WO2021245334A1 - Braking device for working machine - Google Patents

Braking device for working machine Download PDF

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Publication number
WO2021245334A1
WO2021245334A1 PCT/FI2021/050400 FI2021050400W WO2021245334A1 WO 2021245334 A1 WO2021245334 A1 WO 2021245334A1 FI 2021050400 W FI2021050400 W FI 2021050400W WO 2021245334 A1 WO2021245334 A1 WO 2021245334A1
Authority
WO
WIPO (PCT)
Prior art keywords
brake
parking brake
working machine
braking device
sensor
Prior art date
Application number
PCT/FI2021/050400
Other languages
French (fr)
Inventor
Janne LOPONEN
Anssi SARHALUOMA
Original Assignee
Ponsse Oyj
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ponsse Oyj filed Critical Ponsse Oyj
Priority to BR112022024584A priority Critical patent/BR112022024584A2/en
Priority to EP21816952.2A priority patent/EP4161813A1/en
Priority to CN202180036891.4A priority patent/CN115667034A/en
Publication of WO2021245334A1 publication Critical patent/WO2021245334A1/en

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D66/00—Arrangements for monitoring working conditions, e.g. wear, temperature
    • F16D66/02—Apparatus for indicating wear
    • F16D66/021—Apparatus for indicating wear using electrical detection or indication means
    • F16D66/022—Apparatus for indicating wear using electrical detection or indication means indicating that a lining is worn to minimum allowable thickness
    • F16D66/025—Apparatus for indicating wear using electrical detection or indication means indicating that a lining is worn to minimum allowable thickness sensing the position of parts of the brake system other than the braking members, e.g. limit switches mounted on master cylinders
    • 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
    • B60T17/00—Component parts, details, or accessories of power brake systems not covered by groups B60T8/00, B60T13/00 or B60T15/00, or presenting other characteristic features
    • B60T17/18—Safety devices; Monitoring
    • B60T17/22—Devices for monitoring or checking brake systems; Signal devices
    • B60T17/221—Procedure or apparatus for checking or keeping in a correct functioning condition of brake systems
    • 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
    • B60T17/00—Component parts, details, or accessories of power brake systems not covered by groups B60T8/00, B60T13/00 or B60T15/00, or presenting other characteristic features
    • B60T17/18—Safety devices; Monitoring
    • B60T17/22—Devices for monitoring or checking brake systems; Signal devices
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W10/00—Conjoint control of vehicle sub-units of different type or different function
    • B60W10/18—Conjoint control of vehicle sub-units of different type or different function including control of braking systems
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W10/00—Conjoint control of vehicle sub-units of different type or different function
    • B60W10/18—Conjoint control of vehicle sub-units of different type or different function including control of braking systems
    • B60W10/182—Conjoint control of vehicle sub-units of different type or different function including control of braking systems including control of parking brakes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D66/00—Arrangements for monitoring working conditions, e.g. wear, temperature
    • F16D66/02—Apparatus for indicating wear
    • F16D66/021—Apparatus for indicating wear using electrical detection or indication means

