Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
  • B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
  • B60T13/74—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with electrical assistance or drive
  • B60T13/746—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with electrical assistance or drive and mechanical transmission of the braking action
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
  • B60T7/00—Brake-action initiating means
  • B60T7/02—Brake-action initiating means for personal initiation
  • B60T7/08—Brake-action initiating means for personal initiation hand actuated
  • B60T7/10—Disposition of hand control
  • B60T7/107—Disposition of hand control with electrical power assistance

Definitions

• the present invention relates to an actuator, in particular a brake actuator for a parking brake of a motor vehicle, a method for monitoring the operation of an actuator as well as a computer program and a Computerpro ⁇ program product for executing the method.
• a known from the prior art conventional Fest ⁇ parking brake system is usually made of a wheel brake on the two rear wheels of the motor vehicle, a cable pull mechanism and a lockable hand lever for operation by the driver.
• the hand lever is replaced by an electromechanically driven adjusting device, which is set by the driver via an operating button or by a higher-level control unit driving dependent on operation.
• the locking and releasing process is then electronically controlled or regulated by the adjusting device, possibly as a function of current vehicle and Be ⁇ operating parameters, such as driver's request, speed, vehicle weight, vehicle inclination, drive torque, gear ⁇ order.
• a desired value for the ⁇ to it generating braking force is determined from the determined vehicle and operating data then determined by the control or regulation unit and the driving driven such that, provided a proper functioning of the transmission mechanism, this target braking force is enough at the wheel brakes he ⁇ is , However, since varying the ambient parameters, such.
• the two variables actuating force and travel are in unambiguous relation to each other, which, although subject to certain fluctuations, e.g. Temperature-induced changes in length within the transmission mechanism or aging or wear-related influences, but exposed to no sudden changes and thus easy to track and detect.
• the function is perfect, it is possible to uniquely assign a certain actuating force to a specific travel.
• This course of the actuating force over the travel can be stored as a comparison ⁇ curve in the control unit.
• the currently measured actuating force / travel path curve can now be compared with the desired course stored in the control unit. If the transfer mechanism were blocked, it would now the measured force to increase after a much shorter ⁇ ren travel or when a broken transmission mechanism no force increase would have to be measured even with a much larger travel range. In this way, a malfunction of the brake unit can be detected with certainty and de ⁇ speaking security measures are initiated.
• the actuating force in the solution disclosed in the document EP 0 966 376 B1 is measured in or on a brake cable.
• 0,988,203 Bl and DE are ⁇ a set for measuring the restoring force previously only travel-measuring elements as in the document EP ⁇ elements shown 101 02 685 B4.
• the linear change in length of a spring arranged in the force flow is detected by a distance sensor, and the adjusting force is determined from the change in distance with the aid of the spring constant.
• the travel or stroke of the brake elements is also detected on the brake cable, which also here a measuring unit is erforder ⁇ Lich, with a linear stroke can be detected.
• the travel of the window pane is detected by the number of revolutions of the drive shaft of an electric motor.
• the detection of the stroke in an adjusting device for a motor vehicle parking brake using the Umdre ⁇ tion number of a drive wheel is also disclosed in document US 5,180,038.
• the distance measurement for determining the actuating force can also be done with the aid of Hall sensors.
• the exact posi ⁇ tioning of the sensor and encoder units is a prerequisite. But this requires an increased effort in design, installation and possibly adjustment. Accordingly, this type of measurement is also relatively sensitive to component tolerances and environmental influences, which is not unproblematic when used in a particularly harsh and changing environment to which a motor vehicle is generally exposed.
• the actuator should have a compact design and a close-spaced arrangement of the sensors. He should in particular be suitable as a brake actuator for a parking brake ⁇ .
