Work machinery, winch equipment, and position detection device

Abstract

To provide a work machine that can automatically detect the braking force of a wet multi-plate type negative brake device.SOLUTION: There is provided a work machine equipped with a winch device (106) that includes a winch drum (5) and a wet multi-plate type negative control brake device (4) for braking the rotation of the winch drum. The brake device has a clutch plate (CP) composed of a plurality of friction plates (12) and a plurality of mating plates (13) stacked alternately, a pressing member (16) that presses the clutch plate, and an urging member (17) that applies force to the pressing member to generate a braking force. Also included is braking force detection means (7) for detecting information regarding braking force with the pressing member urged by the urging member.SELECTED DRAWING: Figure 4

Description

Technical Field

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[0001] The present invention relates to a working machine, a winch device, and a position detection device used in the winch device.

Background Art

[0002] A winch device is mounted on a crane, which is an example of a working machine. As a conventional technique related to the winch device, for example, the winch device described in Patent Document 1 includes a wet multi-plate brake device. The wet multi-plate brake device generates braking force by pressing clutch plates, which are configured by alternately arranging friction plates with friction facings attached and mating plates, with a pressing spring. Generally, in a crane, a negative control type brake device that applies a brake by the spring force of a pressing spring during non-operation is used.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a negative control type brake device (negative brake device), when the friction facing wears and the thickness of the friction plate decreases, the set dimension of the pressing spring extends and the braking force decreases. However, in the above prior art, there is a problem that the decrease in the braking force cannot be automatically detected.

[0005] The present invention has been made in view of the above actual situation, and its main object is to provide a working machine that can automatically detect the braking force of a wet multi-plate negative control type brake device.

Means for Solving the Problems

[0006] To achieve the above objective, one aspect of the present invention relates to a work machine equipped with a winch device including a winch drum and a wet multi-plate negative control type brake device that applies braking to the rotation of the winch drum, wherein the brake device comprises a clutch plate composed of a plurality of friction plates and a plurality of mating plates stacked alternately, a pressing member that presses the clutch plate against the clutch plate, and a biasing member that biases the pressing member to generate a braking force. A position detection device for detecting information regarding the position of the pressing member or an interlocking member that moves in conjunction with the pressing member, Equipped with, The aforementioned work machine further includes a notification device that, based on the position information, notifies the extent to which the clutch plate has deteriorated relative to its usage limit. It is characterized by the following:

[0007] According to the present invention, the braking force of a wet multi-plate negative control brake system can be automatically detected. Other problems, configurations, and effects will be clarified by the following description of embodiments. [Brief explanation of the drawing]

[0008] [Figure 1] External side view of a crane equipped with a negative brake device according to the first embodiment. [Figure 2] Diagram showing the configuration of the main winch. [Figure 3] (a) is a front view of the friction plate, and (b) is a IIIb-IIIb cross-sectional view of the friction plate shown in (a). [Figure 4] (a) is a cross-sectional view of the negative brake device, and (b) is an enlarged cross-sectional view showing the main part of (a). [Figure 5] A flowchart showing the procedure for calculating the clutch plate margin ratio and notifying the display device. [Figure 6] A flowchart showing the procedure for setting the initial values ​​used to calculate the clutch plate margin ratio. [Figure 7] A projected curve showing the margin of safety. [Figure 8] A comparative diagram of the margin ratios for the main winch and the auxiliary winch. [Figure 9] (a) is a cross-sectional view of a negative brake device according to the second embodiment, and (b) is an enlarged cross-sectional view showing the main part of (a). [Figure 10] A flowchart showing the procedure for setting initial values ​​used to calculate the tolerance ratio of the clutch plate in the second embodiment. [Figure 11] (a) is a cross-sectional view of a negative brake device according to modified example 2-1, and (b) is an enlarged cross-sectional view showing the main part of (a). [Figure 12] (a) is a cross-sectional view of a negative brake device according to modified example 2-2, and (b) is an enlarged cross-sectional view showing the main part of (a). [Modes for carrying out the invention]

[0009] Hereinafter, an embodiment of the negative control type brake device according to the present invention (hereinafter abbreviated as negative brake device or brake device as appropriate) applied to a crane, which is an example of a work machine, will be described with reference to the drawings.

[0010] (First Embodiment) Figure 1 is an external side view of a crane equipped with a negative brake device according to the first embodiment. The crane 100 shown in Figure 1 is a crawler crane and has a traveling body 102, a slewing body 104 that is rotatably mounted on the traveling body 102 via a slewing device 103, a boom 105 that is rake-able attached to the tip of the slewing body 104, and sheaves 110, 111 and sheaves 117, 118 provided at the tip of the boom 105. A bucket 116, which is an example of an attachment, is suspended by a main hoisting rope 112 via sheaves 110 and 117, and an auxiliary hoisting rope 113 via sheaves 111 and 118. Of course, in addition to the bucket 116, other loads and such can also be lifted.

