Work machine

Abstract

The present invention easily performs fine operation of an object to be driven that is driven by a hydraulic actuator.　This work machine (1) comprises: hydraulic actuators (C3, C4, C5, MT); control valves (V1, V2, V7, V8) that change the flow rate of hydraulic oil supplied to the hydraulic actuators; an operation member (41) that operates the control valves; a control device (U1) that controls an output flow rate, which is the flow rate of hydraulic oil output from the control valves to the hydraulic actuators, by controlling the operation of the control valves in accordance with the operation amount of the operation member; and a fine operation mode switch (63) capable of selecting a fine operation mode in which the hydraulic actuators are driven at a speed slower than the speed of normal driving. When the fine operation mode is selected by the fine operation mode switch, the control device controls the operation of the control valve in accordance with the operation amount of the operation member so as to reduce the output flow rate as compared to when the control valve is operated in the case of normal driving with the same operation amount as the operation amount of the operation member for the control valve in the fine operation mode.

Description

Work machine 【0001】 The present invention relates to a work machine such as a backhoe. 【0002】 Conventionally, a work machine disclosed in Patent Document 1 is known. 【0003】 The work machine disclosed in Patent Document 1 includes a hydraulic actuator that drives a driving target such as a boom and an arm. The hydraulic actuator is operated by hydraulic oil output from a control valve. The control valve is operated by an operation member manually operated by an operator. 【0004】 Japanese Patent Application Laid-Open Publication "Japanese Patent Application Laid-Open No. 2022-114939" 【0005】 By the way, in the work by the above work machine, there may be a case where it is desired to finely operate a driving target driven by a hydraulic actuator. In such a case, it may be difficult to finely operate the driving target by the degree of operation of the operation member by the operator. 【0006】 In view of the above problems, an object of the present invention is to enable easy fine operation of a driving target driven by a hydraulic actuator. 【0007】 A work machine according to an aspect of the present invention includes a hydraulic actuator, a control valve that changes the flow rate of hydraulic oil supplied to the hydraulic actuator, an operation member that operates the control valve, and an operation amount of the operation member. A control device that controls the output flow rate, which is the flow rate of the hydraulic oil output from the control valve to the hydraulic actuator, by controlling the operation of the control valve, and a fine operation mode switch that can select a fine operation mode in which the hydraulic actuator is driven at a speed slower than the normal driving speed. When the fine operation mode is selected by the fine operation mode switch, the control device controls the operation of the control valve according to the operation amount of the operation member so as to reduce the output flow rate compared to when the control valve is operated with the same operation amount as the operation amount of the operation member for the control valve in the normal driving case. 【0008】According to the above-mentioned work machine, by switching to the fine-control mode, the object being driven by the hydraulic actuator can be easily fine-tuned. 【0009】 This is a side view of the work machine. This is a top view of the work machine. This is a schematic diagram of the hydraulic system. This is a simplified diagram of the control system. This is a perspective view of the operating member. This is a graph comparing the characteristic curve for normal drive and the characteristic curve for fine operation mode. This is a graph comparing the characteristic curve for normal drive with other characteristic curves in fine operation mode. This is a graph showing the relationship between the output of the control device and time in normal drive. This is a graph showing a modified example of the characteristic curve. This is a graph showing another modified example of the characteristic curve. This is a configuration diagram showing another form of the control valve, etc. This is a configuration diagram showing yet another form of the control valve, etc. 【0010】 The following describes one embodiment of the present invention, with appropriate reference to the drawings. 【0011】 Figure 1 is a schematic side view showing the overall configuration of the work machine 1 according to this embodiment. Figure 2 is a schematic top view of the work machine 1. In this embodiment, a backhoe, which is a slewing work machine, is exemplified as the work machine 1. 【0012】 As shown in Figures 1 and 2, the work machine 1 comprises a machine body (turntable) 2, a travel device 3, and a work device 4. The machine body 2 is equipped with a cabin 5. Inside the cabin 5 is a driver's seat 6 where the operator (driver) sits. 【0013】 In this embodiment, the direction towards the front of the operator seated in the driver's seat 6 of the work machine 1 (direction of arrow A1 in Figures 1 and 2) is described as the front (front of the machine), the direction towards the rear of the operator (direction of arrow A2 in Figures 1 and 2) is described as the rear (rear of the machine), and the direction of arrow K1 in Figures 1 and 2 is described as the front-rear direction. Furthermore, the direction towards the left of the operator (front side in Figure 1, direction of arrow A3 in Figure 2) is described as the left, and the direction towards the right of the operator (back side in Figure 1, direction of arrow A4 in Figure 2) is described as the right. 【0014】Furthermore, the horizontal direction, which is perpendicular to the longitudinal direction (aircraft longitudinal direction) K1, will be described as the aircraft width direction K2 (see Figure 2). The direction from the center of the aircraft 2's width toward the right or left will be described as the outward direction of the aircraft width. In other words, the outward direction of the aircraft width is the direction away from the center of the aircraft 2's width in the aircraft width direction K2. The direction opposite to the outward direction of the aircraft width will be described as the inward direction of the aircraft width. In other words, the inward direction of the aircraft width is the direction approaching the center of the aircraft 2's width in the aircraft width direction K2. 【0015】 As shown in Figures 1 and 2, the travel device 3 comprises a travel frame 3A, a first travel device 3L provided on the left side of the travel frame 3A, and a second travel device 3R provided on the right side of the travel frame 3A. The first travel device 3L and the second travel device 3R are crawler-type travel devices. The travel device 3 is driven by a travel motor M1, which is composed of a hydraulic motor (hydraulic actuator). The first travel device 3L is driven by the first travel motor ML, and the second travel device 3R is driven by the second travel motor MR. The travel device 3 supports the machine body 2 so that it can move. 【0016】 A dozer device 7 is mounted on the front of the traveling device 3. The dozer device 7 is driven by a dozer cylinder C1. The dozer cylinder C1 is composed of a hydraulic cylinder (hydraulic actuator), and the blade 7A of the dozer device 7 is raised and lowered by extending and retracting the dozer cylinder C1. 【0017】 As shown in Figure 1, the machine body 2 is supported on the running gear 3 (running frame 3A) so as to be able to rotate around the pivot axis X1 via a slewing bearing 8. The pivot axis X1 is an axis (longitudinal axis) that extends in the vertical direction and passes through the center of the slewing bearing 8. 【0018】 As shown in Figure 2, the cabin 5 is mounted on one side (left side) of the aircraft body 2 in the width direction K2. The engine E1 is mounted on the other side (right side) of the aircraft body 2 in the width direction K2. The engine E1 is a diesel engine. The engine E1 may also be a gasoline engine, an electric motor, or a hybrid type having both an engine and an electric motor. 【0019】A pressurized oil supply unit 18 is provided at the rear of the prime mover E1. The pressurized oil supply unit 18 is driven by the power of the prime mover E1 to pressurize and discharge the hydraulic fluid used in the hydraulic drive unit. The hydraulic drive unit is, for example, a hydraulic actuator equipped on the work machine 1. 【0020】 As shown in Figure 1, the aircraft body 2 has a base plate (hereinafter referred to as the rotating base plate) 9 that rotates around a rotation axis X1. The rotating base plate 9 is made of steel plate or the like and constitutes the bottom of the aircraft body 2. A reinforcing member, a longitudinal rib 9A, is provided on the upper surface of the rotating base plate 9, extending from the front to the rear. In addition to the longitudinal rib 9A, members that support mounted equipment and other items mounted on the aircraft body 2 are also provided on the rotating base plate 9, thereby forming the rotating frame that forms the skeleton of the aircraft body 2. 【0021】 As shown in Figure 1, the rear of the machine body 2 is equipped with a weight 10 for balancing the weight with the work device 4, a fuel tank T1 for storing fuel for the prime mover E1, and a hydraulic oil tank T2 for storing hydraulic oil. 【0022】 As shown in Figure 2, a slewing motor MT is positioned at the front of the machine body 2 (slewing base plate 9) and in the center of the machine body width direction K2. This slewing motor MT drives the slewing base plate 9 to rotate around the slewing axis X1. The slewing motor MT is a hydraulic motor (hydraulic actuator). A swivel joint S1, which is a rotary joint that allows hydraulic fluid to flow between the hydraulic equipment on the machine body 2 side and the hydraulic equipment on the traveling device 3 side, is provided at the position of the slewing axis X1. A control valve (hydraulic equipment) CV is positioned behind the swivel joint S1. The control valve CV is a sectional type composite control valve (hydraulic equipment) having multiple control valves stacked and coupled in the vertical direction. 