Working machinery, oil degradation detection system, and oil degradation detection method

Abstract

To provide a machine capable of determining the deterioration of oil. [Solution] The work machine 1 comprises a clutch 23, a first control valve device 41, and a controller 48. The first control valve device 41 adjusts the hydraulic pressure supplied to the clutch 23. The controller 48 outputs a command current I to control the first control valve device 41. Based on the value of the command current I, the controller 48 determines whether or not the oil that operates the clutch 23 has deteriorated.

Description

Technical Field

[0001] The present invention relates to a working machine, an oil deterioration determination system, and an oil deterioration determination method.

Background Art

[0002] Transmissions used in working machines and the like are provided with a plurality of hydraulic clutches corresponding to each speed stage (see, for example, Patent Documents 1 and 2). The oil supplied to these hydraulic clutches is exchanged at predetermined operating times.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] There is a user need to increase the interval between oil changes. On the other hand, if deteriorated oil is continuously used, there is a risk of failure. The degree of oil deterioration can be determined by methods such as extracting a small amount of oil from the transmission and analyzing its components. Although using such a method eliminates the need to change the oil at predetermined operating times, it is not the optimal strategy for all users.

[0005] An object of the present disclosure is to provide a working machine, an oil deterioration determination system, and an oil deterioration determination method capable of determining oil deterioration without extracting oil from the transmission.

Means for Solving the Problems

[0006] To achieve the above object, the working machine of the first aspect includes a hydraulic clutch, a control valve device, and a controller. The control valve device adjusts the hydraulic pressure supplied to the hydraulic clutch. The controller outputs a command current for controlling the control valve device. The controller determines whether the oil that operates the hydraulic clutch has deteriorated based on the value of the command current.

[0007] The oil deterioration determination system of the second aspect includes a hydraulic clutch, a control valve device, and a controller. The control valve device adjusts the hydraulic pressure supplied to the hydraulic clutch. The controller outputs a command current for controlling the control valve device. The controller determines whether the oil that operates the hydraulic clutch has deteriorated based on the value of the command current.

[0008] The oil deterioration determination method of the third aspect includes outputting a command current to control a control valve device that adjusts the hydraulic pressure supplied to a hydraulic clutch, and determining whether the oil that operates the hydraulic clutch has deteriorated based on the command current.

Advantages of the Invention

[0009] According to the present disclosure, it is possible to provide a working machine, an oil deterioration determination system, and an oil deterioration determination method capable of determining the deterioration of oil.

Brief Description of the Drawings

[0010] [Figure 1] It is a diagram showing the configuration of a working machine in an embodiment according to the present disclosure. [Figure 2] It is a diagram showing the configuration of a control valve device in an embodiment according to the present disclosure. [Figure 3] It is a diagram showing the configuration of a control valve device in an embodiment according to the present disclosure. [Figure 4] It is a diagram showing the configuration of a control valve device in an embodiment according to the present disclosure. [Figure 5] It is a diagram showing the change in the oil additive component TBN and the change in kinematic viscosity with respect to the usage time. [Figure 6] This figure shows the change in kinematic viscosity in relation to the command current when clutch filling is detected. [Figure 7] This is a flowchart showing the oil degradation determination method in the embodiment of the present disclosure. [Figure 8] (a) This figure shows a predetermined pattern of command current output to the proportional solenoid in the oil degradation determination mode. (b) This figure shows the change in supply pressure to the clutch according to the predetermined pattern of command current in Figure 8(a). (c) This figure shows the switching output of the hydraulic sensor according to the command current in Figure 8(a). [Figure 9] This is a flowchart showing the oil degradation determination method in the embodiment of the disclosure. [Figure 10] This figure shows a hydraulic circuit of a control valve device in a modified embodiment of the present disclosure. [Figure 11] This figure shows the configuration of a control valve device in a modified example of the embodiment described herein. [Modes for carrying out the invention]

[0011] The following description of the working machine 1 in the embodiment of this disclosure will be made with reference to the drawings.

[0012] Figure 1 shows the configuration of the work machine 1 of the embodiment. Examples of work machine 1 include a dump truck, bulldozer, wheel loader, motor grader, forklift, etc. Work machine 1 comprises an engine 11, a power transmission mechanism 12, a travel mechanism 13, a hydraulic pump 14, an oil temperature sensor 15, an operating unit 16, an input device 17, a display device 18, and a hydraulic control device 19.

[0013] The engine 11 is, for example, a diesel engine. The power transmission mechanism 12 is a mechanism for transmitting the driving force from the engine 11 to the running gear 13. The power transmission mechanism 12 has a torque converter 21 and a transmission 22. The torque converter 21 is connected to the output side of the engine. The torque converter 21 transmits the driving force generated by the engine 11 to the transmission 22. The transmission 22 has a plurality of clutches 23-29 and a gearbox (not shown).

[0014] Clutches 23-29 are hydraulic clutches driven by the hydraulic pressure of oil supplied from the hydraulic pump 14, which will be described later. Clutches 23-29 are, for example, the FL clutch 23, FH clutch 24, R clutch 25, 1st clutch 26, 2nd clutch 27, 3rd clutch 28, and 4th clutch 29. The FL clutch 23 and FH clutch 24 are engaged when the vehicle is moving forward. The R clutch 25 is engaged when the vehicle is moving backward. The 1st clutch 26, 2nd clutch 27, 3rd clutch 28, and 4th clutch 29 are engaged when transmitting driving force to their respective transmission gears. In the transmission 22, when moving forward, it is possible to select from 1st to 8th gear by combining either the FL clutch 23 or FH clutch 24 with any of the 1st clutch 26 to 4th clutch 29. When moving backward, it is possible to select from 1st to 4th gear by combining the R clutch 25 with any of the 1st clutch 26 to 4th clutch 29.