[0011] The revolving body 104 is provided with a cab 109. The cab 109 is provided with various operation levers (main hoist operation lever, auxiliary hoist operation lever, luffing operation lever, travel lever, slewing lever, etc.), and the user operates these operation levers to perform the hoisting operation, excavation operation, slewing operation, and travel operation of the crane 100. Instead of the various operation levers, an operation dial or the like may be used. Further, the cab 109 is provided with a display device 90 for displaying various information such as the operating state and warnings of the crane 100, and a controller 80 for controlling the display device 90 (see FIG. 2).

[0012] The main hoist rope 112 and the auxiliary hoist rope 113 are respectively wound around a main hoist winch (first winch device) 106 and an auxiliary hoist winch (second winch device) 107 mounted on the revolving body 104. By driving each winch 106, 107, each rope 112, 113 is wound up or payed out, and the suspended load is lifted or lowered. Then, by suspending the bucket 116 with the main hoist rope 112 and the auxiliary hoist rope 113 and driving the main hoist winch 106 and the auxiliary hoist winch 107 simultaneously, the bucket 116 can be payed down. Also, when lifting or lowering a load, either the main hoist winch 106 or the auxiliary hoist winch 107 may be used.

[0013] A pendant rope 114 is connected to the tip of the boom 105. When the luffing rope 115 is wound up or payed out by driving a luffing winch 108 mounted on the revolving body 104, the boom 105 is luffed via the pendant rope 114.

[0014] Next, the configuration of the negative brake device according to the first embodiment of the present invention will be described. As described above, the crane 100 is equipped with a main hoist winch 106, an auxiliary hoist winch 107, and a luffing winch 108, and each winch 106, 107, 108 is equipped with a negative brake device of the same mechanism. Therefore, in the following description, the negative brake device of the main hoist winch 106 will be described, and the description of the other negative brake devices will be omitted.

[0015] Figure 2 is a configuration diagram of the main hoist winch, Figure 3(a) is a front view of the friction plate, Figure 3(b) is a sectional view taken along line IIIb-IIIb of the friction plate shown in Figure 3(a), Figure 4(a) is a sectional view of the negative brake device, and Figure 4(b) is an enlarged sectional view showing the main part of the negative brake device.

[0016] As shown in Figure 2, the main hoist winch 106 includes a hydraulic motor 1, a negative brake device 2 (hereinafter referred to as the brake device 2), a speed reducer 3, a negative brake device 4 (hereinafter referred to as the brake device 4), a winding drum 5, and a braking force detection means 7 (described later).

[0017] The main hoist winch 106 has a free fall function. The brake device 2 is connected to one output shaft of the hydraulic motor 1, and the brake device 4 is connected to the other output shaft (the output shaft on the speed reducer 3 side). The brake devices 2 and 4 are of a negative control type that applies a brake to the hydraulic motor 1 when not in operation. When the load stops, both brake devices 2 and 4 are in the engaged state (brake state), and both brake devices 2 and 4 hold the load. When the load is hoisted or lowered, the brake device 2 is released, the brake device 4 is put in the engaged state, and the power of the hydraulic motor 1 is transmitted to the winding drum 5. When the load is in free fall, the braking force of the brake device 4 is adjusted with the brake device 2 in the engaged state to control the descending speed of the load. That is, the brake device 2 functions as a clutch device, the brake device 4 functions as a clutch device when the load stops, is hoisted, or is lowered, and functions as a brake device when the load is in free fall.

[0018] Note that since the main hoist winch 106 has a free fall function, it includes the brake device 2 and the brake device 4. However, when it does not have a free fall function, there is no need to include the brake device 4.

[0019] The brake device 4 is a wet multi-plate type and is equipped with multiple friction plates. As shown in Figures 3(a) and (b), the friction plate 12 is constructed by attaching a friction facing 12b to a disc-shaped base plate 12a. Oil grooves 12c are formed in the friction facing 12b, and the friction facing 12b is cooled by the flow of cooling oil into the oil grooves 12c.

[0020] As shown in Figures 4(a) and 4(b), a wet multi-plate clutch plate CP is constructed by rotatably stacking multiple friction plates 12 and multiple mating plates 13 alternately. The base plate 12a of the friction plate 12 and the mating plate 13 are made of metal. The clutch plate CP is constantly biased and pressed against by a compression spring (biasing member) 17, and the brake state of the brake device 4 is released by releasing the biasing force of the compression spring 17. Although not shown in the figures, the brake device 2 is configured similarly.

