }{2}^{\mathrm{H}}\right)\times \mathrm{FN}$$

Since the braking device is designed so that in normal cases the frictional force provided in the first and third frictional contact according to equation (6) is sufficient to hold the working shaft 2, a safety margin of (μ1 ^H + μ2 ^H ) / (μ1 ^H + μ3 ^H ).

Fig. 4 shows a braking device according to a second embodiment in the released state in a lateral section. This braking device is provided for an elevator installation, in which the braking device 24.1, 24.2 to a brake disc of an elevator drive, as in the FIGS. 11 and 12 is shown attached or in which the housing 1, which on an elevator car 16, similar to in Fig. 13 shown, may be fixed, in a first degree of freedom x along a brake rail 2, 15 moves.

With ventilated braking device ( Fig. 4 ) an electromagnet draws an anchor element 4 against the bias of a compression spring 7 in a second degree of freedom y in the housing 1, so that the housing 1 along the brake rail can slide smoothly.

To decelerate the elevator car 16, the electromagnet (or other suitable air actuators) is switched off ( Fig. 5 ), the compression spring 7 presses the anchor element 4 in the second degree of freedom y with a normal force FN against a relative element 3, which is arranged displaceably in the anchor element 4 along the first degree of freedom x and by two-sided compression springs in a normal position A ( Fig. 4 . 5 ) is held. As a result, the relative element 3 is pressed with the normal force FN against the brake rail 2, 15, which in turn is pressed against the housing 1. In this case, in a first contact surface 6.1, in which the brake rail 2 is pressed against the housing 1, in a second contact surface 6.2, in which the relative element 3 touches the brake rail 2, and in a third contact surface 6.3, in the anchor element 4 and relative element. 3 in contact with each other, a first, second and third, respectively Frictional contact closed. In the first and second frictional contact there is sliding friction due to the brake rail 2 moving relative to the housing 1, and stiction in the third frictional contact between the relatively relative and anchoring element 3, 4 resting relative to one another.

$$\Rightarrow \mathrm{FR}{1}^{\mathrm{G}}=\mathrm{FR}{2}^{\mathrm{G}}\mathrm{<}\mathrm{FR}{\mathrm{3}\max }^{\mathrm{H}}$$

As in the first embodiment, the adhesion coefficients μ1 ^H = μ2 ^H >> μ3 ^{H are} selected. Nevertheless, the sliding friction values μ1 ^G = μ2 ^G in the first and second contact surfaces are smaller than the static friction coefficient μ3 ^H in the third contact surface. Since all contact surfaces are subjected to the same normal force FN, the sliding friction force in the first and second friction contact is lower than the maximum static friction force in the third friction contact: $$\mathrm{\mu }{1}^{\mathrm{G}}=\mathrm{\mu }{2}^{\mathrm{G}}<\mathrm{\mu }{3}^{\mathrm{H}}<\mathrm{\mu }{1}^{\mathrm{H}}=\mathrm{\mu }{2}^{\mathrm{H}}$$

$$\Rightarrow \mathrm{FR}{1}^{\mathrm{G}}=\mathrm{FR}{2}^{\mathrm{G}}\mathrm{<}\mathrm{FR}{\mathrm{3}\mathrm{Max}}^{\mathrm{H}}$$

Therefore, the brake rail 2, 15 slides in the first and second frictional contact, the relative element 3 remains in its biased by the compression springs normal position A ( Fig. 5 ). At a standstill, the first and second frictional contact also change from sliding to static friction, the total friction force with which the housing 1 holds the brake rail 2 is limited by the static friction in the first and third frictional contact: $$\mathrm{FRmax}\mathrm{=}\left(\mathrm{\mu }{1}^{\mathrm{H}}+\mathrm{\mu }{3}^{\mathrm{H}}\right)\times \mathrm{FN}$$

As in the first embodiment, a blocking braking device that does not dissolve despite movement of the housing 1 relative to the brake rail 2, as well as too low Gesamtreibkraft FRmax according to equation (6 ") leads to a take away of the relative element 3 by the brake rail 2 in the first degree of freedom x until it is stopped at an upper stop in the anchor element 4 (not shown), whereby a sensor 8 registers the transition of the relative element from the normal position A (FIG. Fig. 5 ) in this brake position B ( Fig. 6 ) and outputs a malfunction message. As soon as the relative element is fixed relative to the anchor element 4 by the stop (not shown) in the first degree of freedom x, the second friction force FR2 counteracts the movement in the second contact surface 6.2, the total friction force increases from FR = (μ1 + μ3) × FN FR = (μ1 + μ2) × FN.