[0015] The running mechanism 13 is a mechanism for moving the vehicle using the driving force from the engine 11. The running mechanism 13 receives the driving force from the engine 11 via the power transmission mechanism 12. The running mechanism 13 has a front axle 31, a rear axle 32, a pair of front tires 33, and a pair of rear tires 34. The driving force transmitted from the transmission 22 is distributed to the front axle 31 and the rear axle 32 via a transfer case (not shown). A pair of front tires 33 are connected to the front axle 31. The pair of front tires 33 are rotated by the driving force from the engine 11 distributed to the front axle 31. The pair of rear tires 34 are rotated by the driving force from the engine 11 distributed to the rear axle 32. In the case of tracked work machines such as bulldozers, the driving force from the engine is usually transmitted to a single axle, which rotates a pair of sprockets instead of tires. This rotates a pair of tracks wrapped around those sprockets.

[0016] The hydraulic pump 14 is driven using the driving force from the engine 11 and generates hydraulic pressure supplied to the clutches 23-29. The working machine 1 has an oil tank 35, a suction filter 36, and a filter 37. Oil is stored in the oil tank 35, and the oil in the oil tank 35 is supplied to the clutches 23-29 by the hydraulic pump 14 via control valve devices 41-47. The suction filter 36 is placed in the oil stored in the oil tank 35 and removes foreign matter mixed in the oil. The filter 37 further filters foreign matter from the oil discharged from the hydraulic pump 14 and supplied to the clutches 23-29.

[0017] The oil temperature sensor 15 measures the temperature of the oil supplied from the hydraulic pump 14 to the clutches 23-29. The oil temperature sensor 15 transmits the measured temperature data to the controller 48.

[0018] The control unit 16 is operated by an operator to control the work machine 1. The control unit 16 has operating members such as an accelerator pedal 38, an inching pedal 39, and a gear shift lever 40. The accelerator pedal 38 is an operating member for setting the rotational speed of the engine 11 to a desired rotational speed. The inching pedal 39 is an operating member that is operated to reduce the vehicle speed by causing slippage in the FL clutch 23 and FH clutch 24. The gear shift lever 40 is an operating member that is operated by the operator to manually shift gears in the transmission 22. When each operating member of the control unit 16 is operated, an operation signal is output to the controller corresponding to the amount or position of the operation.

[0019] The hydraulic control device 19 controls the operation of the clutches 23-29 described above using the hydraulic pressure generated by the hydraulic pump 14. The hydraulic control device 19 includes control valve devices 41-47 and a controller 48.

[0020] The valve gears 41-47 adjust the hydraulic pressure supplied to the clutches 23-29 described above. Specifically, the first valve gear 41 adjusts the hydraulic pressure supplied to the FL clutch 23. The second valve gear 42 adjusts the hydraulic pressure supplied to the FH clutch 24. The third valve gear 43 adjusts the hydraulic pressure supplied to the R clutch 25. The fourth valve gear 44 adjusts the hydraulic pressure supplied to the 1st clutch 26. The fifth valve gear 45 adjusts the hydraulic pressure supplied to the 2nd clutch 27. The sixth valve gear 46 adjusts the hydraulic pressure supplied to the 3rd clutch 28. The seventh valve gear 47 adjusts the hydraulic pressure supplied to the 4th clutch 29.

[0021] The controller 48 includes a processor such as a CPU and a storage device. The storage device includes memory such as RAM or ROM, and auxiliary storage devices such as an HDD (Hard Disk Drive) or SSD (Solid State Drive). The processor executes a program stored in the storage device in order to control the work machine 1.

[0022] The controller 48 can perform gear shift control appropriate to the vehicle's condition by controlling the control valves 41 to 47 based on operation signals from the operation unit 16 and detection signals from various sensors. For example, the controller 48 sends a command signal to the first control valve 41 to supply hydraulic pressure to the FL clutch 23, and also sends a command signal to the seventh control valve 47 to supply hydraulic pressure to the 4th clutch 29. As a result, the FL clutch 23 and the 4th clutch 29 become engaged, and the 7th gear can be selected. In addition, the controller 48 sends a command signal to the second control valve 42 to supply hydraulic pressure to the FH clutch 24, and also sends a command signal to the fourth control valve 44 to supply hydraulic pressure to the 1st clutch 26. As a result, the FH clutch 24 and the 1st clutch 26 become engaged, and the 2nd gear can be selected.

[0023] Furthermore, the controller 48 determines the amount of fuel to be supplied to the engine 11 based on the operation signal from the accelerator pedal 38 and the engine speed. The controller 48 transmits a command signal corresponding to the determined supply amount to an electronic governor (not shown). As a result, the amount of fuel injected from the fuel injection pump (not shown) is adjusted to match the amount operated by the accelerator pedal 38, and the engine speed is controlled. In this way, the operator can control the output of the work implement and the speed of the vehicle.

[0024] Furthermore, when the inching pedal 39 is operated, the controller 48 adjusts the command signal to the first control valve gear 41 or the second control valve gear 42 based on the operation signal from the inching pedal 39, thereby reducing the hydraulic pressure supplied to the FL clutch 23 or the FH clutch 24. This reduces the driving force transmitted from the power transmission mechanism 12 to the running mechanism 13, and thus reduces the vehicle speed.

[0025] Next, the configurations of the control valve devices 41 to 47 will be described. Since the control valve devices 41 to 47 all have similar configurations, the first control valve device 41 will be used as a representative example for explanation. Figures 2 to 4 show the configuration of the first control valve device 41.

[0026] The first control valve device 41 includes a housing 51, a pressure control valve 52, a solenoid control valve 53, and a flow sensor 200 (an example of a fill detection sensor).

[0027] The housing 51 has an input port 61, an output port 62, a first drain port 63, and a second drain port 64. A hydraulic pump 14 is connected to the input port 61. An FL clutch 23 is connected to the output port 62. An oil tank 35 is connected to the first drain port 63 and the second drain port 64, respectively.