[0021] In Figure 4(a), 10 is the output shaft connected to the reduction gear 3, 11 is the coupling spline-coupled to the output shaft 10 and rotating together, 12 is the friction plate spline-coupled to the coupling 11 and rotating together, and also movable in the axial direction, 13 is the mating plate that is alternately stacked with the friction plate 12 and spline-coupled to the casing 14 and movable in the axial direction, and 15 is fastened to the casing 14, forming the bearing housing of the output shaft 10, and also contacts one end of the mating plate 13 to compress the clutch plate CP. The receiving front cover, 16 is a pressing member that contacts the other end of the mating plate 13 and biases the clutch plate CP with the spring force of the pressing spring 17, 18 is a second cover that forms the fixed end face of the pressing spring 17, 19 is a piston (interlocking member) that is fastened to the pressing member 16 and is movable in the axial direction on the inner circumference side of the second cover 18 and constitutes the clutch release cylinder, and 20 is a rear cover (side wall) that is located on the opposite side of the output shaft 10, fastened to the second cover 18 and restricts the amount of movement of the piston 19 on the clutch release side. A recess 20a is formed in the center of the rear cover 20.

[0022] The second cover 18 is provided with a clutch release port 18a that forms an oil passage to the piston 19. By supplying pressurized oil to this clutch release port 18a, the piston 19 and the pressing member 16 move away from the clutch plate CP (to the left in Figure 4(a)) against the biasing force of the pressing spring 17, releasing the pressure contact state (brake state) of the clutch plate CP.

[0023] Here, if a pressure greater than a predetermined value is applied that releases the pressure contact of the clutch plate CP, the braking force will be minimized (fully released). At pressures below the predetermined value, the difference between the thrust of the piston 19 and the biasing force of the compression spring 17 acts as the pressing force on the clutch plate CP, allowing for adjustment of the braking force.

[0024] Furthermore, cooling oil circulates inside the casing 14 to cool the heat generated by the friction plate 12 (wet type). The cooling oil is supplied from the cooling oil inlet port 14a, passes through the oil groove 12c (see Figure 3) formed in the friction facing 12b, and is discharged from the cooling oil outlet port 14b. At this time, a certain internal pressure is generated in the oil chamber on the cooling oil inlet port 14a side due to the resistance of the cooling oil passing through the oil groove 12c.

[0025] Furthermore, in this embodiment, a braking force detection means 7 is provided to detect the contact position of the clutch plate CP (in other words, the amount of wear of the friction facing 12b), which is information related to the braking force. As shown in Figure 4(b), the braking force detection means 7 includes a potentiometer 71, which is a linear displacement detector. The potentiometer 71 converts the mechanical stroke of the rod 71a into an electrical signal by the electronic circuit of the detector body 71b. In this embodiment, the potentiometer 71 is of the rod return type.

[0026] In Figure 4(b), 72 is a detection rod whose tip contacts the pressing member 16, and which detects the position (stroke position) of the pressing member 16 and the piston 19 when the clutch plate CP is pressed against it. 73 is an adapter that seals the cooling oil inside the casing 14 and fixes the detector body 71b so that the rear end of the detection rod 72 is pressed against the rod 71a. 74 is a return spring installed so that the detection rod 72 is pressed against the pressing member 16. The detection rod 72 moves axially in accordance with the displacement of the pressing member 16 and the piston 19. The potentiometer 71 can detect the current position of the pressing member 16 and the piston 19 by detecting the amount of movement of the detection rod 72. In other words, the potentiometer 71 is a position detection device that detects the position of the pressing member 16 and the piston 19.

[0027] As shown in Figure 2, the braking force detection means 7 is electrically connected to the controller 80, and the braking force information detected by the braking force detection means 7, i.e., the position data (detected value) of the pressing member 16 and the piston 19, is input to the controller 80. The controller 80 is also electrically connected to the display device (notification device) 90, and based on the detected value of the braking force detection means 7, the controller 80 calculates the margin rate of the clutch plate CP (degree of wear relative to the usage limit) and displays it on the display device 90.

[0028] Next, we will explain the control process by the controller 80. Figure 5 is a flowchart showing the procedure for the controller to calculate the clutch plate margin ratio and notify the display device.