【0023】 A control device U1 is provided below the cabin 5. The control device U1 is configured using a microcomputer that includes a processor such as a CPU that controls each part of the work machine 1 by executing a control program, and a memory such as an EEPROM that stores the control program. The memory may be configured to communicate with the control device U1. 【0024】 A control device 1B for operating the work machine 1 is provided inside the cabin 5. The control device 1B is installed in front of the driver's seat 6. The driver's seat 6 and the control device 1B constitute the operating section 1C. 【0025】 As shown in Figure 2, the aircraft body 2 has a support bracket 13. The support bracket 13 is fixed to the front of the longitudinal rib 9A and is provided to protrude forward from the aircraft body 2. 【0026】 As shown in Figures 1 and 2, the front of the support bracket 13 is mounted so as to be able to swing around the swing axis X2, which is the axis through which the swing bracket 14 extends in the vertical direction. As shown in Figure 1, the working device 4 is supported on the swing bracket 14 (machine body 2). 【0027】 The work device 4 includes a boom 15 supported on the machine body 2 so as to be able to swing up and down (swing in the vertical direction), an arm 16 swingably connected to the boom 15, and a bucket (working tool) 17 swingably connected to the arm 16. 【0028】 The base of the boom 15 is pivotally attached to the upper part of the swing bracket 14 so as to be rotatable around the horizontal axis (the axis extending in the width direction K2 of the machine body) when the boom 15 is facing the front of the machine body. This allows the boom 15 to swing up and down. 【0029】 The arm 16 is pivotally attached to the boom 15 so as to be rotatable around its horizontal axis when the boom 15 is facing forward. This allows the arm 16 to swing in the forward / backward direction K1 or in the up / down direction. The arm 16 can also swing in the arm cloud direction D1, which is the direction towards the boom 15, and in the arm dump direction D2, which is the direction away from the boom 15. 【0030】In this embodiment, a bucket 17 is shown as a work tool. Alternatively, in place of the bucket, other work tools (attachments) such as pallet forks and manifold forks, or work tools (hydraulic attachments) having hydraulic actuators C6 (see Figure 3), such as grapples, hydraulic crushers, angle brooms, earth augers, snow blowers, sweepers, mowers, and hydraulic breakers, can be attached. 【0031】 The bucket 17 is pivotally supported at its base on the tip side of the arm 16 via a pivot 61. The bucket 17 is also rotatable around the pivot 61 on a horizontal axis when the boom 15 is facing the front of the machine. As a result, the bucket 17 can swing in the bucket cloud direction D4, which is the direction toward the arm 16, and in the bucket dump direction D3, which is the direction toward the arm 16 (scouring and dumping operations are possible). Scooping is the operation of swinging the tip of the claw portion of the bucket 17 toward the arm 16 (bucket cloud direction D4), for example, when scooping up soil or sand. Dumping is the operation of swinging the tip of the claw portion of the bucket 17 toward the arm 16 (bucket dump direction D3), for example, when dropping (discharging) the scooped soil or sand. 【0032】 The swing bracket 14 is swingable by the extension and retraction of the swing cylinder C2 located inside the machine body 2. The boom 15 is swingable up and down by the extension and retraction of the boom cylinder C3. The arm 16 is swingable in the arm cloud direction D1 and the arm dump direction D2 by the extension and retraction of the arm cylinder C4. The bucket 17 is swingable in the bucket cloud direction D4 and the bucket dump direction D3 by the extension and retraction of the bucket cylinder (work tool cylinder) C5. The swing cylinder C2, boom cylinder C3, arm cylinder C4, and bucket cylinder C5 are composed of hydraulic cylinders (hydraulic actuators). The various hydraulic actuators ML, MR, MT, C1 to C6 equipped on the work machine 1 are driven by hydraulic fluid. 【0033】As shown in Figure 3, the hydraulic system for operating the various hydraulic actuators ML, MR, MT, C1 to C6 equipped on the work machine 1 includes a control valve CV, a pressurized oil supply unit 18, and a flow control unit 19. The control valve CV is composed of control valves V1 to V10 for controlling the various hydraulic actuators ML, MR, MT, C1 to C6, an inlet block B2 for pressurized oil intake, and a pair of outlet blocks B1 and B3 for pressurized oil discharge, all arranged in one direction and integrated into a single unit. 【0034】 As shown in Figure 3, the control valve CV is configured by arranging the following components in order (arranged from right to left in Figure 3): a first outlet block B1, a bucket control valve (work tool control valve) V1 that controls the bucket cylinder C5, a boom control valve V2 that controls the boom cylinder C3, a first control valve V3 for the dozer that controls the dozer cylinder C1, a second travel control valve V4 that controls the travel motor MR of the second travel device 3R, an inlet block B2, a first travel control valve V5 that controls the travel motor ML of the first travel device 3L, a second control valve V6 for the dozer that controls the dozer cylinder C1, an arm control valve V7 that controls the arm cylinder C4, a slewing control valve V8 that controls the slewing motor MT, a swing control valve V9 that controls the swing cylinder C2, an SP control valve V10 that controls the attachment actuator (hydraulic actuator) C6 equipped on the hydraulic attachment when the hydraulic attachment is mounted as a work tool instead of the bucket 17, and a second outlet block B3, and connecting them to each other. 【0035】 Each control valve V1 to V10 is configured by incorporating directional control valves DV1 to DV10 (see Figure 4) within the valve body. Directional control valves DV1 to DV10 are valves that switch the direction of hydraulic fluid to the hydraulic actuators ML, MR, MT, C1 to C6 that are to be controlled. Directional control valves DV1 to DV10 (control valves V1 to V10) also change the flow rate of hydraulic fluid supplied (output) to the hydraulic actuators ML, MR, MT, C1 to C6 that are to be controlled. 【0036】Each of the directional control valves DV1 to DV10 is a direct-acting spool-type directional control valve and is a pilot-operated proportional solenoid valve electrically controlled by the control device U1. A pilot-operated proportional solenoid valve controls the direction and flow rate of hydraulic fluid by moving a spool with a pilot control pressure controlled by a proportional solenoid. In this embodiment, the current output from the control device U1 to the control valves V1 to V10 and the pilot control pressure (pilot secondary pressure) controlled based on the value of the current are control elements that act on the control valves V1 to V10 to control the output flow rate, which is the flow rate of hydraulic fluid output from the control valves V1 to V10 to the hydraulic actuators ML, MR, MT, C1 to C6. 【0037】 As shown in Figure 3, the hydraulic pump serving as the source of pressurized oil in this hydraulic system is equipped with a first pump 21 for supplying hydraulic fluid to operate the hydraulic actuators ML, MR, MT, C1 to C6, and a second pump 22 for supplying signal pressurized oil such as pilot control pressure and detection signals. These first pump 21 and second pump 22 are provided in the pressurized oil supply unit 18 and are driven by the prime mover E1. 【0038】 The first pump 21 is composed of a variable displacement hydraulic pump (swashplate type variable displacement axial pump). 【0039】 One pressurized oil discharge port P1 from the first pump 21 is connected to the inlet block B2 via a first discharge path a, and the other pressurized oil discharge port P2 is connected to the inlet block B2 via a second discharge path b. The flow control unit 19 controls the swash plate of the first pump 21. 【0040】 The second pump 22 is composed of a constant-capacity gear pump. The oil discharged from the second pump 22 is discharged from the third pressure oil discharge port P3. 【0041】 The hydraulic fluid supplied to each control valve V1 to V10 is supplied to and discharged from each hydraulic actuator ML, MR, MT, C1 to C6. 【0042】As shown in Fig. 4, the proportional solenoids so1 to so10 of the direction switching valves DV1 to DV10 are connected to the control device U1. Each of the direction switching valves DV1 to DV10 (each control valve V1 to V10) is pilot-operated by a pilot control pressure corresponding to a control signal (current value supplied to the proportional solenoids so1 to so10) transmitted from the control device U1 to the proportional solenoids so1 to so10, so that the direction and flow rate of the hydraulic fluid flowing to the hydraulic actuators ML, MR, MT, C1 to C6 to be controlled are controlled. That is, each of the control valves V1 to V10 is pilot-operated by a pilot control pressure controlled by a control signal (current) transmitted from the control device U1. Each of the control valves V1 to V10 is electronically controlled according to the current value supplied by the control device U1. 【0043】 An operating member 41 (first operating tools 41A to 7 operating tools 41G) for operating each of the direction switching valves DV1 to DV10 (each control valve V1 to V10) is connected to the control device U1. When the operating member 41 is operated by an operator, at least an output signal corresponding to the operation amount is output to the control device U1. The control device U1 detects that the operating member 41 has been operated, and supplies (transmits) a current value (control signal) corresponding to the operation amount of the operating member 41 to the proportional solenoids so1 to so10 of the direction switching valves DV1 to DV10 to be operated. 