JP2013122151A - Work machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a work machine capable of making effective use of energy given by operating oil while securing the operating responsiveness of a hydraulic actuator.SOLUTION: A power shovel includes a control valve 60 for controlling the supply of operating oil to a hydraulic cylinder 70, a main hydraulic pump 32 for supplying the operating oil to the control valve 60, a pilot valve 50 for generating pilot pressure, and a pilot hydraulic pump 33 for supplying the operating oil to the pilot valve 50. It further includes a hydraulic motor 40 provided in at least one of a first main oil path 60a and a first pilot oil path 33a, and adapted to be rotationally driven while receiving the operating oil, to regulate the pressure of the operating oil in the first main oil path 60a or the first pilot oil path 33a depending on rotational resistance against the rotational drive, and a power generation electric motor 41 for giving the rotational resistance to the hydraulic motor 40 while executing power generation with the regeneration of rotationally driving energy given to the hydraulic motor 40 by the operating oil.

Description

  The present invention relates to a working machine configured to perform various operations by operating a hydraulic actuator.

  An example of the work machine is a power shovel configured to perform work such as excavation. In general, a power shovel supplies hydraulic oil discharged from a main hydraulic pump to a hydraulic actuator (for example, a hydraulic motor or a hydraulic cylinder) provided corresponding to each of a traveling device, a turning device, a boom, an arm, a bucket, and the like. By supplying and operating, excavation work can be performed. The hydraulic oil discharged from the main hydraulic pump is once supplied to the control valve, and the supply direction and the supply amount are controlled by this control valve (valve spool in the control valve) and supplied to each hydraulic actuator. Regarding the control control of the control valve, for example, based on the hydraulic oil discharged from a pilot hydraulic pump provided separately from the main hydraulic pump, a pilot pressure corresponding to the operation on the operation lever is generated, and this pilot pressure is generated. A structure that acts on a control valve is well known (see, for example, Patent Documents 1 and 2).

  FIG. 5 shows a hydraulic circuit 500 of a conventional power shovel that controls the operation of the control valve by pilot pressure. When the electric motor 510 as a drive source is driven, hydraulic oil is discharged from the main hydraulic pump 520, and the discharged hydraulic oil is supplied to the hydraulic cylinder 570 via the control valve 560. On the other hand, the hydraulic oil discharged from the pilot hydraulic pump 530 is adjusted to, for example, about 3.5 MPa (hereinafter, this pressure is referred to as “predetermined pilot original pressure”) by the pilot oil passage relief valve 540, and the pilot valve 550. To be supplied. In the pilot valve 550, a pilot pressure corresponding to an operation on the operation lever 551 is generated based on hydraulic oil having a predetermined pilot original pressure. The pilot pressure is output to the control valve 560 so that movement of a valve spool (not shown) in the control valve 560 is controlled.

  In the hydraulic circuit 500, the hydraulic oil from the pilot hydraulic pump 530 is adjusted to a predetermined pilot original pressure by the pilot oil passage relief valve 540, and is always set to the pilot valve 550 regardless of whether the operation lever 551 is operated. It is configured to supply. Therefore, the pilot pressure can be quickly generated according to the operation on the operation lever 551, and the operation responsiveness of the hydraulic cylinder 570 to the operation on the operation lever 551 is ensured.

JP 2004-190439 A JP 2006-105324 A

  Thus, in the hydraulic circuit 500, even when the operation lever 551 is not operated, the hydraulic oil adjusted to the predetermined pilot original pressure is supplied to the pilot valve 550. The hydraulic oil discharged from the pump 530 is returned to the hydraulic oil tank without any work just by converting its energy (kinetic energy) into thermal energy in the relief valve for the pilot oil passage. The energy we had was wasted.

  Therefore, as one of the methods for reducing such waste of energy, the pilot hydraulic pump 530 is driven in accordance with the operation with respect to the operation lever 551 so that the pilot hydraulic pump 530 controls the pilot valve only when the operation lever 551 is operated. A method of supplying hydraulic oil having a predetermined pilot original pressure to 550 is conceivable. When this method is employed, the energy of the hydraulic oil is hardly wasted, but on the other hand, there arises a problem that the operation responsiveness of the hydraulic cylinder 570 to the operation of the operation lever 551 is lowered. As described above, there is a problem that it is difficult to effectively use the energy of the hydraulic oil while ensuring the operation responsiveness of the hydraulic actuator to the operation of the operation lever.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a work machine that can effectively use the energy of hydraulic oil while ensuring the operation response of the hydraulic actuator.