[0029] The controller 80, although not shown in the diagram, consists of hardware including a CPU that performs various calculations, a storage device such as a ROM or HDD that stores programs for executing calculations performed by the CPU, RAM which serves as a workspace for the CPU when executing programs, and a communication interface which is an interface for sending and receiving data with other devices, and software stored in the storage device and executed by the CPU. Each function of the controller 80 is realized when the CPU loads various programs stored in the storage device into RAM and executes them.

[0030] When the engine is started, the controller 80 performs the process shown in Figure 5. First, the controller 80 determines whether the clutch plate CP is in a pressed-together state (S101). For example, the controller 80 determines the pressed-together state of the clutch plate CP based on the pressure of the pressurized oil supplied to the clutch release port 18a (pressure of the clutch release cylinder).

[0031] In the negative control type brake device 4, if the pressure of the clutch release cylinder is below a certain value (for example, the tank pressure), that is, if no brake release pressure is acting on the clutch release cylinder, the controller 80 can determine that the clutch plate CP is in a pressed-together state.

[0032] Alternatively, if the specifications of the crane 100 are such that no pressure is applied to the clutch release cylinder for a predetermined time after the engine starts (or after the main power is turned on), in other words, before the crane 100 starts operation, then the clutch plate CP will always be in a pressed-together state during that predetermined time due to the negative control system. Therefore, the controller 80 may determine that the clutch plate CP is in a pressed-together state if the time elapsed since the engine started (or after the main power was turned on) is within the predetermined time, instead of relying on the pressure of the clutch release cylinder.

[0033] If it is determined that the clutch plate CP is in a pressed state (i.e., a braking state) (S101 / Yes), the controller 80 obtains the detected value from the braking force detection means 7 (potentiometer 71) (S102), and calculates the safety margin of the clutch plate CP by referring to the initial value described later (S104) (S103). If the safety margin reaches the lower limit (reference value / usage limit) (S105 / Yes), the controller 80 notifies the user via the display device 90 of the need to replace the clutch plate CP (especially the friction plate 12) (S106), and stores the calculated safety margin in the memory device (S107). The controller 80 performs the processing in S101 to S107 each time the engine is started and accumulates a record of the safety margin. This record may be output externally periodically as a daily report.

[0034] Next, we will explain the method for calculating the clutch plate margin ratio performed in S103. Figure 6 is a flowchart showing the procedure for setting the initial values ​​(S104) used to calculate the clutch plate margin ratio.

[0035] As shown in Figure 6, the user fully releases the brake device 4 (S104-1) and presses the initial setting button 85 (see Figure 2) located inside the cab 109 (S104-2). The controller 80 stores the value detected by the braking force detection means 7 (potentiometer 71) at that time in its memory as the starting point of piston 19 displacement (S104-3). For example, if the value detected (voltage signal) from the braking force detection means 7 is 3.7V, then 3.7V is stored in the controller 80 as the starting point of piston 19 displacement.

[0036] The user engages the brake device 4 (S104-4) and presses the initial setting button 85 (S104-5). The controller 80 stores the value detected by the braking force detection means 7 at that time in its memory as the contact position of the clutch plate CP when it is new (S104-6). For example, if the value detected by the braking force detection means 7 is 2.5V, then 2.5V is stored in the controller 80 as the contact position (initial value) of the clutch plate CP when it is new.

[0037] The controller 80 calculates the margin of the clutch plate CP from the limit displacement amount from the starting point of piston 19 displacement to the contact position of the clutch plate CP. The braking force detection means 7 corresponds, for example, 0 to 10 mm to 0.5 V to 4.5 V, and 0.4 V / mm is the calibration value. As described above, 3.7 V is the starting point of piston 19 displacement, and 2.5 V is the contact position of the clutch plate CP when new. When the contact position of the clutch plate CP is 6 mm (2.4 V) displaced from the starting point of piston 19 displacement, the margin is set to 0% (limit position), and the contact position of the clutch plate CP when new is set to a margin of 100%.

[0038] In this case, 3.7V - 2.4V = 1.3V is calculated as the limit position for use. Accordingly, the allowable displacement of the clutch plate CP from its contact position when new is 2.5V - 1.3V = 1.2V.

[0039] If the detected value of the braking force detection means 7 is 2.1V, then the current contact position of the clutch plate CP is 0.4V (1mm) displaced from the contact position of 2.5V when new, and the margin of the clutch plate CP at this time is The calculation is 1 - (0.4 / 1.2) × 100 = 67%.