Definitions

  • the invention relates to a pressure medium operated brake for a work ing machine.
  • the invention relates to such a braking device for a work ing machine, in which a working brake and parking brake of the working machine are combined into the same braking device.
  • a brake is used to keep a parked working machine stationary so that it cannot on its own to start moving, or alternatively to stop a moving working machine.
  • a typical working machine brake in particular in forest machine use, is a pressure medium operated, e.g., hydraulically operated, combined working and parking brake whereby the same braking device has means to activate both the parking brake and working brake combined in it.
  • the parking brake is activated, preventing a parked working machine from starting to move by itself.
  • a force is conveyed to the portion of the braking device forming the working brake used to stop the mobile working machine, by means of a pressurised pressure medium, the force activating the working brake to stop the mobile working machine.
  • a braking device of the kind referred to is typically implemented as a braking device of the disc brake type, whereby the braking device comprises a brake disc stack having at least one friction disc provided with a friction surface, and a mating disc forming a counterpart for said at least one friction disc provided with a friction surface, whereby as the brake is activated, in other words, when the brake is in an active usage state the friction disc(s) and mating disc(s) end up in contact against each other, and as the brake opens or releases, the friction disc(s) and mating disc(s) end up free from each other.
  • a braking device of the disc brake type may be a wet disc brake in which a brake disc stack is arranged in a closed enclosure, filled with oil and separated from the brake-activating parts, so in a dif ferent space from the brake-activating parts, or a dry disc brake in which a brake disc stack is arranged in the same space with the brake-activating parts.
  • a problem with a braking device of the type referred to is that the con dition of the brake cannot be easily monitored. At present, manufacturers instruct brakes to be serviced and/or certain components in the brake to be replaced at fixed intervals, or the amount of wear of the brakes to be checked in connection with servicing.
  • the object of the invention is to develop a new type of braking device of a working machine.
  • the invention is based on a pressure medium operated braking device in a working machine comprising at least one sensor arrangement to produce in formation representing the operating ability of a brake, such as to indicate the con dition of a brake disc stack of the braking device.
  • An advantage of the invention is that it is possible to detect, in a simple manner, that at least the thickness of the friction discs and/or mating discs of the brake disc stack of the braking device, that is, at least the combined thickness of the friction discs and/or mating discs is still adequate for the brake to be able to press the friction discs and mating discs against each other to produce adequate braking torque to use or park a working machine safely.
  • the disclosed solution it is possible to detect deficiencies in the operation of an actuator of the brake, such as the so-called bottoming out of the brake, regardless of the operating ability of the brake disc stack.
  • the disclosed solution therefore allows the entire operating ability and servicing need of the braking device to be established.
  • a sensor arrangement arranged in the braking device itself it is possible to indicate brake operating ability also without stopping work.
  • Figure 1 is a schematic side view of a braking device of a working ma chine obliquely from above and partly in cross-section
  • Figure 2 is a schematic side view in cross section of a brake cylinder of the braking device of Figure 1
  • Figure 3 is a schematic view of an arrangement for testing the operating ability of a brake in a working machine
  • Figure 4 is a schematic view of a method for testing the operating ability of a brake in a working machine.
  • Figure 1 is a schematic view, obliquely from above and partly in cross section, of a braking device 1 of a working machine
  • Figure 2 is a schematic side view in cross section of a brake cylinder 2 of the braking device 1 of Figure 1.
  • the braking device 1 shown in Figure 1 is a brake of the disc type, com prising a brake cylinder 2.
  • the brake cylinder 2 comprises an operating mechanism of the brake, in other words, means to control the operation of brake usage, that is, means to both control the brake activation to produce braking power and brake release or opening, so that no braking power is produced.
  • the braking device 1 shown in Figure 1 comprises a disc stack enclosure 3, separate from the brake cylinder 2 but operationally connected thereto, having at least one friction disc 5 provided with a friction surface, and at least one mating disc 6 forming a counterpiece for said at least one friction disc 5.
  • Said at least one friction disc 5 and said at least one mating disc 6 are placed alter nately in relation to each other as a structure forming a brake disc stack 4.
  • the friction disc(s) and mating disc(s) end up in contact against each other to produce braking power, and as the brake is opened or released the friction disc(s) and mating disc(s) end up at least partially separated from each other, so that braking power is no longer produced.
  • the disc stack enclosure 3 forms a closed space which is separate from the brake cylinder 2 and into which a axle 7 extends, which axle may be, for exam- pie, an axle of the working machine wheels, or an axle in contact with the working machine wheel axle, or an axle of a working machine provided with a chain track, which acts on the chain track either indirectly or directly.
  • axle 7 may be, for exam- pie, an axle of the working machine wheels, or an axle in contact with the working machine wheel axle, or an axle of a working machine provided with a chain track, which acts on the chain track either indirectly or directly.
  • the disc stack enclosure 3 has, arranged next to said at least one mating disc 6, in the case of a plurality of mating discs 6, between the mating discs 6, at least one plate-like friction disc 5 having a friction surface directed towards the mating disc 6.
  • Said at least one friction disc 5 may be supported to one or more fixed structures arranged in the disc stack enclosure 3 so that said at least one friction disc 5 cannot rotate at the same time as the axle 7 and the at least one mating disc 6 arranged in connection with it are rotating.
  • Said at least one friction disc 6 and said at least one mating disc 5 form the aforemen tioned brake disc stack 4.
  • the disc stack enclosure 3 is filled with oil so that the friction discs 5 and mating discs 6 are submerged in said oil, whereby the disc brake is of the so-called wet brake disc type.
  • the disc stack enclosure 3 further comprises a brake caliper 8 whose operation when the brake is being activated, that is, when bringing the brake into an active operating state for producing braking power, is arranged to achieve the pressing of at least one friction disc 5 and at least one mating disc 6 of the disc stack 4 against each other.
  • the brake caliper 8 allows said at least friction disc 5 and said at least one mating disc 6 to move away from each other.
  • the brake is activated and opened by means of a chock 9 operated by the brake cylinder 2.
  • the chock 9 moves left as seen in Figures 1 and 2 to produce braking power directed to the brake caliper 8 and further to the brake disc stack 4 by means of the brake cal iper 8.
  • the chock 9 moves back to the right as seen in Figures 1 and 2, ceasing by means of the chock 9 production of braking power directed to the brake caliper 8 and further to the brake disc stack 4 by means of the brake caliper 8.
  • the brake is activated or opened by means of a chock 9 operated by the brake cylinder 2.
  • the chock 9 is part of the brake cylinder 2 forming the oper ating mechanism of the braking device, but the chock 9 could also be a part posi tioned between the brake cylinder 2 and disc stack enclosure 3, separate from the brake cylinder 2 but nevertheless operated by it.
  • the brake cylinder 2 shown in Figures 1 and 2 comprises both the work ing or operating brake 10 as well as the parking or park brake 20.
  • a body of the brake cylinder 2 comprises substantially three interconnected parts, that is, a first body part 2a substantially corresponding to the portion of the working brake 10 of the brake cylinder 2, and a second body part 2b and a third body part 2c, the second body part 2b being located between the first body part 2a and third body part 2c in the axial direction A of the brake cylinder 2.
  • the second body part 2b and third body part 2c substantially correspond to the portion of the parking brake 20 of the brake cylinder 2.
  • Each body part 2a, 2b, 2c forms, on the corresponding body por- tion of the brake cylinder 2, a part forming with its inner parts at least a partially open cylindrical structure.
  • the working brake 10 and parking brake 20 are ar ranged substantially coaxially in the brake cylinder 2.
  • the working brake 10 comprises a control cylinder formed by the first body part 2a, and a piston 11 arranged inside it movably in the axial direction A of the brake cylinder 2.
  • the chock 9 is arranged in connection with the piston 11 of said working brake 10 by means of an intermediate piece 12 of the working brake 10, adapted between the chock 9 and piston 11.
  • the piston 11 of the working brake 10 moves left, as seen in Figures 1 and 2, further moving the chock 9 left and acting on the brake caliper 8 in the disc stack enclosure 3 as described in the above to produce braking power by the effect of the working brake 10.
