EP1751048B1 - Safety brake - Google Patents

Abstract

The invention relates to a safety brake (1). According to the invention, an operating parameter is detected by means of a measuring sensor for each relative position of the brake rotor (2) to the brake stator (3) that lies outside the positive-fit locked position of the brake. Said operating parameter is fed to a generator system (7) in order to supply hydraulic fluid to a piston-cylinder unit (5), which initiates the release of the brake, thus permitting pre-determined functional interdependencies to exist in the operating area of the safety brake (1) that lies outside the locked position of said brake.

Description

The present invention relates to a safety brake according to the preamble of the main claim.

An example of a Safe 7s brake is off US-A-6247575 known.

Such safety brakes are used in mechanical engineering to decelerate known loads to a standstill. In the case of the onset of braking, the braked and still moving load must necessarily come to a standstill.

Here, the impressed by external forces load torque, which is due to the moving load, the braking torque generated between the brake rotor and the brake stator is directed opposite. The braking torque therefore continuously leads to complete destruction of the kinetic energy presented by the load torque. After that, the safety brake is in the brake-lock position, wherein there is stiction between the brake rotor and the brake stator.

Such safety brakes are known, for example, as spring-actuated brakes, which are released by a pressure medium. The springs act as force transmitters, which can even be supported by hydraulic components in their power. However, the function of this force transmitter is canceled in any case by the piston-cylinder unit when the safety brake is shifted to its brake release position.

The braking function is initiated via the spring force, while the controlled pressure medium counteracts this spring force to release the safety brake again.

As an alternative to these passive brakes, active brakes may also be used in which the braking function is induced by a hydraulic or pneumatic pressure medium in addition to or instead of a spring force actuation.

Without limiting the invention brakes come into consideration, which are based on the opposite principle. This is to be understood that the brakes are displaced by the force transmitter in the brake release position while they are acted upon by the pressure medium in the direction of the brake lock position.

For all the brakes of different types mentioned above, therefore, the following statements apply accordingly.

The following is therefore, without limitation of the invention thereto, always spoken only by spring-loaded and vented with pressure medium brakes, as long as it is not expressly pointed to necessary deviations for brakes of other types.

Such safety brakes are used, for example, in mechanical engineering for braking loads, e.g. in escalators, presses, transfer belts or the like.

They are characterized by the fact that in the operating region between the brake release position and the brake lock position, a continuous decrease in the rotational speed of the brake rotor takes place to a standstill. During the continuous decrease The speed is between the brake rotor and the brake stator exclusively on sliding friction, which ultimately passes into static friction with taking the brake lock position. Thereafter, the load is held at a standstill until the brake is vented by the pressure medium.

In such spring-loaded brakes the braking torque is practically fixed by the upcoming spring forces.

This is perceived as a disadvantage, for example, if the braking effect is to be load-dependent. A practical application example is given on escalators.

An overloaded with only a few people escalator is namely slowed down in emergency situations only so slowly that the damage to the passengers is not to be feared although the safety brake is designed for the high braking torque of a fully occupied escalator.

It is therefore an object of the present invention to further develop the known safety brake so that in the operating range defined solely by sliding friction between the brake rotor and the brake stator an adjustment of the maximum braking torque dependent on external operating parameters of this operating range is possible.

This object is achieved by the invention with the features of the main claim.

From the invention there is the advantage that the respective effective braking torque between the maximum braking torque, in which frictional engagement between the brake stator and the brake rotor and the value NULL can be set adjustable to the respective external operating conditions, which naturally can not be constant over time To take account.

This advantage is achieved in that at least one predetermined operating parameter, which occurs as a significant predictor of the safety brake in the operating range outside the brake lock position, detected by a suitable measuring sensor and returned as a manipulated variable in the adjustment of the safety brake, so that the brake function of the safety brake according to each detected operating parameters can be adjusted.

This can e.g. be effected by time-dependent, pressure-dependent, load-dependent, wear-dependent, torque-dependent or speed-dependent influencing the brake-time function.

Such measures may e.g. be required to take into account the time-dependent course of the braking torque depending on the respective state of wear of the brake pads.