【0044】 The first operating tool 41A can operate two operating targets equipped on the working machine 1. For example, the first operating tool 41A can operate the direction switching valve DV8 (swing motor MT) (enable the body 2 to swing) and can operate the direction switching valve DV7 (arm cylinder C4) (enable the arm 16 to swing). 【0045】 Further, the first operating tool 41A has a sensor (operation detection unit) 42 (first sensor 42A) for detecting the operation direction and operation amount. The first sensor 42A is connected to the control device U1. The control device U1 acquires the operation direction and operation amount of the first operating tool 41A from the detection signal of the first sensor 42A, and controls the swing control valve V8 (body 2) and the arm control valve V7 (arm 16) based on the detection signal from the first sensor 42A. 【0046】The second operating tool 41B can also operate two operating targets equipped on the working machine 1. For example, the second operating tool 41B can operate the direction change valve DV2 (boom cylinder C3) (enable the boom 15 to swing) and can operate the direction change valve DV1 (bucket cylinder C5) (enable the bucket 17 to swing). 【0047】 Also, the second operating tool 41B has a sensor (operation detection unit) 42 (second sensor 42B) that detects the operation direction and operation amount. The second sensor 42B is connected to the control device U1. The control device U1 acquires the operation direction and operation amount of the second operating tool 41B based on the detection signal from the second sensor 42B, and controls the boom control valve V2 (boom 15) and the bucket control valve V1 (bucket 17) based on the detection signal from the second sensor 42B. 【0048】 As shown in FIG. 2, the first operating tool 41A and the second operating tool 41B are provided on the operating device 1B, and are constituted by, for example, a handle that an operator sitting on the driver's seat 6 grips and operates. 【0049】 As shown in FIG. 5, the first operating tool 41A and the second operating tool 41B are arranged side by side (left and right) in the machine body width direction K2. The first operating tool 41A is an operating member (left handle) that an operator grips with the left hand. The second operating tool 41B is an operating member (right handle) that an operator grips with the right hand. The first operating tool 41A and the second operating tool 41B have a gripping part 32 that an operator grips (places the palm on) at a middle part in the vertical direction, and have a lever part 33 that protrudes upward from the gripping part 32. A sixth operating tool 41F is provided on the lever part 33 of the first operating tool 41A. A seventh operating tool 41G and a fine operation mode switch 63 described later are provided on the lever part 33 of the second operating tool 41B. 【0050】The third operating device 41C is provided on the control device 1B and is, for example, configured as a lever. The third operating device 41C can operate the directional control valves DV3 and DV6 (dozer cylinder C1) (it can operate the dozer device 7). The third operating device 41C also has a sensor 42 (third sensor 42C) that detects the direction and amount of operation. The third sensor 42C is connected to the control device U1. The control device U1 acquires the direction and amount of operation of the third operating device 41C from the detection signal from the third sensor 42C, and controls the first control valve V3 and the second control valve V6 for the dozer (dozer device 7) based on the detection signal from the third sensor 42C. 【0051】 The fourth operating device 41D and the fifth operating device 41E are, for example, pedals provided on the floor in front of the driver's seat 6 and operated by the operator stepping on them. 【0052】 The fourth operating tool 41D is capable of operating the directional control valve DV5 (first travel motor ML) (operating the first travel device 3L). The fourth operating tool 41D also has a sensor 42 (fourth sensor 42D) that detects the operating direction and amount. The fourth sensor 42D is connected to the control device U1. The control device U1 acquires the operating direction and amount of the fourth operating tool 41D from the detection signal from the fourth sensor 42D, and controls the first travel control valve V5 (first travel device 3L) based on the detection signal from the fourth sensor 42D. 【0053】 The fifth operating tool 41E is capable of operating the directional control valve DV4 (second travel motor MR) (and thus the second travel device 3R). The fifth operating tool 41E also has a sensor 42 (fifth sensor 42E) that detects the direction and amount of operation. The fifth sensor 42E is connected to the control device U1. The control device U1 acquires the direction and amount of operation of the fifth operating tool 41E from the detection signal from the fifth sensor 42E, and controls the second travel control valve V4 (second travel device 3R) based on the detection signal from the fifth sensor 42E. 【0054】The sixth operating device 41F is composed of, for example, a switch (seesaw switch, slide switch, etc.) provided on the first operating device 41A or the second operating device 41B. Figure 5 illustrates the case where the sixth operating device 41F is provided on the first operating device 41A. The sixth operating device 41F can operate the directional control valve DV9 (swing cylinder C2) (it can operate the swing bracket 14). The sixth operating device 41F also has a sensor 42 (sixth sensor 42F) that detects the operating direction and amount. The sixth sensor 42F is connected to the control device U1. The control device U1 acquires the operating direction and amount of the sixth operating device 41F from the detection signal from the sixth sensor 42F, and controls the swing control valve V9 (swing bracket 14) based on the detection signal from the sixth sensor 42F. 【0055】 The seventh operating device 41G is composed of, for example, a switch (seesaw switch, slide switch, etc.) provided on the first operating device 41A or the second operating device 41B. Figure 5 illustrates the case where the seventh operating device 41G is provided on the second operating device 41B. The seventh operating device 41G can operate the directional control valve DV10 (hydraulic actuator of the hydraulic attachment) (it can operate the hydraulic attachment as a work tool). The seventh operating device 41G also has a sensor 42 (seventh sensor 42G) that detects the operating direction and amount. The seventh sensor 42G is connected to the control device U1. The control device U1 acquires the operating direction and amount of the seventh operating device 41G from the detection signal from the seventh sensor 42G, and controls the SP control valve V10 (hydraulic attachment) based on the detection signal from the seventh sensor 42G. 【0056】 The configuration of the sensors 42 (first sensors 42A to seventh sensors 42G) is not particularly limited, but for example, potentiometers can be used. 【0057】The spools of each directional control valve DV1 to DV10 are moved according to the amount of operation of each operating member 41 that operates each directional control valve DV1 to DV10 (each control valve V1 to V10), and the amount of hydraulic fluid corresponding to the amount that each directional control valve DV1 to DV10 is moved is supplied to the controlled hydraulic actuators ML, MR, MT, C1 to C6. In other words, the operating speed of the controlled object can be changed according to the amount of operation of each operating member 41. 【0058】 As described above, each control valve V1 to V10 is operated by the operation of each operating member 41, and thereafter the corresponding hydraulic actuators ML, MR, MT, C1 to C6 are operated. Then the driven objects (machine body 2, traveling device 3, dozer device 7, boom 15, arm 16, bucket 17, hydraulic attachment) driven by the hydraulic actuators ML, MR, MT, C1 to C6 are operated. 【0059】 The operating member 41 operates the control valves V1 to V10 via the control device U1. The operating member 41 also operates the hydraulic actuators ML, MR, MT, C1 to C6 controlled by the control valves V1 to V10, and also operates the drive targets 2, 3L, 3R, 7, 13, 15, 16, and 17 driven by the hydraulic actuators ML, MR, MT, C1 to C6. 【0060】 In the following explanation, the reference numerals for hydraulic actuators, control valves, and driven components may be omitted. 【0061】 In this embodiment, in order to enable the drive target driven by the hydraulic actuator to be easily operated at a very slow speed (to enable easy fine-tuning of the control valve), the work machine 1 is equipped with a fine-tuning mode that drives the hydraulic actuator at a speed slower than the normal driving speed (very slow speed). 【0062】 As shown in Figure 4, the control device U1 has a fine-tuning mode control unit Ua. The fine-tuning mode control unit Ua makes the fine-tuning mode executable and then executes the fine-tuning mode. 【0063】As shown in Figures 4 and 5, the work machine 1 is equipped with a fine-control mode switch 63 operated by an operator. The fine-control mode switch 63 is a switch that allows selection of the fine-control mode (switching to the fine-control mode). The fine-control mode switch 63 is connected to the control device U1. The control device U1 can acquire signals (operation signals) from the fine-control mode switch 63. 【0064】 When the control device U1 receives a signal that the fine-operation mode switch 63 has been turned ON, the fine-operation mode control unit Ua puts the system into a state where the fine-operation mode can be executed. Then, when the hydraulic actuator (control valve) that is the target of the fine-operation mode is operated while the system is in a state where the fine-operation mode can be executed, the hydraulic actuator operates in the fine-operation mode. 【0065】 The fine-tuning mode switch 63 is configured, for example, by a trigger switch provided on the first operating tool 41A or the second operating tool 41B. Figure 5 illustrates the case where the fine-tuning mode switch 63 is provided on the second operating tool 41B. 【0066】 The fine-tuning mode switch 63 is configured such that when it is turned ON, the fine-tuning mode becomes executable and is maintained in that state, and when the fine-tuning mode switch 63 is turned OFF, the fine-tuning mode becomes OFF (the fine-tuning mode is deactivated). 