  • the piston 11 of the working brake 10 is able to move back right, as seen in Figures 1 and 2, also moving the chock 9 back right, by the joint effect of the piston 11 and intermediate piece 12, off the brake caliper
  • the working brake 20 comprises a control cylinder jointly formed by the second body part 2b and third body part 2c, and a piston 21 arranged inside it movably in the axial direction A of the brake cylinder 2.
  • the parking brake 20 fur ther comprises a flexible element 22 acting on the piston 21 in the axial direction A of the brake cylinder 2, in the embodiment of the figures, a coil spring.
  • the park ing brake 20 further comprises an intermediate piece 23 of the parking brake 20, arranged in connection with an intermediate piece 12 of the working brake 10, so that the piston 21 of the parking brake 20 is arranged in connection with the chock
  • the second body part 2b there is further arranged at least one pressure medium fitting 24 to feed a pressurised medium, customarily a hydraulic fluid as mentioned in the above, to the parking brake 20.
  • a pressurised medium customarily a hydraulic fluid as mentioned in the above.
  • the piston 21 of the parking brake 20 is arranged in connection with the chock 9 by means of the intermediate piece 23 of the parking brake 20 and the intermediate piece 12 of the working brake 10, the piston 21 of the parking brake 20 presses, by means of the intermediate piece 23 of the parking brake 20 and the intermediate piece 12 of the working brake 10, the chock 9 to the left, as seen in Figures 1 and 2, acting on the brake caliper 8 in the disc stack enclosure 3 as de scribed in the above to produce braking power by the effect of the parking brake 20.
  • the braking device 1 of the working machine com prises both a working brake 10 and a parking brake 20 as well as a disc stack en closure 3 and brake disc stack 4 shared by them.
  • Figures 1 and 2 do not show an actual working machine or a pressure medium circuit related to using brakes, these being obvious for a person skilled in the art.
  • a problem with working machine brakes of the disc brake type lies in that it is not possible to monitor easily the condition of the brake, in particular the condition of the friction discs 5 and their mating discs 6, such as the remaining thickness of the friction discs 5 and/or mating discs 6 of the brake disc stack 4, or the ability of the actuator of the brake, that is, the brake cylinder 2 to produce ade quate braking torque.
  • FIGS. 1 and 2 further show a solution for monitoring the condition of a brake of a working machine, to produce information illustrating the operating ability or servicing need of the brake.
  • the solution disclosed in Figures 1 and 2 comprises a sensor arrangement 30 comprising at least one sensor 33, by means of which the position of the piston 21 of the parking brake 20 may be determined in the brake cylinder 2, and based on it to indicate whether the brake can even prolude adequate braking torque to safely use or park the working machine.
  • the sensor arrangement 30 shown in Figures 1 and 2 comprises a sen sor 31 which comprises a body structure 32 of the sensor 31 and a detector part 33 connected to the body structure 32.
  • the sensor arrangement 30 shown in Fig ures 1 and 2 further includes an additional body 34 connected as an extension to the third frame part 2c or the brake cylinder 2, that is, the body portion of the brake cylinder 2 corresponding to the parking brake 20 portion of the brake cylinder 2, and comprising an at least partially open space 35 on its inner side in the axial di rection of the brake cylinder 2; by means of this additional body, the sensor 31 may be supported to the brake cylinder 2.
  • the additional body 34 is connected as an extension to the third body part 2c of the brake cylinder 2, corresponding to the portion of the parking brake 20, to the end of the third body part 2c of the brake cylinder 2, towards which the piston 21 of the parking brake 20 moves during an opening movement of the parking brake 20.
  • an open space 35 in connection with the parking brake 20 in order to arrange the sensor 31 and in particular the detector part 33 in it, in connection with the parking brake 20. If there is, depending on the structure of the brake cylinder 2, a suitable space on the inside of the brake cylinder 2 to receive the sensor 31 or at least its detector part 33 to determine the position of the piston
  • the sensor arrangement 30 shown in Figures 1 and 2 further comprises an extension part 36, such as a axle stub, fixed as an extension to the piston 21 of the parking brake 20, which is arranged at its first end 36’ in connection with the end of the piston 21 of the parking brake 20, which is directed towards the addi- tional body 34, so the piston 21 end directed in the direction of the flexible element
  • extension part 36 is the same as the axial direction A of the brake cylinder 2.
  • a second end 36” of the extension part 36 is arranged to extend to the open space 35 of the additional body 34.
  • the senor 31 is supported by its body structure 32 to the additional body 34 so that the detector part 33 of the sensor 31 is placed in the space 35 substantially next to the straight travel path of the extension part 36 in the direction of the axial direction A of the brake cylinder 2, or in the proximity thereof, so that while moving along its travel path the extension part 36 travels on at least a portion thereof past the detector part 33 of the sensor 31.
  • Said detector part 33 of the sensor 31 may be placed in such a position in the space 35 that the extension part 36 travels on at least a por tion thereof past the detector part 33 of the sensor 31 in the immediate vicinity of the detector part 33, as shown in Figure 2, or so that the extension part 36 even touches the detector part 33 of the sensor 31 while travelling past the detector part 33.
  • a mating surface 37 which extends from the second end 36” of the extension part 36 towards its first end 36’ and which either contacts the detector part 33 of the sensor 31 or travels in substantially the immediate vicinity thereof while passing the detector part 33.
  • the condi tion of the brake disc stack 4 of the brake or the condition of the brake cylinder may be indicated at least to the extend of whether the brake even has the prerequisite to produce adequate braking torque to use or park a working machine safely.
  • the pressure medium is released from the parking brake 20, which has been pressing the piston 21 of the parking brake 20 against the flexible element 22 with the parking brake 20 in the opened operating state.
  • the flexible element 22, typically a spring, compressed in the opened operating state of the parking brake 20 presses the piston 21 of the parking brake 20 to the left, as seen in Figures 1 and 2, whereby as disclosed in the above the chock 9 activates the brake disc stack 4 in the brake stack enclosure 3, thereby preventing a parked working machine from moving.
  • the length of the extension part 36 of the piston 21 of the parking brake 20 and the length of its travel path or range in the open space 35 of the additional body 34 of the sensor arrangement 30 is arranged such that if the extension part 36 stays in the active state of the parking brake 20 in the operating range or detec tion range of the detector part 33 of the sensor 31, it maybe assumed that the thick ness of the friction discs 5 and/or mating discs 6 of the brake disc stack 4, that is, their combined thickness, is still adequate for the brake to be able to press the fric tion discs 5 and mating discs 6 against each other to produce adequate braking torque to use or park a working machine safely.
  • the detector part 33 thus detects the presence or location of the extension part 36 of the piston of the parking brake 20 on its operation or detection range, whereby in response to this the sensor 31 indicates, very schematically in Figure 2 by means of a state infor mation signal produced by the sensor 31, shown by an arrow 38, whether the thick- ness of the friction discs 5 and/or mating discs 6 of the brake disc stack 4 is still adequate so that it may be assumed that the brake disc stack 4 still produces enough braking torque to use or park a working machine safely.
  • the state infor mation signal 38 thus indicates the theoretical operating ability of the friction discs 5 and/or mating discs 6 of the brake disc stack 4, in other words the interpretation made on the basis of the thickness of the friction discs 5 and/or mating discs 6 of the brake disc stack 4, on the ability of the brake to press the friction discs 5 and mating discs 6 against each other to produce adequate braking torque to use or park a working machine safely.
  • the extension part 36 of the piston 21 of the parking brake 20 does not in the activated mode of the parking brake 20 anymore stay in the operating range or detection range of the detector part 33 of the sensor 31, but moves with the piston 21 of the parking brake 20 to such an extent to the left, as seen in Figure 2, in relation to the operating range or detection range of the detector part 33, that the extension part 36 moves out of the operating range or detection range of the detector part 33 of the sensor 31.
  • the detector part 33 of the sensor 31 no longer detects the presence or location of the extension part 33 in its operating or detection range.
  • the sensor 31 produces a state information signal 38 based on which it may be interpreted that the friction discs 5 and/or mating discs 6 of the brake disc stack 4 are so worn out that it can no longer be assumed that the brake disc stack 4 pro prises adequate braking torque to use or park a working machine safely.
  • the working machine brake is in need of servicing, insofar as the friction discs 5 and/or mating discs 6 of the brake disc stack 4, at least, are concerned.
  • the detector part 33 of the sensor 31 may be implemented or arranged operational in a number of ways.
