Boom control system for a work machine

Abstract

A boom cylinder (10) drives a boom (6) and has a head-side oil chamber (10h) and a bottom-side oil chamber (10b). A first valve (21) has a first opening portion (21c) that discharges oil of the head-side oil chamber (10h) to a tank (25) and supplies oil from a hydraulic pump (20) to the head-side oil chamber (10h). A second valve (22) has a second opening portion (22c) that discharges oil of the bottom-side oil chamber (10b) to the tank (25) and supplies oil from the hydraulic pump (20) to the bottom-side oil chamber (10b). A controller (30) individually controls an opening degree (D1) of the first opening portion (21c) and an opening degree (D2) of the second opening portion (22c) at the time of work including operation of the boom (6).

Description

Technical Field

[0001] This disclosure relates to the boom control system of operating machinery. Background Technology

[0002] For example, Japanese Patent Application Publication No. 3-66838 (Patent Document 1) discloses the following: a boom floating function is provided in hydraulic excavators and other operating machinery. The boom floating function refers to the function of not discharging working oil from the hydraulic pump to the boom cylinder, and connecting the head side oil chamber and the bottom side oil chamber of the boom cylinder to the oil tank, thereby enabling the boom to swing freely.

[0003] Prior art literature

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 3-66838 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] Construction machinery is used for a variety of purposes. Therefore, in recent years, there has been a demand for boom floating functions that can be applied to various purposes.

[0008] Therefore, the purpose of this disclosure is to provide a boom control system for a work machine that can adjust the boom floating function according to the application.

[0009] Methods for solving problems

[0010] The boom control system of this disclosed work machinery includes a boom, a boom cylinder, a hydraulic pump, an oil tank, a first valve, and a second valve. The boom cylinder drives the boom and has a head side oil chamber and a bottom side oil chamber. The first valve supplies oil from the hydraulic pump to the head side oil chamber and discharges it to the oil tank. The second valve supplies oil from the hydraulic pump to the bottom side oil chamber and discharges it to the oil tank. The first valve has a first opening for discharging oil from the head side oil chamber to the oil tank. The second valve has a second opening for discharging oil from the bottom side oil chamber to the oil tank. The boom control system of the work machinery also includes a controller that individually controls the opening degree of the first opening and the opening degree of the second opening during operation including boom operation.

[0011] Invention Effects

[0012] According to this disclosure, a work machine is capable of adjusting the boom floating function according to its intended use. Attached Figure Description

[0013] Figure 1 This is a perspective view that schematically illustrates the structure of the working machinery in one embodiment of the present disclosure.

[0014] Figure 2 It is shown Figure 1 The diagram shows the structure of the boom control system of the operating machinery.

[0015] Figure 3 It is shown Figure 2 The diagram shows an example of the functional modules of the boom control system.

[0016] Figure 4 This is a flowchart illustrating an example of a boom control method for a working machine according to one embodiment of the present disclosure.

[0017] Figure 5 This is a diagram showing the status of the first and second valves in the digging mode.

[0018] Figure 6 This is a diagram showing the status of the first and second valves in the crusher mode.

[0019] Figure 7 This is a diagram showing the status of the first and second valves in the excavation assistance mode.

[0020] Figure 8 This is a graph showing the relationship between the boom lowering operation amount and the opening degree of the first valve in the digging mode (A), and the relationship between the boom lowering operation amount and the opening degree of the second valve (B).

[0021] Figure 9 This is a graph showing the relationship between the boom lowering operation amount and the opening degree of the first valve in the crusher mode (A), and the relationship between the boom lowering operation amount and the opening degree of the second valve (B).

[0022] Figure 10 This is a graph showing the relationship between the boom lifting operation amount and the opening degree of the first valve in the excavation assistance mode (A), and the relationship between the boom lifting operation amount and the opening degree of the second valve (B).

[0023] Figure 11 This is a side view showing the structure of a working machine that has a crusher as an accessory. Detailed Implementation

[0024] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0025] In the specification and accompanying drawings, the same or corresponding constituent elements are labeled with the same reference numerals, and repeated descriptions are omitted. Furthermore, in the accompanying drawings, structures are sometimes omitted or simplified for ease of explanation. Additionally, at least some of the embodiments and variations can be arbitrarily combined with each other.

