JP2018141290A - Shovel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shovel capable of further improving operability of a swing operation.SOLUTION: A shovel includes an upper swing structure 3, a swing motor 21 for driving the upper swing structure 3, and a lever 26A on which a swing operation of the upper swing structure 3 is performed. Under control of a HB controller 30B, within the entire range of a stroke amount of the lever 26A from a time when torque begins to increase until it reaches the maximum value, the swing motor 21 realizes a torque characteristic including a first range in which the torque hardly increases relative to the increase in the stroke amount of the lever 26A.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an excavator.

  Increases the stroke amount of the operating lever in the entire range of stroke amount of the operating lever from when the torque of the swing drive means (for example, hydraulic motor, electric motor, etc.) starts to increase until the maximum value is reached. Accordingly, there is known an excavator in which the torque of the turning drive means increases uniformly (see, for example, Patent Document 1).

Japanese Patent No. 4704725

  However, since the excavator is used in a wide variety of work sites, it is desirable to further improve the operability of the turning operation by setting a torque characteristic that can cope with various assumed work scenes.

  Then, in view of the said subject, it aims at providing the shovel which can further improve the operativity of turning operation.

In order to achieve the above object, in one embodiment of the present invention,
A swivel,
Swivel drive means for driving the swivel body;
An operation lever for performing a turning operation of the turning body,
The swivel driving means has a first range in which the torque is less likely to increase relative to the increase in the stroke amount within the entire range of the stroke amount of the operating lever from when the torque starts to reach the maximum value. Having torque characteristics including,
An excavator is provided.

  According to the above-mentioned embodiment, the shovel which can improve the operativity of turning operation further can be provided.

It is a side view of an excavator. It is a block diagram which shows roughly an example of the structure centering on the drive system of an shovel. It is a figure which shows the 1st example of the torque characteristic of the electric motor for turning. It is a figure which shows the 2nd example of the torque characteristic of the electric motor for turning. It is a figure which shows the 3rd example of the torque characteristic of the electric motor for turning. It is a figure which shows the 4th example of the torque characteristic of the electric motor for turning.

  Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings.

  First, the basic configuration of the shovel according to the present embodiment will be described with reference to FIGS.

  FIG. 1 is a side view showing an example of an excavator according to the present embodiment.

  The shovel according to the present embodiment includes a lower traveling body 1, an upper revolving body 3 that is mounted on the lower traveling body 1 so as to be able to swivel via a turning mechanism 2, a boom 4, an arm 5, and a bucket 6 as working devices. And a cabin 10 on which the operator is boarded.

  The lower traveling body 1 includes, for example, a pair of left and right crawlers, and each crawler is self-propelled by being hydraulically driven by traveling hydraulic motors 1A and 1B (see FIG. 2).

  The upper turning body 3 is turned with respect to the lower traveling body 1 by being electrically driven by a turning electric motor 21 (see FIG. 2) described later.

  The boom 4 is pivotally attached to the center of the front part of the upper swing body 3 so that the boom 4 can be raised and lowered. An arm 5 is pivotally attached to the tip of the boom 4 and a bucket 6 is vertically attached to the tip of the arm 5. It is pivotally attached so that it can rotate. The boom 4, the arm 5 and the bucket 6 are hydraulically driven by a boom cylinder 7, an arm cylinder 8 and a bucket cylinder 9 as hydraulic actuators, respectively.

  The cabin 10 is mounted on the left side of the front part of the upper swing body 3, and a cockpit where an operator is seated, an operation device 26 described later, and the like are provided therein.

  FIG. 2 is a block diagram illustrating an example of a configuration centering on a drive system of the shovel according to the present embodiment.

  In the figure, the mechanical power line is indicated by a double line, the high-pressure hydraulic line is indicated by a thick solid line, the pilot line is indicated by a broken line, and the electric drive / control line is indicated by a thin solid line.