  • the detector part 33 may require contact with the monitored object whereby in the activated state of the parking brake 20, as the detector part 33 of the sensor 31 touches the extension part 36 arranged in the piston 21 of the parking brake 20, a circuit in the sensor 31 closes through the ex- tension part 36, indicating that the extension part 36 of the piston 21 of the parking brake 20 is still located in the detection or operating range of the detector part 33 of the sensor 31.
  • the detector part 33 of the sensor 31 in the activated state of the parking brake 20 no longer touches the extension part 36 arranged in the piston 21 of the parking brake 20, a circuit in the sensor 31 cannot close, indi cating in turn that the extension part 36 of the piston 21 of the parking brake 20 is located out of the detection or operating range of the detector part 33 of the sensor 31.
  • the detector part 33 of the sensor 31 may also be based on non-contact detection, as shown in Figure 2.
  • the detector part 33 of the sensor 31 may be, for example, an inductive proximity detector based on detecting a change in a magnetic field.
  • the detector part 33 of the sensor 31 may be, for example, a capacitive prox imity detector based on detecting a change in capacitance.
  • the detector part 33 of the sensor 31 may be a Hall sensor, which is a magnetosensitive element based on detection of presence or change of a magnetic field.
  • the extension part 36, or part thereof such as a mating surface 37, of the piston 21 of the parking brake 20 may be brought magnetic, or a magnet may be arranged on the extension part 36, such as on the mating surface 37.
  • an extension part 36 has been arranged on the piston 21 of the parking brake 20, dimensioned to extend in the activated state of the parking brake 20 to the operating or detection range of the detector part 33 of the sensor 31 in case the thickness of the friction discs 5 and/or mating discs 6 of the brake disc stack 4 is considered adequate so that it may be assumed that the friction discs 5 and/or mating discs 6 of the brake disc stack 4 are capable of producing adequate braking power to use or park a working machine safely.
  • the piston 21 of the parking brake 20 may be designed such that it itself extends to the operating or detection range of the detector part 33 of the sensor 31 when the brake disc stack 4 is con sidered operational on the basis of the thickness of the friction discs 5 and/or mat- ing discs 6.
  • a mating surface 37 as de scribed in the above to the end of the piston 21 of the parking brake 20, extending into the open space 35 formed by the additional body 34 of the sensor arrangement 30.
  • a solution of the kind described in the above therefore provides an on/off type of indication on the thickness of the friction discs and/or mating discs of the brake disc stack and on the operating condition of the brake made based on it, or an indication of the operating condition of the brake cylinder.
  • the mutual adaptation of the piston of the parking brake, or its extension part, and the detector part of the sensor is arranged such that when indicating a servicing need, the friction discs and/or mating discs of the brake disc stack still have an ad- equate thickness, at least, so that the brake of a working machine may, as far as it is concerned, produce adequate braking torque to use and park the working ma chine safely.
  • Said condition monitoring procedure of the brake, carried out by the sensor 31, may take place when a parked working machine is brought into use and/or when parking a working machine that has been in use.
  • the state infor- mation signal 38 by the sensor 31, so the state information signal describing the theoretical operating ability of the brake, may thus be produced always before opening an activated parking brake 20 as a working machine is brought into use and/or when parking a working machine that had been used when the parking brake 20 is activated for parking the working machine.
  • the sensor 31 thus pro- Jerusalem information indicative of the operating ability of the brake, which may be evoked without interrupting the work of the working machine.
  • the braking device 1 of the working machine comprises both a working brake 10 and a parking brake 20 as well as a disc stack enclosure 3 shared by them, and a brake disc stack 4 placed in the disc stack enclo- sure 3.
  • the disclosed solution therefore indicates the condition of the brake disc stack 4 shared by both the working brake 10 and parking brake 20 insofar as at least the thickness of the friction discs 5 and/or mating discs 6 of the brake disc stack 4 is concerned.
  • the solution disclosed in the above was disclosed in connec tion with a wet disc brake but is equally usable in connection with a dry disc brake, too.
  • Figure 3 is a schematic view of an arrangement in a working machine for testing the operating ability of a brake in a working machine 40, also with the purpose of producing information indicative of the operating ability of the brake.
  • the working machine 40 is shown in Figure 3 very schematically with a box shown in a dashed line.
  • Figure 3 further schematically shows an axle 41 of the working machine 40 in connection with which a braking device 1 of the kind described in the above is arranged, to produce braking torque BM directed on the axle 41 of the working machine 40 to stop or keep in place the working machine 40.
  • Figure 3 further shows, very schematically, drive power transmission means 42 to produce drive transmission torque DM directed on the axle 41 of the working machine 40 to move or drive the working machine 40.
  • Figure 3 further shows a sensor 43 arranged on the axle 41 of the working machine 40, to indicate the rotation of said axle 41 in response to the working machine 40 moving by the effect of the drive transmission torque DM directed on the axle 41 of the working machine 40.
  • Figure 3 additionally shows, in a schematic manner, at least one con- trol unit 44 in the working machine 40 to control the functions of the working ma chine 40, such as the operation of the drive power transmission means 42 of the working machine 40.
  • the parking brake 20 of the braking device 1 is activated, i.e. turned on, either in response to parking the working machine, having taken place earlier, or deliberate activation of the parking brake 20 for the purpose of testing the brake, either by a user of the working machine or automatically by the control unit 40.
  • the sensor arrangement 30 produces the state information signal 38 describing the theoreti- cal operating ability of the brake of the working machine, as described in the above.
  • the testing procedure of the brakes may be ended and the infor- mation indicated to the user of the working machine either directly or through the control unit 44.
  • the brakes testing procedure may proceed to the following stage where it is examined whether the condition of the friction discs 5 and/or mat ing discs 6 of the brake disc stack 4 or the condition of the brake actuator is such that they are a factually able to produce adequate braking torque to use or stop a working machine safely.
  • the drive power transmission means 42 of the working machine 40 are, by means of a control signal CO-42 produced by the control unit 44, controlled to direct a predetermined amount of drive transmission torque DM on the axle 41 of the working machine 40, and a state information signal 45 is pro- **d, indicating the state of rotation of the axle 41, by means of a sensor 43 ar ranged on the axle 41 of the working machine 40 in response to the drive power transmission torque DM of at most the predetermined magnitude produced for the axle 41 to produce a state information signal 45 indicative of the actual operating ability of the brake of the working machine 40.
  • the brake of the working machine 40 is thus tested in a situation where the goal is to move the working ma chine 40 against an activated brake by a force caused by the predetermined amount of drive transmission torque DM brought on the axle 41. If the state information signal 45 produced by the sensor 43 indicates that the axle 41 is not rotating, the brake may be found to be in order to produce adequate braking torque to use or park the working machine 40 safely. If the state information signal 45 produced by the sensor 43 indicates that the axle 41 is rotating, it may be noted that the operat ing ability of the brake may not be adequate in order to produce adequate braking torque to use or park the working machine 40 safely under every condition. In both cases, the state information signal 45 produced by the sensor 43 may be indicated to the user of the working machine either directly or through the control unit 44.
  • Figure 4 is a schematic view of a method according to the solution for testing the operating ability of a brake in a working machine.
  • the braking device 1 and drive trans mission means 42 are arranged to act on the same axle 41.
  • the axle 41 may be an axle provided with wheels in a working machine, or an axle acting on the chain tracks of the working machine. It is also possible to arrange the braking device 1 and drive transmission means 42 to act on different axles, whereby the axle which the drive transmission means 42 are arranged to act on, may be instead of a work ing machine’s axle provided with wheels or an axle acting on chain tracks, any other axle belonging to the drive transmission means 42 or connected thereto to convey drive transmission torque or force to move the working machine 40.
  • the parking brake of the braking device 1 was activated.
  • the operating ability of the brake of the working machine may be tested by means of the working brake 10 in which case the above embodiment is implemented by using the working brake 10 instead of the parking brake 20.
  • the working brake 10 of the braking device 1 is activated, for example, by a user of the working machine at a suitable stage of a working process of the working machine, such as prior to steering the working machine to a slope working stage. If the actual operating ability of the brake is tested by means of the working brake 10, the parking brake 20 is in such a situation open.