In the first and second exemplary embodiments, the maximum second and third frictional forces were respectively realized by a corresponding selection of the coefficients of friction μ2, μ3, in particular of the static frictional values μ2 ^H , μ3 ^H. Alternatively or additionally, however, the different maximum frictional forces can also be realized in that the third contact surface 6.3 is inclined relative to the normal force. This shows Fig. 7 in a schematic diagram of the forces acting on a relative element 3 forces when exposed to the common normal force FN. This in Fig. 7 The principle shown can be implemented, for example, in the first or second embodiment, in which case the same reference numerals correspond to the same elements, the actuating element 4 in Fig. 7 So for example, the armature disk 4 in the first or the anchor element 4 in the second embodiment corresponds.

Let it first be assumed that the held movable element 2 is under the influence of external forces, for example the load of an elevator car, in the first degree of freedom x in the positive direction (upward in FIG Fig. 7 ) to move. Then, when the actuation element 4 is acted upon by the normal force FN in the second contact surface 6.2, a frictional force FR2 which is the same as the sum of the remaining forces acting on the movable element 2 but can become maximum FR2max = μ2 ^H × FN arises.

The normal force FN acting in the third contact surface 6.3 inclined by the angle (π-α) against the normal force FN splits into two components, the one component FN × sin (α) being perpendicular to the third contact surface 6.3, the other component FN × cos (α) is oriented tangentially to the third contact surface 6.3. The third frictional force acting maximally in the third contact surface 6.3 thus results from the one component to FR3max = μ3 ^H × sin (α) × FN. By a suitable choice of the angle of inclination α, a lower maximum third frictional force can thus be predetermined, for example, with the same friction coefficient. If this frictional force is still projected into the first degree of freedom x, a movement of the relative element 3 relative to the actuating element 4 in the first degree of freedom counteracts only a maximum of a frictional friction force of FR3max = μ3 ^H × sin ² (α) × FN.

How to continue Fig. 7 detects, acts a movement of the relative element 3 relative to the actuator in the first degree of freedom x in the positive direction (upward in Fig. 7 ) In addition, a component FN × cos (α) counter, which increases the total effective maximum third frictional force. When moving in the negative direction (down in Fig. 7 ) reduces these components FN × cos (α), however, the effective maximum third friction force, so that there are different maximum third friction forces in both directions of movement. This can be advantageously used if, for example, the elevator car, which is held by the braking device, is only partially balanced, ie the movable element 2 must be kept stronger in one direction of movement than in the other.

Furthermore, a displacement of the relative element 3 relative to the actuating element 4 inevitably results in a change in a feed path along the degree of freedom y. This change causes an increase or decrease in the normal force FN according to a force characteristic of Zustellaktoren such as the compression spring 7 ( 4 to 6 ). Thus, a braking force can be influenced according to a movement or braking direction.

erfüllt wird. Dies ist nicht zwingend, da in vielen heutigen Anwendungsfällen eine Bremseinrichtung im Normalfall nur zum Halten, bspw. einer Aufzugskabine im Stillstand verwendet wird. Eine Verwendung der Bremseinrichtung zum Bremsen ist lediglich in einem Fehlerfalle erforderlich und stellt somit schon selbst eine Fehlersituation dar. Es ist in diesen Einzelfällen nicht erforderlich, dass das Relativelement 3 in seiner Normallage verbleibt. Es darf durchaus von seiner Normallage in die Bremslage verschoben werden, wodurch dann die entsprechend höhere Bremskraft $$\mathrm{FR}=\mathrm{FR}1+\mathrm{FR}2$$

zur Anwendung gelangt. Dies kann erreicht werden, indem die Reibwerte µ3^H, µ3^G der dritten Kontaktfläche deutlich kleiner als die Reibwerte µ2^H, µ2^G der zweiten Kontaktfläche gewählt werden. $$\mathrm{\mu }{3}^{\mathrm{G}}<\mathrm{\mu }{3}^{\mathrm{H}}<<\mathrm{\mu }{2}^{\mathrm{G}}<\mathrm{\mu }{2}^{\mathrm{H}}$$