[0040] In this embodiment, periodic recording results are stored as chronological data in the storage device of the controller 80 and analyzed to predict when the braking device 4 will fall below a predetermined braking force, and the user is notified of the need to replace consumable parts via the display device 90. The friction plate 12, which is assumed to be a consumable part, decreases in thickness due to wear associated with energy absorption by the friction facing 12b and the accumulation of compression set. Wear of the friction facing 12b has an initial break-in stage in which the amount of wear increases during the pressure contact process with the mating plate 13 several thousand times from when it is new, and after break-in is achieved, it transitions to a steady-state wear region. Furthermore, in the final stage when wear has progressed, it is expected that the thermal load will increase as the area of ​​the oil groove 12c of the friction facing 12b decreases, and the amount of steady-state friction will gradually increase. Compression set accumulates largely in the initial stage when compressive force is applied, and thereafter, it has the property of converging to a certain amount due to the influence of compaction of the facing structure and the decrease in compressive force due to the decrease in thickness.

[0041] Considering these properties, estimating future wear curves from past data is not straightforward. However, since the reduction in the thickness of the friction facing 12b is expected to increase significantly in the initial stages and then become more gradual thereafter, a linear approximation prediction using all past data as the analysis range is likely to deviate from reality. Therefore, by performing a linear approximation prediction using data from the present to a certain past period as the analysis range, and creating predicted margin rate diagrams (graphs) as shown in Figure 7 for target periods such as the most recent 6 months, 12 months, and 24 months, and presenting them to the user, the user can judge which prediction curve is most reasonable considering the operating conditions during that period.

[0042] Furthermore, as mentioned above, the crane 100 is equipped with a main hoisting winch 106, an auxiliary hoisting winch 107, and a luffing winch 108. Both the main hoisting winch 106 and the auxiliary hoisting winch 107 can hoist or lower loads, and the choice of which winch to use is at the user's discretion. As a result, there may be an imbalance in the frequency of use between the braking devices of the main hoisting winch 106 and the auxiliary hoisting winch, which could lead to an imbalance in the wear of the braking devices.

[0043] Therefore, in this embodiment, the controller 80 is configured to create a comparison diagram of the margin ratio shown in Figure 8 and display it on the display device 90. In this way, the user can understand whether there is a bias in the frequency of use of the main winch 106 and the auxiliary winch 107, and by using the winch that is used less frequently, the frequency of use of both winches 106 and 107 can be equalized, and the maintenance interval can be extended.

[0044] Furthermore, as shown in Figure 4(b), in this embodiment, it is preferable that the braking force detection means 7 is provided on the inner circumference side of the large-diameter portion 19a having the largest outer diameter on the outer circumference of the piston 19, and on the inner circumference side of the plurality of compression springs 17. The braking force detection means 7 has a configuration in which a potentiometer 71 is arranged in series with an adapter 73. If it is installed on the outer circumference side of the large-diameter portion 19a of the piston 19, the braking force detection means 7 will overlap with the compression springs 17 in the axial direction, so the amount of axial protrusion from the end face of the second cover 18 will increase, and the brake device 4 will become larger in the axial direction. In this respect, in this embodiment, since the braking force detection means 7 is provided on the inner circumference side of the large-diameter portion 19a of the piston 19 and in the recess 20a of the rear cover 20, the rear end of the potentiometer 71 can be positioned without overlapping with the compression springs 17 in the axial direction, and the axial length of the brake device 4 can be reduced. Furthermore, since the braking force detection means 7 is located within a recess 20a formed in the rear cover 20, which is the side wall on the opposite side of the clutch plate CP and the pressing member 16, the amount of protrusion from the end face of the rear cover 20 can be kept as small as possible, which is preferable.

[0045] The effects and benefits of the first embodiment can be summarized as follows:

[0046] Since the braking force detection means 7 automatically detects the contact position (amount of wear) of the clutch plate CP, the decrease in braking force of the brake device 4 can be checked periodically, allowing the brake device 4 to be used in good condition. Furthermore, since the amount of wear of the clutch plate CP can be checked without disassembling and inspecting the clutch plate CP, the inspection work of the brake device 4 is simplified. Moreover, since the braking force detection means 7 can check the contact position considering the compressive elastic deformation of the friction facing 12b, the accuracy of the clutch plate CP wear inspection is high. In a configuration that includes a means for visually checking the amount of wear of the clutch plate CP, an inspector needs to actually go to the installation site of the brake device, but in this embodiment, the amount of wear of the clutch plate CP can be detected automatically, so the trouble of the inspector going to the site is eliminated.

[0047] Furthermore, the controller 80 calculates the margin of the clutch plate CP and notifies the user via the display screen of the display device 90, allowing the user to easily understand the status of the brake system 4. Moreover, as shown in Figure 7, the user can predict the replacement timing of consumable parts based on the aging data of braking force reduction via the display device 90, making it easier and more convenient to plan maintenance.