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  • Mechanical Engineering (AREA)
  • Transportation (AREA)
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  • Braking Arrangements (AREA)

Abstract

A pressure medium operated braking device (1) for a working machine. The working brake (1) comprises a working brake (10), parking brake (20), and, shared by the working brake (10) and parking brake (20), a brake disc stack (4) which comprises alternately at least one friction disc (5) and at least one mating disc (6) forming a counterpiece for said at least one friction disc (5). The braking device (6) comprises at least one sensor arrangement (30) for indicating the condition of the brake disc stack (4) of the braking device (1). In addition, an arrangement and method for producing information indicative of the operating ability of the brake in a working machine.

Description

BRAKING DEVICE FOR WORKING MACHINE
Background of the invention
The invention relates to a pressure medium operated brake for a work ing machine. In particular, the invention relates to such a braking device for a work ing machine, in which a working brake and parking brake of the working machine are combined into the same braking device.
In working machines, such as bulldozers, bucket loaders or other earth moving machines, forklifts, crane vehicles or other moving load-handling devices as well as harvesters, forwarders, or other forest machines, a brake is used to keep a parked working machine stationary so that it cannot on its own to start moving, or alternatively to stop a moving working machine.
A typical working machine brake, in particular in forest machine use, is a pressure medium operated, e.g., hydraulically operated, combined working and parking brake whereby the same braking device has means to activate both the parking brake and working brake combined in it. In such a case, it is possible to direct a force to the portion of the braking device, which forms the parking brake, by a pressurised pressure medium, the force releasing the parking brake, allowing movement of the working machine. When the force effect of the pressure medium to the parking brake is ceased, the parking brake is activated, preventing a parked working machine from starting to move by itself. In turn, a force is conveyed to the portion of the braking device forming the working brake used to stop the mobile working machine, by means of a pressurised pressure medium, the force activating the working brake to stop the mobile working machine.
A braking device of the kind referred to is typically implemented as a braking device of the disc brake type, whereby the braking device comprises a brake disc stack having at least one friction disc provided with a friction surface, and a mating disc forming a counterpart for said at least one friction disc provided with a friction surface, whereby as the brake is activated, in other words, when the brake is in an active usage state the friction disc(s) and mating disc(s) end up in contact against each other, and as the brake opens or releases, the friction disc(s) and mating disc(s) end up free from each other. A braking device of the disc brake type may be a wet disc brake in which a brake disc stack is arranged in a closed enclosure, filled with oil and separated from the brake-activating parts, so in a dif ferent space from the brake-activating parts, or a dry disc brake in which a brake disc stack is arranged in the same space with the brake-activating parts. A problem with a braking device of the type referred to is that the con dition of the brake cannot be easily monitored. At present, manufacturers instruct brakes to be serviced and/or certain components in the brake to be replaced at fixed intervals, or the amount of wear of the brakes to be checked in connection with servicing. Opening up the braking device in connection with servicing for in specting it takes extra time, in particular since the condition of the brakes does not in many cases yet require the replacement of the friction discs and/or mating discs and/or brake adjustment. It is therefore possible that the need for replacing the brakes, in practice the friction discs and/or mating discs, due to excessive wear is only detected when they no longer grip as desired. As concerns the parking brake, which is often also used as an emergency brake, this may only be detected after a parked machine has unintentionally been able to move by itself, in other words, only after safe parking of the machine has already deteriorated. However, servicing of the brakes is not necessarily possible straight away, so it may be necessary to use various kinds of aids, such as wedges to be placed behind a wheel to make sure the machine is safely parked until the brakes can be serviced. As far as the working brake is concerned, the deteriorated condition of the brake may be noticed only at the stage when the working machine no longer stays where desired during use, or does not stop where desired during use, which for forest machines, for example, may come up in connection with ever-increasing work on a slope, for example.
With regard to the brake of a working machine brake, it is therefore nec essary to accomplish a solution where the condition of the brake of a working ma chine maybe determined when desired.
Brief description of the invention The object of the invention is to develop a new type of braking device of a working machine.
The solution according to the invention is characterised by what is dis closed in the independent claims.
The invention is based on a pressure medium operated braking device in a working machine comprising at least one sensor arrangement to produce in formation representing the operating ability of a brake, such as to indicate the con dition of a brake disc stack of the braking device.
An advantage of the invention is that it is possible to detect, in a simple manner, that at least the thickness of the friction discs and/or mating discs of the brake disc stack of the braking device, that is, at least the combined thickness of the friction discs and/or mating discs is still adequate for the brake to be able to press the friction discs and mating discs against each other to produce adequate braking torque to use or park a working machine safely. With the disclosed solution, it is possible to determine, in addition to or instead of information indicating the con dition of the brake disc stack, the ability of an actuator of the brake, acting directly or indirectly on the brake disc stack, to produce braking torque. With the disclosed solution, it is possible to detect deficiencies in the operation of an actuator of the brake, such as the so-called bottoming out of the brake, regardless of the operating ability of the brake disc stack. The disclosed solution therefore allows the entire operating ability and servicing need of the braking device to be established. By means of a sensor arrangement arranged in the braking device itself, it is possible to indicate brake operating ability also without stopping work.
Some embodiments of the invention are disclosed in the dependent claims.
Brief description of the drawings
The invention is now described in closer detail in connection with pre ferred embodiments and with reference to the accompanying drawings, in which Figure 1 is a schematic side view of a braking device of a working ma chine obliquely from above and partly in cross-section,
Figure 2 is a schematic side view in cross section of a brake cylinder of the braking device of Figure 1,
Figure 3 is a schematic view of an arrangement for testing the operating ability of a brake in a working machine, and
Figure 4 is a schematic view of a method for testing the operating ability of a brake in a working machine.
For reasons of clarity, some embodiments of the invention are illus trated in the figures in a simplified form. In the figures, like reference numerals identify like elements.
Detailed description of the invention
Figure 1 is a schematic view, obliquely from above and partly in cross section, of a braking device 1 of a working machine, and Figure 2 is a schematic side view in cross section of a brake cylinder 2 of the braking device 1 of Figure 1.
The braking device 1 shown in Figure 1 is a brake of the disc type, com prising a brake cylinder 2. The brake cylinder 2 comprises an operating mechanism of the brake, in other words, means to control the operation of brake usage, that is, means to both control the brake activation to produce braking power and brake release or opening, so that no braking power is produced.
Further, the braking device 1 shown in Figure 1 comprises a disc stack enclosure 3, separate from the brake cylinder 2 but operationally connected thereto, having at least one friction disc 5 provided with a friction surface, and at least one mating disc 6 forming a counterpiece for said at least one friction disc 5. Said at least one friction disc 5 and said at least one mating disc 6 are placed alter nately in relation to each other as a structure forming a brake disc stack 4. As the brake is activated, the friction disc(s) and mating disc(s) end up in contact against each other to produce braking power, and as the brake is opened or released the friction disc(s) and mating disc(s) end up at least partially separated from each other, so that braking power is no longer produced.
The disc stack enclosure 3 forms a closed space which is separate from the brake cylinder 2 and into which a axle 7 extends, which axle may be, for exam- pie, an axle of the working machine wheels, or an axle in contact with the working machine wheel axle, or an axle of a working machine provided with a chain track, which acts on the chain track either indirectly or directly. In the space delimited by the disc stack enclosure 3, there is at least one mating disc 6 arranged in connection with said axle 7, whereby said at least one mating disc 6 may rotate with the axle 7 as the working machine is moving. Further, the disc stack enclosure 3 has, arranged next to said at least one mating disc 6, in the case of a plurality of mating discs 6, between the mating discs 6, at least one plate-like friction disc 5 having a friction surface directed towards the mating disc 6. Said at least one friction disc 5 may be supported to one or more fixed structures arranged in the disc stack enclosure 3 so that said at least one friction disc 5 cannot rotate at the same time as the axle 7 and the at least one mating disc 6 arranged in connection with it are rotating. Said at least one friction disc 6 and said at least one mating disc 5 form the aforemen tioned brake disc stack 4. The disc stack enclosure 3 is filled with oil so that the friction discs 5 and mating discs 6 are submerged in said oil, whereby the disc brake is of the so-called wet brake disc type.
The disc stack enclosure 3 further comprises a brake caliper 8 whose operation when the brake is being activated, that is, when bringing the brake into an active operating state for producing braking power, is arranged to achieve the pressing of at least one friction disc 5 and at least one mating disc 6 of the disc stack 4 against each other. Similarly, when the brake is being opened, that is, when the production of braking power is being ceased, the operation of the brake caliper 8 allows said at least friction disc 5 and said at least one mating disc 6 to move away from each other. The brake is activated and opened by means of a chock 9 operated by the brake cylinder 2. To activate the brake for producing braking power, the chock 9 moves left as seen in Figures 1 and 2 to produce braking power directed to the brake caliper 8 and further to the brake disc stack 4 by means of the brake cal iper 8. When the brake is being opened, the chock 9 moves back to the right as seen in Figures 1 and 2, ceasing by means of the chock 9 production of braking power directed to the brake caliper 8 and further to the brake disc stack 4 by means of the brake caliper 8. As disclosed in the preceding paragraph, the brake is activated or opened by means of a chock 9 operated by the brake cylinder 2. In the solutions shown in the figures, the chock 9 is part of the brake cylinder 2 forming the oper ating mechanism of the braking device, but the chock 9 could also be a part posi tioned between the brake cylinder 2 and disc stack enclosure 3, separate from the brake cylinder 2 but nevertheless operated by it.
The brake cylinder 2 shown in Figures 1 and 2 comprises both the work ing or operating brake 10 as well as the parking or park brake 20. A body of the brake cylinder 2 comprises substantially three interconnected parts, that is, a first body part 2a substantially corresponding to the portion of the working brake 10 of the brake cylinder 2, and a second body part 2b and a third body part 2c, the second body part 2b being located between the first body part 2a and third body part 2c in the axial direction A of the brake cylinder 2. The second body part 2b and third body part 2c substantially correspond to the portion of the parking brake 20 of the brake cylinder 2. Each body part 2a, 2b, 2c forms, on the corresponding body por- tion of the brake cylinder 2, a part forming with its inner parts at least a partially open cylindrical structure. The working brake 10 and parking brake 20 are ar ranged substantially coaxially in the brake cylinder 2.
The working brake 10 comprises a control cylinder formed by the first body part 2a, and a piston 11 arranged inside it movably in the axial direction A of the brake cylinder 2. The chock 9 is arranged in connection with the piston 11 of said working brake 10 by means of an intermediate piece 12 of the working brake 10, adapted between the chock 9 and piston 11.
