CN115667034A

CN115667034A - Brake device for working machine

Info

Publication number: CN115667034A
Application number: CN202180036891.4A
Authority: CN
Inventors: 扬内·洛波宁; 安西·萨尔哈卢奥马
Original assignee: Ponsse Oyj
Current assignee: Ponsse Oyj
Priority date: 2020-06-03
Filing date: 2021-06-01
Publication date: 2023-01-31
Also published as: EP4161813A1; BR112022024584A2; FI129996B; FI20205577A1; WO2021245334A1

Abstract

A pressure medium operated brake device (1) for a working machine. The service brake (1) comprises a service brake (10), a parking brake (20), and a brake disc pack (4) shared by the service brake (10) and the parking brake (20), which brake disc pack comprises alternately at least one friction disc (5) and at least one mating disc (6) which forms a counterpart for the at least one friction disc (5). The brake device (6) comprises at least one sensor arrangement (30) for indicating the status of a brake disc pack (4) of the brake device (1). Further, an arrangement and a method for generating information indicative of the operational capability of a brake in a work machine.

Description

Brake device for working machine

Technical Field

The present invention relates to a pressure medium operated brake for a work machine. In particular, the invention relates to such a brake device for a work machine, wherein the work brake and the parking brake of the work machine are integrated into the same brake device.

Background

In work machines such as, for example, dozers, bucket loaders or other earth moving machines, fork-lift trucks, crane vehicles or other mobile load handling devices, as well as harvesters, transtainers or other forestry machines, brakes are used to keep a parked work machine stationary so that the work machine cannot start moving by itself, or alternatively to stop a moving work machine.

A typical work machine brake used in particular in forest machines is a combined work and parking brake operated by pressure medium, for example hydraulically, whereby the same brake device has means to activate both the work brake and the parking brake incorporated in the brake device. In this case, a force may be directed by the pressurized pressure medium to the part of the brake device forming the parking brake, which force releases the parking brake, allowing the work machine to move. When the force action of the pressure medium on the parking brake is ended, the parking brake is activated, so that the parked working machine is prevented from starting to move by itself. Accordingly, by means of the pressurized pressure medium, a force is transmitted to the part of the brake device forming the service brake for stopping the moving work machine, which force activates the service brake for stopping the moving work machine.

A brake device of the kind in question is usually realized as a brake device of the disc brake type, whereby the brake device comprises a brake disc pack having at least one friction disc provided with a friction surface and a mating disc forming a counterpart for the at least one friction disc provided with a friction surface, whereby the friction disc and the mating disc are finally in contact against each other when the brake is activated, in other words when the brake is in an activated use state, and are finally disengaged from each other when the brake is switched off or released. A braking device of the disc brake type may be a wet disc brake, wherein the brake disc pack is arranged in a closed enclosure filled with oil and separated from the brake-activated portion, so that the brake disc pack is arranged in the same space as the brake-activated portion, in a different space from the brake-activated portion, or in a dry disc brake.

A problem with brake devices of the type described is that the condition of the brake cannot be easily monitored. Currently, manufacturers are directing service of the brakes and/or periodic replacement of certain components in the brakes, or checking the amount of wear of the brakes in connection with service. Opening the brake device for checking the brake device during maintenance takes additional time, in particular because the state of the brake does not in many cases also require a replacement of the friction and/or counter-disc and/or an adjustment of the brake. Replacement of the brake, and indeed the friction and/or mating discs, may be required because excessive wear is only detected when the friction and/or mating discs no longer grip as required. In connection with parking brakes, which are also often used as emergency brakes, excessive wear may only be detected after the parked machine has been able to inadvertently move itself, in other words, may only be detected after the safe parking of the machine has degraded. However, it is not always possible to service the brakes immediately, and it may therefore be necessary to use various types of aids, such as wedges to be placed behind the wheels, to ensure that the machine is safely parked until the brakes can be serviced. In the case of a working brake, the state of degradation of the brake can be noticed only at a stage when the work machine is no longer staying at the desired place during use, or is not stopped at the desired place during use, which may be relevant for example for forestry machines in connection with work on an increasing slope.

For the braking of the work machine brake, it is therefore desirable to achieve a solution in which the state of the work machine brake can be determined when needed.

Disclosure of Invention

The invention aims to develop a novel brake device of a working machine.

The solution according to the invention is characterized by what is disclosed in the independent claims.

The invention is based on a pressure medium operated brake device in a work machine, which brake device comprises at least one sensor arrangement to generate information representing the operational capacity of the brake in order to indicate the status of a brake disc pack of the brake device.

An advantage of the invention is that it is possible to detect in a simple manner at least the thickness of the friction and/or mating discs of the brake disc set of the brake device, i.e. at least the combined thickness of the friction and/or mating discs, still sufficient for the brake to be able to press the friction and mating discs against each other to generate a sufficient braking torque to safely use or park the work machine. With the disclosed solution, it is possible to determine the ability of the actuator of the brake to act directly or indirectly on the brake disc set to generate a braking torque, in addition to or instead of the information indicative of the state of the brake disc set. By means of the disclosed solution, it is possible to detect defects in the operation of the actuator of the brake, such as so-called brake bottoming, regardless of the operational capability of the brake disc pack. The disclosed solution thus allows determining the overall operational capacity and the need for maintenance of the braking device. By means of the sensor arrangement arranged in the brake device itself, it is also possible to indicate the brake operation capability without stopping the operation.