• the actuator in this case comprises an input member, an output drive ⁇ element, which is coupled to the drive element via at least one e- lastisches element, a first sensor for detecting a change in position of the drive element and a second sensor for detecting a change in position of the output member.
• the proposed solution provides to determine both the force and the travel using a Differenzwegstation.
• either the lifting or rotating path of two elements coupled via an elastic element (drive and output element), which are arranged in the force flow, can be measured relative to the stationary environment.
• the drive and the driven element can thus be arranged to be either rotational or translationally movable.
• the stroke or rotary travel can be measured via simple pulse generator units.
• the drive element can be driven by the drive side, for example, by an electric motor.
• the drive movement is transmitted via the elastic element on the Ab ⁇ drive element, which in turn is fixedly coupled to the output ⁇ side of the transmission unit. It can be provided at least one tension element which is connected to the output element.
• the operated actuator may be designed as a brake actuator for the parking brake of a motor vehicle. This will be explained below ⁇ to:
• the travel differential is continuously determined by the control unit and the drive remains activated until the actuating travel difference corresponding to the force command value has been reached.
• Due to the design drive and driven component are arranged in the immediate vicinity, which also allows a close-spaced arrangement of the sensors, for example on a common carrier unit in the surrounding housing.
• the at least one tension element is a spindle.
• the output element is a spindle nut on which a driven gear is mounted.
• the spindle nut and the output gear can advantageously be integrally formed with each other.
• the drive member may be a drive gear which is with- means of at least one driving finger or other geeig ⁇ net designed driving element and the at least one elastic member in driving connection with the driven gear ⁇ .
• the drive gear can be rotatably mounted on the spindle nut.
• the elastic element may consist of several individual printing o- consist of the tension springs, which are Kreisli ⁇ never arranged for example on a between the drive and driven wheel. However, it may also consist of a concentrically arranged coil spring, an elastomeric component or another elastic, suitably arranged component.
• the actuator can be designed as a so-called "180 ° two-line puller".
• the spindle nut is shared against ⁇ provisional threads formed at each end of the spindle nut a spindle with a brake cable arranged.
• the drive element and the output element are arranged to be translationally movable.
• the output element may be a linearly movably mounted driven slide, which is connected to a brake cable.
• the drive element may be a linearly movably mounted drive carriage, wherein the drive carriage and the output carriage are braced against one another by means of the elastic element.
• the elastic element may advantageously be a tension-compression spring in this embodiment.
• the drive carriage may be connected to a drive spindle which engages a drive spindle nut coupled to a drive gear. Both the drive carriage and the output carriage can be provided with a corresponding external toothing along their respective longitudinal extent.
• the measuring arrangement for detecting the operability of the actuator can therefore be arranged between a spindle and a traction cable coupled to the spindle via the measuring arrangement.
• the drive gear can be driven by an electric motor ⁇ .
• the electric motor is then engaged, for example via a worm, with a toothed wheel which drives the spindle nut.
• the rotational movement of the electric motor is converted into a translational movement.
• the actuator can therefore also be designed as a so-called “single-wire puller”.
• the first sensor and the second sensor may be Hall sensors, wherein advantageously the first sensor is arranged opposite to an outer toothing of the drive element and the second sensor is arranged opposite an outer toothing of the output element.
• a corresponding method for monitoring the operation of an actuator includes the steps of determining the Heilände ⁇ tion of the drive element by the first sensor, Determining the change in position of the output element by means of the second sensor, calculating a difference of Lüände ⁇ ments, determining a braking force from the calculated difference and a known spring-spring travel characteristic of the elastic member, and determining thenosfä ⁇ ability of the parking brake by means of a Comparison of a value pair or value triplet with known critical value pairs or value triples formed from the determined position changes, possibly with the additional use of the determined braking force.