Other embodiments relate to the consideration of any leaks in pressurized system. As is known, these are hydraulic or pneumatic systems, which are naturally also subject to a certain amount of wear and thus are exposed to the risk of leakage.

With incoming wear or leakage occurring the piston-cylinder unit for the displacement of the brake stator relative to the brake rotor would pass through a greater free travel, if - as before - the corresponding operating parameters would not be detected and returned to the encoder system.

The advantage of the invention is therefore also in a time- and wear-independent constant mode of action the safety brake, which is supplemented by further embodiments.

This is to be understood in particular as a torque-dependent control, in which via a torque-measuring sensor, e.g. a predetermined course of the braking torque can be achieved.

In addition, certain pre-pressures can be realized, so that the force applied via the force transmitter maximum braking force is limited.

In the case of a not released with pressure fluid but actuated with pressure medium safety brake could also limit the maximum braking force in this way.

If a piston-cylinder unit is provided for the encoder system, it is easy to arrange a linear motor in the connection between the measuring sensor and the encoder system, which acts on the piston-cylinder unit as a function of the one or more operating parameters (n) respectively detected.

For this purpose, embodiments are given.

Suitable linear motors are in particular electromagnetic direct drives, which are controlled by a servo controller.

Such motors consist of only the rotor and stator together and are controlled via the servo controller with high dynamics.

In this case, the detected operating parameters can optionally be impressed on the servo controller via appropriate electrical circuits as electrical input signals via simple electrical circuits.

If electrically operated linear motors are used, they offer the additional advantage of freedom from wear.

However, it is also essential that in contrast to the known antilock braking systems for vehicle brakes the operating range of the safety brake according to the invention, within which the respective braking torque is a proportional function to the / measured operating parameter (s) is always limited to the range of sliding friction between the brake rotor and the brake stator ,

It should be expressly stated in this respect that the invention should not be in the area of application, which is in the transition region between sliding friction and static friction as in ABS, but that it is always assumed that a fixed predetermined load torque, which is to be counteracted by the predetermined braking torque that with increasing load moment also the braking torque increases and vice versa.

Expediently, the respective braking torque runs as a function of the time required to decelerate the load torque to standstill after a mathematically as strictly monotone writable rule, after the shutdown of the system all the masses involved have come to rest.

Furthermore, it is proposed that the rotor of the linear motor is pre-positioned by a further linear motor.

In this way, a predetermined pressure can build up in the hydraulic or pneumatic system and thus predetermine a certain limit torque, which is less than the maximum possible braking torque.

In particular, using a spring-loaded and fluidly ventilated safety brake can be on the another linear motor to achieve a relief of the brake springs by a predetermined pressure and in this way simply specify a limit torque.

In this case, the further linear motor forms a rearward stop for the rotor of the first linear motor, which can be acted upon from time to time by this tracked zero point, so to speak.

Preferably, an embodiment is used for the further linear motor, which is held in the respective prepositioned position under self-locking.

A preferred embodiment consists in a spindle motor.

This embodiment offers advantages in particular when e.g. due to power failure the previously determined braking torque must then be available again.

In addition, predetermined functions of the safety brake can be stored in the operating range between brake release position and outside the brake lock position in function blocks, which can sit using appropriate transducer in the connection between the measuring sensor and the encoder system.

As significant factors that can be detected via the measuring sensor, in addition to internal pressure state variables such as pressure, temperature, leakage loss and mechanical state variables of the safety brake into consideration such. Wear or path-dependent pressurization.

With regard to further influencing variables which may be considered here, however, changing external loads should also be mentioned in particular insofar as it makes sense to influence the braking function as a function of the external loads.

The invention can also be applied to couplings, provided they serve as safety couplings, e.g. as slip clutches with predetermined release torque. For these safety couplings, the above and following description applies accordingly.