The exemplary embodiments make reference to a coordination of the sliding and static friction coefficients of the friction surfaces in order to be able to reliably detect a malfunction both during sole holding as well as during braking and subsequent holding. This is achieved by the condition $$\mathrm{\mu }{2}^{\mathrm{G}}<\mathrm{\mu }{3}^{\mathrm{H}}<\mathrm{\mu }{2}^{\mathrm{H}}$$

is fulfilled. This is not mandatory, since in many of today's applications a braking device is normally used only for holding, for example, an elevator car at a standstill. A use of the braking device for braking is only necessary in an error case and therefore already constitutes an error situation itself. It is not necessary in these individual cases that the relative element 3 remains in its normal position. It may well be moved from its normal position in the braking position, which then the correspondingly higher braking force $$\mathrm{FR}=\mathrm{FR}1+\mathrm{FR}2$$

used. This can be achieved by selecting the coefficients of friction μ3 ^H , μ3 ^{G of} the third contact surface to be significantly smaller than the coefficients of friction μ2 ^H , μ2 ^{G of} the second contact surface. $$\mathrm{\mu }{3}^{\mathrm{G}}<\mathrm{\mu }{3}^{\mathrm{H}}<<\mathrm{\mu }{2}^{\mathrm{G}}<\mathrm{\mu }{2}^{\mathrm{H}}$$

Of course, combinations of the embodiments shown are possible. For example, several second and third contact surfaces can be combined to form a first contact surface, which additionally increases the safety margin.

In a preferred embodiment, the braking device is 24.1, 24.2 as in the Fig. 10 shown in a drive 20 of an elevator installation 18 (as described below with reference to FIG Fig. 13 is explained) ein- or grown. The drive 20 includes one or more traction sheaves or traction wheels 22 which is integrated or mounted in a drive shaft 2. The drive shaft 2 is driven by a motor 21 and held by the brake device 24.1, 24.2 at a standstill or braked, if necessary. In some cases, a translation can be arranged between the motor 21 and the drive shaft 2. The drive 20 thus also includes the braking device 24.1, 24.2 which usually two substantially identical units is divided. Each of the units is in its braking position (B) taken in a position to the moving body and hold on. According to a first embodiment of the drive, the two units are assembled into a single braking device and arranged at one end of the drive shaft. The drive shaft in this embodiment corresponds to the movable element 2. This type of arrangement is cost-effective, since the braking device can be pre-assembled, for example, as a complete unit.
According to an embodiment of the drive 20 according to the invention, the two units of the braking device 24.1, 24.2 are attached to the two ends of the drive shaft 2. This means that the traction sheave 22 is arranged between the units of the braking device 24.1, 24.2. When braking a braking or holding torque is thus distributed away from the traction sheave 22 on the two units. This results in much better power distributions in the drive shaft 2 and a risk of failure of the brake device due to a breakage of the drive shaft 2 is reduced.
Ideally, the braking effect between normal position and braking position is doubled. This is the case when the coefficient of friction μ3 in the third contact surface is approximately zero. Using brake assembly with a plurality of brake devices connected in series 24.1, 24.2 such as in the Fig. 8a and 8b shown, the brake force gain between normal and braking position can be influenced. If, for example, a plurality of brake discs 5 and relative elements 3 or static elements 1 can be arranged one behind the other, a desired brake gains can be achieved by carrying out the freewheeling path of the individual relative or static elements. In the example according to Fig. 8a and 8b are three second contact surfaces 6.2, which only come into effect in the braking position to a first contact surface 6.1. Neglecting the frictional force of the third contact surface 6.3 thus results in a quadrupling of the braking force upon reaching the braking position. A person skilled in the art can determine any combinations

11 and FIG. 12 show an alternative arrangement of an elevator drive 20 with brake devices that do not belong to the invention. Here are several braking devices 24.1, 24.2, 24.3, etc. as in 4 to 6 described distributed over a circumference of a brake disc 2, which forms a unit with the drive shaft.