[0026] This disclosure applies to any work machinery, besides hydraulic excavators, that has a boom and a boom cylinder for driving the boom, including work machinery that performs boom operation such as wheel loaders. In the following description, "up," "down," "front," "rear," "left," and "right" refer to the position of the machine seated in front of it. Figure 1 The operator of the driver's seat 4S in the cab 4 shown is in the reference direction.

[0027] <Structure of Operating Machinery>

[0028] First, use Figure 1 The structure of the working machine in this embodiment will be described.

[0029] Figure 1 This is a perspective view that schematically illustrates the structure of the working machinery in one embodiment of the present disclosure. (As shown...) Figure 1 As shown, the hydraulic excavator 100 has a main body 1 and a working device 2 that operates hydraulically. The main body 1 has a rotating body 3 and a traveling body 5. The traveling body 5 has a pair of tracks 5Cr and a travel motor 5M. The hydraulic excavator 100 can travel by rotating the tracks 5Cr. The travel motor 5M is provided as the drive source for the traveling body 5. The travel motor 5M is a hydraulic motor that operates hydraulically. It should be noted that the traveling body 5 may also have wheels (tires).

[0030] The slewing body 3 is mounted on and supported by the traveling body 5. The slewing body 3 is capable of rotating relative to the traveling body 5 about the slewing shaft RX. The slewing body 3 has a cab 4. An operator's seat 4S is provided inside the cab 4 for the operator to sit in. The operator (crew) sits in the cab 4 and can operate the working device 2, rotate the slewing body 3 relative to the traveling body 5, and travel the hydraulic excavator 100 based on the traveling body 5.

[0031] The rotating body 3 has an engine hood 9 and a counterweight located at the rear of the rotating body 3. The engine hood 9 covers the engine compartment. The engine unit (engine, exhaust system, etc.) is located in the engine compartment.

[0032] The working device 2 is supported on the rotating body 3. The working device 2 has a boom 6, a stick 7, and a bucket 8. The working device 2 also has a boom cylinder 10, a stick cylinder 11, and a bucket cylinder 12.

[0033] The boom 6 is connected to the main body 1 (driving body 5 and rotating body 3) in a rotatable manner. Specifically, the base end of the boom 6 is connected to the rotating body 3 in a manner that allows it to rotate around the boom base pin 13.

[0034] The stick 7 is rotatably connected to the boom 6. Specifically, the base end of the stick 7 is connected to the front end of the boom 6 in a manner that allows it to rotate around the boom top pin 14. The bucket 8 is rotatably connected to the stick 7. Specifically, the base end of the bucket 8 is connected to the front end of the stick 7 in a manner that allows it to rotate around the stick top pin 15.

[0035] One end of the boom cylinder 10 is connected to the slewing body 3, and the other end is connected to the boom 6. The boom 6 is driven relative to the main body 1 through the boom cylinder 10. Through this drive, the boom 6 can rotate in the vertical direction relative to the slewing body 3 with the boom base pin 13 as the fulcrum.

[0036] One end of the stick cylinder 11 is connected to the boom 6, and the other end is connected to the stick 7. The stick 7 is driven relative to the boom 6 via the stick cylinder 11. Through this drive, the stick 7 can rotate relative to the boom 6 in the vertical or longitudinal direction with the boom top pin 14 as the fulcrum.

[0037] One end of the bucket cylinder 12 is connected to the stick 7, and the other end is connected to the bucket connecting rod. The bucket 8 is driven relative to the stick 7 via the bucket cylinder 12. Through this drive, the bucket 8 can rotate vertically relative to the stick 7 with the top pin 15 of the stick as the fulcrum.

[0038] <Structure of boom control system>

[0039] Next, use Figure 2 The structure of the boom control system in this embodiment will be described.

[0040] Figure 2 It is shown Figure 1 The diagram shows the structure of the boom control system of the operating machinery. (See diagram for example.) Figure 2 As shown, the control system of the boom 6 in the working machine 100 includes a boom cylinder 10, a hydraulic pump 20, a first valve 21, a second valve 22, inspection valves 23 and 24, an oil tank 25, a controller (control unit) 30, operating devices 16a to 16c, a working mode setting unit 17, and a floating switching unit 18.

[0041] The boom cylinder 10 has a head side oil chamber 10h and a bottom side oil chamber 10b. The hydraulic pump 20 supplies working oil to the head side oil chamber 10h and the bottom side oil chamber 10b of the boom cylinder 10 respectively.