[0028] The pressure control valve 52 is a component that adjusts the hydraulic pressure supplied to the FL clutch 23 and has a spool 65. The spool 65 is provided to be movable in the axial direction (left-right direction in Figure 2) within the housing 51. A valve chamber 66 is formed within the housing 51, and the approximately central part of the spool 65 in the axial direction is located within the valve chamber 66. A feedback chamber 67 is formed inside one axial end of the spool 65 (hereinafter referred to as the "base end"). The valve chamber 66 and the feedback chamber 67 are in communication via a flow path 68 formed within the spool 65. A spring 69 is provided between the feedback chamber 67 and the inner wall surface of the housing 51, and the spring 69 biases the spool 65 toward the other axial end (hereinafter referred to as the "tip end"). A pilot chamber 70 is formed inside the tip end of the spool 65, and a pressure receiving surface 71 is formed on the end face of the tip end of the spool 65.

[0029] When the spool 65 is positioned at the tip end (the position where it contacts the valve seat body 78 of the electromagnetic control valve 53 described later) due to the biasing force of the spring 69, the spool 65 blocks the input port 61 from the valve chamber 66 and connects the valve chamber 66 to the second drain port 64. Conversely, when the spool 65 is positioned at the base end against the biasing force of the spring 69, the spool 65 connects the input port 61 to the valve chamber 66 and blocks the valve chamber 66 from the second drain port 64 (see Figure 3).

[0030] Furthermore, a flow path 72 is formed inside the housing 51, and the space where the input port 61 and the pressure-receiving surface 71 are located is in communication with the flow path 72. The portion of the flow path 72 on the input port 61 side is a flow path 74 with a larger diameter than the flow path 73 on the pressure-receiving surface 71 side. A screw plug 75 is provided at the connection point between this flow path 74 and the flow path 73. The threaded portion of the screw plug 75 is screwed into the small-diameter flow path 73, and the head of the screw plug 75 is located inside the large-diameter flow path 74. As a result, a minute annular gap 76 is formed between the outer circumferential surface of the head of the screw plug 75 and the inner circumferential surface of the flow path 74. In addition, a throttling flow path 77 is formed inside the screw plug 75, connecting the gap 76 and the flow path 73.

[0031] The electromagnetic control valve 53 includes a valve seat body 78, a valve body 79, a connecting member 80, and a proportional solenoid 81.

[0032] The valve seat body 78 is positioned opposite the tip of the spool 65 and is fixed to one end of the connecting member 80. A pilot chamber 82 is formed at the base end of the valve seat body 78. The base end surface of the valve seat body 78 (the left side in the figure) and the tip surface of the spool 65 (the right side in the figure) can come into contact with and separate from each other, and the pilot chamber 82 of the valve seat body 78 and the pilot chamber 70 of the spool 65 are in communication. A valve housing chamber 83 is formed inside the valve seat body 78. In addition, a drain passage 84 extending in the axial direction and a drain passage 85 extending in the radial direction are formed inside the valve seat body 78. The drain passage 84 connects the pilot chamber 82 and the valve housing chamber 83. The drain passage 85 passes through the valve housing chamber 83 and penetrates the valve seat body 78 radially. The drain passage 85 connects the drain passage 84 to the outer circumference of the valve seat body 78, and one end of the drain passage 85 is connected to the first drain port 63. In addition, a valve seat surface 86 is formed on the right inner wall surface of the valve housing chamber 83.

[0033] The valve body 79 has a spherical shape and is housed in the valve housing chamber 83 so as to be movable in the left-right direction.

[0034] The connecting member 80 connects the valve seat body 78 and the proportional solenoid 81. A plunger 87, which is provided to be movable in the axial direction (left-right direction in Figure 2), is inserted inside the connecting member 80. The tip of the plunger 87 is inserted into the valve housing chamber 83 so as to be movable in the axial direction and is in contact with the valve body 79.

[0035] The proportional solenoid 81 moves the plunger 87 axially back and forth when it receives a command current from the controller 48.

[0036] When the command current from the controller 48 to the proportional solenoid 81 is zero, as shown in Figure 2, the plunger 87 moves towards the proportional solenoid 81 and is retracted. As a result, the valve body 79 is pushed away from the valve seat surface 86 by the hydraulic pressure in the pilot chambers 70 and 82. This opens the drain passage 84 and the drain passage 85 into communication. As a result, the oil from the hydraulic pump 14 flows sequentially through the input port 61, the gap 76 in the passage 74, the throttling passage 77 of the screw plug 75, passage 73, the pilot chambers 70 and 82, the drain passage 84, the drain passage 85, and the first drain port 63 before being discharged to the oil tank 35. In this case, since the pilot pressure in the pilot chamber 70 does not rise, the spool 65 moves to the right due to the biasing force of the spring 69 and is positioned in contact with the valve seat body 78. As a result, the space between the input port 61 and the valve chamber 66 is closed, while the space between the valve chamber 66 and the second drain port 64 is opened into communication. Therefore, no pressure is generated in the valve chamber 66. Since the valve chamber 66 is in communication with the FL clutch 23 via the output port 62, no hydraulic pressure is generated in the FL clutch 23. As a result, the FL clutch 23 remains open.

[0037] Next, when a predetermined command current I is applied from the controller 48 to the proportional solenoid 81, the plunger 87 is pushed out toward the valve body 79 with a force corresponding to the magnitude of the command current, and its tip presses the valve body 79 against the valve seat surface 86. As a result, as shown in Figure 3, the drain passages 84 and 85 are narrowed, and the space between the pilot chamber 70 and the first drain port 63 is narrowed.

[0038] As a result, a pilot pressure corresponding to the magnitude of the command current I is generated in the pilot chamber 70. Then, the spool 65 moves towards the base end (left side in the diagram) until it reaches a position where this pilot pressure and the biasing force of the spring 69 are balanced. In this state, the space between the valve chamber 66 and the second drain port 64 is closed, and the space between the valve chamber 66 and the input port 61 is opened. Therefore, oil from the hydraulic pump 14 flows into the FL clutch 23 via the input port 61, the valve chamber 66, and the output port 62. The opening degree of the pressure control valve 52 at this time, i.e., the flow rate of oil flowing from the output port 62 towards the clutch, changes according to the magnitude of the command current to the proportional solenoid 81.