【0067】 The fine-tuning mode switch 63 employs a momentary switch, which switches to the ON state each time it is pressed. Alternatively, an alternate-operation switch (self-holding type switch) may be used instead of the momentary switch. The alternate-operation method means that when the fine-tuning mode switch 63 is operated once (ON operation), it becomes ON, and even if the hand is released from the fine-tuning mode switch 63, it maintains this ON state. When the fine-tuning mode switch 63 is operated (OFF operation) from the ON state, the ON state is released and it becomes OFF. 【0068】A separate switch may be provided for turning off (deactivating) the fine-tuning mode, in addition to the fine-tuning mode switch 63. 【0069】 Figures 6 and 7 are graphs (figures showing characteristic curves) that show the relationship between the operating amount of the operating member 41, where the horizontal axis represents the operating amount of the operating member 41, and the vertical axis represents the output current to the control valve corresponding to the object being operated. The characteristic curves shown in Figures 6 and 7 can also be described as characteristic curves that show the relationship between the control element acting on the control valve (the current output from the control device to the control valve) and the operating amount of the operating member 41. 【0070】 In this embodiment, the fine control mode is configured to be applied to, for example, the work device 4 (boom 15, arm 16, bucket 17) and the machine body 2. In other words, the output current in Figures 6 and 7 refers to the output current output to the boom control valve V2, arm control valve V7, bucket control valve V1, and slewing control valve V8. The pilot secondary pressure (pilot control pressure) applied to each control valve changes in proportion to the output current. Therefore, the operating members 41 are the first operating tool 41A and the second operating tool 41B. By providing the fine control mode switch 63 on the first operating tool 41A or the second operating tool 41B, it is possible to switch to the fine control mode without taking your hand off the operating member 41 that operates the drive target (machine body 2, boom 15, arm 16, and bucket 17) on which the fine control mode is performed. In other words, the operator can immediately select (switch to) the fine control mode when they want to use it. 【0071】 Furthermore, the targets on which the fine control mode is executed are not limited to the machine body 2, boom 15, arm 16, and bucket 17. In other words, the devices on which the fine control mode is executed can be any device consisting of a control valve controlled by the control device U1, a hydraulic actuator operated by the hydraulic fluid output from the control valve, and a drive target driven by the hydraulic actuator. 【0072】 Furthermore, in the following explanation, the aircraft body 2, boom 15, arm 16, and bucket 17 may sometimes be simply referred to as the driven objects 2, 15, 16, and 17. 【0073】 In Figures 6 and 7, characteristic curve I (first characteristic curve) shows the characteristic curve when the driven objects 2, 15, 16, and 17 are driven under normal conditions (when not in fine-tuning mode). 【0074】 Characteristic line II (second characteristic line) in Figure 6 and characteristic line III (third characteristic line) in Figure 7 represent characteristic lines in the fine-tuning mode, respectively. Characteristic line II is the characteristic line according to the first embodiment. Characteristic line III is the characteristic line according to the second embodiment (a different characteristic line from characteristic line II). 【0075】 In this embodiment, the characteristic curves for the boom 15, arm 16, bucket 17, and machine body 2 in the fine control mode are set to be the same. However, the characteristic curves for the boom 15, arm 16, and bucket 17 in the fine control mode may be set separately from the characteristic curves for the machine body 2 in the fine control mode. Alternatively, the characteristic curves for the boom 15, arm 16, bucket 17, and machine body 2 may each be set individually in the fine control mode. 【0076】 The characteristic curve in the fine-operation mode (control of the operation of the control valve in the fine-operation mode) may be set separately for one of the hydraulic actuators and the remaining hydraulic actuators in a work machine 1 equipped with multiple hydraulic actuators in which the fine-operation mode is performed, or it may be set separately for multiple hydraulic actuators and the remaining multiple hydraulic actuators, or it may be set for each hydraulic actuator. 【0077】 As shown in Figures 6 and 7, the characteristic curve I has a dead zone characteristic curve section Ia, a rise characteristic curve section Ib, a flow rate increase characteristic curve section Ic, a shortcut characteristic curve section Id, and a constant flow rate characteristic curve section Ie. 【0078】In Figures 6 and 7, the manipulated amount G0 corresponds to the non-operated position where the operating member 41 is not being operated. The manipulated amount G1 is the amount at which the pilot secondary pressure begins to rise. At manipulated amount G1, the pilot secondary pressure switches from 0 to Pa (rises rapidly to Pa). The portion of the characteristic curve I corresponding to manipulated amount G0 to manipulated amount G1 (dead zone characteristic curve portion Ia) is horizontal, where the pilot secondary pressure remains at 0. The portion of the characteristic curve I corresponding to manipulated amount G1 (rise characteristic curve portion Ib) is vertical. 【0079】 The dead zone characteristic curve section Ia of characteristic curve I is the portion where the output flow rate remains zero from the neutral position of the operating member 41 until the amount of operation of the operating member 41 increases to a predetermined threshold. The same applies to the dead zone characteristic curve sections IIa of characteristic curve II and IIIa of characteristic curve III, which will be described later. The threshold value for the amount of operation of the operating member 41 is set commonly for both normal operation (characteristic curve I) and fine operation mode (characteristic curves II and III). 【0080】 The rising characteristic curve section Ib of characteristic curve I is the portion where the output flow rate increases from zero to a predetermined flow rate when the amount of operation of the operating member 41 reaches a threshold. The same applies to the rising characteristic curve section IIb of characteristic curve II and the rising characteristic curve section IIIb of characteristic curve III, which will be described later. The predetermined flow rate that increases from zero in the rising characteristic curve section is set in common for both normal operation (characteristic curve I) and fine operation mode (characteristic curve II, characteristic curve III). 【0081】 The manipulated variable G2 is the manipulated variable when the pilot secondary pressure is Pb. The pilot secondary pressure Pb is the pilot control pressure when the control valves V1, V2, V7, V8 (hydraulic actuators C3, C4, C5, MT, and driven objects 2, 15, 16, 17) are activated. In other words, it is the pilot control pressure when the spool of the control valve starts moving and hydraulic fluid is output from the control valve. The activation point a1 is a point on the characteristic curve I (increased flow rate characteristic curve section Ic) where the pilot secondary pressure is Pb. 【0082】The manipulated amount G3 is the manipulated amount corresponding to a predetermined position just before the end of the operating range (stroke end) of the operating member 41. The portion of characteristic line I corresponding to manipulated amounts G1 to G3 (increased flow rate characteristic line portion Ic) has an upward sloping shape, where the pilot secondary pressure gradually (proportionally) increases as the manipulated amount increases. At manipulated amount G3, the pilot secondary pressure switches from Pc to the maximum output pressure Pd (rises sharply to Pd). The portion of characteristic line I corresponding to manipulated amount G3 (shortcut characteristic line portion Id) is vertical. 【0083】 The manipulated amount G4 is the amount when the operating member 41 is operated to the stroke end of the operating range (full operation). From manipulated amount G3 to manipulated amount G4, the pilot secondary pressure is constant at the maximum output pressure Pd. The portion of the characteristic curve I corresponding to manipulated amount G3 to manipulated amount G4 (constant flow characteristic curve section Ie) is horizontal, with the pilot secondary pressure fluctuating at Pd. 【0084】 When hydraulic actuators C3, C4, C5, and MT are driven normally, the control device U1 controls the control valves V1, V2, V7, and V8 based on the characteristic curve I. 【0085】 Next, we will explain characteristic curve II. 【0086】 In explaining this characteristic curve II, we will omit explanations of parts that are common to characteristic curve I as much as possible, and mainly explain the parts that differ from characteristic curve I. 【0087】 As shown in Figure 6, the characteristic curve II has a dead zone characteristic curve section IIa, a rise characteristic curve section IIb, a flow rate increase characteristic curve section IIc, and a constant flow rate characteristic curve section IId. 【0088】 In Figure 6, the manipulated amount G0 is the manipulated amount corresponding to the non-operated position, the manipulated amount G1 is the manipulated amount at which the pilot secondary pressure begins to rise, and the manipulated amount G4 is the manipulated amount when the operating member 41 is fully operated. The manipulated amount G5 is the manipulated amount at which the pilot secondary pressure corresponds to Pb. The starting point a2 is a point on characteristic line II (increased flow rate characteristic line section IIc) where the pilot secondary pressure is Pb. The pilot secondary pressure Pe is the maximum pressure when the driven objects 2, 15, 16, and 17 are operated at a slow speed. 