[0042] The first valve 21 has openings 21a, 21b and a first opening 21c. Opening 21a is a port connected to the hydraulic pump 20. Opening 21b is a port connected to the head-side oil chamber 10h. The first opening 21c is a port that discharges working oil from the head-side oil chamber 10h to the oil tank 25 through connection with the oil tank 25.

[0043] The second valve 22 has openings 22a, 22b and a second opening 22c. Opening 22a is a port connected to the hydraulic pump 20. Opening 22b is a port connected to the bottom oil chamber 10b. The second opening 22c is a port that discharges working oil from the bottom oil chamber 10b to the oil tank 25 through connection with the oil tank 25.

[0044] The first valve 21 and the second valve 22 each have a spool valve. The spool valves of the first valve 21 and the second valve 22 are designed with the same dimensions.

[0045] A first valve 21 is connected between the head-side oil chamber 10h and the hydraulic pump 20. As a result, working oil can be supplied from the hydraulic pump 20 to the head-side oil chamber 10h through the first valve 21.

[0046] An oil tank 25 is connected to the head-side oil chamber 10h via a first valve 21. Thus, the working oil in the head-side oil chamber 10h can be discharged to the oil tank 25 through the first valve 21.

[0047] The head-side oil chamber 10h is connected to the oil tank 25 by means of a clamping inspection valve 23. Thus, oil in the oil tank 25 can be supplied to the head-side oil chamber 10h through the inspection valve 23.

[0048] A second valve 22 is connected between the bottom oil chamber 10b and the hydraulic pump 20. Thus, working oil can be supplied from the hydraulic pump 20 to the bottom oil chamber 10b through the second valve 22.

[0049] An oil tank 25 is connected to the bottom oil chamber 10b via a second valve 22. Thus, the working oil in the bottom oil chamber 10b can be discharged into the oil tank 25 through the second valve 22.

[0050] The bottom oil chamber 10b is connected to the oil tank 25 by clamping an inspection valve 24. Thus, oil in the oil tank 25 can be supplied to the bottom oil chamber 10b through the inspection valve 24.

[0051] Operating device 16a is, for example, a lever for the operator to operate the boom 6. Operating device 16b is, for example, a lever for the operator to operate the stick 7. Operating device 16c is, for example, a lever for the operator to operate the bucket 8. The operating parameters of each of the operating devices 16a to 16c are detected, for example, by a potentiometer, a Hall effect IC (Integrated Circuit), etc., and are input as control signals to the controller 30.

[0052] The operation mode setting unit 17 is, for example, an input device for the operator to perform input operations. The operation mode setting unit 17 may be, for example, a display device consisting of a touch panel. In this case, multiple operation modes of the working device 2 are displayed in the operation mode setting unit 17. The operation modes of the working device 2 may include, for example, scrape-off mode, crusher mode, and excavation assist mode. The operator selects and touches one of the multiple operation modes displayed in the operation mode setting unit 17. A signal indicating the operation mode selected by the operator is input as a control signal to the controller 30.

[0053] Excavation work refers to the work of cutting away the surface of the ground to prepare the land. Crushing work refers to the work of breaking up rock or hard strata.

[0054] The floating switch 18 is, for example, a toggle switch. By operating the floating switch 18, the operator can selectively switch between enabling and disabling the boom floating function. The switching signal for enabling or disabling the function, selected by the operator, is input as a control signal to the controller 30.

[0055] The controller 30 receives control signals from the operating devices 16a-16c, the work mode setting unit 17, and the float switching unit 18. During operations including the operation of the boom 6, the controller 30 independently controls the operation of the spool valves in the first valve 21 and the second valve 22 based on the input control signals. Therefore, during operations including the operation of the boom 6, the opening degree of the first opening 21c and the opening degree of the second opening 22c are independently controlled by the controller 30. The controller 30 independently controls the opening degree of each of the first opening 21c and the second opening 22c based on the work mode selected by the work mode setting unit 17.

[0056] <Structure of Functional Modules in the Boom Control System>

[0057] Next, use Figure 3 right Figure 2 The structure of the functional modules of the boom control system shown is explained.