• any change in position of the drive ⁇ elements and the resulting difference can be stored.
• Such a value triplet could play about a jammed brake system.
• a computer program for carrying out a method described above has program code means for performing all the steps of a method according to the invention when the computer program is executed on a computer, in particular a control unit associated with the actuator.
• a computer program product comprising program code means which are stored on a computer readable medium, such as hard disks, floppy disks, CD-ROMs, DVDs, etc., to perform all Schrit ⁇ te a method described above, when the computer program on a computer, in particular a associated with the actuator Control unit, running.
• a computer readable medium such as hard disks, floppy disks, CD-ROMs, DVDs, etc.
• FIG. 1 shows a cross-sectional view of a first exporting ⁇ approximate shape of an actuator.
• Figure 2 shows a first embodiment of an elastic
• FIG. 3 shows a second embodiment of an elastic
• FIG. 4 shows a cross-sectional view of a region of an actuator according to the invention in a second embodiment.
• FIG. 5 shows a simplified flowchart of a method for monitoring the function of a parking brake in steps S1 to S6.
• an actuator 10 is shown in a first embodiment.
• the actuator 10 is used in the present example for actuating a parking brake in a motor vehicle.
• a conventional electric motor (not shown) having a drive screw 74 as to ⁇ drive unit.
• A consisting of a drive gear 20, a driven gear 30 and a spindle nut 32 spindle gear is to implement the rotational movement of the Electric motor (not shown) used in a linear lifting movement.
• the driven gear 30 is formed integrally with the spindle nut 32 and is about driving finger 80, 82, 84 and at least one elastic element 40, 42, 44, 46 in Mit Spotify ⁇ connection with the drive gear 20, which by means of a La ⁇ gers 93 rotatably mounted on the Spindle nut 32 is mounted.
• the elastic element may be tension-compression springs 40, 42, 44 arranged on a circular line, as shown in FIG. However, it may also be provided a coil spring 46, as shown in Figure 3.
• the spindle nut 32 is rotatably supported by two bearings 90, 92 in a housing 94.
• the drive gear 20 is engaged by a drive worm 74 which is driven by the electric motor.
• the actuator shown in Figure 1 is designed as a so-called "180 ° Zieh puller", so that the spindle nut 32 is provided with opposite threads and two counter-rotating spindles 50, 54.
• the spindles 50, 54 are engaged with the spindle nut 32 and are linearly moveable but secured against rotation relative to the housing 94.
• On the spindles 50, 54 a respective brake cable 52, 56 is fixed, to which the linear movement of the corresponding spindle 50, 54 is transmitted.
• the drive gear 20 has an external toothing 24.
• the output gear 30 has an outer toothing 34.
• An active Hall sensor 60, 62 is arranged in each case in the area of the external toothings 24, 34 of the drive gearwheel 20 and of the output gearwheel 30.
• the respective Hall sensor 60, 62 is damped by the corresponding external toothing 24, 34 of the drive gear 20 and the output gear 30.
• Upon rotation of the drive 20 and the output gear 30 is formed by the moving past the Hall sensors 60, 62 by gears 24, 34, one pulse per tooth. By counting the pulses so the respective rotation angle of the drive 20 and of the output gear 30 can be determined.
• the spindle drive can be so from the number of pulses of the output gear, the linear stroke of the spindle and thus the brake cables determine.
• the numbers of pulses of the drive gear 20 and driven gear 30 ferenz from the difference can be the difference angle of rotation between drive and driven wheel and the light transmitted through the elastic member 40, 42, 44, 46 torque determine which in turn is proportio ⁇ nal to the restoring force.
• the measured data are transmitted to a control or regulating unit (not illustrated), which evaluates the Messda ⁇ th and controls the electric motor accordingly.
• FIG. 4 shows an actuator 100 in a second embodiment.
• a corresponding brake cable 500 is connected to a spindle 700 via a measuring arrangement.
• a movement of the spindle 700 is effected by a spindle gear and an electric motor similar to the first embodiment, wherein the spindle nut 720 is of course connected without interposition of the measuring arrangement shown in Figure, but directly via a drive gear to an electric motor.
• the measuring device in the second embodiment consists of a drive carriage 200 coupled to the spindle 700 and further comprising an output carriage 300 coupled to a brake cable 500.