Fig. 13 shows an elevator system 18 with elevator drive 20 which is arranged in the upper region of a chute 12. The elevator drive 20 drives the elevator car 16 by means of the traction wheel 22 via carrying and propelling means 13. The carrying and propelling means 13 connects the elevator car 16 to a counterweight 17, so that, corresponding to a driving direction the elevator drive the cabin 16 upwards, and the counterweight 17 is moved downwards or reversed accordingly with a changed direction of rotation of the elevator drive. If the elevator drive 20 is held by its brake devices 24.1, 24.2, the car and counterweight 17 are also at a stop or at a standstill. In the example shown, cab 16 and counterweight 17 are connected via pulleys 14 to the carrying and propellant 13. Thus, the forces acting on the drive 20 forces are halved.
Alternatively, the drive 20 may also be arranged instead of one of the deflection rollers 14.

The two units of the braking device attached to the two ends of the drive shaft 2. This means that the traction sheave 22 is arranged between the units of the braking device 24.1, 24.2. When braking a braking or holding torque is thus distributed away from the traction sheave 22 on the two units. This results in much better power distributions in the drive shaft 2 and a risk of failure of the brake device due to a breakage of the drive shaft 2 is reduced.

If the individual units or devices of the brake assembly, preferably units as in the embodiments of the Fig. 4 to Fig. 7 are shown and explained, arranged directly on the elevator car, it is advantageous to divide the brake units on both sides of the elevator car. The resulting braking and holding forces can thus be introduced in half each in the corresponding brake or guide rails. If, in a corresponding manner, the brake arrangement is divided among, for example, four brake devices, two of the brake devices are advantageously arranged below the elevator car and the remaining two brake devices are arranged in the upper region of the elevator car. This not only optimizes the introduction of force into the brake or guide rails, but also optimizes the introduction of force into the elevator car itself.
The person skilled in the art will recognize further advantageous arrangements. For example, he distributes the brake units on the elevator car and counterweight or on the car, or counterweight and pulleys or traction sheaves. This allows a distribution of braking and holding forces on different components or load zones. This increases the reliability because individual components are only burdened with partial forces.

Claims (23)

1. Lift drive (20) for driving and holding a lift cage (16) or a travel body, comprising

   - a traction wheel (22) for providing a driving and/or holding force for the lift cage (16) or travel body,

   - a motor (21) for driving the traction wheel (22),

   - a brake arrangement for holding the traction wheel (22) and

   - a drive shaft (2) connecting the traction wheel (22), the motor (21) and the brake arrangement together,

   wherein the brake arrangement comprises at least two brake devices (24.1, 24.2), characterised in that the traction wheel (22) is arranged between the brake devices (24.1, 24.2) and the brake devices (24.1, 24.2) are arranged substantially at the ends of the drive shaft (2).
2. Lift drive (20) according to claim 1, characterised in that the brake devices (24.1, 24.2) arranged on either side of the traction wheel (22) are individually activated so that a monitoring logic system (11) can ascertain whether one brake device (24.1, 24.2) alone is in a position of keeping the lift cage (16) at standstill.
3. Lift drive (20) according to claim 2, characterised in that

   - activation of the brake devices (24.1, 24.2) is carried out for application thereof with a delay in time or

   - during a stop of the lift cage (16) one brake device (24.1, 24.2) is briefly released and the monitoring logic system (11) ascertains during the time in which one of the brake devices (24.1, 24.2) is applied whether the one brake device (24.1, 24.2) alone is in a position of keeping the lift cage (16) at standstill.
4. Lift drive according to any one of the preceding claims, wherein the brake device (24.1, 24.2) is provided with