[0058] Figure 3 It is shown Figure 2 The diagram shows an example of the functional modules of a boom control system. Figure 3 As shown, the controller 30 has an operation mode determination unit 31, a floating switch determination unit 32, a floating action start determination unit 33, a first valve control unit 34, and a second valve control unit 35.

[0059] The operation mode determination unit 31 receives a control signal indicating the operation mode from the operation mode setting unit 17. Based on the control signal input from the operation mode setting unit 17, the operation mode determination unit 31 determines the operation mode selected by the operator.

[0060] This operating mode includes, for example, a digging mode, a crushing mode, and a digging-assisted mode. The digging mode refers to a setting where the boom 6 is in a floating state, allowing the bucket 8 to move along the unevenness of the ground during digging operations. The crushing mode refers to... Figure 11 When the crusher 8a is used as an accessory as shown, the setting reduces the vibration of the working device caused by the crusher 8a. The digging assist mode refers to the setting that makes the boom 6 float so as to release the load applied to the bucket 8 during digging.

[0061] The operation mode determination unit 31 determines which operation mode the operator has selected, such as digging mode, crusher mode, or digging assist mode. The operation mode determination unit 31 outputs a determination signal to the float switching determination unit 32.

[0062] The floating switch determination unit 32 receives a switching signal from the floating switch unit 18 indicating whether the boom floating function should be executed or not. When receiving a determination signal from the operation mode determination unit 31, the floating switch determination unit 32 determines whether to execute or not execute the boom floating function based on the switching signal input from the floating switch unit 18. The floating switch determination unit 32 then outputs the determination signal to the floating operation start determination unit 33.

[0063] The boom floating start determination unit 33 determines whether to start boom floating operation based on the operation of the operating device 16a performed by the operator. For example, in the case of the working mode being excavation mode or crusher mode, the boom floating start determination unit 33 determines the start of boom floating operation based on the boom lowering operation signal. Alternatively, for example, in the case of the working mode being excavation assist mode, the boom floating start determination unit 33 determines the start of boom floating operation based on the boom raising operation signal.

[0064] When the floating motion start determination unit 33 determines that the boom floating motion has started, it outputs control signals based on the operation amount of the operating device 16a to the first valve control unit 34 and the second valve control unit 35, respectively. Thus, the boom floating motion is started when an operation signal is input from the operating device 16a to the floating motion start determination unit 33.

[0065] The first valve control unit 34 controls the operation of the first valve 21 based on the control signal from the floating action start determination unit 33. Meanwhile, the second valve control unit 35 controls the operation of the second valve 22 based on the control signal from the floating action start determination unit 33.

[0066] <Boom Control Methods>

[0067] Next, use Figures 2 to 10 The boom control method implemented by the above-mentioned boom control system will be described.

[0068] Figure 4 This is a flowchart illustrating an example of a boom control method for a working machine according to one embodiment of the present disclosure. Figure 5 , Figure 6 as well as Figure 7 These are diagrams showing the status of the first and second valves in the excavation mode, crusher mode, and excavation assist mode, respectively. Figure 8 , Figure 9 as well as Figure 10 The figures are respectively showing the relationship between the boom operation amount and the opening degree of the first valve in the digging mode, crusher mode, and digging assist mode (A), and the relationship between the boom operation amount and the opening degree of the second valve (B).

[0069] like Figure 3 as well as Figure 4 As shown, the operator inputs a work mode using the work mode setting unit 17. At this time, the operator, for example, touches any one of the multiple work modes displayed on the work mode setting unit 17. Thus, a work mode is selected in the work mode setting unit 17.

[0070] As described above, multiple operating modes include, for example, digging mode, crushing mode, and digging assist mode. The operator selects, for example, one of these modes through the aforementioned input operation. A signal indicating the operating mode selected by the operator is input as a control signal to the operating mode determination unit 31 of the controller 30 (step S1: Figure 4 ).

[0071] When the operation mode determination unit 31 receives a control signal indicating the operation mode from the operation mode setting unit 17, it determines the operation mode selected by the operator based on the control signal (step S2). For example, the operation mode determination unit 31 determines which of the following operation modes the operator has selected: digging mode, crusher mode, and digging assist mode.

[0072] (Mining Mode)

[0073] If the operation mode determined by the operation mode determination unit 31 is the digging mode, the float switching determination unit 32 determines whether the boom floating function is effective based on the switching signal from the float switching unit 18 (step S3a: Figure 4 ).