[0039] The flow sensor 200 comprises a flow detection valve 100 and a sensor unit 300. The flow detection valve 100 is housed in a housing 51 alongside a pressure control valve 52 and an electromagnetic control valve 53. The sensor unit 300 is located on the right side of the flow detection valve 100 in the diagram.

[0040] The flow detection valve 100 has a spool 111 inserted into a housing 51 so as to be movable in the left-right direction in the figure. The spool 111 forms an oil chamber 112 and an oil chamber 113 within the housing 51. An orifice 114 is formed in the spool 111 between the oil chambers 112 and 113. The spool 111 has a projection 111a at its left end in the figure that protrudes into the oil chamber 113. The oil chamber 113 communicates with the output port 62 via a flow path 117. The oil chamber 112 communicates with the valve chamber 66 via a flow path 118. If the pressure-receiving areas of the spool 111 facing oil chambers 112 and 113 are A1, A2, and A3 respectively in the left-right direction, then there is a relationship "A1+A3>A2" between the pressure-receiving area to the right (A1+A3) and the pressure-receiving area to the left (A2). Therefore, when the hydraulic pressure in oil chamber 112 and oil chamber 113 becomes equal, the spool 111 moves to the right.

[0041] The sensor unit 300 includes a spring 301, a cap member 302, a detection pin 303, a fixing member 304, a spring 305, an output pin 306, and a sealing member 307. The spring 301 is inserted into a concave spring chamber 121 formed in the axial center of the right end of the spool 111 in the figure. The cap member 302 is fitted onto the outer circumference of the right end of the spool 111. The detection pin 303 is attached with a projection approximately in the center of the detection pin 303 sandwiched between the cap member 123 and the spring 122. The detection pin 303 is pressed against the cap member 302 by the biasing force of the spring 301. The right tip of the detection pin 303 penetrates the cap member 302 and protrudes to the right. The fixing member 304 is attached to the outer surface of the housing 151 to the right of the cap member 302 by bolts. Spring 305 is inserted between the fixing member 304 and the cap member 302. The biasing force of spring 305 presses the cap member 302 to the left. Output pin 306 is positioned opposite the detection pin 303. Output pin 306 is attached by the fixing member 304. Sealing member 307 is positioned on the outer surface of fixing member 304 to close the gap with output pin 306. Point a, the midpoint of the series connection of resistors R1 and R2, is connected to the right side of output pin 306 via lead wire 308, and a predetermined DC voltage V is applied to both ends of the series connection of resistors R1 and R2. Housing 51 is grounded. Point a is connected to controller 48.

[0042] When the FL clutch 23 is filled with pressurized oil, the pressure difference between oil chamber 112 and oil chamber 113 disappears, causing the spool 111 to move to the right, as shown in Figure 4. At this time, the pressure in oil chamber 112 pushes the cap member 302 to the right against the biasing force of the spring 305, causing the detection pin 303 to contact the output pin 306. As a result, the potential at point a drops to 0V (ground potential). The controller 48 can detect this falling edge of the potential at point a and determine that the filling is complete. Thus, the controller 48 can obtain information that the FL clutch 23 has been filled with oil. In addition, the controller 48 outputs a command current I to the proportional solenoid 81, supplying oil to the FL clutch 23. Therefore, the controller 48 can obtain the magnitude of the command current when the FL clutch 23 is filled.

[0043] In this embodiment, the work machine 1 determines whether the oil operating the clutches 23-29 has deteriorated based on the value of the command current when the fill of the clutches 23-29 is detected in the oil deterioration determination mode. First, we will explain how oil deterioration can be determined from the value of the command current.

[0044] Figure 5 shows the changes in TBN (Total Base Number) and kinematic viscosity of the oil additive component with respect to usage time at a given oil temperature. The horizontal axis in Figure 5 represents usage time. The time increases from left to right. The vertical axis on the left of Figure 5 represents the amount of TBN, the oil additive component. The vertical axis on the right of Figure 5 represents the kinematic viscosity of the oil. The change in the amount of TBN is shown by a thin line, and the change in kinematic viscosity is shown by a thick line. As the oil is used, the amount of TBN decreases and the kinematic viscosity increases. When the amount of TBN reaches zero, the kinematic viscosity increases sharply. The kinematic viscosity when the amount of TBN reaches zero is shown in μe. It can be seen that the oil deteriorates as TBN decreases, and the kinematic viscosity also increases. If the kinematic viscosity at the start of use is μ0, the amount of change in kinematic viscosity is from μ0 to μ e up to Δμ a If the kinematic viscosity increases by Δμ, it can be determined that the oil has deteriorated. Note that the amount of change in kinematic viscosity used to determine oil deterioration is set with a margin of error (Δμ). aIt may be a value smaller than

[0045] FIG. 6 is a diagram showing the change in kinematic viscosity with respect to the value of the command current I when the control valve devices 41 to 47 detect filling to the clutch at a predetermined oil temperature. The horizontal axis of FIG. 6 indicates the value of the command current I when filling is detected. The origin of the horizontal axis is the initial value I0 of the command current when the filling of the clutch is detected. The initial value I0 of the command current indicates, for example, the value of the command current I when filling is detected after oil is put into the clutch at the time of oil change or product shipment. The vertical axis indicates the kinematic viscosity. As shown in FIG. 6, it can be seen that as the value of the command current I when filling is detected increases, the kinematic viscosity also increases. From this, it can be seen that the deterioration of the oil can be determined from the change in the value of the command current I when the filling of the clutch is detected.