  First, the excavator hydraulic drive system according to the present embodiment includes an engine 11, a speed reducer 13, a main pump 14, and a control valve 17. Further, as described above, the hydraulic drive system according to the present embodiment includes the traveling hydraulic motors 1A and 1B, the boom cylinder 7 and the arm cylinder 8 that hydraulically drive the lower traveling body 1, the boom 4, the arm 5 and the bucket 6, respectively. And a bucket cylinder 9 and the like.

  The engine 11 is a main power source in the hydraulic drive system, and is mounted on the rear part of the upper swing body 3. The engine 11 rotates at a constant target rotational speed under the control of an engine controller 30C (see FIG. 3) described later. The engine 11 is, for example, a diesel engine using light oil as fuel, and drives the main pump 14 and the pilot pump 15 via the speed reducer 13. The engine 11 drives the motor generator 12 via the speed reducer 13 and causes the motor generator 12 to generate power.

  The speed reducer 13 is mounted on the rear part of the upper swing body 3, and includes two input shafts to which the engine 11 and a motor generator 12 to be described later are connected, and one main pump 14 and a pilot pump 15 that are coaxially connected in series. Has an output shaft. The reduction gear 13 can transmit the power of the engine 11 and the motor generator 12 to the main pump 14 and the pilot pump 15 at a predetermined reduction ratio. Further, the reduction gear 13 can distribute and transmit the power of the engine 11 to the motor generator 12, the main pump 14, and the pilot pump 15 at a predetermined reduction ratio.

  The main pump 14 is mounted at the rear of the upper swing body 3 and supplies hydraulic oil to the control valve 17 through the high-pressure hydraulic line 16. The main pump 14 is driven by the engine 11 or the engine 11 and the motor generator 12. The main pump 14 is, for example, a variable displacement hydraulic pump, and a regulator (not shown) controls the angle (tilt angle) of the swash plate under the control of an excavator controller 30A described later, thereby increasing the stroke length of the piston. It is possible to adjust and control the discharge flow rate (discharge pressure).

  The control valve 17 is a hydraulic control device that is mounted at the center of the upper swing body 3 and controls the hydraulic drive system in accordance with the operation of the operation device 26 by the operator. As described above, the control valve 17 is connected to the main pump 14 via the high-pressure hydraulic line 16, and hydraulic oil supplied from the main pump 14 is supplied to the traveling hydraulic motors 1 </ b> A (for right) and 1 </ b> B (for left). ), The boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9 can be supplied. Specifically, the control valve 17 is a valve unit including a plurality of hydraulic control valves (direction switching valves) that control the flow rate and flow direction of hydraulic oil supplied from the main pump 14 to each of the hydraulic actuators.

  The electric drive system according to the present embodiment includes a motor generator 12, a turning electric motor 21, a turning speed reducer 24, a current sensor 21 s, a resolver 22, and a mechanical brake 23.

  The motor generator 12 is an assist power source for the hydraulic drive system, and is mounted on the rear part of the upper swing body 3. The motor generator 12 is connected to a power storage system 120 including a capacitor 19 via an inverter 18A, and is powered by the three-phase AC power supplied from the capacitor 19 and the turning motor 21 via the inverter 18A. To drive the main pump 14 and the pilot pump 15. The motor generator 12 is driven by the engine 11 to perform a power generation operation, and can supply the generated power to the capacitor 19 and the turning motor 21. Switching control between the power running operation and the power generation operation of the motor generator 12 is realized by driving and controlling the inverter 18A by a hybrid controller (HB controller) 30B described later.