[0074] If the floating switch determination unit 32 determines that the boom floating function is invalid, normal control is performed (step S4a: Figure 4 In normal control, the boom 6, stick 7, and bucket 8 ( Figure 1 ) corresponds to operating devices 16a~16c ( Figure 2 Driven by the operation quantity.

[0075] If the floating switch determination unit 32 determines that the boom floating function is effective, the floating action start determination unit 33 determines whether to start the floating action. The determination of whether to start the floating action is made by whether the operator has performed a boom lowering operation (step S5a:). Figure 4 The floating motion start determination unit 33 determines whether the operator has performed a boom lowering operation based on the operation signal input from the operation device 16a.

[0076] If the floating motion start determination unit 33 determines that no boom lowering operation has been performed, normal control is performed (step S4a: Figure 4 ).

[0077] When the floating action start determination unit 33 determines that a boom lowering operation has been performed, the first valve control unit 34 controls the operation of the first valve 21, and the second valve control unit 35 controls the operation of the second valve 22. Thus, as... Figure 5 As shown, the operation of the first valve 21 and the second valve 22 is controlled by opening the first opening 21c of the first valve 21 and the second opening 22c of the second valve 22 (step S6a: Figure 4 ).

[0078] The first valve 21 has a slide valve 21s that controls the opening and closing of openings 21a, 21b and the first opening 21c respectively. The second valve 22 has a slide valve 22s that controls the opening and closing of openings 22a, 22b and the second opening 22c respectively. The first valve 21 and the second valve 22 each have, for example, a solenoid (not shown).

[0079] The controller 30 drives the slide valve 21s of the first valve 21 by inputting an electrical signal to the solenoid of the first valve 21. Thus, the operation of the slide valve 21s is controlled to open both the opening 21b and the first opening 21c of the first valve 21. This allows the working oil in the head-side oil chamber 10h of the boom cylinder 10 to be discharged into the oil tank 25 through the opening 21b and the first opening 21c.

[0080] The controller 30 drives the spool valve 22s of the second valve 22 by inputting an electrical signal to the solenoid of the second valve 22. As a result, the operation of the spool valve 22s is controlled to open both the opening 22b and the second opening 22c of the second valve 22. This allows the working oil in the bottom oil chamber 10b of the boom cylinder 10 to be discharged into the oil tank 25 through the opening 22b and the second opening 22c.

[0081] like Figure 5 As shown, in the digging mode, when the boom cylinder 10 is extended, the working oil in the head side oil chamber 10h is discharged to the oil tank 25 via the first valve 21, and the oil in the oil tank 25 is supplied to the bottom side oil chamber 10b via the inspection valve 24. Conversely, in the digging mode, when the boom cylinder 10 is retracted, the working oil in the bottom side oil chamber 10b is discharged to the oil tank 25 via the second valve 22, and the oil in the oil tank 25 is supplied to the head side oil chamber 10h via the inspection valve 23.

[0082] In the excavation mode, the opening degrees D1 and D2 of the first opening 21c and the second opening 22c are controlled according to the amount of descent of the boom 6 based on the operating device 16a. Specifically, as... Figure 8 As shown in (A), the controller 30 controls the first valve 21 in such a way that the greater the lowering operation of the boom 6 of the operating device 16a, the greater the opening degree D1 of the first opening 21c. Additionally, as... Figure 8 As shown in (B), the controller 30 controls the second valve 22 in such a way that the greater the amount of lowering operation of the boom 6 based on the operating device 16a, the greater the opening degree D2 of the second opening 22c.

[0083] like Figure 8 (A) and Figure 8 As shown in (B), the opening degree D1 of the first opening 21c and the opening degree D2 of the second opening 22c can also be set to be approximately the same relative to the boom lowering operation amount.

[0084] (Crusher Mode)

[0085] like Figure 3 as well as Figure 4 As shown, when the operation mode determined by the operation mode determination unit 31 is the crusher mode, the floating switch determination unit 32 determines whether the boom floating function is effective (step S3b: Figure 4 The floating switch judgment unit 32 determines whether the boom floating function is effective based on the switching signal from the floating switch unit 18.

[0086] If the floating switch determination unit 32 determines that the boom floating function is invalid, normal control is performed (step S4b: Figure 4 ).