In the following the invention will be explained in more detail with reference to embodiments

Figur 1

ein erstes Ausführungsbeispiel der Erfindung

Figur 2

ein Ausführungsbeispiel der Erfindung mit einem Funktionsnetzwerk Druck-Zeit

Figur 3

ein Ausführungsbeispiel der Erfindung mit wegabhängiger Steuerung

Figur 4

ein Ausführungsbeispiel der Erfindung mit Funktionsnetzwerk Drehzahl-Kraft

Figur 5

ein Ausführungsbeispiel der Erfindung mit Funktionsnetzwerk Drehmoment-Zeit

Figur 6

ein Ausführungsbeispiel der Erfindung mit Verschleißüberwachung

Figur 7

ein Ausführungsbeispiel der Erfindung mit zwei hintereinander geschalteten Linearmotoren

Show it

FIG. 1

a first embodiment of the invention

FIG. 2

an embodiment of the invention with a function network pressure-time

FIG. 3

an embodiment of the invention with path-dependent control

FIG. 4

an embodiment of the invention with functional network speed-force

FIG. 5

an embodiment of the invention with functional network torque-time

FIG. 6

An embodiment of the invention with wear monitoring

FIG. 7

An embodiment of the invention with two linear motors connected in series

Unless otherwise stated below, the following description applies to all figures.

The figures show a safety brake 1. In such safety brake 1 is a stationary mounted Bremsstator 3 ago with a relative to rotating brake rotor. 2

Between brake stator 3 and brake rotor 2, one or more brake pads are arranged so that the attacking load torque can be decelerated by the oppositely directed braking torque to a stop.

The stationary arrangement of the brake stator 3 serves with the onset of braking as an abutment to direct the initiated by the load torque in the brake rotor 2 forces and moments in the foundation.

In the embodiments shown, it is a spring-loaded and hydraulically ventilated safety brake.

In this safety brake - generally speaking - the braking torque is determined by the force of a force transmitter 4. During the relative rotation twischen brake rotor 2 and the brake stator 3 is applied to the brake pads exclusively on sliding friction, which passes into stiction only at a standstill.

In the present case, a plurality of helical springs 4 are provided in the present case, which press the axially movable but not co-rotating part of the brake stator 3 against the brake pads provided with brake pads of the brake rotor 2, as soon as the braking effect should begin.

The braking effect is canceled here by pressurizing a filled with a pressure medium piston-cylinder unit 5 by an axial relative movement between brake rotor 2 and brake stator 3 is used by the pressurization with pressure medium and in this way the respective braking torque is variable until reaching the brake release position.

To act on the piston-cylinder unit 5, which consists of a piston 5a and an associated cylinder 5b, serves an encoder system 7, which is connected via a pressure medium line 6 with the piston-cylinder unit 5.

The encoder system 7 is designed here as a piston-cylinder unit and connected to a tank 8, which always refills the pressure medium located in the closed space between the piston-cylinder unit 5 and the piston-cylinder unit 7 as required.

It is essential that the safety brake 1 comprises at least one measuring sensor 9a-k, which in the region of the axial relative movement between the brake rotor 2 and the brake stator 3 and in each case outside the operating range defined by the brake lock position for detecting at least one predetermined operating parameter. In this case, the measuring sensor 9a-k cooperates with the encoder system 7 such that in this operating range and in any case outside the brake lock position, the respective braking torque is a function of each detected operating parameter, wherein the predetermined by the coil springs braking torque - here subtractive - is supplemented by a mathematical Function according to which the encoder system 7 changes the pressure in the piston-cylinder unit 5 in directly proportional or indirectly proportional dependence on the value of the respectively detected operating parameter.

Under brake lock position in the present case that position is understood in which there is a state of stiction between the brake rotor 2 and the brake stator 3.

In consideration of the fact that there is an operating range not unequivocally associated with the sliding friction and the friction friction region, which is traversed, for example, in the operation of an antilock brake system, the present invention differs from this known one State of the art in that the respective operating range should be defined exclusively by the present sliding friction.

The encoder system 7 is also designed here as a piston-cylinder unit and is acted upon by a linear motor 10 which sits in the connection between the measuring sensor 9a-k and the encoder system 7.

The linear motor 10 is controlled by a control unit, which includes at least the one detected operating parameter 9 a-k as a necessary input variable.

In this way it is ensured that the feed of the linear motor 10 and thus the respective discharge of pressure medium from the piston-cylinder unit of the encoder system 7 takes place in the piston-cylinder unit 5 of the slave system in the form of a previously recognized dependence on this operating parameter.