  The turning electric motor 21 (an example of the turning drive means) is provided in the turning mechanism 2 that connects the lower traveling body 1 and the upper turning body 3, and is a power running that drives the upper turning body 3 under the control of the HB controller 30B. Operation and regenerative operation in which regenerative electric power is generated to swing and brake the upper revolving structure 3 are performed. The turning electric motor 21 is connected to the power storage system 120 via the inverter 18B, and is driven by the three-phase AC power supplied from the capacitor 19 and the motor generator 12 via the inverter 18B. The turning electric motor 21 supplies regenerative power to the capacitor 19 and the motor generator 12 via the inverter 18B. Thereby, the capacitor 19 can be charged or the motor generator 12 can be driven by the regenerative power. Switching control between the power running operation and the regenerative operation of the turning electric motor 21 is realized by driving and controlling the inverter 18B by the HB controller 30B. A resolver 22, a mechanical brake 23, and a turning speed reducer 24 are connected to the rotating shaft 21 </ b> A of the turning electric motor 21.

  The turning speed reducer 24 is connected to the rotating shaft 21A of the turning electric motor 21 and decelerates the output (torque) of the turning electric motor 21 at a predetermined reduction ratio, thereby increasing the torque and turning the upper turning body 3. To drive. That is, during the power running operation, the turning electric motor 21 drives the upper turning body 3 to turn through the turning speed reducer 24. Further, the turning speed reducer 24 increases the inertial rotational force of the upper turning body 3 and transmits it to the turning electric motor 21 to generate regenerative power. That is, during the regenerative operation, the turning electric motor 21 performs regenerative power generation by the inertial rotational force of the upper turning body 3 transmitted through the turning speed reducer 24 and turns the upper turning body 3 by turning.

  The current sensor 21s detects the current of each of the three phases (U phase, V phase, W phase) of the turning electric motor 21. The current sensor 21s is provided, for example, in a power path between the turning electric motor 21 and the inverter 18B. The current sensor 21s transmits a detection signal corresponding to the current of each of the three phases of the turning electric motor 21 to the HB controller 30B.

  The resolver 22 detects the rotation position (rotation angle) of the turning electric motor 21 and the like. The resolver 22 transmits a detection signal corresponding to the detected rotation angle to the HB controller 30B.

  Under the control of the HB controller 30B, the mechanical brake 23 mechanically generates a braking force with respect to the upper swing body 3 (specifically, the rotating shaft 21A of the swing electric motor 21). While turning and braking, the stopped state of the upper turning body 3 is maintained.

  The power storage system 120 of the excavator according to the present embodiment includes a capacitor 19, a DC bus 110, and a step-up / down converter 100. For example, the right front portion of the upper swing body 3 together with the inverters 18A and 18B of the electric drive system. Mounted on.

  The capacitor 19 is an example of a power storage device that supplies power to the motor generator 12 and the turning motor 21 and charges the generated power of the motor generator 12 and the turning motor 21.

  The DC bus 110 is disposed between the inverters 18 </ b> A and 18 </ b> B and the step-up / down converter 100, and controls power transfer between the capacitor 19, the motor generator 12, and the turning electric motor 21.

  The step-up / step-down converter 100 switches between the step-up operation and the step-down operation so that the voltage value of the DC bus 110 falls within a certain range according to the operation state of the motor generator 12 and the turning electric motor 21. Switching control between the step-up / step-down converter 100 and the step-down operation is realized by the HB controller 30B based on the voltage detection value of the DC bus 110, the voltage detection value of the capacitor 19, and the current detection value of the capacitor 19.

  The shovel operating system according to the present embodiment includes a pilot pump 15, an operating device 26, a pressure sensor 29, and the like.

  The pilot pump 15 is mounted on the rear part of the upper swing body 3 and supplies pilot pressure to the operating device 26 via the pilot line 25. The pilot pump 15 is, for example, a fixed displacement hydraulic pump, and is driven by the engine 11 or the engine 11 and the motor generator 12.