[0046] For example, the command current value I e at which the kinematic viscosity reaches μ shown in FIG. 5 e Thus, the change Δμ e in kinematic viscosity from μ0 to μ a corresponds to the change ΔI e from the value I0 of the command current to I a That is, when the command current value changes by ΔI a it can be determined that the kinematic viscosity changes by Δμ a and the oil has deteriorated. Note that since the kinematic viscosity varies depending on the oil temperature, FIGS. 5 and 6 show the relationship at the same oil temperature.

[0047] Returning to Figure 1, the input device 17 is configured by the operator for the work machine 1. It is preferable that the operator, unlike the operator (i.e., user) mentioned earlier, be a service worker from the manufacturer of the work machine 1. When determining oil degradation, the operator connects the input device 17 and display device 18 to the controller 48 and operates the input device 17 to execute the oil degradation determination mode. It is preferable to use a mobile computer such as a laptop or tablet as the input device 17 and display device 18. When the operator operates the input device 17, an input signal corresponding to the operation is output to the controller 48. The input device 17 can be a keyboard, mouse, or touch panel.

[0048] The display device 18 displays various measured values ​​from the work machine 1. The display device 18 displays the input screen when operating the input device 17. The display device 18 displays the screen based on the display signal from the controller 48. In the oil deterioration judgment mode, the display device 18 displays the oil temperature detected by the oil temperature sensor 15.

[0049] Furthermore, the controller 48 transitions to an oil degradation determination mode for determining oil degradation based on the input signal from the input device 17. In the oil degradation determination mode, the controller 48 displays the oil temperature on the display device 18 based on the value detected by the oil temperature sensor 15.

[0050] The control in the oil degradation determination mode will now be described. Figures 7 and 9 are flowcharts showing the oil degradation determination method in Embodiment 1 of this disclosure.

[0051] During an oil change or product shipment (an example of a first predetermined timing), the oil degradation determination mode is executed and the initial value I0 of the command current is obtained.

[0052] When an operator uses the input device 17 to input the execution of the oil deterioration judgment mode during an oil change or product shipment, the controller 48 acquires the command signal to execute the oil deterioration judgment mode in step S11 of Figure 7.

[0053] Next, in step S12, the controller 48 acquires the value detected by the oil temperature sensor 15 and determines whether the oil temperature is at a predetermined temperature. At this time, the controller 48 displays the oil temperature on the display device 18. The operator checks the oil temperature on the display device 18 and adjusts the oil temperature to reach the predetermined temperature. For example, the operator can raise the oil temperature by operating the accelerator pedal 38 to increase the engine speed while the torque converter 21 is stalled. The control remains in standby mode until it is determined in step S12 that the oil temperature has reached the predetermined temperature. Note that the predetermined temperature is not necessarily a specific temperature in the strict sense, but may have a certain range. That is, the controller 48 may determine whether the value detected by the oil temperature sensor 15 is within a predetermined temperature range.

[0054] If it is determined in step S12 that the oil temperature has reached a predetermined temperature, in step S13 the controller 48 displays a control execution button on the display device 18 to obtain the command current value at the time of fill detection.

[0055] Next, when the operator presses the execute button using the input device 17, in step S14, the controller 48 acquires the command current value at the time the first control valve device 41 detects that the FL clutch 23 has reached fill. The controller 48 stores current command data indicating a predetermined pattern of command current, which will be described later. The controller 48 outputs the predetermined pattern of command current to the proportional solenoid 81 of the first control valve device 41 to acquire the command current value at the time the flow sensor 200 detects that the FL clutch 23 has reached fill. Acquired command current value I f This value is stored by the controller 48 as the initial command current value I0.

[0056] The control in step S14 will be explained using Figures 8(a) to 8(c). Figure 8(a) is a diagram showing a predetermined pattern of command current I in the oil degradation determination mode. In Figure 8(a), the horizontal axis represents time, and the vertical axis represents the value of the command current. Figure 8(b) is a diagram showing the change in supply pressure P to the FL clutch 23 in accordance with the command current I in Figure 8(a). In Figure 8(b), the horizontal axis represents time, and the vertical axis represents the value of the supply oil pressure. Figure 8(c) is a diagram showing the switching output from the flow sensor 200 in accordance with the command current I in Figure 8(a). In Figure 8(c), the horizontal axis represents time, and the vertical axis represents the detection signal from the flow sensor.

[0057] The controller 48 outputs a command current in a predetermined pattern shown in Figure 8(a) to the proportional solenoid 81. The controller 48 outputs a command current value I for a full trigger at the maximum level from time t1. g This is supplied to the proportional solenoid 81 for a predetermined period. As a result, the plunger 87 of the proportional solenoid 81 is set to the commanded current value I g The spool is pushed out to the left with a force corresponding to the command current I, and its tip presses the valve body 79 against the valve seat surface 86. As a result, the valve seat surface 86 is closed, the drain passages 84 and 85 are narrowed, and the space between the pilot chamber 70 and the first drain port 63 is narrowed. As a result, a pilot pressure corresponding to the magnitude of the command current I is generated in the pilot chamber 70. Then, the spool 65 moves towards the base end (left side in the figure) to a position where this pilot pressure and the biasing force of the spring 69 are balanced (see Figure 3). In this state, the space between the valve chamber 66 and the second drain port 64 is closed, and the space between the valve chamber 66 and the input port 61 is opened. Therefore, oil from the hydraulic pump 14 flows into the FL clutch 23 via the input port 61, the valve chamber 66 and the output port 62. As a result, the command current I g A large flow of pressurized oil, proportional to the size of the clutch, flows into the FL clutch in a short time until it reaches near-fill state.

[0058] At this time, the pressurized oil flows in through the orifice 114, creating a pressure difference between the oil chamber 112 and the oil chamber 113. Due to the relationship between this pressure difference and the respective areas A1, A2, and A3 of the spool, a force acts on the spool 111 to the left, causing the protruding portion 111a of the spool 111 to contact the inner surface of the housing 151 in the oil chamber 113. As a result, the detection pin 303 and the output pin 306 are not in contact, and the potential at point a maintains a predetermined voltage V1.