【0089】 The portion of characteristic curve II corresponding to the manipulated amount G0 to G1 (dead zone characteristic curve section IIa) is horizontal, with the pilot secondary pressure remaining at 0. The portion of characteristic curve II corresponding to the manipulated amount G1 (rising characteristic curve section IIb) is vertical. The portion of characteristic curve II corresponding to the manipulated amount G1 to G6 (a predetermined manipulated amount) (increased flow rate characteristic curve section IIc) is upward sloping, with the pilot secondary pressure gradually (proportionally) increasing as the manipulated amount increases. Therefore, in the increased flow rate characteristic curve section IIc, the output flow rates from the control valves V1, V2, V7, and V8 are controlled to increase as the manipulated amount of the operating member 41 gradually increases. Furthermore, the inclination of the increased flow rate characteristic curve section IIc of characteristic curve II is smaller than that of the increased flow rate characteristic curve section Ic of characteristic curve I, and larger than that of the increased flow rate characteristic curve section IIIc of characteristic curve III, which will be described later. In other words, the flow rate increase characteristic line section IIc of characteristic line II is located between the flow rate increase characteristic line section Ic of characteristic line I and the flow rate increase characteristic line section IIIc of characteristic line III. 【0090】 The portion of characteristic curve II corresponding to the manipulated amount G6 to the manipulated amount G4 (constant flow rate characteristic curve section IId) is horizontal, with the pilot secondary pressure remaining constant (Pe). Therefore, in the constant flow rate characteristic curve section IId, the output flow rates from the control valves V1, V2, V7, and V8 are controlled to remain constant even when the manipulated amount of the operating member 41 is increased. 【0091】When hydraulic actuators C3, C4, C5, and MT are driven in fine operation mode, the control device U1 (fine operation mode control unit Ua) controls the control valves V1, V2, V7, and V8 based on characteristic line II. Specifically, when the fine operation mode is selected by the fine operation mode switch 63, the control device U1 (fine operation mode control unit Ua) controls the control valves V1, V2, V7, and V8 based on characteristic line II, which shows the relationship between the control elements acting on the control valves V1, V2, V7, and V8 and the operating amount of the operating member 41 in order to control the output flow rate of the control valves V1, V2, V7, and V8, and characteristic line II has an increasing flow rate characteristic line section IIc in which the control elements are increased so that the output flow rate gradually increases as the operating amount of the operating member 41 is increased to a predetermined operating amount (G6), and a constant flow rate characteristic line section IId in which the control elements are kept constant so that the output flow rate is constant in the operating amount range (G6-G4) above the predetermined operating amount (G6). 【0092】 Next, we will explain characteristic curve III. 【0093】 In explaining Characteristic Line III, we will omit explanations of parts that are common to Characteristic Line I and Characteristic Line II as much as possible, and mainly explain the parts that differ from Characteristic Line I and Characteristic Line II. 【0094】 As shown in Figure 7, characteristic curve III has a dead zone characteristic curve section IIIa, a rise characteristic curve section IIIb, and a flow rate increase characteristic curve section IIIc. 【0095】 In Figure 7, the manipulated amount G0 is the manipulated amount corresponding to the non-operated position, the manipulated amount G1 is the manipulated amount at which the pilot secondary pressure begins to rise, and the manipulated amount G4 is the manipulated amount when the operating member 41 is fully operated. The manipulated amount G7 is the manipulated amount when the pilot secondary pressure is Pb. The starting point a3 is a point on characteristic line III (increased flow rate characteristic line section IIIc) where the pilot secondary pressure is Pb. 【0096】 In the characteristic curve III (increased flow rate characteristic curve section IIIc), until the operating member 41 is operated from operating amount G1 to operating amount G4, the pilot secondary pressure gradually (proportionally) increases from Pa to Pe as the operating member 41 is operated. 【0097】Alternatively, the work machine 1 may be equipped with either characteristic wire II or characteristic wire III, or it may be equipped with both characteristic wire II and characteristic wire III, allowing the user to select either one. 【0098】 Comparing characteristic line I with characteristic line II or characteristic line III, it can be seen that in the fine-operation mode, the control device U1 (fine-operation mode control unit Ua) is configured to control the operation of the control valves V1, V2, V7, and V8 according to the amount of operation of the operating member 41, so as to reduce the output flow rate when the control valves V1, V2, V7, and V8 are operated by the same amount of operation as the operating member 41 in the fine-operation mode. 【0099】 Therefore, by executing the fine-control mode, the speed of the driven objects 2, 15, 16, and 17 can be suppressed compared to the normal drive case, and the control valves V1, V2, V7, and V8 (hydraulic actuators C3, C4, C5, MT, driven objects 2, 15, 16, and 17) can be easily fine-controlled. 【0100】 Incidentally, regarding characteristic curve III, making the slope smaller (gentler) makes it easier to operate the drive targets 2, 15, 16, and 17 with fine movements. However, as the slope of characteristic curve III decreases, the starting point a3 moves further away from the starting point a1 (see Figure 7), so the hydraulic actuator will not move unless the operating member 41 is moved a large amount. In this case, the degree to which the start of movement of the drive targets 2, 15, 16, and 17 is delayed in the fine-operation mode becomes greater compared to the normal drive mode. The operator has memorized the amount of movement (operating position) of the operating member 41 when driving the drive targets 2, 15, 16, and 17 in normal drive mode, and if the drive targets 2, 15, 16, and 17 do not move unless the operating member 41 is moved a larger amount than the operating position in normal drive mode, it will feel unnatural and make it difficult to operate intuitively (if the sense of grasping the start of movement is poor, it will be difficult to drive the work device 4 and rotate the machine body 2). However, if the slope of characteristic curve III is increased (made steeper), the starting point a3 moves closer to the starting point a1, but the movement of the driven objects 2, 15, 16, and 17 becomes faster, affecting fine control when the motor is fully operated. 【0101】 In contrast, with characteristic curve II, the slope of the increased flow rate characteristic curve section IIc is greater than the slope of characteristic curve III, so the starting point a2 can be brought closer to the starting point a1 than to the starting point a3 (comparing characteristic curve II and characteristic curve III, characteristic curve II can reduce the deviation of the starting point compared to the normal drive case), the timing of the start of movement is not hindered as much, and the operating member 41 is easier to handle (improving the fine operability in the inching range). Furthermore, with characteristic curve II, the output on the larger side of the operating amount of the operating member 41 is limited by the constant flow rate characteristic curve section IId, so the speed of the driven objects 2, 15, 16, and 17 when fully operated is suppressed, and even if operated suddenly, the sudden movement of the driven objects 2, 15, 16, and 17 can be suppressed. In other words, fine operation with characteristic curve II compared to characteristic curve III can reduce the deviation of the starting point between the normal drive case and the fine operation mode drive, while suppressing the speed during operation. 【0102】 Here, regarding the control based on the characteristic curve II described above, from the perspective of program generation, the target output current (the current that controls the control valves V1, V2, V7, and V8 in the fine-operation mode) is set according to a value obtained by reducing the input side of the operation (the input signal transmitted from the operating member 41) by a predetermined percentage, and a limiting current is also set. If the target output current is greater than the limiting current, the target output current is set to the same value as the limiting current. In other words, until the operating member 41 is operated from operating amount G1 to operating amount G6, a target output current corresponding to (proportional to) the operating amount of the operating member 41 is output to generate a rising flow rate increasing characteristic curve section IIc. In the region where the operating member 41 is operated to an operating amount G6 or more, the target output current is cut by the limiting current to generate a constant flow rate characteristic curve section IId. In this way, by setting a limiting current separately from the target output current, even if the slope of the flow rate increasing characteristic curve section IIc of the characteristic curve II is freely set (while keeping the initial current high), the maximum current can be suppressed by the limiting current. This makes it easier to set the parameters for the desired operation. 【0103】Incidentally, when the hydraulic actuators C3, C4, C5, and MT are normally driven, if the fine-tuning mode is selected and the output (current value) that the control device U1 outputs to the control valves V1, V2, V7, and V8 to control the output flow rate suddenly drops from the output in the normal driving state to the output in the fine-tuning mode, the hydraulic actuators C3, C4, C5, and MT and the driven objects 2, 15, 16, and 17 may suddenly decelerate, causing a shock to the hydraulic actuators C3, C4, C5, and MT and the driven objects 2, 15, 16, and 17. 