In the first body part 2a of the brake cylinder 2, there is arranged at least one pressure medium fitting 13 to feed a pressurised medium, customarily a hy- draulic fluid, to the working brake 10. When a pressurised pressure medium is fed to the working brake 10, the piston 11 of the working brake 10 moves left, as seen in Figures 1 and 2, further moving the chock 9 left and acting on the brake caliper 8 in the disc stack enclosure 3 as described in the above to produce braking power by the effect of the working brake 10. When the pressurised pressure medium is released from the working brake 10, the piston 11 of the working brake 10 is able to move back right, as seen in Figures 1 and 2, also moving the chock 9 back right, by the joint effect of the piston 11 and intermediate piece 12, off the brake caliper
8 in the disc stack enclosure 3, thereby releasing the working brake 10.
The working brake 20 comprises a control cylinder jointly formed by the second body part 2b and third body part 2c, and a piston 21 arranged inside it movably in the axial direction A of the brake cylinder 2. The parking brake 20 fur ther comprises a flexible element 22 acting on the piston 21 in the axial direction A of the brake cylinder 2, in the embodiment of the figures, a coil spring. The park ing brake 20 further comprises an intermediate piece 23 of the parking brake 20, arranged in connection with an intermediate piece 12 of the working brake 10, so that the piston 21 of the parking brake 20 is arranged in connection with the chock
9 by means of the intermediate piece 23 of the parking brake 20 and the interme diate piece 12 of the working brake 10. In the second body part 2b, there is further arranged at least one pressure medium fitting 24 to feed a pressurised medium, customarily a hydraulic fluid as mentioned in the above, to the parking brake 20. When the parking brake 20 is active to produce braking power, a pres surised pressure medium is not fed to the parking brake 20 but the flexible element 22 presses the piston 21 of the parking brake 20 to the left, as seen in Figures 1 and 2. Because the piston 21 of the parking brake 20 is arranged in connection with the chock 9 by means of the intermediate piece 23 of the parking brake 20 and the intermediate piece 12 of the working brake 10, the piston 21 of the parking brake 20 presses, by means of the intermediate piece 23 of the parking brake 20 and the intermediate piece 12 of the working brake 10, the chock 9 to the left, as seen in Figures 1 and 2, acting on the brake caliper 8 in the disc stack enclosure 3 as de scribed in the above to produce braking power by the effect of the parking brake 20.
When a pressurised pressure medium is fed to the control cylinder of the parking brake 20 through said at least one pressure medium fitting 24, the pis ton 21 of the parking brake 20 moves in the axial direction A of the brake cylinder 2, to the right in Figures 1 and 2, compressing the flexible element 22 against the spring-back force of the flexible element 22. Because the piston 21 of the parking brake 20 is arranged in connection with the chock 9 by means of the intermediate piece 23 of the parking brake 20 and the intermediate piece 12 of the working brake 10, the moving of the piston 21 of the parking brake 20 to the right, as seen in Figures 1 and 2, causes the chock 9, too, to move to the right and off the brake caliper 8 in the disc stack enclosure 3, thereby releasing the parking brake 20. When the pressure medium fed into the control cylinder of the parking brake 20 is released from the control cylinder of the parking brake 20, that is, when the pressure medium fed into the control cylinder of the parking brake 20 flows out of the control cylinder of the parking brake 20, the force stored in the flexible element 22 as a result of its compression causes movement of the piston 21 of the parking brake 20 away from said flexible element 22, that is, to the left as seen in Figures 1 and 2, to bring the parking brake 20 into an active operating state.
In the example above, the braking device 1 of the working machine com prises both a working brake 10 and a parking brake 20 as well as a disc stack en closure 3 and brake disc stack 4 shared by them. For reasons of clarity, Figures 1 and 2 do not show an actual working machine or a pressure medium circuit related to using brakes, these being obvious for a person skilled in the art.
A problem with working machine brakes of the disc brake type lies in that it is not possible to monitor easily the condition of the brake, in particular the condition of the friction discs 5 and their mating discs 6, such as the remaining thickness of the friction discs 5 and/or mating discs 6 of the brake disc stack 4, or the ability of the actuator of the brake, that is, the brake cylinder 2 to produce ade quate braking torque. As the thickness of the friction discs 5 and mating discs 6 is reduced due to wear resulting from using the brakes, the available lengths of travel of the piston 11 of the working brake 10 or chock 9 of the piston 21 of the parking brake 20 are not necessarily enough any more to transmit adequate power from the flexible element 22 to bring the friction discs 5 and mating discs 6 of the brake disc stack 4 against each other to produce adequate braking power whereby the friction discs 5 and mating discs 6 must be replaced with new ones, or, if possible, the brake should at least be readjusted. Figures 1 and 2 further show a solution for monitoring the condition of a brake of a working machine, to produce information illustrating the operating ability or servicing need of the brake. The solution disclosed in Figures 1 and 2 comprises a sensor arrangement 30 comprising at least one sensor 33, by means of which the position of the piston 21 of the parking brake 20 may be determined in the brake cylinder 2, and based on it to indicate whether the brake can even pro duce adequate braking torque to safely use or park the working machine. The sensor arrangement 30 shown in Figures 1 and 2 comprises a sen sor 31 which comprises a body structure 32 of the sensor 31 and a detector part 33 connected to the body structure 32. The sensor arrangement 30 shown in Fig ures 1 and 2 further includes an additional body 34 connected as an extension to the third frame part 2c or the brake cylinder 2, that is, the body portion of the brake cylinder 2 corresponding to the parking brake 20 portion of the brake cylinder 2, and comprising an at least partially open space 35 on its inner side in the axial di rection of the brake cylinder 2; by means of this additional body, the sensor 31 may be supported to the brake cylinder 2. So, the additional body 34 is connected as an extension to the third body part 2c of the brake cylinder 2, corresponding to the portion of the parking brake 20, to the end of the third body part 2c of the brake cylinder 2, towards which the piston 21 of the parking brake 20 moves during an opening movement of the parking brake 20. With the aid of the additional body 34, it is possible to arrange an open space 35 in connection with the parking brake 20 in order to arrange the sensor 31 and in particular the detector part 33 in it, in connection with the parking brake 20. If there is, depending on the structure of the brake cylinder 2, a suitable space on the inside of the brake cylinder 2 to receive the sensor 31 or at least its detector part 33 to determine the position of the piston
21 of the parking brake 20 in the direction of movement of the piston 21, an addi- tional body is unnecessary.
The sensor arrangement 30 shown in Figures 1 and 2 further comprises an extension part 36, such as a axle stub, fixed as an extension to the piston 21 of the parking brake 20, which is arranged at its first end 36’ in connection with the end of the piston 21 of the parking brake 20, which is directed towards the addi- tional body 34, so the piston 21 end directed in the direction of the flexible element
22 of the piston 21. The axial direction of said extension part 36 is the same as the axial direction A of the brake cylinder 2. A second end 36” of the extension part 36 is arranged to extend to the open space 35 of the additional body 34.
In the sensor arrangement 30 shown in Figures 1 and 2, the sensor 31 is supported by its body structure 32 to the additional body 34 so that the detector part 33 of the sensor 31 is placed in the space 35 substantially next to the straight travel path of the extension part 36 in the direction of the axial direction A of the brake cylinder 2, or in the proximity thereof, so that while moving along its travel path the extension part 36 travels on at least a portion thereof past the detector part 33 of the sensor 31. Said detector part 33 of the sensor 31 may be placed in such a position in the space 35 that the extension part 36 travels on at least a por tion thereof past the detector part 33 of the sensor 31 in the immediate vicinity of the detector part 33, as shown in Figure 2, or so that the extension part 36 even touches the detector part 33 of the sensor 31 while travelling past the detector part 33. On the flank surface of the extension part 36 is arranged a mating surface 37 which extends from the second end 36” of the extension part 36 towards its first end 36’ and which either contacts the detector part 33 of the sensor 31 or travels in substantially the immediate vicinity thereof while passing the detector part 33. Based on the mutual interaction of the sensor part 33 of the sensor 31 and the ex- tension part 36 of the piston 21 of the parking brake 20, or lack thereof, the condi tion of the brake disc stack 4 of the brake or the condition of the brake cylinder may be indicated at least to the extend of whether the brake even has the prerequisite to produce adequate braking torque to use or park a working machine safely.
When the parking brake 20 of Figures 1 and 2 is activated, the pressure medium is released from the parking brake 20, which has been pressing the piston 21 of the parking brake 20 against the flexible element 22 with the parking brake 20 in the opened operating state. In such a case, the flexible element 22, typically a spring, compressed in the opened operating state of the parking brake 20, presses the piston 21 of the parking brake 20 to the left, as seen in Figures 1 and 2, whereby as disclosed in the above the chock 9 activates the brake disc stack 4 in the brake stack enclosure 3, thereby preventing a parked working machine from moving.
The length of the extension part 36 of the piston 21 of the parking brake 20 and the length of its travel path or range in the open space 35 of the additional body 34 of the sensor arrangement 30 is arranged such that if the extension part 36 stays in the active state of the parking brake 20 in the operating range or detec tion range of the detector part 33 of the sensor 31, it maybe assumed that the thick ness of the friction discs 5 and/or mating discs 6 of the brake disc stack 4, that is, their combined thickness, is still adequate for the brake to be able to press the fric tion discs 5 and mating discs 6 against each other to produce adequate braking torque to use or park a working machine safely. In such a case, the detector part 33 thus detects the presence or location of the extension part 36 of the piston of the parking brake 20 on its operation or detection range, whereby in response to this the sensor 31 indicates, very schematically in Figure 2 by means of a state infor mation signal produced by the sensor 31, shown by an arrow 38, whether the thick- ness of the friction discs 5 and/or mating discs 6 of the brake disc stack 4 is still adequate so that it may be assumed that the brake disc stack 4 still produces enough braking torque to use or park a working machine safely. The state infor mation signal 38 thus indicates the theoretical operating ability of the friction discs 5 and/or mating discs 6 of the brake disc stack 4, in other words the interpretation made on the basis of the thickness of the friction discs 5 and/or mating discs 6 of the brake disc stack 4, on the ability of the brake to press the friction discs 5 and mating discs 6 against each other to produce adequate braking torque to use or park a working machine safely.