[0048] Furthermore, as shown in Figure 8, the controller 80 compares which clutch plate CP of the main winch 106 and the auxiliary winch 107 is worn out, and displays the comparison result on the display device 90. By looking at this screen, the user can equalize the usage frequency of the main winch 106 and the auxiliary winch 107, thereby extending the lifespan of the brake devices of both winches.

[0049] Furthermore, by positioning the braking force detection means 7 on the inner circumference side of the large-diameter portion 19a of the piston 19, and locating the rear end of the potentiometer 71 within the recess 20a of the rear cover 20, it is possible to prevent the brake device 4 from becoming larger due to the installation of the braking force detection means 7. Therefore, the brake device 4 with the braking force detection means 7 can be mounted directly onto existing cranes.

[0050] Here, there is also a positive control system for brakes, in which the braking force is determined by the magnitude of the brake control pressure. Therefore, even if the friction facing wears down, as long as it remains, the braking force can be maintained by increasing the force pressing the clutch plates together.

[0051] On the other hand, in the case of a negative control system as in this embodiment, if the set dimension of the compression spring 17 increases due to a decrease in the thickness of the friction facing 12b, the braking force will decrease accordingly. Therefore, in a negative control system, it is important to accurately grasp the decrease in braking force. In this respect, it is preferable to have a configuration in which the position of the pressing member 16 that presses the clutch plate CP against the piston 19 that is linked to the pressing member 16 can be automatically detected by the braking force detection means 7, as in this embodiment, because it is possible to accurately grasp the decrease in the braking force of the brake device 4.

[0052] (Second Embodiment) Figure 9(a) is a cross-sectional view of the negative brake device according to the second embodiment, and Figure 9(b) is an enlarged cross-sectional view showing the main part of the negative brake device according to the second embodiment.

[0053] The negative brake device 240 according to the second embodiment (hereinafter referred to as the brake device 240) is characterized in that it is equipped with an indicator 6, which is a visual confirmation means, in addition to the braking force detection means 7 shown in the first embodiment. This characteristic will be explained in detail below, and components that overlap with those of the first embodiment will be denoted by the same reference numerals and their descriptions will be omitted.

[0054] Indicator 6 allows the user to visually check the scale to determine the contact position of the clutch plate CP and to roughly determine the amount of wear on the friction facing 12b.

[0055] The configuration of the indicator 6 will now be explained in detail. In Figure 9(b), 61 is a detection rod that contacts the pressing member 16 and detects the positions of the pressing member 16 and the piston 19, 62 is an adapter that seals the cooling oil inside the casing 14 and through which the rear end of the detection rod 61 passes, and 63 is a return spring that is installed so as to press the detection rod 61 against the pressing member 16. The rear end of the detection rod 61 is exposed from the adapter 62, and the amount of protrusion of the detection rod 61 from the adapter 62 changes as the detection rod 61 moves in the axial direction. The inspector can confirm the pressure contact position of the clutch plate CP by visually checking the amount of protrusion of the detection rod 61. In this embodiment, the clutch plate CP should be replaced when the rear end of the detection rod 61 becomes flush with the end face of the adapter 62. The indicator 6 is provided at a position radially outward from the braking force detection means 7, but its position is arbitrary.

[0056] In the second embodiment, the reduction in braking force of the brake device 240 can be roughly determined by visually checking the amount of protrusion of the detection rod 61 when the clutch plate CP is pressed against the surface. Incidentally, although the installation of the return spring 63 is not essential for the components of the indicator 6, it is preferable to install the return spring 63 in order to prevent the contact between the detection rod 61 and the pressing member 16 from being disconnected due to internal pressure caused by the resistance of the passage of the cooling oil.

[0057] As shown in Figures 9(a) and 9(b), in the second embodiment, the detection rod 61 is configured to contact the pressing member 16, similar to the detection rod 72 of the braking force detection means 7, but it may also be configured to contact the piston 19.

[0058] As described above, in the second embodiment, the indicator 6 and the braking force detection means 7 are provided together, so in addition to achieving the same effects as in the first embodiment, it is convenient because it is possible to perform both automatic detection of the pressure contact position by the potentiometer 71 and visual confirmation by the indicator 6.

[0059] In the second embodiment, the inclusion of an indicator 6 allows for the calculation of the clutch plate CP margin using different initial values ​​than those used in the first embodiment. The method for calculating the clutch plate CP margin in the second embodiment will be described below. Figure 10 is a flowchart showing the procedure for setting the initial values ​​used to calculate the clutch plate margin in the second embodiment.