  In order to achieve the above object, a work machine according to the present invention (for example, the power shovel 1 in the embodiment) is for an actuator to a hydraulic actuator (for example, the hydraulic cylinder 70 in the embodiment) that operates by receiving supply of hydraulic oil. A control valve that controls supply of hydraulic oil, an actuator hydraulic oil supply source that supplies the actuator hydraulic oil to the control valve (for example, the main hydraulic pump 32 in the embodiment), and controls the operation of the control valve. A pilot pressure generating means (for example, the pilot valve 50 in the embodiment) for generating a pilot pressure for the pilot pressure, and a pilot hydraulic oil supply source for supplying the pilot hydraulic oil as a basis of the pilot pressure to the pilot pressure generating means ( For example, the pilot oil in the embodiment An actuator supply oil passage for supplying the actuator hydraulic oil from the actuator hydraulic oil supply source to the control valve (for example, the first main oil passage in the embodiment). 60a), and a pilot supply oil passage for supplying the pilot hydraulic oil from the pilot hydraulic oil supply source to the pilot pressure generating means (for example, the first pilot oil passage 33a and the second pilot oil in the embodiment) Provided in at least one of the passages 33b) and driven to rotate by receiving the actuator hydraulic fluid or the pilot hydraulic fluid, thereby operating in the actuator supply oil passage or the pilot supply oil passage. Actuating oil to a pressure according to the rotational resistance of this rotational drive The rotational resistance is applied to pressure adjusting means (for example, the hydraulic motor 40 in the embodiment) and the hydraulic oil pressure adjusting means, and the hydraulic oil pressure adjusting means receives from the actuator hydraulic oil or the pilot hydraulic oil. Regenerative power generation means (for example, the electric motor 41 for power generation in the embodiment) that regeneratively generates rotational drive energy is provided.

  In the work machine described above, the actuator is provided in the actuator supply oil passage or the pilot supply oil passage corresponding to the hydraulic oil pressure adjusting means, and is provided in the actuator supply oil passage or the pilot supply oil passage. Based on the detection result of the pressure detection means (for example, the pressure sensor 80 in the embodiment) and the detection result of the pressure detection means, the operation in the actuator supply oil path or the pilot supply oil path is detected. Rotational resistance control means (for example, rotational resistance control controller 81 in the embodiment) that controls the rotational resistance applied to the hydraulic oil pressure adjusting means by the regenerative power generation means so that the oil pressure becomes a predetermined pressure. It is preferable to provide.

  Further, it is preferable that the hydraulic oil pressure adjusting means is constituted by a hydraulic motor that is rotationally driven in response to the actuator hydraulic fluid or the pilot hydraulic fluid.

  Furthermore, the regenerative power generation means is constituted by an electric motor, and the electric motor causes the rotation resistance corresponding to the applied power to act on the hydraulic oil pressure adjusting means, and in the hydraulic oil pressure adjusting means. It is preferable that regenerative power generation is performed when a rotational driving force is input.

  In the above working machine, it is preferable that the hydraulic oil pressure adjusting means is provided in the pilot supply oil passage.

  The work machine according to the present invention receives hydraulic oil and is rotationally driven to adjust the hydraulic oil to a pressure corresponding to the rotational resistance at this time, and the hydraulic oil pressure adjusting means has rotational resistance. And a regenerative power generation means for regenerating the rotational drive energy received from the hydraulic oil by the hydraulic oil pressure adjusting means. For this reason, by providing the hydraulic oil pressure adjusting means, for example, in the pilot supply oil passage, the hydraulic oil in the pilot supply oil passage can be adjusted by the hydraulic oil pressure adjusting means. The energy of hydraulic oil can be extracted as a rotational motion. And since the rotational motion taken out by the hydraulic oil pressure adjusting means is converted into electric energy (electric power) that can be reused by the regenerative power generating means and recovered, the hydraulic oil can be constantly supplied to the pilot pressure generating means. The energy of hydraulic oil is unlikely to be wasted. Therefore, while always supplying the hydraulic oil to the pilot pressure generating means and ensuring the operation responsiveness of the hydraulic actuator, the energy of the hydraulic oil is recovered as electric energy and can be used effectively.