Consequently, it is possible in this way to use state variables that are internal to the pressure medium, mechanical state variables or even external loads as influencing variables for the time-dependent, force-dependent, torque-dependent control of the safety brake.

For an easy-to-implement control of the linear motor 10, it is proposed to use an upstream servo-controller 11 which, if appropriate via a corresponding converter, receives the detected operating parameter as an input signal.

In particular, for linear motors 10 with electric drive can be achieved in this way simple signal dependencies and the electric drive for the linear motor 10 is subject to virtually no wear.

In addition, it is proposed that the interaction between the measuring sensor 9a-k and the encoder system 7 always be limited to the operating range of the sliding friction between the brake rotor 2 and the brake stator 3 according to a predetermined function.

This includes in particular the detection of the respective operating speed, at least as long as the operating speed is greater than zero, as has been found within this operating range of the safety brake control of the braking torque as desirable.

This is to be pointed out once again that with detection of the respective speed as an influencing variable for a control of the safety brake in particular all speeds are possible, which are greater than zero. A practical embodiment could be seen to smoothly and smoothly decelerate a load via the braking torque by increasingly reducing the braking torque, which must of course be greater than the load torque is also increasingly reduced to bring about the standstill virtually jerk-free.

It is therefore important to predetermine the course of the respective braking torque over the time required for braking the load torque to a standstill after a strictly monotone running function.

Within the scope of the present invention, a strictly monotonically running function is to be understood as a function curve in which two arbitrarily consecutive abscissa values can always be assigned two exclusively smaller or larger ordinate values, so that such a function has practically no turning points.

Additionally is in FIG. 7 shown that the rotor of the linear motor 10 is pre-positioned by another linear motor 12.

For this purpose, the further linear motor 12 either engages on the housing of the linear motor 10 and displaces it with its respective rotor position or the further linear motor 12 engages directly on the rotor of the linear motor 10 while the stator of the linear motor 10 is stationary.

In any case, however, the rotor of the linear motor 10 is pre-positioned by the further linear motor 12.

As FIG. 7 shows the further linear motor 12 is designed as a spindle motor, the spindle 13 is in each of the pre-positioning corresponding position under self-locking.

The spindle 13 can form a rear stop 14 for the rotor of the linear motor 10 in this way.

In addition to this show the Figures 2 . 4 and 5 in that the function of the operating parameter respectively represented and detected in an exemplary manner is stored in a function module 15, which sits in the connection between measuring sensor 9a-k and the encoder system 7.

In this way, predetermined functional relationships can be driven out of the detected operating parameter (s) with regard to the desired braking torque.

As examples of the operating parameters to be recorded, the FIGS. 1 . 2 . 3 . 4 . 5 . 6 and 7 Measuring sensors 9a, 9b, which serve to detect pressure-medium-internal state variables.

These are, for example, pressures P and temperatures T to understand.

In addition show Figures 3 . 4 and 6 Embodiments in which measuring sensors 9c to j are provided, which serve to detect mechanical state variables of the brake.

In the embodiment of FIG. 3 it is the detection of the respective feed in the piston-cylinder unit 5, which can be seen, for example, as the equivalent of the maximum predetermined braking torque.

In the embodiment of FIG. 4 the rotational speed is detected on the brake rotor 2 via a corresponding sensor 9j. In the embodiment of FIG. 6 is detected via a sensor 9e each of the present brake wear and the piston-cylinder unit 5 readjusted accordingly.

Especially FIG. 5 also shows an embodiment in which a measuring sensor 9k is used to detect the respective current load torque in order to readjust the braking force accordingly.

The present invention is not limited to the embodiments shown, in particular with regard to the possible operating parameters to be detected, as long as the operating parameters are detected in that operating range which is outside the brake locking position.