[0060] As shown in Figure 10, the user measures the amount of protrusion of the indicator 6 when the clutch plate CP is pressed together, that is, in the initial state when the brake device 240 is not released (S104-11), and registers the measured amount of protrusion of the indicator 6 as the initial value by operating an input unit (not shown) of the controller 80 (S104-12). For example, if the amount of protrusion of the indicator 6 is 3 mm, the user inputs the value 3.0 to the controller 80. The detected value of the braking force detection means 7 at that time (for example, 2.5V) is then stored as the pressed-to-contact position of the clutch plate CP when it is new (S104-13).

[0061] In the second embodiment, the controller 80 calculates a margin ratio, where the amount of protrusion of the indicator equals the amount of movement possible up to the usage limit.

[0062] The braking force detection means 7 corresponds, for example, to 0.5V to 4.5V for 0 to 10 mm, with a calibration value of 0.4V / mm. As described above, if the initial value is set to 2.5V (i.e., indicator protrusion amount of 3.0 mm), the controller 80 will determine this state as a 100% margin. If the value detected by the braking force detection means 7 becomes 2.1V due to aging, then 2.5V - 2.1V = 0.4V, meaning that the clutch plate CP has worn down by 1 mm, corresponding to 0.4V.

[0063] Therefore, the margin rate at this time is The calculation is 1 - (1.0 / 3.0) × 100 = 67%.

[0064] Thus, in the second embodiment, since both the indicator 6 and the braking force detection means 7 are provided, setting the initial value in calculating the margin ratio becomes easier.

[0065] (Variation 2-1) Next, a modified version of the second embodiment will be described. Figure 11(a) is a cross-sectional view of the negative brake device according to modified version 2-1, and Figure 11(b) is an enlarged cross-sectional view showing the main part of the negative brake device according to modified version 2-1.

[0066] The negative brake device 240-1 (hereinafter referred to as brake device 240-1) according to modified example 2-1 is characterized by the fact that some parts of the indicator 6 and the braking force detection means 7 are shared. Specifically, the detection rod 61 of the indicator 6 and the detection rod 72 of the braking force detection means 7 are shared parts, and the detection rod 72 is used instead of the detection rod 61. For this purpose, a contact portion 19b is provided that protrudes inward from the piston 19 and abuts against the detection rod 72. Even with this configuration, the function of the indicator 6 as an indicator for visually checking the amount of wear on the clutch plate CP is not impaired because the detection rod 72 moves axially in conjunction with the displacement of the piston 19.

[0067] According to this modified example 2-1, by making the detection rod 61 of the indicator 6 and the detection rod 72 of the potentiometer 71 common parts, the number of parts can be reduced, resulting in lower costs. Furthermore, the reduced number of parts simplifies the assembly of the brake device 240-1.

[0068] (Variation 2-2) Figure 12(a) is a cross-sectional view of the negative brake device according to modified example 2-2, and Figure 12(b) is an enlarged cross-sectional view showing the main part of the negative brake device according to modified example 2-2.

[0069] In the negative brake device 240-2 (hereinafter referred to as brake device 240-2) according to modified example 2-2, similar to modified example 2-1, the detection rod 61 of the indicator 6 and the detection rod 72 of the braking force detection means 7 are common parts, and the detection rod 72 is used instead of the detection rod 61. For this purpose, a contact portion 16a is provided that protrudes axially from the pressing member 16 and abuts against the detection rod 72. Even with this configuration, the detection rod 72 moves axially in conjunction with the displacement of the pressing member 16, so the function of the indicator 6 as an indicator for visually checking the amount of wear on the clutch plate CP is not impaired.

[0070] According to this modified example 2-2, by making the detection rod 61 of the indicator 6 and the detection rod 72 of the potentiometer 71 common parts, the number of parts can be reduced, resulting in lower costs. Furthermore, the reduced number of parts simplifies the assembly of the brake device 240-2.

[0071] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention. All technical matters included in the technical concept described in the claims are subject to the present invention. The embodiments described above are preferred examples, but those skilled in the art can realize various alternatives, modifications, variations, or improvements from the contents disclosed herein, and these are included in the technical scope described in the appended claims.

[0072] Furthermore, while a crawler crane was given as an example of a crane, the present invention is not limited to this and can be applied to all types of cranes, including other mobile cranes such as wheel cranes, truck cranes, rough terrain cranes, and all-terrain cranes, as well as tower cranes, overhead cranes, jib cranes, retractable cranes, stacker cranes, gantry cranes, unloaders, and foundation machinery such as earth drills. The present invention can also be applied to other work machinery besides cranes, such as road construction machinery, hydraulic excavators, and wheel loaders.