  The operating device 26 includes levers 26A and 26B and a pedal 26C. The operation device 26 is provided in the vicinity of the cockpit of the cabin 10, and an operation input means for an operator to operate each operation element (the lower traveling body 1, the upper swing body 3, the boom 4, the arm 5, the bucket 6, etc.). It is. In other words, the operating device 26 is used for hydraulic actuators (travel hydraulic motors 1A and 1B, boom cylinders 7, arm cylinders 8, bucket cylinders 9 and the like) and electric actuators (turning electric motor 21 and the like) that drive the operating elements. It is an operation input means for performing an operation. The operation device 26 (lever 26A, 26B and pedal 26C) is connected to the control valve 17 via a hydraulic line 27, respectively. As a result, a pilot signal (pilot pressure) corresponding to the operating state of the lower traveling body 1, the boom 4, the arm 5, the bucket 6 and the like in the operating device 26 is input to the control valve 17. Therefore, the control valve 17 can drive each hydraulic actuator according to the operation state in the operation device 26. The operating device 26 is connected to a pressure sensor 29 via a hydraulic line 28.

  As described above, the pressure sensor 29 is connected to the operating device 26 via the hydraulic line 28, and the pilot pressure on the secondary side of the operating device 26, that is, the pilot pressure corresponding to the operating state of each operating element in the operating device 26. Is detected. The pressure sensor 29 is connected to the shovel controller 30A, and a pressure signal (pressure detection value) corresponding to the operation state of the lower traveling body 1, the upper swing body 3, the boom 4, the arm 5, the bucket 6 and the like in the operation device 26 is obtained. , And input to the excavator controller 30A.

  The shovel control system according to the present embodiment includes a shovel controller 30A, an HB controller 30B, and the like.

  The shovel controller 30A performs drive control of the shovel in cooperation with various controllers (control devices) including the HB controller 30B. For example, the shovel controller 30A may control the operation of the entire shovel (various devices mounted on the shovel) based on bidirectional communication with various controllers centering on the HB controller 30B (overall control).

  The HB controller 30B performs drive control of the electric drive system based on various types of information transmitted from the shovel controller 30A (for example, a drive command including a detection value of the pressure sensor 29 corresponding to an operation state with respect to the operation device 26). For example, the HB controller 30 </ b> B drives the inverter 18 </ b> A based on the detection value detected by the pressure sensor 29 and corresponding to the operation state of the operation device 26, and the operation state (power running operation and power generation operation) of the motor generator 12. Perform switching control. Further, for example, the HB controller 30B drives the inverter 18B based on the detection value corresponding to the operation state of the operation device 26 detected by the pressure sensor 29, and the operation state (power running operation and regenerative operation) of the turning electric motor 21. ) Switching control. At this time, the HB controller 30B performs speed control and torque control of the turning electric motor 21 based on, for example, detection values of the current sensor 21s and the resolver 22. Further, for example, the HB controller 30B drives the buck-boost converter 100 based on a detection value detected by the pressure sensor 29 and corresponding to the operation state of the operation device 26, and switches between the charged state and the discharged state of the capacitor 19. Take control.

  The functions of the excavator controller 30A, the HB controller 30B, and the like may be realized by arbitrary hardware, software, or a combination thereof. For example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only a microcomputer including only memory) and I / O (input-output interface) may be used.

  Next, referring to FIGS. 3 to 6, torque characteristics with respect to the operation (turning operation) of the upper swing body 3 in the operating device 26 (lever 26 </ b> A) of the turning electric motor 21 realized under the control of the hybrid controller 30 </ b> B. Will be explained. Hereinafter, the description will be made on the assumption that the turning operation is realized by an operation on the lever 26A (an example of the operation lever).

  FIG. 3 is a diagram showing a first example (torque characteristic 300) of the characteristic (torque characteristic) of torque T with respect to the operation amount (stroke amount) C of the turning operation of the electric motor 21 for turning according to the present embodiment.