LIST OF REFERENCE NUMBERS

1

safety brake

2

brake rotor

3

brake stator

4

force transmitter

5

Piston-cylinder unit

5a

piston

5b

cylinder

6

Pressure medium line

7

encoder system

8th

tank

9a

Measuring sensor (pressure-medium-internal state variable)

9b

Measuring sensor (pressure-medium-internal state variable)

9c

Measuring sensor (mechanical state variable)

9d

Measuring sensor (mechanical state variable)

9e

Measuring sensor (mechanical state variable)

9f

Measuring sensor (mechanical state variable)

9g

Measuring sensor (mechanical state variable)

9h

Measuring sensor (mechanical state variable)

9i

Measuring sensor (mechanical state variable)

9j

Measuring sensor (mechanical state variable)

9k

Measuring sensor (external load)

10

linear motor

11

servo controller

12

another linear motor

13

spindle

14

backward stop

15

function module

Claims (14)

1. Safety brake (1) having a brake rotor (2) and a brake stator (3), whose braking moment predetermined by the force of a force transmitter (4) until the brake locking position has been reached is first used during a commencing braking procedure for completely nullifying the kinetic energy of a load to be braked and is then used to keep the load in the brake locking position, wherein the predetermined braking moment can be altered by means of relative movement between the brake rotor (2) and brake stator (3) caused by the pressurisation of a piston cylinder unit (5) filled with a pressure medium, in that for this purpose the piston cylinder unit (5) is connected in a communicative manner to a transmitter system (7) via a pressure medium line (6), characterised in that at least one measuring sensor (9a,b,c,d,e,f,g,h,i,j,k) is provided and is used, in the range of relative movement between the brake rotor (2) and brake stator (3) and outside the operating range defined by the brake locking position, to detect at least one predetermined operating parameter, and in that the measuring sensor (9a,b,c,d,e,f,g,h,i,j,k) co-operates with the transmitter system (7) such that in this operating range outside the brake locking position the respective braking movement is a function of the operating parameter detected in each case.
2. Safety brake (1) as claimed in Claim 1, characterised in that the transmitter system (7) is a piston cylinder unit, and in that a linear motor (10) is located in the connection between the measuring sensor (9a,b,c,d,e,f,g,h,i,j,k) and transmitter system (7) and influences the piston cylinder unit depending upon the detected operating parameter(s) (9a,b,c,d,e,f,g,h,i,j,k).
3. Safety brake (1) as claimed in Claim 2, characterised in that the linear motor (10) is servo-controlled via an upstream servo-controller (11).
4. Safety brake (1) as claimed in Claim 3, characterised in that the detected operating parameter(s) is (are) impressed upon the servo-controller (11) as an input signal.
5. Safety brake (1) as claimed in any one of Claims 2 to 4, characterised in that the linear motor (10) can be operated electrically.
6. Safety brake (1) as claimed in any one of Claims 1 to 5, characterised in that the co-operation between the measuring sensor (9a,b,c,d,e,f,g,h,i,j,k) and transmitter system (7) according to a fixedly predetermined function remains constantly limited to the operating range of the sliding friction between the brake rotor (2) and brake stator (3).
7. Safety brake (1) as claimed in any one of Claims 1 to 6, characterised in that the course of the respective braking moment over the time required to brake the load moment until standstill progresses according to a strictly monotone function.
8. Safety brake (1) as claimed in any one of Claims 2 to 7, characterised in that the armature of the linear motor (10) is pre-positioned by a further linear motor (12).
9. Safety brake (1) as claimed in Claim 8, characterised in that the further linear motor (12) is held in its position, corresponding in each case to the pre-positioning, under self-locking,
10. Safety brake (1) as claimed in any one of Claims 8 to 9, characterised in that the further linear motor (12) is designed as a spindle motor whose spindle (13) forms a rearward stop (14) for the armature of the linear motor (10).
11. Safety brake (1) as claimed in any one of Claims 1 to 10, characterised in that the function of the respectively detected operating parameter (9a,b,c,d,e,f,g,h,i,j,k) is stored in a function block (15) which is located in the connection between the measuring sensor (9a,b,c,d,e,f,g,h,i,j,k) and transmitter system (7).
12. Safety brake (1) as claimed in any one of Claims 1 to 11, characterised in that at least one measuring sensor (9a,b) is used to detect state variables within the pressure medium.
13. Safety brake (1) as claimed in any one of Claims 1 to 12, characterised in that at least one measuring sensor (9c,d,e,f,g,h,i,j) is used to detect mechanical state variables of the brake.
14. Safety brake (1) as claimed in any one of Claims 1 to 13, characterised in that at least one measuring sensor (9k) is used to detect external loads.

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