【0104】 In this embodiment, when the hydraulic actuators C3, C4, C5, and MT are normally driven, and the fine-operation mode is selected by the fine-operation mode switch 63, the control device U1 is configured to gradually decrease the output that it outputs to the control valves V1, V2, V7, and V8 in order to control the output flow rate, from the output in the normal driving case to the output in the fine-operation mode, as time passes. 【0105】 According to this, when the fine-tuning mode is selected while the hydraulic actuators C3, C4, C5, and MT are normally driven, a sudden drop in the output that the control device U1 outputs to the control valves V1, V2, V7, and V8 can be suppressed, and shocks to the hydraulic actuators C3, C4, C5, MT, and the driven objects 2, 15, 16, and 17 can be suppressed. 【0106】 The output reduction amount, which is the amount by which the control device U1 reduces the output output to the control valves V1, V2, V7, and V8 from the output in normal operation mode to the output in fine operation mode, may be set individually for each control valve V1, V2, V7, and V8. 【0107】 Furthermore, in the fine-tuning mode, the amount or percentage by which the output flow rate, which is the flow rate of hydraulic fluid output from the control valve to the hydraulic actuators C3, C4, C5, and MT, is reduced compared to normal operation may be set for each hydraulic actuator. 【0108】Furthermore, even when the fine-tuning mode is deactivated, if the output (current value) that the control device U1 outputs to the control valves V1, V2, V7, V8 in order to control the output flow rate suddenly increases from the output in the fine-tuning mode to the output in the normal drive mode, the hydraulic actuators C3, C4, C5, MT and the driven objects 2, 15, 16, 17 driven by the hydraulic actuators C3, C4, C5, MT may suddenly accelerate, causing a shock to the hydraulic actuators C3, C4, C5, MT and the driven objects 2, 15, 16, 17. 【0109】 In this embodiment, when the fine-tuning mode is deactivated, the control device U1 is configured to gradually increase the output from the output in the fine-tuning mode to the output in the normal drive mode as time passes. 【0110】 According to this, when the fine-tuning mode is released, a sudden increase in the output flow rate of control valves V1, V2, V7, and V8 can be suppressed, and shocks to the hydraulic actuators C3, C4, C5, MT and the driven objects 2, 15, 16, and 17 can be suppressed. 【0111】 Figure 8 is an illustrative diagram showing the control to reduce the output of the control device U1 to the control valves V1, V2, V7, and V8, and the control to restore the output of the control device U1, when the fine operation mode is selected while the hydraulic actuators C3, C4, C5, and MT are normally driven. 【0112】 Figure 8 is a graph showing the relationship between time and the steering wheel power ratio, with time on the horizontal axis and the steering wheel power ratio on the vertical axis (this is an illustrative diagram representing characteristic line IV, which shows the relationship between time and the steering wheel power ratio). 【0113】 The handle operation output ratio is the ratio (percentage) of the output (current) that the control device U1 outputs to the control valves V1, V2, V7, V8 based on the operation of the operating member 41 when the hydraulic actuators C3, C4, C5, and MT are normally driven, with the output being set to 100%. 【0114】In Figure 8, n% is the ratio of the output of control device U1 in fine-tuning mode to the output of control device U1 when hydraulic actuators C3, C4, C5, and MT are normally driven. Time t1 indicates the time when fine-tuning mode is selected (fine-tuning mode switch 63 is turned ON). Time t2 indicates the time when the output of control device U1 decreases to the output of control device U1 in fine-tuning mode. 【0115】 As shown in the reduced characteristic line section IVa of characteristic line IV in Figure 8, when the fine-tuning mode is selected while the hydraulic actuators C3, C4, C5, and MT are normally driven, the output ratio of the control device U1 gradually decreases over time (as time progresses from time t1 to time t2) from the output ratio of the control device U1 when it is normally driven (100%) to the output ratio of the control device U1 in fine-tuning mode (n%). 【0116】 Furthermore, in Figure 8, time t3 indicates the point in time when the fine-tuning mode is deactivated (the fine-tuning mode switch 63 is turned OFF). Time t4 indicates the point in time when the output of the control device U1 returns to the output of the control device U1 when it is normally driven. 【0117】 As shown in the rising characteristic curve section IVb of characteristic curve IV in Figure 8, when the fine-tuning mode is released, the ratio of the output of the control device U1 gradually increases over time (as time progresses from time t3 to time t4) from the ratio of the output of the control device U1 in fine-tuning mode (n%) to the ratio of the output of the control device U1 when it is normally driven (100%). 【0118】 In Figure 8, the time TIb required to increase the output of the control device U1 is shorter than the time TIa required to decrease the output of the control device U1. This allows the output of the control device U1 to be quickly restored when the fine-tuning mode is released. 【0119】In the above embodiment, the degradation characteristic line IVa in Figure 8 is shown as a straight line, but it is not limited to this. For example, as shown in Figure 9, the degradation characteristic line IVa can be divided into multiple stages. More specifically, the degradation characteristic line IVa may be composed of multiple line segments with different slopes (for example, a first constituent line IVaa, a second constituent line IVab, and a third constituent line IVac). The first constituent line IVaa has the largest slope, the second constituent line IVab has a smaller slope than the first constituent line IVaa, and the third constituent line IVac has a smaller slope than the second constituent line IVab. 【0120】 Furthermore, the degraded characteristic line IVa may be curved, as shown in Figure 10. In short, the degraded characteristic line IVa should be configured such that the output of the control device U1 gradually decreases over time. 【0121】 As shown in Figure 4, the prime mover E1 is connected to the control device U1. The control device U1 can control the rotational speed of the prime mover E1. In this embodiment, for example, when the prime mover E1 is driven at a rotational speed exceeding a predetermined speed (not limited to, but for example, 1600 rpm), and the fine-tuning mode is selected by the fine-tuning mode switch 63, the control device U1 is configured to reduce the rotational speed of the prime mover E1 to the predetermined speed and fix it at that predetermined speed. 【0122】 According to this, ambient noise can be reduced and energy savings can be achieved when in fine-tuning mode. In addition, the operator can be notified that fine-tuning mode is in operation by the engine noise. 【0123】 Furthermore, when the fine-tuning mode is deactivated, the control device U1 may be configured to automatically restore the rotational speed of the prime mover E1 to the rotational speed it was at before the fine-tuning mode was activated. 【0124】 According to this, when the operator deactivates the fine-tuning mode, they do not need to return the rotational speed of the prime mover E1 to the rotational speed it was at before the fine-tuning mode was selected, thus improving operability. 【0125】As shown in Figure 4, the work machine 1 is equipped with a display device (monitor) MO. The display device MO is installed, for example, near the driver's seat 6. The display device MO is connected to the control device U1. When the fine-operation mode is selected by the fine-operation mode switch 63, a signal is output from the control device U1 to the display device MO, and an indication that the fine-operation mode is selected is displayed on the display device MO. 【0126】 According to this, the operator can visually confirm that the fine-tuning mode is selected using the display device MO. 【0127】 In the above hydraulic system, each control valve V1 to V10 (each directional control valve DV1 to DV10) is configured as a pilot-operated proportional solenoid valve, and the control device U1 controls the pilot control pressure by controlling the current value supplied to each control valve V1 to V10, thereby controlling each control valve V1 to V10. However, the system is not limited to this configuration. 【0128】 For example, as shown in Figure 11, each control valve V1 to V10 may be configured as a pilot-operated switching valve that is pilot-operated by pilot control pressure acting on a pair of pilot pressure receiving sections Va1 and Va2, and a pair of proportional solenoid valves V21 and V22 controlled by a control device U1 may be provided, with pilot control pressure supplied from one proportional solenoid valve V21 to one pilot pressure receiving section Va1, and pilot control pressure supplied from the other proportional solenoid valve V22 to the other pilot pressure receiving section Va2, thereby controlling the direction and flow rate of the hydraulic fluid to the hydraulic actuators MT, ML, MR, C1 to C6. 【0129】 In the modified example shown in Figure 11, the pilot control pressure (pilot secondary pressure) output from proportional solenoid valves V21 and V22 is a control element that acts on control valves V1 to V10 to control the output flow rate, which is the flow rate of hydraulic fluid output from control valves V1 to V10 to hydraulic actuators MT, ML, MR, and C1 to C6. 【0130】Alternatively, as shown in Figure 12, each control valve V1 to V10 may be configured as a proportional electromagnetic directional and flow control valve in which the spool is directly driven by a proportional solenoid so11 supplied with current from the control device U1. 