  As shown in FIG. 3, the torque characteristic 300 (hereinafter simply referred to as the torque characteristic 300 of the turning electric motor 21) with respect to the operation amount C of the turning electric motor 21 according to the present example is the torque characteristic 300C1 (the lever 26A of the lever 26A). Unlike when the operation amount C increases) and 300C2 (when the operation amount C of the lever 26A decreases), regardless of whether the operation amount of the lever 26A increases or decreases, the torque T operates the lever 26A. Interlocks with quantities in a one-to-one correspondence. Specifically, the torque characteristic 300 of the turning electric motor 21 is a dead zone S31 in which the torque is maintained at a minimum value (zero) with respect to an increase in the operation amount C of the lever 26A (the operation amount C of the lever 26A is from zero). A relatively small range between a predetermined value C1 (> 0) and an increase interval S32 (lever) in which the torque T increases from the minimum value (zero) to the maximum torque Tmax in accordance with an increase in the operation amount C of the lever 26A. 26A, the operation amount C is an intermediate range between the predetermined value C1 and the predetermined value C2 (> C1)), and the maximum torque section S33 (where the torque T is maintained at the maximum torque Tmax as the operation amount C increases). The operation amount C of the lever 26A has a predetermined value C2 (<Cmax) and a relatively large range between the maximum operation amount Cmax).

  The increase section S32 is located at the start and end of the increase section S32, and an increase promotion section in which an increase in the torque T is promoted with respect to an increase in the operation amount C of the lever 26A (that is, the torque T is relatively easy to increase). S321 (the range between the operation amount C of the lever 26A from the predetermined value C1 to the predetermined value C3 (> C1)), S323 (the operation amount C of the lever 26A is from the predetermined value C4 (> C3) to the predetermined value C2 (> C4) )) And other sections (increasing acceleration) between the increase promotion sections S321 and S323 (that is, the range in which the operation amount C of the lever 26A is between the predetermined value C3 and the predetermined value C4). An increase suppression section S322 in which an increase in the torque T with respect to the operation amount C of the lever 26A is suppressed more than in the sections S321 and S323). That is, the torque characteristic 300 of the turning electric motor 21 according to the present example is within the entire range of the operation amount C of the lever 26A from when the torque T starts to increase until the maximum torque Tmax is reached. And an increase suppression section S322 (an example of the first range) in which the torque T is relatively difficult to increase.

  In the increase promotion section S321, the torque characteristic 300 of the turning electric motor 21 has a torque curve in which the torque increase rate with respect to the operation amount C of the lever 26A increases, that is, a downward convex curve shape. For this reason, in the increase promotion section S321, the torque T of the turning electric motor 21 increases upward as the operation amount C of the lever 26A increases.

  On the other hand, in the increase suppression section S322, the torque characteristic 300 of the turning electric motor 21 changes discontinuously from the end position of the increase promotion section S321, and is constant in a state where the torque increase rate with respect to the operation amount C of the lever 26A is very small. Maintained. That is, in the increase suppression section S322, the torque T of the turning electric motor 21 increases at a very small and substantially constant increase rate according to the increase in the operation amount C of the lever 26A. Therefore, in the increase suppression section S322, the torque T of the turning electric motor 21 hardly increases.

  In the increase suppression section S322, the torque increase rate with respect to the operation amount C of the lever 26A may be set to substantially zero (that is, a mode in which the torque T is kept constant).

  On the other hand, in the increase promotion section S323, the torque characteristic 300 of the turning electric motor 21 changes discontinuously from the end position of the increase suppression section S322, and the torque increase rate with respect to the operation amount C of the lever 26A is similar to the increase promotion section S321. It becomes relatively large. Specifically, the torque characteristic 300 of the turning electric motor 21 is in a state in which the torque increase rate with respect to the operation amount C of the lever 26A is relatively large at the start position of the increase promotion section S323, as in the end position of the increase promotion section S321. In addition, the maximum torque Tmax at the end position (when the operation amount C of the lever 26A is a predetermined value C2) while the torque increase rate with respect to the operation amount C of the lever 26A is decreased (that is, in a convex curve shape upward). To reach. In other words, in the increase promotion section S323, the torque T of the turning electric motor 21 reaches the maximum torque Tmax while increasing in the bottom part with respect to the increase in the operation amount C of the lever 26A.