[0087] If the floating switch determination unit 32 determines that the boom floating function is effective, the floating action start determination unit 33 determines whether to start the floating action. The determination of whether to start the floating action is made by checking whether the operator has performed a boom lowering operation (step S5b). Figure 4 The floating motion start determination unit 33 determines whether the operator has performed a boom lowering operation based on the operation signal input from the operation device 16a.

[0088] If the floating motion start determination unit 33 determines that no boom lowering operation has been performed, normal control is performed (step S4b: Figure 4 ).

[0089] Furthermore, when the floating action start determination unit 33 determines that a boom lowering operation has been performed, the first valve control unit 34 controls the operation of the first valve 21, and the second valve control unit 35 controls the operation of the second valve 22. Thus, as... Figure 6 As shown, the operation of the first valve 21 and the second valve 22 is controlled such that the opening degree D1 of the first opening 21c in the first valve 21 is smaller than the opening degree D2 of the second opening 22c in the second valve 22 (step S6b: Figure 4 ).

[0090] In crusher mode, the slide valve 21s is controlled by the controller 30 with opening 21a closed and opening 21b and the first opening 21c open. As a result, the working oil in the head side oil chamber 10h of the boom cylinder 10 can be discharged to the oil tank 25 through opening 21b and the first opening 21c.

[0091] In addition, in crusher mode, the slide valve 22s is controlled by the controller 30 with opening 22a closed and opening 22b and second opening 22c open. This allows the working oil in the bottom oil chamber 10b of the boom cylinder 10 to be discharged into the oil tank 25 through opening 22b and second opening 22c.

[0092] Here, the controller 30 controls the opening degree D1 of the first opening 21c to be smaller than the opening degree D2 of the second opening 22c. Therefore, as Figure 9 (A) and Figure 9 As shown in (B), although the greater the boom lowering operation, the greater the opening degree D1 and D2, the increase in opening degree D1 is smaller than the increase in opening degree D2.

[0093] It should be noted that in the crusher mode, the first opening 21c can also be completely closed by the slide valve 21s.

[0094] like Figure 6As shown, in crusher mode, when the boom cylinder 10 is extended, the working oil in the head side oil chamber 10h is discharged to the oil tank 25 via the first valve 21, and the oil in the oil tank 25 is supplied to the bottom side oil chamber 10b via the inspection valve 24. Conversely, in crusher mode, when the boom cylinder 10 is retracted, the working oil in the bottom side oil chamber 10b is discharged to the oil tank 25 via the second valve 22, and the oil in the oil tank 25 is supplied to the head side oil chamber 10h via the inspection valve 23.

[0095] (Excavation Assist Mode)

[0096] like Figure 3 as well as Figure 4 As shown, when the operation mode determined by the operation mode determination unit 31 is the excavation assist mode, the float switching determination unit 32 determines whether the boom float function is effective (step S3c: Figure 4 The floating switch judgment unit 32 determines whether the boom floating function is effective based on the switching signal from the floating switch unit 18.

[0097] If the floating switch determination unit 32 determines that the boom floating function is invalid, normal control is performed (step S4c: Figure 4 ).

[0098] If the floating switch determination unit 32 determines that the boom floating function is effective, the floating action start determination unit 33 determines whether to start the floating action. The determination of whether to start the floating action is made by whether the operator has performed a boom lifting operation (step S5c). Figure 4 The floating motion start determination unit 33 determines whether the operator has performed a boom lifting operation based on the operation signal input from the operation device 16a.

[0099] If the floating motion start determination unit 33 determines that no boom lifting operation has been performed, normal control is performed (step S4c: Figure 4 ).

[0100] Furthermore, when the floating action start determination unit 33 determines that a boom lifting operation has been performed, the first valve control unit 34 controls the operation of the first valve 21, and the second valve control unit 35 controls the operation of the second valve 22. Thus, as... Figure 7 As shown, the opening degree D2 of the second opening 22c is controlled to be smaller than the opening degree D1 of the first opening 21c (step S6c: Figure 4 At this point, the second opening 22c is, for example, closed.

[0101] In the excavation assistance mode, the spool valve 21s is controlled by the controller 30 with the opening 21b and the first opening 21c open. As a result, the working oil in the head side oil chamber 10h of the boom cylinder 10 can be discharged to the oil tank 25 through the opening 21b and the first opening 21c.