  In the work machine described above, the hydraulic oil is adjusted by the pressure detection means for detecting the pressure of the hydraulic oil in the actuator supply oil path or the pilot supply oil path, and the regenerative power generation means so that the pressure of the hydraulic oil becomes a predetermined pressure. It is preferable to include rotation resistance control means for controlling rotation resistance applied to the pressure means. When configured in this manner, it is possible to control the rotational resistance that acts while feeding back the pressure detected by the pressure detection means, and it is possible to maintain the hydraulic oil pressure at a predetermined target pressure.

  Moreover, it is preferable that the hydraulic oil pressure adjusting means is constituted by a hydraulic motor that is driven to rotate by receiving the hydraulic oil. In the case of this configuration, it becomes possible to efficiently convert the energy of the hydraulic oil into a rotational motion (with little loss) and take it out, thereby increasing the recovery efficiency of the energy of the hydraulic oil.

  Furthermore, it is preferable that the regenerative power generation means is constituted by an electric motor. When configured in this manner, for example, the rotational resistance can be controlled by controlling the supply of electric power to the electric motor, and the rotational driving force in the hydraulic oil pressure adjusting means can be efficiently regenerated.

  In the work machine described above, it is preferable that the hydraulic oil pressure adjusting means is provided in the pilot supply oil passage. In the case of this configuration, by always supplying hydraulic oil to the pilot pressure generating means, it is possible to recover and reuse the energy of the hydraulic oil while ensuring the operation response of the hydraulic actuator.

It is a perspective view of a power shovel as an example of a work machine to which the present invention is applied. It is the hydraulic circuit of the said power shovel. It is explanatory drawing for demonstrating control of the electric motor for electric power generation. It is a flowchart regarding control of the electric motor for electric power generation. It is the hydraulic circuit of the conventional power shovel.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a crawler-type power shovel 1 as an example of a working machine to which the present invention is applied. First, the overall configuration of the power shovel 1 will be described with reference to FIG.

  The power shovel 1 includes a traveling device 4 configured by providing traveling mechanisms 3 and 3 on the left and right of a traveling carriage 2 (vehicle body) that is substantially H-shaped in a plan view, and a swinging portion that can swing up and down at the rear portion of the traveling carriage 2. The blade 5 provided on the swivel base 2, the swivel base 6 provided at the upper part of the traveling carriage 2, the shovel mechanism 7 provided at the front part of the swivel base 6, and the upper part of the swivel base 6. It is composed of an operator cabin 8 (vehicle body) for boarding the driver.

  A pair of left and right traveling mechanisms 3, 3 constituting the traveling device 4 is provided between a driving sprocket wheel 9 provided at the left and right front part of the traveling carriage 2 and an idler wheel 10 provided at the left and right rear parts of the traveling carriage 2. The crawler belt 11 is wound around. The drive sprocket wheel 9 is rotationally driven by a traveling hydraulic motor (not shown) that is hydraulically operated. The blade 5 is swung by the operation of a hydraulically driven blade cylinder (not shown), and the swivel base 6 is swung by a swivel hydraulic motor (not shown) that is hydraulically operated. The traveling hydraulic motor is provided corresponding to each of the pair of left and right drive sprocket wheels 9.

  The shovel mechanism 7 includes a boom 12 pivotably connected to the front of the swivel base 6, and an arm 13 pivotally connected to the tip of the boom 12 so as to swing up and down within the undulating surface of the boom 12. The bucket 14 is pivotally connected to the tip of the arm 13 so as to be swingable up and down, a hydraulically driven boom cylinder 15, an arm cylinder 16, and a bucket cylinder 17. The boom 12 is raised and lowered by a boom cylinder 15, the arm 13 is swung by an arm cylinder 16, and the bucket 14 is swung by a bucket cylinder 17. In the following description, a traveling hydraulic motor, a blade cylinder, and the like that are hydraulically operated are collectively referred to as a “hydraulic actuator”.