[0059] Next, as shown in Figure 8(a), the controller 48 reduces the command current to a command current value I corresponding to a predetermined small flow rate. s It outputs the command current I. s Because it is pressed with a small force corresponding to its size, the gap with the valve seat surface 86 increases due to the pilot fluid in the pilot chamber 70, and the pilot pressure in the pilot chambers 70 and 82 is the command current value I s The force decreases until it balances with the magnitude of the force. The pilot room 70 has a command current value I s A pilot pressure corresponding to the magnitude of the spring is generated, and the spool 65 moves to the right until it reaches a position where this pilot pressure balances with the biasing force of the spring 69 (see Figure 4). As a result, the opening between the valve chamber 66 and the input port 61 decreases, and the commanded current value I is generated in the valve chamber 66. s A small pressure corresponding to the size of the pressure is generated, and pressurized oil is sequentially introduced into the FL clutch 23 at a small flow rate through the oil chamber 112, orifice 114, oil chamber 113, and flow path 117. At this time, a differential pressure is generated between the oil chamber 112 and the oil chamber 113 until the FL clutch 23 is filled with oil. This differential pressure causes a force to act to the left on the spool 111 and the detection pin 303, the detection pin 303 and the output pin 306 remain in a non-contact state, and the potential at point a maintains a predetermined voltage V1.

[0060] When pressurized oil is introduced at a small flow rate and low clutch pressure, once the FL clutch 23 is filled with pressurized oil, the differential pressure between oil chamber 112 and oil chamber 113 disappears. Due to the relationship between the pressure-receiving areas A1, A2, and A3 of the spool 111, the spool 111 moves to the right. At this time, the pressure in oil chamber 112 pushes the cap member 302 to the right against the biasing force of the spring 305, causing the detection pin 303 to contact the output pin 306 (see Figure 4). As a result, as shown in Figure 8(c), the potential at point a drops to 0V at time t2, allowing the controller 48 to detect the falling edge of the potential at point a and determine that the fill is complete.

[0061] In other words, time t2 is the time when the oil filling to the FL clutch 23 is completed. Note that in Figure 8(c), the potential is also falling at time t1, which is due to the commanded current value I g This is because a large flow rate is generated when the fluid is applied, and the flow sensor 200 detects this.

[0062] When the filling is completed at time t2, the controller 48 commands a current I to return the potential value at point a, which is 0V at the end of the filling at time t2, back to V1, as shown in Figure 8(a). s From current value I A The pressure is reduced to this level. This reduces the hydraulic pressure supplied to the FL clutch 23, lowering the pressure in the oil chamber 113 which is in communication with the FL clutch 23 via the flow path 117 and output port 62, causing the spool 111 to move to the left. The movement of the spool 111 causes the detection pin 303 and the output pin 306 to separate, and the potential at point a returns to V1. Note that the current value I A The size of the pressure P of the FL clutch 23 is detected by the flow sensor 200. f The following values ​​are set, and the hydraulic pressure generated is sufficient to maintain contact between the clutch plates against the spring force of the piston return spring (not shown) of the FL clutch 23. Therefore, at this time, the FL clutch 23 remains filled with pressurized oil, and the potential of the output signal of the flow sensor 200 becomes V1.

[0063] Next, as shown in Figure 8(a), the controller 48 controls the value of the command current I from time t2 to time t3. A From current value I B The command current is output to the proportional solenoid 81 so that it gradually increases until it reaches a certain value.

[0064] As the command current I gradually increases from time t2 to time t3, the supply pressure P to the FL clutch 23 increases between time t2 and time t3, as shown in Figure 8(b). A From P B It gradually increases until it reaches [a certain value].

[0065] Therefore, at time tf during the period from time t2 to time t3, the supply pressure P to the FL clutch 23 is pressure P f When the pressure reaches this point, the differential pressure between oil chamber 112 and oil chamber 113 disappears, and due to the relationship of the pressure-receiving areas A1, A2, and A3 of the spool 111, the spool 111 moves to the right, and the detection pin 303 contacts the output pin 306. The flow sensor 200 outputs a falling-edge signal to the controller 48 again. Note that the current value I A and current value I B During the period from time t2 to time t3, the flow sensor 200 outputs a falling edge signal (set pressure P f It is set as the value (which is the result of this).

[0066] The controller 48 outputs a falling edge signal at time t f The command current value I is output to the proportional solenoid 81. f The controller 48 measures the acquired command current value I. f This is stored in memory. In this way, the command current value I obtained by executing the oil degradation determination mode during oil changes or product shipment, etc. f This is defined as the initial command current value I0.

[0067] As described above, the controller 48 obtains the initial command current value I0.

[0068] Next, after a predetermined period has elapsed since the initial command current value I0 was acquired, or after a predetermined usage time has elapsed (an example of a second predetermined timing), the operator executes the oil degradation determination mode. Figure 9 is a flowchart showing the oil degradation determination method executed at this time.

[0069] When the operator inputs the command to execute the oil deterioration determination mode using the input device 17, in step S21, the controller 48 acquires the command signal to execute the oil deterioration determination mode.

[0070] Next, in step S22, the controller 48 acquires the value detected by the oil temperature sensor 15 and determines whether the oil temperature is at a predetermined temperature. At this time, the controller 48 displays the oil temperature on the display device 18. The operator checks the oil temperature on the display device 18 and adjusts it so that the oil temperature reaches the predetermined temperature. The adjustment can be performed in the same way as in step S12 described above. The control remains in standby mode until it is determined in step S22 that the oil temperature has reached the predetermined temperature. The predetermined temperature in step S22 is the same value as the predetermined temperature in step S12 when the initial command current value was acquired. This is because the kinematic viscosity of the oil changes with temperature, so it is necessary to detect the change in kinematic viscosity at the same temperature. As with step S12, the predetermined temperature is not necessarily a specific temperature in the strict sense, but may have a certain range. That is, the controller 48 may determine whether the value detected by the oil temperature sensor 15 is within a predetermined temperature range.