[0102] Additionally, in the excavation assistance mode, the opening degree D2 of the second opening 22c is smaller than the opening degree D1 of the first opening 21c, or it becomes 0 (closed). Preferably, the second opening 22c is completely closed.

[0103] In the excavation assistance mode, the opening degree of the first opening 21c and the second opening 22c is controlled according to the lifting operation amount of the boom 6 based on the operating device 16a. Specifically, as Figure 10 As shown in (A), the controller 30 controls the first valve 21 in such a way that the greater the lifting operation amount of the boom 6 of the operating device 16a, the greater the opening degree D1 of the first opening 21c. Additionally, as... Figure 10 As shown in (B), even if the lifting operation amount of the boom 6 based on the operating device 16a increases, the opening degree D2 of the second opening 22c remains basically unchanged, or the second opening 22c remains closed.

[0104] As explained above, in this embodiment, the controller 30 controls the opening degree D1 of the first opening 21c in the first valve 21 and the opening degree D2 of the second opening 22c in the second valve 22 separately.

[0105] In addition, the controller 30 controls the opening degree D1 and D2 separately based on the working mode of the working device 2 (e.g., digging mode, crusher mode, digging assist mode).

[0106] Based on the judgment that the operation mode is mining mode, controller 30, such as Figure 5 as well as Figure 8 As shown in (A) and (B), the controller 30 controls the opening of both the first opening 21c and the second opening 22c. Based on the determination that the operating mode is crusher mode, the controller 30... Figure 6 as well as Figure 9 As shown in (A) and (B), the control is such that the opening degree D1 is smaller than the opening degree D2. The controller 30, based on the judgment that the operating mode is excavation assistance mode, ... Figure 7 as well as Figure 10 As shown in (A) and (B), the opening degree D2 is controlled to be smaller than the opening degree D1.

[0107] <Effect>

[0108] Next, the effects of this implementation method will be explained.

[0109] In this embodiment, Figure 5 ~as Figure 7 As shown, the controller 30 independently controls the opening degree D1 of the first opening 21c in the first valve 21 and the opening degree D2 of the second opening 22c in the second valve 22. This allows for independent control of the discharge of working oil from the head side oil chamber 10h and the bottom side oil chamber 10b of the boom cylinder 10 to the oil tank 25. Therefore, there is no need to provide an opening for boom floating in the spool valve, and there is no need to prepare a valve for switching boom floating functions that is different from the main valve; the boom floating function can be adjusted according to the application.

[0110] Furthermore, in this embodiment, the controller 30 controls the opening degree D1 and D2 independently based on the working mode of the working device 2 (e.g., digging mode, crusher mode, digging assist mode). This allows for the adjustment of the boom floating function of the working machine according to the intended use of the digging mode, crusher mode, digging assist mode, etc.

[0111] In addition, in this embodiment, such as Figure 5 as well as Figure 8 As shown in (A) and (B), the controller 30 controls the opening of both the first opening 21c and the second opening 22c based on the judgment that the working mode is the digging mode.

[0112] Therefore, the boom 6 can move freely in the vertical direction in response to external forces. Thus, during excavation operations, the bucket 8 can easily move along the unevenness of the ground. In addition, by performing the boom floating function while the bucket 8 is in the air, the boom can be lowered until the boom 6 contacts the ground using the weight of the working device 2.

[0113] In addition, such as Figure 11 As shown, when the crusher 8a is used as an accessory, damage to the insert pin, the cross blade 8aa, and the cross blade retainer is easily caused when the cross blade 8aa is operating in dry conditions. Therefore, when the crusher 8a is in operation, the front end of the cross blade 8aa needs to be in contact with the material to be crushed.

[0114] In this embodiment, such as Figure 6 as well as Figure 9 As shown in (A) and (B), the controller 30 controls the opening degree D1 to be smaller than the opening degree D2 based on the judgment result that the working mode is the crusher mode.

[0115] Therefore, the boom 6 is easy to move towards the lowering side (the side where the boom cylinder 10 retracts), but not easy to move towards the raising side (the side where the boom cylinder 10 extends). Therefore, in the crusher mode, preventing the tip of the cross blade 8aa from separating from the object being crushed can prevent damage to the insert pin, cross blade 8aa, etc., and damage to the cross blade holder.