In case the condition of the brake disc stack 4, in other words, the thick ness of the friction discs 5 and/or mating discs 6 of the brake disc stack 4, is no longer adequate for the assumption to be made that the brake disc stack 4 produces enough braking torque to use or park a working machine safely, or the brake cyl inder 2 has broken so that the brake bottoms out, so to speak, the extension part 36 of the piston 21 of the parking brake 20 does not in the activated mode of the parking brake 20 anymore stay in the operating range or detection range of the detector part 33 of the sensor 31, but moves with the piston 21 of the parking brake 20 to such an extent to the left, as seen in Figure 2, in relation to the operating range or detection range of the detector part 33, that the extension part 36 moves out of the operating range or detection range of the detector part 33 of the sensor 31. In such a case, the detector part 33 of the sensor 31 no longer detects the presence or location of the extension part 33 in its operating or detection range. In response to this, the sensor 31 produces a state information signal 38 based on which it may be interpreted that the friction discs 5 and/or mating discs 6 of the brake disc stack 4 are so worn out that it can no longer be assumed that the brake disc stack 4 pro duces adequate braking torque to use or park a working machine safely. In such a case it may therefore be interpreted that the working machine brake is in need of servicing, insofar as the friction discs 5 and/or mating discs 6 of the brake disc stack 4, at least, are concerned. Alternatively, the interpretation may be made that the brake cylinder 2 has broken so that the brake cannot be assumed to produce adequate braking torque to use or park a working machine safely. The detector part 33 of the sensor 31 may be implemented or arranged operational in a number of ways. The detector part 33 may require contact with the monitored object whereby in the activated state of the parking brake 20, as the detector part 33 of the sensor 31 touches the extension part 36 arranged in the piston 21 of the parking brake 20, a circuit in the sensor 31 closes through the ex- tension part 36, indicating that the extension part 36 of the piston 21 of the parking brake 20 is still located in the detection or operating range of the detector part 33 of the sensor 31. Similarly, if the detector part 33 of the sensor 31 in the activated state of the parking brake 20 no longer touches the extension part 36 arranged in the piston 21 of the parking brake 20, a circuit in the sensor 31 cannot close, indi cating in turn that the extension part 36 of the piston 21 of the parking brake 20 is located out of the detection or operating range of the detector part 33 of the sensor 31.
The detector part 33 of the sensor 31 may also be based on non-contact detection, as shown in Figure 2. According to such an embodiment, the detector part 33 of the sensor 31 may be, for example, an inductive proximity detector based on detecting a change in a magnetic field. According to a second embodiment of this type, the detector part 33 of the sensor 31 may be, for example, a capacitive prox imity detector based on detecting a change in capacitance. According to a third em bodiment of this type, the detector part 33 of the sensor 31 may be a Hall sensor, which is a magnetosensitive element based on detection of presence or change of a magnetic field. When a Hall sensor is used, the extension part 36, or part thereof such as a mating surface 37, of the piston 21 of the parking brake 20 may be brought magnetic, or a magnet may be arranged on the extension part 36, such as on the mating surface 37.
In the embodiment disclosed in the above, an extension part 36 has been arranged on the piston 21 of the parking brake 20, dimensioned to extend in the activated state of the parking brake 20 to the operating or detection range of the detector part 33 of the sensor 31 in case the thickness of the friction discs 5 and/or mating discs 6 of the brake disc stack 4 is considered adequate so that it may be assumed that the friction discs 5 and/or mating discs 6 of the brake disc stack 4 are capable of producing adequate braking power to use or park a working machine safely. Instead of using the extension part 36, the piston 21 of the parking brake 20 may be designed such that it itself extends to the operating or detection range of the detector part 33 of the sensor 31 when the brake disc stack 4 is con sidered operational on the basis of the thickness of the friction discs 5 and/or mat- ing discs 6. In such a case, it is also possible to arrange a mating surface 37 as de scribed in the above to the end of the piston 21 of the parking brake 20, extending into the open space 35 formed by the additional body 34 of the sensor arrangement 30.
A solution of the kind described in the above therefore provides an on/off type of indication on the thickness of the friction discs and/or mating discs of the brake disc stack and on the operating condition of the brake made based on it, or an indication of the operating condition of the brake cylinder. Advantageously, the mutual adaptation of the piston of the parking brake, or its extension part, and the detector part of the sensor is arranged such that when indicating a servicing need, the friction discs and/or mating discs of the brake disc stack still have an ad- equate thickness, at least, so that the brake of a working machine may, as far as it is concerned, produce adequate braking torque to use and park the working ma chine safely. Said condition monitoring procedure of the brake, carried out by the sensor 31, may take place when a parked working machine is brought into use and/or when parking a working machine that has been in use. The state infor- mation signal 38 by the sensor 31, so the state information signal describing the theoretical operating ability of the brake, may thus be produced always before opening an activated parking brake 20 as a working machine is brought into use and/or when parking a working machine that had been used when the parking brake 20 is activated for parking the working machine. The sensor 31 thus pro- duces information indicative of the operating ability of the brake, which may be evoked without interrupting the work of the working machine.
In the examples above, the braking device 1 of the working machine comprises both a working brake 10 and a parking brake 20 as well as a disc stack enclosure 3 shared by them, and a brake disc stack 4 placed in the disc stack enclo- sure 3. The disclosed solution therefore indicates the condition of the brake disc stack 4 shared by both the working brake 10 and parking brake 20 insofar as at least the thickness of the friction discs 5 and/or mating discs 6 of the brake disc stack 4 is concerned. The solution disclosed in the above was disclosed in connec tion with a wet disc brake but is equally usable in connection with a dry disc brake, too.
Figure 3 is a schematic view of an arrangement in a working machine for testing the operating ability of a brake in a working machine 40, also with the purpose of producing information indicative of the operating ability of the brake. The working machine 40 is shown in Figure 3 very schematically with a box shown in a dashed line. Figure 3 further schematically shows an axle 41 of the working machine 40 in connection with which a braking device 1 of the kind described in the above is arranged, to produce braking torque BM directed on the axle 41 of the working machine 40 to stop or keep in place the working machine 40.
Figure 3 further shows, very schematically, drive power transmission means 42 to produce drive transmission torque DM directed on the axle 41 of the working machine 40 to move or drive the working machine 40. Figure 3 further shows a sensor 43 arranged on the axle 41 of the working machine 40, to indicate the rotation of said axle 41 in response to the working machine 40 moving by the effect of the drive transmission torque DM directed on the axle 41 of the working machine 40. Figure 3 additionally shows, in a schematic manner, at least one con- trol unit 44 in the working machine 40 to control the functions of the working ma chine 40, such as the operation of the drive power transmission means 42 of the working machine 40.
According to an embodiment of testing the operation ability of a brake of a working machine, the parking brake 20 of the braking device 1 is activated, i.e. turned on, either in response to parking the working machine, having taken place earlier, or deliberate activation of the parking brake 20 for the purpose of testing the brake, either by a user of the working machine or automatically by the control unit 40. In response to an active operating state of the parking brake 20, the sensor arrangement 30 produces the state information signal 38 describing the theoreti- cal operating ability of the brake of the working machine, as described in the above. If the state information signal 38 indicates that the brake has not got the ability to produce adequate braking torque to use or stop the working machine safely on the basis of inadequate thickness of the friction discs 5 and/or mating discs 6 of the brake disc stack 4, the testing procedure of the brakes may be ended and the infor- mation indicated to the user of the working machine either directly or through the control unit 44.
If the state information signal 38 of the sensor arrangement 30 indicates that, on the basis of adequate thickness of the friction discs 5 and/or mating discs 6 of the brake disc stack 4 or as concerns the brake actuator, the brake has at least theoretically the ability to produce adequate braking torque to use or stop a work ing machine safely, the brakes testing procedure may proceed to the following stage where it is examined whether the condition of the friction discs 5 and/or mat ing discs 6 of the brake disc stack 4 or the condition of the brake actuator is such that they are a factually able to produce adequate braking torque to use or stop a working machine safely. At this stage of the testing procedure, while the parking brake 20 is still activated, the drive power transmission means 42 of the working machine 40 are, by means of a control signal CO-42 produced by the control unit 44, controlled to direct a predetermined amount of drive transmission torque DM on the axle 41 of the working machine 40, and a state information signal 45 is pro- duced, indicating the state of rotation of the axle 41, by means of a sensor 43 ar ranged on the axle 41 of the working machine 40 in response to the drive power transmission torque DM of at most the predetermined magnitude produced for the axle 41 to produce a state information signal 45 indicative of the actual operating ability of the brake of the working machine 40.
At the latter stage of the testing procedure, the brake of the working machine 40 is thus tested in a situation where the goal is to move the working ma chine 40 against an activated brake by a force caused by the predetermined amount of drive transmission torque DM brought on the axle 41. If the state information signal 45 produced by the sensor 43 indicates that the axle 41 is not rotating, the brake may be found to be in order to produce adequate braking torque to use or park the working machine 40 safely. If the state information signal 45 produced by the sensor 43 indicates that the axle 41 is rotating, it may be noted that the operat ing ability of the brake may not be adequate in order to produce adequate braking torque to use or park the working machine 40 safely under every condition. In both cases, the state information signal 45 produced by the sensor 43 may be indicated to the user of the working machine either directly or through the control unit 44. Figure 4 is a schematic view of a method according to the solution for testing the operating ability of a brake in a working machine.
In Figure 3, for reasons of clarity, the braking device 1 and drive trans mission means 42 are arranged to act on the same axle 41. The axle 41 may be an axle provided with wheels in a working machine, or an axle acting on the chain tracks of the working machine. It is also possible to arrange the braking device 1 and drive transmission means 42 to act on different axles, whereby the axle which the drive transmission means 42 are arranged to act on, may be instead of a work ing machine’s axle provided with wheels or an axle acting on chain tracks, any other axle belonging to the drive transmission means 42 or connected thereto to convey drive transmission torque or force to move the working machine 40.
In the above embodiment for testing the operating ability of the brake of the working machine, the parking brake of the braking device 1 was activated. Alternatively, the operating ability of the brake of the working machine may be tested by means of the working brake 10 in which case the above embodiment is implemented by using the working brake 10 instead of the parking brake 20. In this case, the working brake 10 of the braking device 1 is activated, for example, by a user of the working machine at a suitable stage of a working process of the working machine, such as prior to steering the working machine to a slope working stage. If the actual operating ability of the brake is tested by means of the working brake 10, the parking brake 20 is in such a situation open. In this case, too, before activat ing the working brake 10, it is possible to determine, based on the activation of the parking brake 20 and the state information signal 38 of the sensor arrangement 30, produced in response thereto, whether the brake has at least a theoretical ability to produce adequate braking torque to use and park the working machine safely.
With the disclosed arrangement and method for testing the operating ability of a brake of a working machine, it may be ensured that the operating ability of the brake is adequate for use when the working machine is parked and when it is being used, as well as in emergency braking situations where the emergency braking action is typically based on the use of the parking brake of the braking de vice. Ensuring the adequate operating ability of brakes in forest work machines, in particular, is more and more important due to more of the work being performed on a slope as timber harvesting and transportation also moves to harvesting sites that are more difficult to reach than the current ones. Those skilled in the art will find it obvious that, as technology advances, the basic idea of the invention may be implemented in many different ways. The invention and its embodiments are thus not restricted to the above-described ex amples but may vary within the scope of the claims.