[0071] If it is determined in step S22 that the oil temperature has reached a predetermined temperature, in step S23 the controller 48 displays a control execution button on the display device 18 to obtain the command current value at the time of fill detection.

[0072] Next, when the operator presses the execution button using the input device 17, in step S24, the controller 48 determines the command current value I when the first control valve device 41 detects that the FL clutch 23 has reached fill. fThe command current value in step S24 is obtained in the same way as the initial command current value I0 in step S14.

[0073] Next, in step S25, the controller 48 obtains the command current value I f The difference between this value and the initial command current value I0 is calculated, and the difference is a predetermined threshold ΔI a Determine whether the difference is greater than or equal to ΔI. a If the above is determined, in step S26 the controller 48 determines that the oil has deteriorated. Then, in step S27 the controller 48 displays an indication on the display device 18 that the oil has deteriorated, and the control ends.

[0074] Furthermore, in step S25, the acquired command current value I f The difference between this value and the initial command current value I0 is a predetermined threshold ΔI a If the value is less than the specified value, the controller 48 determines that the oil has not deteriorated and terminates the control process.

[0075] In the work machine 1 of this embodiment, the controller 48 determines whether the oil supplied to the clutches 23-29 has deteriorated based on the value of the command current I. This allows for a longer oil change interval and prevents the oil from being used beyond its lifespan. Furthermore, by extending the oil change interval, waste can be reduced and costs can be lowered.

[0076] The work machine 1 of this embodiment has a flow sensor 200 that detects the filling of oil into the clutch. The controller 48 determines whether or not the oil has deteriorated based on the command current value at the time of filling detection. This makes it possible to determine the deterioration of the oil using the flow sensor 200 that detects the filling of the clutch oil without adding any additional configurations.

[0077] Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the invention.

[0078] The control valve device in the above embodiment uses a sensor that detects the fill level by detecting the oil flow rate, but is not limited to this, and a sensor that detects the fill level by detecting the oil pressure may also be used.

[0079] Figure 10 shows the hydraulic circuit of a control valve device 141 equipped with a pressure switch 91 (an example of a fill detection sensor, an example of a detection sensor) as an example of a type that detects fill by detecting the oil pressure. Components having the same function as the control valve device 41 of the above embodiment are denoted by the same reference numerals. Compared to the control valve device 41, the control valve device 141 is not equipped with a flow sensor 200, but is equipped with a pressure switch 91. The pressure switch 91 detects when the pressure at the output port 62, i.e., the pressure supplied to the FL clutch 23, reaches a predetermined set pressure P f When this happens, an ON signal is sent to the controller 48. The controller 48 obtains the command current value when it receives the ON signal from the pressure switch 91. The controller 48 then obtains the initial current value I, as in the above embodiment. o And the command current value I obtained afterwards f The difference and the threshold ΔI s By comparing it with the oil, we can determine whether or not the oil has deteriorated.

[0080] Figure 11 shows the configuration of a control valve device 241 equipped with a pressure sensor 54 (an example of a fill detection sensor, an example of a detection sensor) as an example of a type that detects fill by detecting the oil pressure. Compared to the control valve device 41, the control valve device 241 has a pressure sensor 54 instead of a flow sensor 200. The pressure sensor 54 is denoted by the same reference numerals as the control valve device 41 of the above embodiment for components having the same function. The pressure sensor 54 is provided facing a flow path 88 that communicates with the valve chamber 66 and detects the hydraulic pressure supplied to the valve chamber 66. Since the valve chamber 66 is connected to an output port 62, the pressure sensor 54 can detect the hydraulic pressure supplied to the FL clutch 23. The pressure sensor 54 transmits the detected pressure value to the controller 48. The controller 48 receives the pressure P of the FL clutch 23 when it fills. f The pressure value from the pressure sensor 54 is stored in advance, and P f The command current value is acquired when it reaches [a certain value]. The controller 48 acquires the initial current value I, similar to the embodiment described above. o And the command current value I obtained afterwards f The difference and the threshold ΔI s By comparing it with the oil, we can determine whether or not the oil has deteriorated.

[0081] Also, the pressure P during filling. f The oil deterioration may also be determined by the change in the command current value when a predetermined pressure value is detected by the pressure sensor 54.

[0082] Furthermore, oil degradation may be determined by the difference in the detected value of the pressure sensor 54 at a predetermined command current value. That is, when the oil is changed or when the product is shipped, the oil degradation determination mode is executed, and the controller 48 acquires the detected value of the pressure sensor 54 at a predetermined command current value as the initial pressure value. After a predetermined period has elapsed since the acquisition of the initial pressure value, or after a predetermined usage time has elapsed, the oil degradation determination mode is executed by an operator, and the controller 48 acquires the detected value of the pressure sensor 54 at the same temperature and the same command current value as when the initial pressure value was acquired. If the difference between the acquired detected value and the initial pressure value exceeds a predetermined threshold, the controller 48 can determine that the oil has deteriorated.

[0083] In the above embodiment, the controller 48 has a threshold ΔI set for a predetermined temperature that has been set in advance. a It remembers, but the threshold ΔI at each of several different temperatures a A table containing the settings may be stored. In this case, the temperature at which the initial command current value I0 is obtained can be any temperature, so step S12 is not necessarily required. However, in step S22, it is necessary to determine whether the temperature is the same as the temperature at which the initial command current value I0 was obtained. The temperature at which the command current value is obtained is preferably, for example, 60°C to 80°C.

[0084] In the above embodiment, the presence of oil in the clutch is detected by a control valve device, but this is not the only option. For example, a sensor for detecting the rotational speed of the clutch's input shaft and a sensor for detecting the rotational speed of the output shaft may be provided, and the filling of the clutch with oil may be detected based on the difference between the rotational speeds of the input shaft and the output shaft. When the difference between the rotational speeds of the input shaft and the output shaft falls below a predetermined value, it can be determined that the filling of the clutch with oil is complete.