[0116] In addition, in cases such as dismantling, hard objects are sometimes crushed. In such cases, if the load caused by crushing is not released, the working device 2 may break.

[0117] In this embodiment, such as Figure 7 as well as Figure 10 As shown in (A) and (B), the controller 30 controls the opening degree D2 to be smaller than the opening degree D1 based on the judgment result that the operation mode is the excavation assistance mode.

[0118] Therefore, the boom 6 is less likely to move towards the lowering side (the side where the boom cylinder 10 retracts) and more likely to move towards the raising side (the side where the boom cylinder 10 extends). Thus, when digging hard objects, the boom 6 retracts towards the raising side, thereby releasing the load caused by digging. This improves the aging resistance of the working device 2.

[0119] It should be noted that in the above implementation method, Figure 2 as well as Figure 3 The controller 30 can be mounted on the work machine 100, or it can be configured separately from the work machine 100. When the controller 30 is configured separately from the work machine 100, the controller 30 can be wirelessly connected to the work mode setting unit 17, the float switching unit 18, the operating devices 16a-16c, the first valve 21, the second valve 22, etc. The controller 30 is, for example, a processor, which can be a CPU (Central Processing Unit).

[0120] It should be understood that all aspects of the embodiments disclosed herein are illustrative and not restrictive. The scope of the invention is shown by the technical solutions rather than the foregoing description, and includes all modifications of the same meaning and scope.

[0121] Explanation of reference numerals in the attached figures:

[0122] 1...Main body; 2...Working device; 3...Rotating body; 4...Cab; 4S...Driver's seat; 5...Traveling body; 5Cr...Tracks; 5M...Traveling motor; 6...Boom; 7...Stick; 8...Bucket; 8a...Crusher; 8aa...Cross blade; 9...Engine hood; 10...Boom cylinder; 10b...Bottom side oil chamber; 10h...Head side oil chamber; 11...Stick cylinder; 12...Bucket cylinder; 13...Boom base pin; 14...Boom top pin; 15...Stick top pin; 16a, 16b, 16c...Operating device; 17...Operating mode setting unit; 18... Floating switching unit; 20... Hydraulic pump; 21... First valve; 21a, 21b, 22a, 22b... Openings; 21c... First opening; 21s, 22s... Spool valves; 22... Second valve; 22c... Second opening; 23, 24... Inspection valves; 25... Oil tank; 30, 50... Controller; 31... Operation mode judgment unit; 32... Floating switching judgment unit; 33... Floating action start judgment unit; 34... First valve control unit; 35... Second valve control unit; 50k... Storage unit; 100... Hydraulic excavator; D1, D2... Opening degree; RX... Slewing shaft.

Claims

1. A boom control system of a work machine, the work machine including: a boom; a boom cylinder that drives the boom, having a head-side oil chamber and a bottom-side oil chamber; a hydraulic pump; a tank; a first valve that supplies oil from the hydraulic pump to the head-side oil chamber and discharges the oil to the tank; and a second valve that supplies oil from the hydraulic pump to the bottom-side oil chamber and discharges the oil to the tank, characterized in that the first valve has a first opening portion that discharges oil of the head-side oil chamber to the tank, the second valve has a second opening portion that discharges oil of the bottom-side oil chamber to the tank, the boom control system of the work machine further includes a controller that individually controls an opening degree of the first opening portion and an opening degree of the second opening portion in accordance with a work mode selected from a plurality of work modes during a work including an operation of the boom, thereby controlling a boom float function.

2. The boom control system of the work machine according to claim 1, characterized in that the controller individually controls the opening degree of the first opening portion and the opening degree of the second opening portion based on the work mode of a working device having the boom and the boom cylinder.

3. The boom control system of the work machine according to claim 1 or 2, characterized in that the controller controls both the first opening portion and the second opening portion to be opened based on a result of a determination that the work mode is a digging mode.

4. The boom control system of the work machine according to claim 1 or 2, characterized in that the controller controls the opening degree of the first opening portion to be smaller than the opening degree of the second opening portion based on a result of a determination that the work mode is a crusher mode.

5. The boom control system of the work machine according to claim 1 or 2, characterized in that the controller controls the opening degree of the second opening portion to be smaller than the opening degree of the first opening portion based on a result of a determination that the work mode is a digging assist mode. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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