Some embodiments of the invention are disclosed in the dependent claims.

Drawings

The invention will now be described in more detail in connection with preferred embodiments and with reference to the accompanying drawings, in which:

figure 1 is a schematic side view partly in cross section and seen from above of a braking device of a working machine,

figure 2 is a schematic side view in cross section of a brake cylinder of the brake apparatus of figure 1,

FIG. 3 is a schematic illustration of an arrangement for detecting the operational capability of a brake in a work machine, an

Fig. 4 is a schematic illustration of a method for detecting the operational capability of a brake in a work machine.

For the purpose of clarity, some embodiments of the invention are illustrated in simplified form in the accompanying drawings. In the drawings, like numbering represents like elements.

Detailed Description

Fig. 1 is a schematic diagram of a brake device 1 of a working machine viewed from obliquely above and partially in cross section, and fig. 2 is a schematic side view of a brake cylinder 2 of the brake device 1 of fig. 1 in cross section.

The brake device 1 shown in fig. 1 is a disc brake, the brake device 1 comprising a brake cylinder 2. The brake cylinder 2 comprises an operating mechanism of the brake, in other words, the brake cylinder 2 comprises means for controlling the operation of using the brake, that is, means for controlling both the brake application to generate brake power and the brake release or disconnection so that no brake power is generated.

Furthermore, the brake device 1 shown in fig. 1 comprises a disc package 3 separate from the brake cylinder 2 but operatively connected to the brake cylinder 2, which disc package 3 has at least one friction disc 5 and at least one mating disc 6, the at least one friction disc 5 being provided with a friction surface, the at least one mating disc 6 forming a counterpart for the at least one friction disc 5. The at least one friction disc 5 and the at least one mating disc 6 are alternately placed with respect to each other in a configuration that forms the brake disc pack 4. When the brake is applied, the friction and mating discs eventually contact each other against which braking power is generated, and when the brake is disconnected or released, the friction and mating discs eventually at least partially separate from each other such that braking power is no longer generated.

The disc package 3 forms an enclosed space which is separate from the brake cylinder 2 and into which a shaft 7 extends, the shaft 7 may be, for example, a shaft of a work machine wheel, or a shaft in contact with a work machine wheel axle, or a shaft of a work machine provided with a caterpillar on which the shaft 7 acts directly or indirectly. In the space delimited by the disc pack enclosure 3 there is at least one mating disc 6 arranged in connection with said shaft 7, whereby said at least one mating disc 6 can rotate together with the shaft 7 when the work machine is moved. Furthermore, the disc pack enclosure 3 has at least one disc-shaped friction disc 5 arranged adjacent to the at least one mating disc 6, the at least one disc-shaped friction disc 5 being arranged between the mating discs 6 in the presence of a plurality of mating discs 6, the at least one disc-shaped friction disc 5 having a friction surface oriented towards the mating discs 6. The at least one friction disc 5 may be supported as one or more fixed structural members arranged in the disc pack enclosure 3 such that the at least one friction disc 5 cannot rotate together while the shaft 7 and the at least one mating disc 6 arranged in connection with the shaft 7 rotate. The at least one friction disc 6 and the at least one mating disc 5 form the aforementioned brake disc pack 4. The disc pack enclosure 3 is filled with oil so that the friction discs 5 and the mating discs 6 are immersed in said oil, whereby the disc brake is of the so-called wet brake disc type.

The disc pack enclosure 3 further comprises a brake caliper 8, the operation of the brake caliper 8 being configured to effect pressing of the at least one friction disc 5 and the at least one mating disc 6 of the disc pack 4 against each other when the brake is activated, i.e. when the brake is placed in an activated operating state for generating braking power. Similarly, when the brake is switched off, i.e. when the generation of brake power ceases, the brake caliper 8 is operated to allow the at least one friction disc 5 and the at least one mating disc 6 to move away from each other. The brake is activated and deactivated by means of a wedge 9 operated by the brake cylinder 2. To activate the brake for generating brake power, the wedge 9 is moved to the left as seen in fig. 1 and 2 to generate brake power which is directed to the brake caliper 8 and further to the brake disc pack 4 by means of the brake caliper 8. When the brake is switched off, the wedge 9 moves back to the right as seen in fig. 1 and 2, so that the generation of brake power by means of the wedge 9, which is directed to the brake caliper 8 and further by means of the brake caliper 8 to the brake disc pack 4, is stopped.

As disclosed in the preceding paragraph, the brake is activated or deactivated by means of a wedge 9 operated by the brake cylinder 2. In the solution shown in the figures, the wedge 9 is part of the brake cylinder 2 forming the operating mechanism of the brake device, but the wedge 9 may also be part of a part positioned between the brake cylinder 2 and the disc pack enclosure 3, separate from the brake cylinder 2, but still operated by the brake cylinder 2.