   - a static element (1),

   - a movable element (2) movable relative to the static element in a first degree of freedom (ϕ; x) in correspondence with a direction of travel of the travel body, wherein a first frictional contact in a first contact surface (6.1) can be formed between the static element (1) and the movable element (2) by a normal force (FN) acting in a second degree of freedom (y), wherein in the first frictional contact a first friction force (FR1) opposes movement of the movable element relative to the static element (1), and

   - a relative element (3) adjustable in the second degree of freedom (y) in the direction of the movable element (2), wherein a second frictional contact in a second contact surface (6.2) is formed between the movable element (2) and the relative element (3) by the normal force (FN), wherein in the second frictional contact a second friction force (FR2) opposes movement of the movable element relative to the relative element,

   characterised in that the relative element (3) is movable in the first degree of freedom (ϕ; x) relative to the static element (1) between a normal position (A) and a braking position (B), wherein the relative element (3) is biased into the normal position (A).
5. Lift drive (20) according to claim 4, characterised in that a movement of the relative element (3) out beyond the braking position (B) is blocked.
6. Lift drive (20) according to one of the preceding claims 4 and 5, wherein the brake device (24.1, 24.2) further comprises

   - an actuating element (4) which is fixed in the first degree of freedom (ϕ; x) relative to the static element (1) and which is adjustable in the second degree of freedom (y) in the direction of the movable element (2), wherein a third frictional contact in a third contact surface (6.3) in which a third friction force (FR3) opposes movement of the relative element (3) relative to the actuating element (4) is formed between the actuating element (4) and the relative element (3), in adjusted state, by the normal force (FN);

   wherein the second and third contact surfaces (6.2, 6.3) are so constructed that a maximum second friction force (FR2max) of the second contact surface (6.2) is greater than a maximum third friction force (FR3max) of the third contact surface (6.3).
7. Lift drive (20) according to any one of the preceding claims 4 to 6, characterised in that the brake device (24.1, 24.2) further comprises a sensor device (8) for detecting the normal and/or braking position (A, B) of the relative element (3).
8. Lift drive (20) according to claim 7, characterised in that the monitoring logic system (11) evaluates signals of the sensor device (8), a control signal of the brake device (24.1, 24.2) and a movement state of the movable element (2) and determines a function of the brake device (24.1, 24.2).
9. Lift drive (20) according to claim 8, characterised in that the monitoring logic system ascertains, as function, a fault function when:

   - the control signal of the brake device (24.1, 24.2) indicates "applied", the movement state of the movable element (2) indicates "0" and the relative element (3) is disposed in its braking position (B); or

   - the control signal of the brake device (24.1, 24.2) indicates "released", the movement state of the movable element (2) indicates "≠0" and the relative element (3) is disposed in its braking position (B).
10. Lift drive (20) according to one of the preceding claims 8 and 9, characterised in that the monitoring logic system ascertains, as function, a normal function when:

    - the control signal of the brake device (24.1, 24.2) indicates "applied", the movement state of the movable element (2) indicates "0" and the relative element (3) is disposed in its normal position (A); or

    - the control signal of the brake device (24.1, 24.2) indicates "applied", the movement state of the movable element (2) indicates "≠0" and the relative element (3) is disposed in its braking position (B); or