  Thus, in the present embodiment, the torque characteristic 300 of the turning electric motor 21 is obtained by operating the lever 26A in the increasing section S32 in which the torque T of the turning electric motor 21 increases from the minimum value (zero) to the maximum torque Tmax. An increase suppression section S322 in which the torque increase rate with respect to the amount C is suppressed is included. That is, the torque characteristic 300 of the turning electric motor 21 is relatively in relation to the increase of the operation amount C within the entire range of the operation amount C of the lever 26A from when the torque T starts to increase until reaching the maximum torque Tmax. An increase suppression section S322 in which the torque T is difficult to increase is included. Thus, for example, as in the torque characteristic 300C1 of the comparative example shown in FIG. 3, the state of the torque increase rate in the increase promotion section S321 (that is, the torque T increases rapidly) in accordance with the increase in the operation amount of the lever 26A. When the torque T of the turning electric motor 21 reaches the maximum torque Tmax in the intermediate region of the lever 26A, in the case of the torque characteristic 300 of the present embodiment, the torque T of the turning electric motor 21 is maximum. Since the operation amount C of the lever 26A that reaches the torque Tmax can be brought close to the maximum operation amount Cmax, the range in which the operator can adjust the torque T of the turning electric motor 21 can be expanded, and the operability of the operator is improved. be able to. For example, it is possible to improve the operability of the operator in a scene where it is desired to adjust the torque T corresponding to the load on the object to be pressed (for example, earth and sand) during the pressing and turning operation of the shovel.

  In the present embodiment, the torque T of the turning electric motor 21 is different from the torque characteristics 300C1 and 300C2 according to the comparative example, regardless of whether the operation amount of the lever 26A is increasing or decreasing. Interlocks with the quantity C on a one-to-one basis As a result, the torque T follows on a one-to-one basis with respect to the change in the operation amount C of the lever 26A, so that the operability of the operator can be further improved. For example, when the reaction force suddenly disappears due to the movement of the pressing object during pressing operation of the shovel, if the lever 26A is returned, the operation amount C can be obtained even in a region where the operation amount C of the lever 26A is relatively large. Since the torque T can be immediately reduced following the decrease in the torque, a situation in which the upper swing body 3 turns excessively can be suppressed and the operability of the operator can be improved.

  Further, in the present embodiment, the increase suppression section S322 is located in an intermediate region of the operation amount C of the lever 26A between the increase promotion sections S321 and S323. This makes it easier for the operator to adjust the torque T of the turning electric motor 21 in the intermediate range of the operation amount C of the lever 26A. Further, when the operation amount C of the lever 26A requires the torque T further from the intermediate state, the operator increases the operation amount C of the lever 26A to increase the increase suppression section S322 to the increase promotion section S323. Therefore, it is easy to feel the change (increase) in the torque T, and the operability of the operator can be improved from this point.

  In the present embodiment, in the increase promotion section S323 positioned at the end of the increase section S32, the torque increase rate of the turning electric motor 21 with respect to the operation amount C of the lever 26A is decreased. In other words, in the increase promotion section S323, the torque T of the turning electric motor 21 increases due to the bottom recess. As a result, the rate of increase in torque gradually decreases as the operation amount C of the lever 26A increases, and the operation amount C of the lever 26A at which the torque T of the turning electric motor 21 reaches the maximum torque Tmax is further increased to the maximum operation amount Cmax. Since the range in which the operator can adjust the torque T of the turning electric motor 21 can be further expanded, the operability of the operator can be further improved.

  Next, FIG. 4 is a diagram illustrating a second example (torque characteristic 400) of the torque T with respect to the operation amount C of the turning operation of the turning electric motor 21 according to the present embodiment. Hereinafter, a description will be given centering on differences from the first example.

  In addition, since the dead zone S41 and the maximum torque zone S43 in this example are the same as the dead zone S31 and the maximum torque zone S33 in the first example, description thereof is omitted.