Claims

Claims
1. A pressure medium operated braking device (1) for a working ma chine, the braking device (1) comprising a working brake (10), parking brake (20), and, shared by the working brake (10) and parking brake (20), a brake disc stack (4) which comprises alter nately at least one friction disc (5) and at least one mating disc (6) forming a coun terpiece for said at least one friction disc (5), characterised in that the braking device (1) comprises at least one sensor arrangement (30) for producing information indicative of the operating ability of the brake.
2. A braking device as claimed in claim 1 for a working machine, char- acterisedin that the braking device (1) comprises a brake cylinder (2) shared by the working brake (10) and parking brake (20), and in that the working brake (10) and parking brake (20) are arranged substantially coaxially in the brake cylinder (2).
3. A braking device as claimed in claim 1 or 2 for a working machine, characterised in that the braking device (20) comprises at least one piston (21) of the parking brake (20) and in that said at least one sensor arrangement (30) is arranged in connection with the parking brake (20) to determine the position of the piston (21) of the parking brake (20) in an active operating state of the parking brake (20).
4. A braking device as claimed in claim 3 for a working machine, char- acterisedin that the parking brake (20) comprises a control cylinder of the parking brake (20), formed by at least one body part (2b, 2c) of the brake cylinder (2), at least one piston (21) of the parking brake (20), arranged in the con trol cylinder of the parking brake (20), at least one flexible element (22) arranged in connection with the piston (21) of the parking brake (20), and at least one pressure medium fitting (24) through which the pressure medium may flow into the control cylinder of the parking brake (20) and out there from, and wherein the flow of the pressure medium into the control cylinder of the parking brake (20) causes a movement of the piston (21) of the parking brake (20) against said flexible element (22), causing the flexible element (20) to be compressed, the movement of the piston (21) of the parking brake (20) against said flexible element (22) causing the parking brake (20) to open, and wherein the flow of the pressure medium out of the control cylinder of the park ing brake (20) causes, for bringing the parking brake (20) to an active operating state, movement of the piston (21) of the parking brake (20) away from said flexi ble element (22) by the effect of the force stored in the flexible element (22) as a result of its compression.
5. A braking device as claimed in claim 3 or 4 for a working machine, c h a r a c t e r i s e d in that the braking device (20) comprises an extension part (36) connected to the piston (21) of the parking brake (20), and in that said at least one sensor ar rangement (30) is arranged to determine the position of the extension part (36) of the piston (21) in relation to said sensor arrangement (30) in order to determine the position of the piston (21) in relation to said sensor arrangement (30) in an active operating state of the parking brake (20).
6. A braking device as claimed in claim 4 or 5 for a working machine, c h a r a c t e r i s e d in that the extension part (36) of the piston (21) of the parking brake (20) is arranged in the axial direction of the piston (21) in connection with the end of the piston (21), directed in the direction of the flexible element (22).
7. A braking device as claimed in any one of the preceding claims for a working machine, c h a r a c t e r i s e d in that the sensor arrangement (30) comprises at least one sensor (31) com prising a body structure (32) of the sensor (31) and a detector part (33) of the sen- sor (31), whereby the sensor (31) is arranged to be supported, by the body struc ture (32), in connection with the body part (2b, 2c) of the parking brake (20) to arrange the detector part (33) of the sensor (31) next to the travel path, or imme diate vicinity thereof, of the piston (21) of the parking brake (20) or the extension part (36) connected thereto.
8. A braking device as claimed in claim 7 for a working machine, c h a r - a c t e r i s e d in that the sensor arrangement (30) comprises an additional body (34) ar ranged in connection with the body part (2b, 2c) of the parking brake (20), inside which there is an open space (35) into which open space the piston (21) of the parking brake (20), or the extension part (35) connected thereto, is arranged to extend, and in that the sensor (31) is arranged, by means of the body structure (32) of the sensor (31), to said additional body (34) so that the detector part (33) of the sensor (31) is arranged in said open space (35) next to the travel path, or immedi ate vicinity thereof, of the piston (21) of the parking brake (20) or the extension part (36) connected thereto.
9. A braking device as claimed in any one of the preceding claims for a working machine, c h a r a c t e r i s e d in that the sensor arrangement (30) com prises a Hall sensor.
10. A braking device as claimed in any one of the preceding claims for a working machine, c h a r a c t e r i s e d in that the braking device (1) comprises at least one chock (9) arranged between the brake cylinder (2) and a brake caliper (8) controlling the operation of the brake disc stack (4) so that when the working (10) or parking brake (20) is being released, the chock (9) is arranged to move off from contact with to the brake caliper (8), achieving the brake to open, and in that when the working (10) or parking brake (20) is being activated the chock (9) is arranged to move into contact with the brake caliper (8) to produce braking torque by means of the brake disc stack (4).
11. A braking device as claimed in any one of the preceding claims for a working machine, c h a r a c t e r i s e d in that the braking device (1) is a wet disc brake which comprises a substantially closed, oil-filled disc stack enclosure (3) in which said brake disc stack (4) resides.
12. An arrangement for producing information indicative of an operat ing ability of a brake in a working machine (40), the working machine (40) com prising at least one braking device (1) as claimed in any one of claims 1 to 11 for producing braking torque (BM) directed on at least one axle (41) of the working machine, and in the arrangement the sensor arrangement (30) of the braking device (1) is configured to produce a state information signal (38) describing the theoretical operating ability of the brake of the working machine (40), when the parking brake (20) is active.
13. An arrangement as claimed in claim 12, c h a r a c t e r i s e d in that the working machine (40) further comprises at least one control unit (44) for controlling the operation of the work ing machine (40), drive power transmission means (42) to produce drive transmission torque DM directed on at least one axle (41) of the working machine (40), belong ing to or connected to the drive power transmission means (42), and at least one sensor (43) arranged in said axle (41) belonging to or con nected to the drive power transmission means (42) to indicate a state information signal (45) indicative of the rotation of said axle (41) in response to the effect of the drive power transmission torque (DM) directed on said axle (41), and in the arrangement while the working brake (10) or parking brake (20) is active, the control unit (44) is configured to control the drive power transmission means (42) of the working machine to produce a predetermined amount of drive transmission torque (DM) directed on the axle (41) belonging to or connected to the drive power transmission means (42), and the sensor (43) arranged on said axle (41) belonging to or connected to the drive power transmission means (42), is configured to produce a state infor mation signal (45) indicative of the state of rotation of said axle (41) in response to the drive power transmission torque (DM) of at most the predetermined magni- tude directed on said axle (45) to produce a state information signal (45) indicative of the actual operating ability of the brake.
14. A method for producing information indicative of an operating abil ity of a brake in a working machine (40), the working machine (40) comprising at least one braking device as claimed in any one of claims 1 to 11 for producing braking torque (BM) directed on at least one axle (41) of the working machine (40), and in the method a state information signal (38) indicative of the theoretical operating ability of the brake of the working machine (40) is produced by a sensor arrange ment (30) of the braking device (1) when the parking brake (20) is active.
15. A method as claimed in claim 14, c h a r a c t e r i s e d in that the working machine (40) further comprises at least one control unit (44) for controlling the operation of the work ing machine (40), drive power transmission means (42) to produce drive transmission torque (DM) directed on an axle (41) of the working machine (40), belonging to or connected to the drive power transmission means, and at least one sensor (43) arranged on said axle (41) belonging to or con nected to the drive power transmission means (42) to indicate a state information signal (45) indicative of the rotation of said axle (41) in response to the effect of the drive power transmission torque (DM) directed on said axle (41), and in the method controlling, by means of the control unit (44), while the working brake (10) or parking brake (20) is active, the drive power transmission means (42) of the working machine (40) to direct a predetermined amount of drive transmission torque (DM) on the axle (41) belonging to or connected to the drive power trans- mission means (42), and producing a state information signal (45) indicative of the state of rota tion of said axle (41) by a sensor (43) arranged on the axle (41) belonging to or connected to the drive power transmission means (42) of the working machine (40), in response to the drive power transmission torque (DM) of at most the pre- determined magnitude directed on said axle (41) to produce a state information signal (45) indicative of the actual operating ability of the brake.
PCT/FI2021/050400 2020-06-03 2021-06-01 Braking device for working machine WO2021245334A1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
BR112022024584A BR112022024584A2 (en) 2020-06-03 2021-06-01 ARRANGEMENT AND METHOD FOR TESTING AN ABILITY TO OPERATE A BRAKE ON A FOREST SERVICE MACHINE
EP21816952.2A EP4161813A1 (en) 2020-06-03 2021-06-01 Braking device for working machine
CN202180036891.4A CN115667034A (en) 2020-06-03 2021-06-01 Brake device for working machine

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI20205577 2020-06-03
FI20205577A FI129996B (en) 2020-06-03 2020-06-03 Braking device for working machine

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WO2021245334A1 true WO2021245334A1 (en) 2021-12-09

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PCT/FI2021/050400 WO2021245334A1 (en) 2020-06-03 2021-06-01 Braking device for working machine

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EP (1) EP4161813A1 (en)
CN (1) CN115667034A (en)
BR (1) BR112022024584A2 (en)
FI (1) FI129996B (en)
WO (1) WO2021245334A1 (en)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090084637A1 (en) * 2005-01-08 2009-04-02 Dunlop Aerospace Limited Electrically actuated aircraft brakes
US20120221184A1 (en) * 2011-02-28 2012-08-30 Pfohl Kevin L Measuring Brake Wear
US20160214594A1 (en) * 2015-01-26 2016-07-28 Siemens Industry, Inc. Methods and system for verifying a brake system in a vehicle
EP3072763A1 (en) * 2015-03-25 2016-09-28 Honeywell International Inc. Brake disc stack wear measurement
US20190263375A1 (en) * 2018-02-27 2019-08-29 Airbus Operations Limited Vehicle braking

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090084637A1 (en) * 2005-01-08 2009-04-02 Dunlop Aerospace Limited Electrically actuated aircraft brakes
US20120221184A1 (en) * 2011-02-28 2012-08-30 Pfohl Kevin L Measuring Brake Wear
US20160214594A1 (en) * 2015-01-26 2016-07-28 Siemens Industry, Inc. Methods and system for verifying a brake system in a vehicle
EP3072763A1 (en) * 2015-03-25 2016-09-28 Honeywell International Inc. Brake disc stack wear measurement
US20190263375A1 (en) * 2018-02-27 2019-08-29 Airbus Operations Limited Vehicle braking

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BR112022024584A2 (en) 2022-12-27
EP4161813A1 (en) 2023-04-12
CN115667034A (en) 2023-01-31
FI20205577A1 (en) 2021-12-04
FI129996B (en) 2022-12-15

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