    - the control signal of the brake device (24.1, 24.2) indicates "released", the movement state of the movable element (2) indicates "≠0" and the relative element (3) is disposed in its normal position (A).
11. Lift drive (20) according to any one of the preceding claims 6 to 10, characterised in that the second contact surface (6.2) of the brake device (24.1, 24.2) has a higher coefficient of friction (µ), particularly a higher coefficient of static friction (µ^H), than the third contact surface (6.3).
12. Lift drive (20) according to any one of the preceding claims 6 to 11, characterised in that the third contact surface (6.3) of the brake device (24.1, 24.2) has an inclination relative to the normal force (FN).
13. Lift drive (20) according to any one of the preceding claims 6 to 12, characterised in that the relative element (3) and/or the actuating element (4) of the brake device (24.1, 24.2) is or are so moved by the normal force (FN) in the second degree of freedom (y) that the first, second and third frictional contacts are formed.
14. Lift drive (20) according to any one of the preceding claims 6 to 13, characterised in that the brake device (24.1, 24.2) further comprises a brake element (5) which is fixed in the first degree of freedom (ϕ) relative to the movable element (2) and is so moved by the normal force (FN) in the second degree of freedom (y) that the first, second and third frictional contacts are formed.
15. Lift drive (20) according to any one of the preceding claims 6 to 14, characterised in that the movable element (2) and the static element (1) of the brake device (24.1, 24.2) are so moved, in particular deformed, relative to one another by the normal force (FN) in the second degree of freedom (y) that the first, second and third frictional contacts are formed.
16. Lift drive (20) according to any one of the preceding claims 6 to 15, characterised in that the actuating element (4) of the brake device (24.1, 24.2) is biased, particularly via resilient means (7), by the normal force (FN) and selectably released electromagnetically and/or hydraulically.
17. Lift drive (20) according to any one of the preceding claims 6 to 16, characterised in that the brake device (24.1, 24.2) comprises a plurality of relative elements (3) as well as actuating elements (4) respectively associated therewith, wherein a second frictional contact in a second contact surface (6.2) is formed between each relative element (3) and the movable element (2) by a normal force (FN) and a third frictional contact in a third contact surface (6.3) is formed between each relative element (3) and the associated actuating element (4) by the normal force (FN).
18. Method of driving and holding a lift cage (16) or a travel body by means of a lift drive (20), with

    - a traction wheel (22) for providing a driving or holding force for the lift cage (16),

    - a motor (21) for driving the traction wheel (22),

    - a brake arrangement for holding the traction wheel (22) and

    - a drive shaft (2) connecting the traction wheel (22), the motor (21) and the brake arrangement together, wherein the brake arrangement comprises at least two brake devices (24.1, 24.2), which brake devices (24.1, 24.2) are arranged on either side of the traction wheel (22), wherein

    in a first method step a first brake device (24.1) is actuated, preferably released,
    in a second method step the effectiveness of the brake device (24.1, 24.2) in braking or holding engagement is checked and
    in a third method step either the first brake device (24.1) is actuated back again, preferably applied, or a second brake device (24.2) is actuated.
19. Lift installation (18) with a lift drive (20) according to any one of claims 1 to 17, characterised in that

    - the lift drive (20) is arranged in stationary position in a travel shaft (12) and the lift drive (20) can raise, lower and hold the lift cage (16) by way of a supporting and driving means (13) connecting the lift drive (20) with the lift cage (16) or

    - the lift drive (20) is arranged at the lift cage (16) and the lift drive (20) transmits a traction force to the travel shaft (12) by means of traction wheel (22) and the lift cage (16) can be raised, lowered and/or held by means of this traction force.
20. Lift installation according to claim 19, characterised in that one of the static element (1) and the movable element (2) of the brake device (24.1, 24.2) or the lift drive (20) is arranged to be fixed in terms of inertia and the other one of the static element (1) and the movable element (2) of the brake device (24.1, 24.2) is so coupled with a travel body, in particular with a cage of the lift installation, that it can hold and/or brake this.
21. Lift installation according to claim 19 or 20, characterised in that the normal force (FN) is so dimensioned that an adhesion force produced in the normal position (A) of the brake device (24.1, 24.2) of the lift drive (20) is sufficient to hold the travel body together with its permissible load.
22. Lift installation according to any one of claims 19 to 21, characterised in that the normal force (FN) is so dimensioned that a sliding force produced in the braking position (B) of the brake device (24.1, 24.2) of the lift drive (20) is sufficient to securely brake the travel body together with its permissible load.
23. Lift installation according to any one of claims 19 to 22, characterised in that the sliding force produced in the braking position (B) of the brake device (24.1, 24.2) of the lift drive (20) is at least 50% greater than the adhesion force produced in the normal position (A) of the brake device (24.1, 24.2).

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