The brake cylinder 2 shown in fig. 1 and 2 comprises both an operating or operating brake 10 and a parking or parking brake 20. The body of the brake cylinder 2 substantially comprises three interconnected parts, namely a first body part 2a, which first body part 2a substantially corresponds to the part of the service brake 10 of the brake cylinder 2, and a second body part 2b and a third body part 2c, which second body part 2b is located between the first body part 2a and the third body part 2c in the axial direction a of the brake cylinder 2. The second body portion 2b and the third body portion 2c substantially correspond to the portion of the parking brake 20 of the brake cylinder 2. Each

body portion

2a, 2b,2c forms part of a cylindrical structure, the inner part of which is formed to be at least partially open, on the corresponding body portion of the brake cylinder 2. The service brake 10 and the parking brake 20 are arranged substantially coaxially in the brake cylinder 2.

The service brake 10 comprises a control cylinder formed by the first body part 2a and a piston 11 arranged movably inside the first body part 2a in the axial direction a of the brake cylinder 2. The wedge 9 is arranged to be connected to a piston 11 of said service brake 10 by means of an intermediate piece 12 of the service brake 10, the intermediate piece 12 being adapted to be located between the wedge 9 and the piston 11.

In the first body part 2a of the brake cylinder 2, at least one pressure medium fitting 13 is arranged to supply pressurized medium, typically hydraulic fluid, to the service brake 10. When pressurized pressure medium is supplied to the service brake 10, the piston 11 of the service brake 10 is moved to the left as seen in fig. 1 and 2, so that the wedge 9 is moved further to the left and acts on the brake caliper 8 in the disc package 3 as described above to generate brake power by the action of the service brake 10. When the pressurized pressure medium is released from the service brake 10, the piston 11 of the service brake 10 can move back to the right as seen in fig. 1 and 2, so that the wedge 9 is also moved back to the right away from the brake caliper 8 in the disc package 3 by the coupling action of the piston 11 with the intermediate piece 12, thereby releasing the service brake 10.

The service brake 20 comprises a control cylinder formed by the second body part 2b and the third body part 2c in a jointed manner, and a piston 21, which piston 21 is arranged inside the control cylinder in a movable manner in the axial direction a of the brake cylinder 2. The parking brake 20 further comprises a flexible element 22, which flexible element 22 acts on the piston 21 in the axial direction a of the brake cylinder 2, in the embodiment of the figures the flexible element 22 is a coil spring. The parking brake 20 further comprises an intermediate piece 23 of the parking brake 20 arranged in connection with the intermediate piece 12 of the service brake 10, such that the piston 21 of the parking brake 20 is arranged in connection with the wedge 9 by means of the intermediate piece 23 of the parking brake 20 and the intermediate piece 12 of the service brake 10. In the second body part 2b there is also arranged at least one pressure medium fitting 24 for supplying pressurized medium, typically hydraulic fluid as mentioned above, to the parking brake 20.

When the parking brake 20 is activated to generate braking power, pressurized pressure medium is no longer supplied 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 fig. 1 and 2. Since the piston 21 of the parking brake 20 is arranged to be connected with the wedge 9 by means of the intermediate piece 23 of the parking brake 20 and the intermediate piece 12 of the service brake 10, the piston 21 of the parking brake 20 presses the wedge 9 to the left as seen in fig. 1 and 2 by means of the intermediate piece 23 of the parking brake 20 and the intermediate piece 12 of the service brake 10, acting on the brake caliper 8 in the disc pack enclosure 3 as described above, to generate brake power by the action of the parking brake 20.

When pressurized pressure medium is supplied to the control cylinder of the parking brake 20 through the at least one pressure medium fitting 24, the piston 21 of the parking brake 20 is moved to the right in fig. 1 and 2 in the axial direction a of the brake cylinder 2, thereby compressing the flexible element 22 against the resilient force of the flexible element 22. Since the piston 21 of the parking brake 20 is arranged in connection with the wedge 9 by means of the intermediate piece 23 of the parking brake 20 and the intermediate piece 12 of the service brake 10, a movement of the piston 21 of the parking brake 20 to the right as can be seen in fig. 1 and 2 moves the wedge 9 also to the right and away from the brake caliper 8 in the disc package 3, whereby the parking brake 20 is released.

When the pressure medium supplied to the control cylinder of the parking brake 20 is released from the control cylinder of the parking brake 20, i.e. when the pressure medium supplied to 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 due to the compression of the flexible element 22 moves the piston 21 of the parking brake 20 away from said flexible element 22, i.e. to the left as seen in fig. 1 and 2, to place the parking brake 20 in an active operating state.

In the above example, the brake device 1 of a work machine comprises both a work brake 10 and a parking brake 20 as well as a disc pack enclosure 3 and a disc pack 4 which are shared by the work brake 10 and the parking brake 20. For the sake of clarity, fig. 1 and 2 do not show the actual work machine or the pressure medium circuit in connection with the use of brakes, as will be clear to a person skilled in the art.

A problem with a work machine brake of the disc brake type is that it is not possible to easily monitor the status of the brake, in particular the status of the friction discs 5 and the mating discs 6 of the friction discs 5, such as the remaining thickness of the friction discs 5 and/or the mating discs 6 of the brake disc set 4, or the capacity of the actuator of the brake, i.e. the capacity of the brake cylinder 2 to generate a sufficient braking torque. When the thickness of the friction and mating discs 5, 6 is reduced due to wear caused by the use of the brake, the available stroke length of the piston 11 of the service brake 10 or the available stroke length of the wedges 9 of the piston 21 of the parking brake 20 is not necessarily sufficient to transfer enough power from the flexible element 22 to bring the friction and mating discs 5, 6 of the brake disc set 4 against each other to generate enough braking power, whereby the friction and mating discs 5, 6 have to be replaced with new friction and mating discs 5, 6 or, if possible, at least the brake should be readjusted.