【0131】 In the modified example shown in Figure 12, the current output from the control device U1 to the control valves V1 to V10 is a control element that acts on the control valves V1 to V10 to control the output flow rate, which is the flow rate of the hydraulic fluid output from the control valves V1 to V10 to the hydraulic actuators MT, ML, MR, C1 to C6. 【0132】 The other components are configured in the same manner as in the above embodiment. 【0133】 A preferred embodiment of the present invention provides a work machine 1 as described in the following items. 【0134】 (Item 1) A work machine 1 comprising: hydraulic actuators C3, C4, C5, MT; control valves V1, V2, V7, V8 for changing the flow rate of hydraulic fluid supplied to the hydraulic actuators; an operating member 41 for operating the control valves; a control device U1 for controlling the output flow rate, which is the flow rate of hydraulic fluid output from the control valves to the hydraulic actuators, by controlling the operation of the control valves according to the amount of operation of the operating member 41; and a fine operation mode switch 63 for selecting a fine operation mode for driving the hydraulic actuators at a slower speed than the normal drive speed, wherein the control device U1 controls the operation of the control valves according to the amount of operation of the operating member 41 so as to reduce the output flow rate when the control valves are operated with the same amount of operation as the amount of operation of the operating member 41 for the control valves in the fine operation mode when the fine operation mode is selected by the fine operation mode switch 63, the control device U1 controls the operation of the control valves according to the amount of operation of the operating member 41 so as to reduce the output flow rate compared to when the control valves are operated in the normal drive state with the same amount of operation as the amount of operation of the operating member 41 for the control valves in the fine operation mode. 【0135】 According to the work machine 1 related to item 1, by switching to the fine control mode, the drive target driven by the hydraulic actuator can be easily finely controlled. 【0136】(Item 2) The control device U1 controls the control valve based on a characteristic line II that shows the relationship between a control element that acts on the control valve to control the output flow rate and the amount of operation of the operating member 41 when the fine operation mode is selected by the fine operation mode switch 63, the characteristic line II having an increasing flow rate characteristic line section IIc in which the control element is increased so that the output flow rate gradually increases as the amount of operation of the operating member 41 is increased to a predetermined operating amount G6, and a constant flow rate characteristic line section IId in which the control element is kept constant so that the output flow rate is constant in the operating amount range above the predetermined operating amount. 【0137】 According to the work machine 1 related to item 2, the start of the control valve can be accelerated by increasing the slope of the increased flow rate characteristic section IIc, thereby accelerating the start of movement of the hydraulic actuator (the object driven by the hydraulic actuator). Furthermore, the maximum output of the control valve can be suppressed by the constant flow rate characteristic section IId. In other words, even if the slope of the increased flow rate characteristic section IIc is increased, the speed of the hydraulic actuator can be suppressed when the operating member 41 is operated to a large extent (such as when the operating member 41 is fully operated). 【0138】 (Item 3) The work machine 1 according to Item 1 or 2, wherein when the hydraulic actuator is normally driven and the fine operation mode is selected by the fine operation mode switch 63, the control device U1 gradually reduces the output that the control device U1 outputs to the control valve in order to control the output flow rate from the output in the normal drive case to the output in the fine operation mode case as time passes. 【0139】 According to the work machine 1 related to item 3, when switching from normal drive to fine operation mode, it is possible to suppress the sudden decrease in the output flow rate of the control valve (causing the hydraulic actuator and the driven object driven by the hydraulic actuator to suddenly decelerate) which can cause a shock to occur in the hydraulic actuator and the driven object driven by the hydraulic actuator. 【0140】(Item 4) The work machine 1 according to Item 3, wherein when the fine operation mode is released, the control device U1 gradually increases the output from the output in the fine operation mode to the output in the normal operation mode as time passes. 【0141】 According to the work machine 1 related to item 4, when the fine operation mode is released, it is possible to suppress the sudden increase in the output flow rate of the control valve (which causes the hydraulic actuator and the driven object driven by the hydraulic actuator to suddenly accelerate) and prevent shock from occurring in the hydraulic actuator and the driven object driven by the hydraulic actuator. 【0142】 (Item 5) The work machine 1 according to any one of items 1 to 4, comprising a hydraulic pump 21 that supplies hydraulic fluid to the control valve to operate the hydraulic actuator, and a prime mover E1 that drives the hydraulic pump 21, wherein the control device U1 reduces the rotational speed of the prime mover E1 to the predetermined rotational speed when the fine operation mode is selected by the fine operation mode switch 63 when the prime mover E1 is being driven at a rotational speed exceeding a predetermined rotational speed. 【0143】 According to the work machine 1 related to item 5, ambient noise can be reduced and energy savings can be achieved. In addition, the operator can be made aware that it is in fine-tuning mode. 【0144】 (Item 6) The work machine 1 according to Item 5, wherein the control device U1 automatically restores the rotational speed of the prime mover E1 to the predetermined rotational speed before the fine operation mode was executed when the fine operation mode is deactivated. 【0145】 According to the work machine 1 related to item 6, when the operator deactivates the fine control mode, it is not necessary to return the rotational speed of the prime mover E1 to the rotational speed before selecting the fine control mode, thereby improving operability. 【0146】 (Item 7) The operating member 41 is composed of a member that is grasped and operated by an operator, and the fine operation mode switch 63 is provided on the operating member 41. The work machine according to any one of items 1 to 6. 【0147】According to the work machine 1 related to item 7, it is possible to switch to the fine control mode without taking one's hand off the operating member 41 that operates the drive target for which the fine control mode is performed. In other words, the operator can immediately select (switch to) the fine control mode when they want to use it. 【0148】 (Item 8) The work machine 1 according to any one of items 1 to 7, which is equipped with a display device MO that indicates that the fine operation mode is selected. 【0149】 According to the work machine 1 related to item 8, the operator can visually confirm that the fine-tuning mode is selected using the display device MO. 【0150】 (Item 9) A work machine 1 according to any one of Items 1 to 8, comprising a plurality of hydraulic actuators on which the fine operation mode is performed, wherein the amount or percentage by which the output flow rate is reduced compared to the normal operation state in the fine operation mode is set for each hydraulic actuator. 【0151】 According to the work machine 1 related to item 9, it is possible to make optimal settings for fine-tuning the drive target driven by each hydraulic actuator. 【0152】 (Item 10) The control device U1 controls the control valve based on characteristic lines II and III, which are characteristic lines showing the relationship between a control element that acts on the control valve to control the output flow rate and the amount of operation of the operating member 41, and which have dead zone characteristic line sections IIa and IIIa from the neutral position of the operating member 41 until the amount of operation of the operating member 41 increases to a predetermined threshold, and the threshold is set in common for the normal operation and the fine operation mode, according to any one of items 1 to 9. 【0153】 According to the work machine 1 related to item 10, the amount of operation of the operating member 41 from the time the spool of the control valve starts moving until hydraulic fluid is output from the control valve can be made common to both normal operation mode and fine operation mode. 【0154】 (Item 11) The work machine 1 according to Item 10, wherein the characteristic curve has rise characteristic curve sections IIb and IIIb that increase the output flow rate from zero to a predetermined flow rate when the amount of operation of the operating member 41 reaches the threshold, and the predetermined flow rate is set to be common to the normal operation mode and the fine operation mode. 【0155】 According to the work machine 1 related to item 11, in both normal driving and fine-tuning modes, the time it takes for the output flow rate to increase from zero to a predetermined flow rate when the amount of operation of the operating member 41 reaches a threshold can be kept approximately constant. 【0156】 Although one embodiment of the present invention has been described above, the embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than the foregoing description, and all modifications within the meaning and scope of equivalents of the claims are intended to be included. 【0157】 1 Work machine 2 Machine body 41 Operating member 63 Fine operation mode switch II Characteristic line IIc Increased flow rate characteristic line IId Constant flow rate characteristic line C3 Hydraulic actuator C4 Hydraulic actuator C5 Hydraulic actuator MO Display device MT Hydraulic actuator U1 Control device Ua Fine operation mode control unit V1 Control valve V2 Control valve V7 Control valve V8 Control valve