  The operator cabin 8 is formed in a rectangular box shape in which the top, bottom, front, rear, left and right are surrounded, and an operator seat 18 for the driver to sit forward is provided inside. A pair of right operation levers 19 and a left operation lever 20 for operating the excavator mechanism 7 and the like are provided on the left and right sides of the operator seat 18. A pair of right travel operation levers 21 and left travel operation levers 22 for operating the travel device 4 are provided. The right travel operation lever 21 is an operation lever for operating a travel hydraulic motor disposed on the right side of the travel device 4, and the left travel operation lever 22 is a travel hydraulic pressure disposed on the left side of the travel device 4. This is an operating lever for operating the motor.

  In the power shovel 1 configured as described above, an operator sits on the operator seat 18 and tilts the right work operation lever 19 and the left work operation lever 20 back and forth and right and left, or the right travel operation lever 21. Further, the left excavation lever 22 is tilted back and forth, whereby the excavator 1 can be run forward and backward, the excavator mechanism 7 and the like are operated, and excavation work and the like can be performed.

  So far, the overall configuration of the power shovel 1 has been described. The power shovel 1 configured as described above includes a hydraulic circuit 30 having an electric motor 31 as a drive source as shown in FIG. 2, and the hydraulic circuit 30 controls the supply of hydraulic oil to the hydraulic actuator. Is called. The hydraulic circuit 30 will be described below with additional reference to FIGS.

  The hydraulic circuit 30 is roughly divided into a main oil passage 35 for supplying hydraulic oil to the hydraulic actuator, and a pilot oil passage 36 for applying a pilot pressure to a control valve provided corresponding to each hydraulic actuator. Composed. FIG. 2 shows a control valve 60 that is controlled by the pilot pressure generated by the pilot valve 50 corresponding to the right work operating lever 19, and a hydraulic cylinder that is controlled by the control valve 60 to supply hydraulic oil. 70 is extracted and shown.

  The main oil passage 35 includes a main hydraulic pump 32 driven by the electric motor 31, a hydraulic cylinder 70 as one of hydraulic actuators, and a control valve 60 that controls supply of hydraulic oil to the hydraulic cylinder 70. Consists of The main hydraulic pump 32 and the control valve 60 are connected by a first main oil passage 60a, and the control valve 60 and the hydraulic oil tank 39 are connected by a second main oil passage 60b.

  The main hydraulic pump 32 is a variable displacement hydraulic pump configured to be able to control the discharge amount of hydraulic oil in accordance with the inclination angle of the swash plate. It is controlled according to the tilting operation, and is configured to be able to discharge hydraulic oil in an amount corresponding to the required amount. The main hydraulic pump 32 is rotationally driven by the electric motor 31 to suck up the hydraulic oil in the hydraulic oil tank 39 and discharge it to the first main oil passage 60a.

  The control valve 60 is configured to have a valve spool (not shown) movably inside, and the supply amount and supply direction of hydraulic oil to the hydraulic cylinder 70 are controlled according to the movement position of the valve spool. . The first main oil passage 60a is provided with a main oil passage relief valve (not shown) for adjusting the working oil in the first main oil passage 60a to a predetermined main pressure, and the second main oil passage 60b is provided with a filter 38 that filters and collects dust and the like mixed in the hydraulic oil.

  In the main oil passage 35 configured as described above, when the electric motor 31 is driven, the hydraulic oil discharged from the main hydraulic pump 32 is regulated to a predetermined main pressure by the main oil passage relief valve and 1 is supplied to the control valve 60 via the main oil passage 60a, and further supplied to the hydraulic cylinder 70 in the supply direction and supply amount controlled by the control valve 60. The hydraulic fluid returned from the hydraulic cylinder 70 to the control valve 60 and the hydraulic fluid that has been supplied to the control valve 60 via the first main oil passage 60a but has not been supplied to the hydraulic cylinder 70 are retained. The hydraulic oil tank 39 is returned and stored via the second main oil passage 60b.

  The pilot oil passage 36 includes a fixed displacement pilot hydraulic pump 33, a hydraulic motor 40, a power generation electric motor 41, a pilot valve 50, a pressure sensor 80, a rotation resistance control controller 81, a current control circuit 82, and a battery 90. Is done. The pilot hydraulic pump 33 and the hydraulic motor 40 are connected by a first pilot oil passage 33a. The first pilot oil passage 33a and the pilot valve 50 are connected by a second pilot oil passage 33b. 2 main oil passage 60b is connected by the third pilot oil passage 33c.