Fig. 1 and 2 also show solutions for monitoring the state of the brakes of a work machine to generate information that explains the operational capacity or need for maintenance of the brakes. The solution disclosed in fig. 1 and 2 comprises a sensor arrangement 30, which sensor arrangement 30 comprises at least one sensor 33, by means of which sensor 33 the position of the piston 21 of the parking brake 20 in the brake cylinder 2 can be determined and, on the basis of this position, it is indicated whether the brake can smoothly generate sufficient brake torque to safely use or park the work machine.

The sensor arrangement 30 shown in fig. 1 and 2 comprises a sensor 31, the sensor 31 comprising a body structure 32 of the sensor 31 and a detector portion 33 connected to the body structure 32. The sensor arrangement 30 shown in fig. 1 and 2 further comprises an additional body 34, the additional body 34 being connected as an extension to the third frame part 2c or to the brake cylinder 2, i.e. to the body part of the brake cylinder 2 corresponding to the parking brake 20 part of the brake cylinder 2, and the additional body 34 comprising an at least partially open space 35 located inside the additional body 34 in the axial direction of the brake cylinder 2; by means of which the sensor 31 can be supported to the brake cylinder 2. Thus, the additional body 34 is connected as an extension to the third body part 2c of the brake cylinder 2 corresponding to the part of the parking brake 20, i.e. to the end of the third body part 2c of the brake cylinder 2 towards which the piston 21 of the parking brake 20 is moved during the switch-off movement of the parking brake 20. By means of the additional body 34, an open space 35 can be arranged in connection with the parking brake 20, so that the sensor 31 and in particular the detector part 33 located in the space 35 is arranged in connection with the parking brake 20. An additional body is not necessary if, depending on the structure of the brake cylinder 2, there is a suitable space inside the brake cylinder 2 to receive the sensor 31 or at least the detector portion 33 of the sensor 31 to determine the position of the piston 21 of the parking brake 20 in the direction of movement of the piston 21.

The sensor arrangement 30 shown in fig. 1 and 2 further comprises an extension 36, such as a shaft root, as an extension fixed to the piston 21 of the parking brake 20, the extension 36 being arranged to be connected at its first end 36' with the end of the piston 21 of the parking brake 20, the extension 36 being oriented towards the additional body 34, whereby the piston 21 is finally oriented in the direction of the flexible element 22 of the piston 21. The axial direction of the extension 36 is the same as the axial direction a of the brake cylinder 2. The second end 36 "of the extension portion 36 is arranged to extend to the open space 35 of the additional body 34.

In the sensor arrangement 30 shown in fig. 1 and 2, the sensor 31 is supported to the additional body 34 by the body structure 32 of the sensor 31 such that the detector portion 33 of the sensor 31 is placed substantially close to, or in the vicinity of, the linear travel path of the extension portion 36 in the direction of the axial direction a of the brake cylinder 2 in the space 35 such that the extension portion 36 travels over at least a part thereof past the detector portion 33 of the sensor 31 when moving along the travel path of the extension portion 36. Said detector portion 33 of the sensor 31 may be placed in such a position in the space 35 that the extension portion 36 travels over at least a part of the extension portion 36 in close proximity to the detector portion 33 as shown in fig. 2 past the detector portion 33 of the sensor 31, or that the extension portion 36 even touches the detector portion 33 of the sensor 31 when traveling past the detector portion 33. On the side surface of the extension portion 36 a mating surface 37 is arranged, which mating surface 37 extends from the second end 36 "of the extension portion 36 towards the first end 36' of the extension portion 36, and which mating surface 37 contacts the detector portion 33 of the sensor 31 or runs substantially next to the detector portion 33 when passing the detector portion 33. Based on the interaction of the sensor portion 33 of the sensor 31 with the extension 36 of the piston 21 of the parking brake 20, or the absence of the interaction of the sensor portion 33 of the sensor 31 with the extension 36 of the piston 21 of the parking brake 20, the state of the brake disc pack 4 or the state of the brake cylinders of the brake can be used at least to some extent to indicate whether the brake actually has a prerequisite to generate a sufficient brake torque to safely use or park the work machine.

When the parking brake 20 of fig. 1 and 2 is activated, the pressure medium is released from the parking brake 20, which pressure medium has pressed the piston 21 of the parking brake 20 against the flexible element 22 and the parking brake 20 is in the off-operating state. In this case, the flexible element 22, typically a spring, which is compressed in the off-operating state of the parking brake 20 presses the piston 21 of the parking brake 20 to the left as seen in fig. 1 and 2, whereby the wedge 9 activates the brake disc pack 4 in the disc pack enclosure 3, as disclosed above, preventing the parked working machine from moving.