• the two Schlit ⁇ th 200, 300 are mounted in a housing 940 independently movable linearly.
• a compression spring 400 is arranged, which serves as an elastic element according to the invention and the the carriage 200, 300 braced against each other.
• the actuator Upon actuation of the actuator, the tensile force is transmitted from the Antriebsschlit ⁇ th 200 via the compression spring 400 on the driven carriage 300.
• Each carriage 200, 300 includes a linearly arranged Ver ⁇ teeth 240, 340 on an outer side. Opposite the per ⁇ donating toothing, a Hall sensor 600, 620 is arranged, which is attenuated by the individual teeth.
• both carriages 200, 300 Upon actuation of the actuator or when applying the brake, both carriages 200, 300 move uniformly until the brake elements of the wheel brakes (not shown) come to rest. As a result, the driven carriage 300 is stopped in its movement. If the drive remains activated, the drive carriage 200 continues to move in the tightening direction (to the right in FIG. 4) until the desired braking force has been reached.
• the Stellwegdifferenz is a measure of the tensile force in the brake cable 500.
• This embodiment is particularly suitable for so-called Einseilzieher and has the advantage that the tension in the brake cable 500, that can be measured here directly without influences of a Ge ⁇ gear translation.
• a puller Zweiseil- a separate measuring ⁇ device is optionally provided in each cable.
• the Hall sensors 600, 620 at a fixed location in the housing 940 possibly on a common support element, in ⁇ example, designed as a printed circuit board circuit carrier, can be mounted in a spatially compact arrangement.
• the use of Hall sensors is ren 60, 62, 600, 620 particularly advantageous because they have a ver ⁇ tively large tolerance to incorrect positioning of the sensor and transmitter unit. This eliminates the need for expensive adjustment work during assembly who ⁇ the. Furthermore, the positioning of the sensors 60, 62, 600, 620 in the housing 94, 940 during assembly without direct reference to the transmitter units or the external gears 24, 34, 240, 340 and subsequent adjustment of the measured values is possible.
• FIG. 5 shows a simplified flow diagram for the function ⁇ monitoring of a parking brake, which comprises an actuator up.
• the method includes the sequence steps indicated in FIG. 5 with S 1 to S 6:
• Step S1 Determining the change in position of the Antriebsele ⁇ management 20, 200 by means of the second sensor 60, 600th
• Step S2 Determining the change in position of the output element 30, 32, 300 by means of the second sensor 62, 620th
• step Sl and S2 time ⁇ Lich parallel.
• Step S3 Calculate a difference of the position changes.
• Step S4 Calculation of a braking force from the difference of the position change and a known spring force-deflection characteristic of the elastic element ments 40, 42, 44, 46, 400, optionally un ⁇ ter using additional system-specific parameters, which are placed together with the spring force spring deflection characteristic in a memory SK available.
• Step S5 Determining the Operability of the Fest ⁇ parking brake 10, 100 by means of a comparison of value combinations formed from the determined and / or calculated values with stored in a memory WK, predetermined value combinations.
• step S5 If, in step S5, the proper functioning of the parking brake is determined, is carried out in step v ⁇ branching a branch to sequence step S6.
• Step S6 outputting a signal for functional confirmation to the control unit of the actuator and / or to the operator.
• step S5 If, in step S5, a malfunction of the parking brake is determined, is carried out in the branching step V a ⁇ Ver branching to procedural step S7.
• Step S7 Outputting a signal for initializing an emergency routine in the control unit and generating an indication signal that indicates the malfunction to the operator.

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• Engineering & Computer Science (AREA)
• Transportation (AREA)
• Mechanical Engineering (AREA)
• Braking Arrangements (AREA)
• Regulating Braking Force (AREA)

Applications Claiming Priority (2)

Publications (1)

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• 2006
  • 2006-07-26 DE DE102006034597A patent/DE102006034597A1/de not_active Withdrawn
• 2007
  • 2007-05-22 US US12/374,436 patent/US20090308701A1/en not_active Abandoned
  • 2007-05-22 WO PCT/EP2007/054926 patent/WO2008012123A1/de active Application Filing
  • 2007-05-22 EP EP07729367A patent/EP2049375A1/de not_active Withdrawn
  • 2007-05-22 CN CNA2007800278797A patent/CN101495352A/zh active Pending

Non-Patent Citations (1)

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