Claims

1. A work machine comprising: a hydraulic actuator; a control valve for changing the flow rate of hydraulic fluid supplied to the hydraulic actuator; an operating member for operating the control valve; a control device for controlling the output flow rate, which is the flow rate of hydraulic fluid output from the control valve to the hydraulic actuator, by controlling the operation of the control valve according to the amount of operation of the operating member; and a fine operation mode switch for selecting a fine operation mode for driving the hydraulic actuator at a speed slower than the normal driving speed, wherein the control device controls the operation of the control valve according to the amount of operation of the operating member so that when the fine operation mode is selected by the fine operation mode switch, the output flow rate is reduced compared to when the control valve is operated in the normal driving state with the same amount of operation of the operating member as the amount of operation of the control valve in the fine operation mode.

2. The work machine according to claim 1, wherein the control device controls the control valve based on a characteristic curve that shows the relationship between a control element that acts on the control valve to control the output flow rate and the amount of operation of the operating member when the fine operation mode is selected by the fine operation mode switch, the characteristic curve having an increasing flow rate characteristic line portion in which the control element is increased so that the output flow rate gradually increases as the amount of operation of the operating member is increased to a predetermined amount, and a constant flow rate characteristic line portion in which the control element is kept constant so that the output flow rate is constant in the operating amount range above the predetermined amount.

3. The work machine according to claim 1 or 2, wherein when the hydraulic actuator is normally driven and the fine operation mode is selected by the fine operation mode switch, the control device gradually reduces the output that the control device outputs to the control valve in order to control the output flow rate from the output in the normal drive case to the output in the fine operation mode case as time passes.

4. The work machine according to claim 3, wherein the control device, when the fine-tuning mode is released, gradually increases the output from the output in the fine-tuning mode to the output in the normal drive mode as time passes.

5. The work machine according to claim 1 or 2, comprising: a hydraulic pump that supplies hydraulic fluid for operating the hydraulic actuator to the control valve; and a prime mover that drives the hydraulic pump, wherein the control device reduces the rotational speed of the prime mover to the predetermined rotational speed when the fine operation mode is selected by the fine operation mode switch when the prime mover is being driven at a rotational speed exceeding a predetermined rotational speed.

6. The work machine according to claim 5, wherein the control device automatically restores the rotational speed of the prime mover to the predetermined rotational speed before the fine-tuning mode was executed when the fine-tuning mode is deactivated.

7. The work machine according to claim 1 or 2, wherein the operating member is composed of a member that is grasped and operated by an operator, and the fine operation mode switch is provided on the operating member.

8. The work machine according to claim 1 or 2, further comprising a display device that indicates that the fine-tuning mode is selected.

9. The work machine according to claim 1, comprising a plurality of hydraulic actuators on which the fine-operation mode is performed, wherein the amount or percentage by which the output flow rate is reduced compared to that during normal operation in the fine-operation mode is set for each hydraulic actuator.

10. The work machine according to claim 1 or 2, wherein the control device controls the control valve based on a characteristic curve that shows the relationship between a control element acting on the control valve to control the output flow rate and the amount of operation of the operating member when the fine operation mode is selected by the fine operation mode switch, the characteristic curve having a dead zone characteristic curve portion in which the output flow rate remains zero from the neutral position of the operating member until the amount of operation of the operating member increases to or above a predetermined threshold, and the threshold is set to be common to the normal operation and the fine operation mode.

11. The work machine according to claim 10, wherein the characteristic curve has a rising characteristic curve portion that increases the output flow rate from zero to a predetermined flow rate when the amount of operation of the operating member reaches the threshold, and the predetermined flow rate is set to be common to the normal operation mode and the fine operation mode.

Images