  As shown in FIG. 4, in the present embodiment, the torque characteristic 400 differs from the torque characteristics 300C1 and 300C2 according to the comparative example, as in the first example, in which the operation amount of the lever 26A is increased or decreased. Regardless, the torque T interlocks with the operation amount of the lever 26A in a one-to-one correspondence. Specifically, in the torque characteristic 400 of the turning electric motor 21, the torque T is minimized between the dead zone section S41 and the maximum torque section S43 according to the increase in the operation amount C of the lever 26A, as in the first example. It includes an increasing section S42 (an intermediate range between the operation amount C of the lever 26A from the predetermined value C1 to the predetermined value C2 (> C1)) increasing from the value (zero) to the maximum torque Tmax.

  As in the first example (FIG. 3) described above, the increase section S42 includes the increase promotion sections S421 and S423 located at the start and end of the increase section S42 and the increase suppression section S422 located between the increase promotion sections S421 and S423. including.

  On the other hand, unlike the above-described first example (FIG. 3), the increase suppression section S422 continuously changes between the adjacent increase promotion sections S421 and S423. Specifically, as illustrated in FIG. 4, the increase suppression section S422 is adjacent to the increase suppression section S422B and the start and end of the increase suppression section S422B, and the end position of the increase promotion section S421 and the start end of the increase promotion section S423. It includes transition sections S422A and S422C that realize a continuous change between the position and the increase suppression section S422B. Thereby, since the change between increase promotion area S421, S423 and increase suppression area S422 becomes smooth, the sudden feeling of the change of the torque T of the electric motor 21 for rotation can be suppressed.

  Next, FIG. 5 is a diagram showing a third example (torque characteristic 500) of the characteristic of the torque T with respect to the operation amount C of the turning operation of the turning electric motor 21 according to the present embodiment. In the following, the description will focus on the parts different from the first example.

  In addition, since the dead zone S51 and the maximum torque zone S53 in this example are the same as the dead zone S31 and the maximum torque zone S33 in the first example, description thereof is omitted.

  As shown in FIG. 5, in this embodiment, the torque characteristic 500 is different from the torque characteristics 300C1 and 300C2 according to the comparative example, as in the first example. Regardless of the torque T, the torque T is interlocked with the operation amount of the lever 26A in a one-to-one correspondence. Specifically, the torque characteristic 500 of the turning electric motor 21 is similar to that in the first example, and the torque T varies between the dead zone S51 and the maximum torque zone S53 according to the increase in the operation amount C of the lever 26A. It includes an increasing section S52 (an intermediate range between the operation amount C of the lever 26A from the predetermined value C1 to the predetermined value C2 (> C1)) increasing from zero to the maximum torque Tmax.

  The increase section S52 is located at the start of the increase section S52, and the torque increase rate of the turning electric motor 21 with respect to the operation amount C of the lever 26A increases, that is, the torque T increases upward as the operation amount C of the lever 26A increases. In this manner, the increase in the torque T is promoted with respect to the increase in the operation amount C of the lever 26A, and the increase promotion section S521 (the operation amount C of the lever 26A) similar to the first example (increase promotion section S321 in FIG. 3). Is a range between the predetermined value C1 and the predetermined value C3), and an increase suppression section S522 in which the torque increase rate with respect to the operation amount C of the lever 26A is suppressed (the operation amount C of the lever 26A is a predetermined value). C3 to a predetermined value C2).