The length of the extension 36 of the piston 21 of the parking brake 20 and the length or extent of the travel path of this extension 36 in the open space 35 of the additional body 34 of the sensor arrangement 30 are arranged such that: if the extension 36 stays in the operating range or detection range of the detector portion 33 of the sensor 31 in the activated state of the parking brake 20, it may be assumed that the thickness of the friction and/or mating discs 5, 6 of the brake disc set 4, i.e. the combined thickness of the friction and mating discs 5, 6, is still sufficient for the brake to be able to press the friction and mating discs 5, 6 against each other to generate sufficient brake power to safely use or park the work machine. In this case, the detector portion 33 thus detects the presence or position of the extension 36 of the piston of the parking brake 20 over the operating range or detection range of the detector portion 33, whereupon in response to this detection the sensor 31 indicates by means of a status information signal generated by the sensor 31, which is very schematically indicated in fig. 2 by an arrow 38, whether the thickness of the friction discs 5 and/or mating discs 6 of the brake disc pack 4 is still sufficient such that it can be assumed that the brake disc pack 4 still produces sufficient braking torque to safely use or park the work machine. The status information signal 38 thus indicates the theoretical operational capability of the friction and/or mating discs 5, 6 of the brake disc set 4, in other words the ability of the brake to press the friction and mating discs 5, 6 against each other to generate sufficient braking torque to safely use or park the work machine, based on the thickness of the friction and/or mating discs 5, 6 of the brake disc set 4.

In the case of a certain state of the brake disc pack 4, in other words if the thickness of the friction discs 5 and/or mating discs 6 of the brake disc pack 4 is no longer sufficient to assume that the brake disc pack 4 generates sufficient braking torque to safely use or park the work machine, or the brake cylinder 2 has been damaged such that the brake bottoms out, it can be said that the extension 36 of the piston 21 of the parking brake 20 in the active mode of the parking brake 20 is no longer held in the operating range or detection range of the detector portion 33 of the sensor 31, but is moved to the left, as seen in fig. 2, with respect to the operating range or detection range of the detector portion 33 of the parking brake 20 such that the extension 36 moves out of the operating range or detection range of the detector portion 33 of the sensor 31. In this case, the detector portion 33 of the sensor 31 no longer detects the presence or position of the extension portion 33 in the operating range or detection range of the detector portion 33. In response thereto, the sensor 31 generates a status information signal 38, on the basis of which status information signal 38 it can be interpreted that the friction discs 5 and/or the mating discs 6 of the brake disc pack 4 are worn out such that it can no longer be assumed that the brake disc pack 4 generates sufficient braking torque to safely use or park the work machine. In this case, it can therefore be interpreted that the work machine brake needs servicing, at least in terms of the friction discs 5 and/or the mating discs 6 of the brake disc pack 4. Alternatively, the following explanation may be made: the brake cylinder 2 has been damaged so that it cannot be assumed that the brake generates sufficient braking torque to safely use or park the work machine.

The detector portion 33 of the sensor 31 may be operatively implemented or arranged in a variety of ways. The detector portion 33 may need to be in contact with the monitored object, whereby in the activated state of the parking brake 20, when the detector portion 33 of the sensor 31 touches the extension 36 arranged in the piston 21 of the parking brake 20, the circuit in the sensor 31 is closed by the extension 36, indicating that the extension 36 of the piston 21 of the parking brake 20 is still located in the detection range or operating range of the detector portion 33 of the sensor 31. Similarly, if the detector portion 33 of the sensor 31 no longer touches the extension 36 arranged in the piston 21 of the parking brake 20 in the activated state of the parking brake 20, the circuit in the sensor 31 cannot be closed, thereby indicating that the extension 36 of the piston 21 of the parking brake 20 is outside the detection range or operating range of the detector portion 33 of the sensor 31.

The detector portion 33 of the sensor 31 may also be based on non-contact detection as illustrated in fig. 2. According to such an embodiment, the detector portion 33 of the sensor 31 may be an inductive proximity detector, for example, based on detecting changes in a magnetic field. According to a second embodiment of this type, the detector portion 33 of the sensor 31 may be a capacitive proximity detector, for example based on detecting a change in capacitance. According to a third embodiment of this type, the detector portion 33 of the sensor 31 may be a hall sensor, which is a magneto-sensitive element based on detecting the presence or change of a magnetic field. When a hall sensor is used, the extension 36 or a part of the extension, such as the mating surface 37, of the piston 21 of the parking brake 20 may be magnetic, or a magnet may be arranged on the extension 36, such as the mating surface 37.

In the embodiment disclosed above, an extension 36 has been arranged on the piston 21 of the parking brake 20, which extension 36 is dimensioned to extend into the operating range or detection range of the detector portion 33 of the sensor 31 in the activated state of the parking brake 20, it being possible to assume that the friction discs 5 and/or mating discs 6 of the brake disc set 4 are able to generate sufficient brake power to safely use or park the work machine if the thickness of the friction discs 5 and/or mating discs 6 of the brake disc set 4 is considered sufficient. Instead of using the extension 36, the piston 21 of the parking brake 20 may be designed such that it extends itself to the operating range or detection range of the detector portion 33 of the sensor 31 when the brake disc set 4 is deemed to be operable based on the thickness of the friction disc 5 and/or the mating disc 6. In this case, it is also possible to arrange a mating surface 37 as described 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 type described above therefore provides an indication as to the thickness of the friction and/or mating discs of the brake disc pack and as to the type of on/off operation of the brake or the operation state of the brake cylinder, which is made as a function of this thickness. Advantageously, the mutual adaptation of the piston of the parking brake, or of the extension of the piston, and the detector portion of the sensor is arranged such that: when a need for maintenance is indicated, the friction and/or mating discs of the brake disc pack still have a sufficient thickness, at least such that the brake of the work machine can generate a sufficient braking torque in terms of this thickness to safely use and park the work machine. The status monitoring step of the brakes performed by the sensors 31 may take place when putting a parked work machine into use and/or when parking a work machine that has been put into use. The status information signal 38 generated by the sensor 31, i.e. the status information signal describing the theoretical operating capability of the brake, can therefore always be generated before the activated parking brake 20 is released when the work machine is put into use and/or when the already used work machine is parked with the parking brake 20 activated for parking the work machine. Thus, the sensor 31 generates information indicative of the operational capability of the brake, which can be generated without interrupting the operation of the work machine.