[0085] In the above embodiment, it was determined that the oil had deteriorated when the amount of change in the command current value exceeded a predetermined threshold. However, it is also possible to determine that the oil has deteriorated when the command current value itself exceeds a predetermined value, rather than when the amount of change exceeds a predetermined value.

[0086] In the above embodiment, the controller 48 of the work machine 1 performs the oil degradation determination, but this is not the only option. For example, information on the command current at the time of fill detection may be transmitted from the work machine 1 to the operator's computer, and the operator's computer may perform the oil degradation determination. Communication between the operator's computer and the work machine 1 may be done via wired or wireless connection. The detection value of the oil temperature sensor 15 may also be transmitted to the operator's computer.

[0087] In the above embodiment, steps S13 and S23 are provided, but they may not be provided. In this case, when a predetermined temperature is reached in steps S12 and S22, control may be started to acquire the command current value at the time of fill detection in steps S14 and S24.

[0088] In the above embodiment, the oil degradation was determined using the value of the command current output to the first control valve device 41, but it is not limited to this, and the oil degradation may also be determined using the value of the command current output to any of the control valve devices 42 to 47. [Industrial applicability]

[0089] According to the present invention, it is possible to provide a work machine capable of determining oil deterioration, an oil deterioration determination system, and an oil deterioration determination method. [Explanation of symbols]

[0090] 1: Working machinery 23: FL Clutch 41: First valve gear 48: Controller

Claims

1. Hydraulic clutch and A control valve device for adjusting the hydraulic pressure supplied to the hydraulic clutch, A controller that outputs a command current for controlling the control valve device, The controller determines whether or not the oil that operates the hydraulic clutch has deteriorated based on the value of the command current. A type of machinery used for industrial work.

2. The control valve device has a fill detection sensor for detecting the oil fill in the hydraulic clutch, The controller determines whether the oil has deteriorated based on the value of the command current at the time of fill detection. The work machine according to claim 1.

3. The control valve device has a detection sensor that detects information regarding the oil pressure in the hydraulic clutch, The controller determines whether the oil that operates the hydraulic clutch has deteriorated based on the value of the command current and the pressure information. The work machine according to claim 1.

4. The information relating to the pressure includes information on the pressure value of the oil in the hydraulic clutch. The detection sensor detects the oil pressure value in the hydraulic clutch, The controller determines whether the oil has deteriorated based on the pressure value at a predetermined command current value. The work machine according to claim 3.

5. The system further includes an oil temperature sensor for detecting the temperature of the oil supplied to the hydraulic clutch, The controller determines whether the oil has deteriorated based on the temperature and the value of the commanded current. The work machine according to claim 1.

6. The controller determines that the oil has deteriorated when the difference between the value of the command current at the time of fill detection at a first predetermined timing and the value of the command current at the time of fill detection at a second predetermined timing exceeds a predetermined threshold. The working machine according to claim 2.

7. The controller determines that the oil has deteriorated when the difference between the pressure value at the predetermined command current value at a first predetermined timing and the pressure value at the predetermined command current value at a second predetermined timing exceeds a predetermined threshold. The work machine according to claim 4.

8. The first predetermined timing is the timing of the oil change or the timing of the shipment of the work machine. The work machine according to claim 6 or 7.

9. The system further includes an oil temperature sensor for detecting the temperature of the oil supplied to the hydraulic clutch, The temperature of the oil at the first predetermined timing and the temperature of the oil at the second predetermined timing are the same. The work machine according to claim 6 or 7.

10. The controller stores the predetermined threshold values ​​corresponding to each of a plurality of different temperatures. The controller determines whether the oil has deteriorated using the predetermined threshold corresponding to the temperature measured by the oil temperature sensor. The working machine according to claim 9.

11. Hydraulic clutch and A control valve device for adjusting the hydraulic pressure supplied to the hydraulic clutch, The system includes a controller that outputs a command current for controlling the control valve device, The controller determines whether or not the oil that operates the hydraulic clutch has deteriorated based on the value of the command current. Oil degradation detection system.

12. To output a command current in order to control the control valve device that adjusts the hydraulic pressure supplied to the hydraulic clutch, The system includes determining whether or not the oil that operates the hydraulic clutch has deteriorated based on the command current, Method for determining oil degradation.

13. The system further includes detecting the fill of the oil in the hydraulic clutch, Based on the value of the command current at the time of fill detection, it is determined whether or not the oil has deteriorated. The method for determining oil degradation according to claim 12.

14. The system further includes detecting information regarding the oil pressure in the hydraulic clutch, Based on the value of the command current and the pressure information, it is determined whether or not the oil that operates the hydraulic clutch has deteriorated. The method for determining oil degradation according to claim 12.

15. The information relating to the pressure includes information on the pressure value of the oil in the hydraulic clutch. The pressure value of the oil in the hydraulic clutch is detected, The system determines whether the oil has deteriorated based on the pressure value at a predetermined command current value. The method for determining oil degradation according to claim 14.

16. The system further includes detecting the temperature of the oil supplied to the hydraulic clutch, Based on the temperature and the value of the commanded current, it is determined whether or not the oil has deteriorated. The method for determining oil degradation according to claim 12.

17. If the difference between the value of the command current at the time of fill detection at a first predetermined timing and the value of the command current at the time of fill detection at a second predetermined timing exceeds a predetermined threshold, it is determined that the oil has deteriorated. The method for determining oil degradation according to claim 13.

18. If the difference between the pressure value at the predetermined command current value at the first predetermined timing and the pressure value at the predetermined command current value at the second predetermined timing exceeds a predetermined threshold, it is determined that the oil has deteriorated. The method for determining oil degradation according to claim 15.

19. The system further includes detecting the temperature of the oil supplied to the hydraulic clutch, The temperature of the oil at the first predetermined timing and the temperature of the oil at the second predetermined timing are the same. The method for determining oil deterioration according to claim 17 or 18.

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