  In the increase suppression section S522, the torque increase rate of the turning electric motor 21 with respect to the operation amount C of the lever 26A decreases, that is, the torque T increases in the bottom portion as the operation amount C of the lever 26A increases. In an aspect, an increase in torque T is suppressed. Specifically, in the increase suppression section S522, the torque T of the turning electric motor 21 decreases while the torque increase rate with respect to the operation amount C of the lever 26A decreases from the end position of the increase promotion section S521 (that is, an upward convex curve). At the end position (when the operation amount C of the lever 26A is a predetermined value C2), the maximum torque Tmax is reached. As a result, in the increase suppression section S522, the torque increase rate with respect to the operation amount C of the lever 26A gradually decreases according to the increase of the operation amount C of the lever 26A, and the above-described first example (FIG. 3) and the like. Similarly, since the operation amount C of the lever 26A at which the torque T of the turning electric motor 21 reaches the maximum torque Tmax can be brought close to the maximum operation amount Cmax, the range in which the operator can adjust the torque T of the turning electric motor 21 is expanded. Thus, the operability of the operator can be improved.

  6 is a diagram showing a fourth example (torque characteristic 600) of the torque T characteristic with respect to the operation amount C of the turning operation of the turning electric motor 21 according to the present embodiment. In the following, the description will focus on the parts different from the first example.

  As shown in FIG. 6, in this embodiment, the torque characteristic 600 is different from the torque characteristics 300C1 and 300C2 according to the comparative example, and the torque T does not depend on whether the operation amount of the lever 26A is increased or decreased. The lever 26A operates in a manner corresponding to the amount of operation of the lever 26A. Specifically, the torque characteristic 600 includes a dead zone section S61, an increase section S62, and a maximum torque section S63, as in the first example.

  On the other hand, in the present embodiment, in the dead zone S61, the torque T of the turning electric motor 21 is maintained at the predetermined value T1 (> 0) as a minimum value, and the operation amount C of the lever 26A is increased in the increase zone S62. Accordingly, the torque increases from a predetermined value T1 as a minimum value to a maximum torque Tmax. Thereby, for example, when the torque characteristic is adopted as the limit torque characteristic during the shovel pressing operation, the torque when the operation amount C of the lever 26A is returned to a relatively small region during the shovel pressing operation. If T becomes zero, the upper turning body 3 is pushed back by a reaction force from the object of pressing, and such a situation can be suppressed.

  In this embodiment, the case where the upper swing body 3 is driven by the turning electric motor 21 has been described. However, instead of the turning electric motor 21, for example, the upper rotating body is driven by a hydraulic motor (another example of the swing drive means). 3 may be configured to rotate. Also in this case, the same effect can be obtained by applying the embodiment shown in FIGS. 3 to 6 as the torque characteristics of the hydraulic motor. Specifically, for example, by applying a technique such as adjusting the pressure on the secondary side of the operating device 26 (lever 26A) with a pressure reducing valve or the like, the torque characteristic with respect to the operation amount C of the lever 26A is appropriately adjusted. Good.

  As mentioned above, although the form for implementing this invention was explained in full detail, this invention is not limited to this specific embodiment, In the range of the summary of this invention described in the claim, various Can be modified or changed.

3 Upper swing body 21 Electric motor for turning (turning drive means)
26 Operating device 26A Lever (operating lever)
300, 400, 500, 600 Torque characteristics

Claims (5)

A swivel,
Swivel drive means for driving the swivel body;
An operation lever for performing a turning operation of the turning body,
The swivel driving means has a first range in which the torque is less likely to increase relative to the increase in the stroke amount within the entire range of the stroke amount of the operating lever from when the torque starts to reach the maximum value. Having torque characteristics including,
Excavator. The torque characteristic includes a second range that is adjacent to both ends of the first range and the torque is likely to increase relatively with respect to an increase in the stroke amount at each of the first and last in the entire range.
The excavator according to claim 1. 3. The excavator according to claim 2, wherein the torque of the turning driving unit increases in a rising manner with respect to an increase in the stroke amount in the first second range in the entire range. The torque characteristic includes a range in which the torque increases at the bottom with respect to an increase in the stroke amount at the end of the entire range.
The excavator according to any one of claims 1 to 3. The torque of the turning drive means is linked with the stroke amount of the operation lever on a one-to-one basis regardless of whether the stroke amount is increasing or decreasing.
The excavator according to any one of claims 1 to 4.

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