In the above example, the brake device 1 of the work machine includes both the work brake 10 and the parking brake 20 and the disc pack enclosure 3 shared by the work brake 10 and the parking brake 20, and the disc pack 4 placed in the disc pack enclosure 3. The disclosed solution thus indicates the state of the brake disc pack 4 shared by both the service brake 10 and the parking brake 20, at least in terms of the thickness of the friction discs 5 and/or the mating discs 6 of the brake disc pack 4. The solution disclosed above is disclosed in connection with wet disc brakes, but it is equally useful in connection with dry disc brakes.

Fig. 3 is a schematic illustration of an arrangement in a work machine for detecting the operation capability of a brake in the work machine 40, which arrangement also has the purpose of generating information indicative of the operation capability of the brake. The work machine 40 is very schematically illustrated in fig. 3 by the box shown in dashed lines. Fig. 3 also schematically shows a shaft 41 of the work machine 40, with which shaft 41 a braking device 1 of the type described above is arranged in connection to generate a braking torque BM directed on the shaft 41 of the work machine 40 to stop or hold the work machine 40 in place.

Fig. 3 also very schematically shows a drive power transmission means 42, which drive power transmission means 42 generates a drive transmission torque DM directed on a shaft 41 of the work machine 40 to move the work machine 40 or to drive the work machine 40. Fig. 3 also shows a sensor 43 disposed on the shaft 41 of the work machine 40, the sensor 43 indicating rotation of the shaft 41 in response to the work machine 40 moving by action of the drive transmission torque DM directed on the shaft 41 of the work machine 40. Fig. 3 additionally shows in a schematic manner at least one control unit 44 in the work machine 40, which at least one control unit 44 controls functions of the work machine 40, such as the operation of the drive power transmission means 42 of the work machine 40.

According to an embodiment of detecting the operational capability of the brakes of the work machine, the parking brake 20 of the brake arrangement 1 is activated, i.e. activated, either in response to parking of the work machine having previously occurred, or by deliberate activation of the parking brake 20 by the user of the work machine or automatically by the control unit 40 for the purpose of detecting the brakes. In response to the active operating state of the parking brake 20, the sensor arrangement 30 generates a state information signal 38 as described above to describe the theoretical operating capability of the brakes of the work machine. If the status information signal 38 indicates that the brake does not have the ability to generate sufficient braking torque to safely use or park the work machine based on an insufficient thickness of the friction discs 5 and/or mating discs 6 of the brake disc set 4, the detection step of the brake may be ended and this information may be indicated to the user of the work machine directly or via the control unit 44.

If the status information signal 38 of the sensor arrangement 30 indicates that, on the basis of a sufficient thickness of the friction and/or mating discs 5, 6 of the brake disc set 4 or, in the case of a brake actuator, the brake at least theoretically has the ability to generate a sufficient braking torque to safely use or park the work machine, the brake detection step can proceed to the following stage: it is checked whether the state of the friction and/or mating discs 5, 6 of the brake disc set 4 or the state of the brake actuator is such that they are indeed able to generate sufficient brake torque to safely use or park the work machine. At this stage of the detection step, with the parking brake 20 still activated, the drive power transmission means 42 of the work machine 40 is controlled by means of the control signal CO-42 generated by the control unit 44 to direct a predetermined amount of drive transmission torque DM onto the shaft 41 of the work machine 40, and a status information signal 45 indicative of the rotational status of the shaft 41 is generated by means of a sensor 43 arranged on the shaft 41 of the work machine 40 in response to the drive power transmission torque DM produced for the shaft 41 of at most a predetermined magnitude, to generate a status information signal 45 indicative of the actual operational capacity of the brakes of the work machine 40.

At a later stage of the detection step, the brake of the work machine 40 is thus detected in the following cases: in this case, the goal is to move the work machine 40 by overcoming the activated brake with a force caused by a predetermined amount of drive transmission torque DM applied on the shaft 41. If the status information signal 45 generated by the sensor 43 indicates that the shaft 41 is not rotating, the brakes may be found to be sufficient to produce sufficient braking torque to safely use or park the work machine 40. If the status information signal 45 generated by the sensor 43 indicates that the shaft 41 is rotating, it may be noted that the operational capacity of the brakes may not be sufficient to produce sufficient braking torque to safely use or park the work machine 40 under any circumstances. In both cases, the status information signal 45 generated by the sensor 43 may be directed to the user of the work machine directly or via the control unit 44. Fig. 4 is a schematic diagram of a method according to a solution for detecting the operational capability of a brake in a work machine.