[0073] Furthermore, the negative braking device of the present invention may be applied not only to winches, but also to, for example, the braking devices of slewing devices and traveling devices, and may also be applied to parking brakes.

[0074] Furthermore, in the above-described embodiment, a configuration example was explained in which a controller 80 and a display device 90 are provided inside the cab 109, and the margin ratio of the clutch plate CP is calculated based on the detected value from the braking force detection means 7 and displayed on the display device 90. However, instead of this configuration, the detected value detected by the braking force detection means 7 may be output externally (for example, to a control room) via a communication line, the margin ratio of the clutch plate may be calculated by an externally provided controller and displayed on an externally provided display device, or printed on paper as a work report. In this case, a graph like the one shown in Figures 7 and 8 may also be printed on paper along with the current margin ratio.

[0075] Furthermore, the method for calculating the margin of the clutch plate CP is not limited to the embodiments described above. Any calculation method that can determine how much the clutch plate CP has deteriorated relative to its usage limit is acceptable. Also, the way the margin of the margin is displayed is arbitrary and may be displayed in a way other than as a percentage.

[0076] Furthermore, the braking force detection means 7 only needs to be able to detect information regarding the braking force of the brake device. For example, it can detect parameters that change according to the wear of the friction plate 12, such as the width of the clutch plate CP when the clutch plate CP is pressed, the length of the compression spring 17, and the tip position of the compression spring 17, and detect these as information regarding the braking force. Alternatively, if the braking force detection means 7 is configured to detect the pressing force of the compression spring 17, it may be composed of a sensor such as a load cell that detects the pressing force. However, if the means for detecting information regarding the braking force is a position detection device that detects the positions of the pressing member 16 and the piston 19, which are located on the rear side (opposite side of the output shaft 10) of the brake device, then it is only necessary to measure the movement of the pressing member 16 and the piston 19, which simplifies the configuration of the braking force detection means. [Explanation of Symbols]

[0077] 1. Hydraulic motor 2. Brake system 3 Reducer 4. Brake system 5. Winding Drum (Winch Drum) 6. Indicators (Visual Inspection Methods) 7. Braking force detection means 10 Output shaft 12 Friction plate 12a Base Plate 12b Friction facing 12c oil groove 13 Opponent's board 14 Casing 14a Cooling oil inlet port 14b Coolant outlet port 15 Front cover 16 Pressing member 16a Contact area 17 Compression spring (biasing member) 18 Second cover 18a Clutch release port 19. Piston (interlocking component) 19a Piston large diameter section 19b Contact site 20 Rear cover (side wall) 20a recess 61. Detection rod (visual confirmation means) 62 adapters 63. Return spring 71. Potentiometer (Linear Displacement Detector / Position Detection Device) 71a Rod 71b Detector body 72 Detection rod (braking force detection means) 73 Adapter 74. Return spring 80 Controllers 85 Initial settings button 90 Display devices (notification devices) 100 Cranes 102 Running body 103 Swivel device 104 Rotating body 105 Boom 106 Main hoist winch (First winch device / Winch device) 107 Auxiliary winch (second winch device / winch device) 108. Luffing winch (winch device) 109 Cab 240, 240-1, 240-2 Brake system

Claims

1. In a work machine equipped with a winch device including a winch drum and a wet multi-plate negative control type brake device that applies braking to the rotation of the winch drum, The aforementioned brake device, A clutch plate is constructed by alternately stacking multiple friction plates and multiple mating plates, A pressing member that presses the clutch plate against it, A biasing member that biases the aforementioned pressing member to generate a braking force, The system includes a position detection device that detects information regarding the position of the pressing member or an interlocking member that moves in conjunction with the pressing member, The aforementioned work machine is The device further includes a notification device that, based on the position information, notifies the extent to which the clutch plate has deteriorated relative to its usage limit. The position detection device is characterized by detecting the position of the pressing member or the interlocking member when the brake device is in a braking state.

2. In the work machine described in claim 1, The position detection device is characterized by detecting the position of the pressing member or the interlocking member before the start of operation of the work machine.

3. In the work machine described in claim 1, The aforementioned brake device, In the axial direction, it has a front cover provided on one end side that receives the pressing reaction force of the clutch plate, and a rear cover provided on the other end side. The rear cover has a recess formed therein. A work machine characterized in that at least a part of the position detection device is provided within the recess.

4. In the work machine described in claim 1, A work machine further comprising a visual confirmation means that allows the position of the pressing member or the interlocking member to be visually confirmed.

5. In the work machine described in claim 4, A work machine characterized in that the position detection device and a part of the visual confirmation means are composed of common parts.

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