In fig. 3, the braking device 1 and the drive transmission means 42 are arranged to act on the same shaft 41 for the sake of clarity. The shaft 41 may be a shaft provided with wheels in the work machine or a shaft acting on a caterpillar of the work machine. It is also possible to arrange the brake device 1 and the drive transmission means 42 to act on different axles, whereby the axle on which the drive transmission means 42 is arranged to act may replace the axle of the work machine on which the wheels are provided, or the axle acting on the caterpillar, belong to the drive transmission means 42 or any other axle connected to the drive transmission means 42 to transmit a drive transmission torque or force to move the work machine 40.

In the above embodiment for detecting the operation capability of the brake of the working machine, the parking brake of the brake device 1 is applied. Alternatively, the operational capacity of the brakes of the work machine may be detected by means of the service brake 10, in which case the above embodiment is implemented by using the service brake 10 instead of the parking brake 20. In this case, the service brake 10 of the brake device 1 is activated, for example, by a user of the work machine before an appropriate phase of the working process of the work machine, such as for example before maneuvering the work machine to a ramp working phase. If the actual operating capability of the brake is detected by means of the service brake 10, the parking brake 20 is switched off in such a case. In this case, too, before the service brake 10 is applied, it can be determined, on the basis of the application of the parking brake 20 and the status information signal 38 of the sensor arrangement 30 generated in response thereto, whether the brake has at least the theoretical capacity to generate sufficient brake torque for safely using and parking the work machine.

By the disclosed arrangement and method for detecting the operating capability of the brake of a work machine, it can be ensured that the operating capability of the brake is sufficient for use when the work machine is parked and when the work machine is in use, as well as in emergency braking situations, in which the emergency braking function is usually based on the use of a parking brake of the brake device. In particular, it is increasingly important to ensure sufficient running capacity of the brake in the forest work machine, since more work is being done on slopes and since timber harvesting and transport also moves to more difficult-to-reach harvesting yards than today.

It will be obvious to a person skilled in the art that as the technology advances, the basic idea of the invention can be implemented in many different ways. The invention and its embodiments are thus not limited to the examples described above, but may vary within the scope of the claims.

Claims

1. A pressure medium operated brake device (1) for a work machine, the brake device (1) comprising:

a service brake (10), a parking brake (20) and a brake disc pack (4), the brake disc pack (4) being common to the service brake (10) and the parking brake (20), the brake disc pack (4) comprising alternating at least one friction disc (5) and at least one mating disc (6), the at least one mating disc (6) forming a counterpart for the at least one friction disc (5),

it is characterized in that the preparation method is characterized in that,

the brake device (1) comprises at least one sensor arrangement (30), the at least one sensor arrangement (30) being used to generate information indicative of the operational capability of the brake.

2. The brake apparatus for a work machine according to claim 1,

the brake device (1) comprises a brake cylinder (2), the brake cylinder (2) is shared by the service brake (10) and the parking brake (20), and the service brake (10) and the parking brake (20) are arranged substantially coaxially in the brake cylinder (2).

3. The brake device for a working machine according to claim 1 or 2,

the brake device (20) comprises at least one piston (21) of the parking brake (20), and the at least one sensor arrangement (30) is arranged in connection with the parking brake (20) for determining a position of the piston (21) of the parking brake (20) in an active operating state of the parking brake (20).

4. The brake device for a work machine according to claim 3, characterized in 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), the at least one piston (21) being arranged in the control cylinder of the parking brake (20),

at least one flexible element (22), the at least one flexible element (22) being arranged in connection with the piston (21) of the parking brake (20), and

at least one pressure medium fitting (24) via which pressure medium can flow into the control cylinder of the parking brake (20) and can flow out of the control cylinder of the parking brake (20), and wherein

The flow of the pressure medium into the control cylinder of the parking brake (20) results in a movement of the piston (21) of the parking brake (20) against the flexible element (22) resulting in the flexible element (20) being compressed, a movement of the piston (21) of the parking brake (20) against the flexible element (22) resulting in a disconnection of the parking brake (20), and wherein

The flow of the pressure medium out of the control cylinder of the parking brake (20) causes the piston (21) of the parking brake (20) to be moved away from the flexible element (22) by the action of the force stored in the flexible element (22) as a result of the compression of the flexible element (22) for placing the parking brake (20) in an active operating state.

5. The brake apparatus for a work machine according to claim 3 or 4,

the brake device (20) comprises an extension (36), the extension (36) being connected to the piston (21) of the parking brake (20), and the at least one sensor arrangement (30) is arranged to determine a position of the extension (36) of the piston (21) relative to the sensor arrangement (30) in order to determine the position of the piston (21) relative to the sensor arrangement (30) in an active operating state of the parking brake (20).

6. The brake device for a working machine according to claim 4 or 5,

the extension (36) of the piston (21) of the parking brake (20) is arranged in connection with an end of the piston (21) in the axial direction of the piston (21), the extension (36) being oriented in the direction of the flexible element (22).

7. The brake apparatus for a work machine of any one of the preceding claims,

the sensor arrangement (30) comprises at least one sensor (31), the at least one sensor (31) comprising a body structure (32) of the sensor (31) and a detector portion (33) of the sensor (31), whereby the sensor (31) is arranged to be supported by the body structure (32), to be connected with the body portions (2b, 2c) of the parking brake (20) to arrange the detector portion (33) of the sensor (31) close to or in close proximity to a travel path of the piston (21) of the parking brake (20) or to the extension portion (36) of the piston (21).

8. The brake apparatus for a work machine of claim 7,

the sensor arrangement (30) comprises an additional body (34), which additional body (34) is arranged in connection with the body parts (2b, 2c) of the parking brake (20), inside of which additional body (34) there is an open space (35), into which open space the piston (21) of the parking brake (20) or the extension part (35) connected to the piston (21) is arranged to extend, and the sensor (31) is arranged to the additional body (34) by means of the body structure (32) of the sensor (31) such that the detector part (33) of the sensor (31) is arranged in the open space (35) close to the piston (21) of the parking brake (20) or to the travel path of the extension part (36) of the piston (21) or close to the travel path.

9. Braking device for a working machine according to any one of the preceding claims, characterized in that the sensor arrangement (30) comprises a Hall sensor.

10. A braking device for a work machine according to any one of the preceding claims, characterized in that the braking device (1) comprises at least one wedge (9), which at least one wedge (9) is arranged between the brake cylinder (2) and a brake caliper (8), which brake caliper (8) controls the operation of the brake disc pack (4) such that, when the work brake (10) or the parking brake (20) is released, the wedge (9) is arranged to move away from contact with the brake caliper (8) in order to effect disconnection of the brake, and, when the work brake (10) or the parking brake (20) is activated, the wedge (9) is arranged to move into contact with the brake caliper (8) in order to generate a braking torque by means of the brake disc pack (4).

11. A braking arrangement for a work machine according to any one of the preceding claims, characterised in that the braking arrangement (1) is a wet disc brake comprising a substantially closed, oil-filled disc package (3), the brake disc pack (4) being located in the disc package (3).

12. An arrangement for generating information indicative of the operational capacity of a brake in a work machine (40), the work machine (40) comprising:

at least one brake arrangement (1) according to any one of claims 1 to 11, the at least one brake arrangement (1) being for generating a braking torque (BM) directed on at least one shaft (41) of the work machine, and in which arrangement:

the sensor arrangement (30) of the brake device (1) is configured to generate a status information signal (38) when a parking brake (20) is activated, the status information signal (38) describing a theoretical operating capacity of the brake of the work machine (40).

13. The arrangement according to claim 12, characterized in that the working machine (40) further comprises:

at least one control unit (44), the at least one control unit (44) being used for controlling the operation of the working machine (40),

a drive power transmission means (42), the drive power transmission means (42) generating a drive transmission torque DM directed on at least one shaft (41) of the work machine (40), the at least one shaft (41) belonging to or being connected to the drive power transmission means (42), and

at least one sensor (43), said at least one sensor (43) being arranged in said shaft (41) belonging to or connected to said drive power transmission means (42) to indicate a status information signal (45) in response to the action of said drive power transmission torque (DM) directed on said shaft (41), said status information signal (45) indicating the rotation of said shaft (41), and in said arrangement:

-the control unit (44) is configured to control the drive power transmission means (42) of the work machine to generate a predetermined amount of the drive power transmission torque (DM) directed on the shaft (41) belonging to or connected to the drive power transmission means (42) with the service brake (10) or the parking brake (20) applied, and

the sensor (43) arranged on the shaft (41) belonging to or connected to the drive power transmission means (42) is configured to generate a status information signal (45) indicative of the rotational status of the shaft (41) in response to the drive power transmission torque (DM) directed on the shaft (45) of at most a predetermined magnitude, thereby generating a status information signal (45) indicative of the actual operational capacity of the brake.

14. A method for generating information indicative of the operational capability of a brake in a work machine (40), the work machine (40) comprising:

at least one brake arrangement according to any one of claims 1-11 for generating a brake torque (BM) directed on at least one axle (41) of the work machine (40), and in which method:

-generating a status information signal (38) indicative of a theoretical operating capability of the brake of the work machine (40) by means of a sensor arrangement (30) of the brake device (1) when the parking brake (20) is activated.

15. The method of claim 14, wherein the work machine (40) further comprises:

a drive power transmission means (42), which drive power transmission means (42) generates a drive transmission torque DM which is directed on a shaft (41) of the working machine (40), to which shaft (41) belongs or is connected, and

at least one sensor (43), said at least one sensor (43) being arranged on the shaft (41) belonging to or connected to the drive power transmission means (42) to indicate a status information signal (45) in response to the effect of the drive power transmission torque (DM) directed on the shaft (41), said status information signal (45) indicating the rotation of the shaft (41), and in that the method:

-controlling the drive power transmission means (42) of the work machine (40) by means of the control unit (44) to direct a predetermined amount of drive transmission torque (DM) on the shaft (41) belonging to or connected to the drive power transmission means (42) with the service brake (10) or the parking brake (20) applied, and

generating a status information signal (45) indicative of a rotational status of the shaft (41) in response to the driving power transmission torque (DM) directed on the shaft (41) of at most a predetermined magnitude by means of a sensor (43) arranged on the shaft (41) belonging to or connected to the driving power transmission means (42), thereby generating a status information signal (45) indicative of an actual operational capability of the brake.