  The pilot hydraulic pump 33 is rotationally driven by the electric motor 31 to suck up the hydraulic oil in the hydraulic oil tank 39 and discharge it to the first pilot oil passage 33a.

  The hydraulic motor 40 is provided at a connecting portion between the first pilot oil passage 33a and the third pilot oil passage 33c, and receives hydraulic oil discharged from the pilot hydraulic pump 33 to the first pilot oil passage 33a and is driven to rotate. Is done. The output shaft of the hydraulic motor 40 is connected to a motor drive shaft 42 (see FIG. 3) of the electric motor 41 for power generation, and the motor drive shaft 42 of the electric motor 41 for power generation is driven by the hydraulic motor 40 being driven to rotate. It is configured to be rotationally driven. For this reason, the rotational resistance is applied to the motor drive shaft 42 as will be described later, whereby the rotational resistance can be applied to the hydraulic motor 40, and the hydraulic oil in the first pilot oil passage 33a and the second pilot oil passage 33b. Can be adjusted to a pressure corresponding to the rotational resistance of the hydraulic motor 40.

  As shown in FIG. 3, the electric motor 41 for power generation includes a motor drive shaft 42 that is rotatably disposed in the center portion, and a plurality of coils 43 that are disposed so as to surround the motor drive shaft 42. It is configured with. The motor drive shaft 42 includes a shaft main body 42a and a plurality of magnets 42b arranged on the surface of the shaft main body 42a in the circumferential direction. Therefore, the rotational resistance acting on the motor drive shaft 42 can be controlled by controlling the direction in which the current flows and the magnitude of the current for each coil 43. In the power shovel 1 according to the present embodiment, the electric motor for power generation is set so that the hydraulic oil in the first pilot oil passage 33a and the second pilot oil passage 33b has a predetermined pilot original pressure of, for example, about 3.5 MPa. The rotational resistance of the hydraulic motor 40 is controlled by 41.

  On the other hand, when the hydraulic motor 40 is rotated by receiving hydraulic oil, the motor drive shaft 42 connected to the output shaft of the hydraulic motor 40 is rotationally driven. When the shaft 42 is rotationally driven, a current is generated in the coil 43, and this current is stored in the battery 90 via the current control circuit 82 (details will be described later). In this way, the electric motor 41 for power generation controls the rotational resistance of the hydraulic motor 40, so that the hydraulic oil in the first pilot oil passage 33a (second pilot oil passage 33b) is adjusted to a pressure corresponding to this rotational resistance. A function of adjusting pressure and a function of performing regenerative power generation based on the rotational driving force in the hydraulic motor 40 are provided.

  The control valve 60 is configured such that a valve spool (not shown) is movably inserted into the control valve 60, and the hydraulic oil supplied from the main hydraulic pump 32 is passed through an oil passage corresponding to the moving position of the valve spool. The supply direction and supply amount of hydraulic oil to the hydraulic actuator 70 are controlled by supplying the hydraulic actuator 70 via the hydraulic actuator 70.

  The pilot valve 50 is supplied with hydraulic oil discharged from the pilot hydraulic pump 33 and adjusted to a predetermined pilot original pressure by the hydraulic motor 40. Based on the hydraulic oil having the predetermined pilot original pressure, the right operation lever is operated. The pilot pressure corresponding to the tilting operation with respect to 19 is generated. The pilot pressure generated in this manner is output to the pilot ports 61 and 62 provided at the end of the control valve 60, so that the movement control of the valve spool according to the operation with respect to the right working operation lever 19 can be performed. Done.

  The pressure sensor 80 is provided in the first pilot oil passage 33 a, and the pressure of the hydraulic oil in the first pilot oil passage 33 a (second pilot oil passage 33 b), that is, the hydraulic oil supplied to the pilot valve 50. The pressure can be detected. The pressure detected by the pressure sensor 80 is output to the rotation resistance controller 81.

  The rotation resistance controller 81 controls the direction of the current supplied to each coil 43 via the current control circuit 82 and the magnitude of the current, so that the rotation resistance acting on the motor drive shaft 42 according to the Fleming left-hand rule. Can be controlled.

  As shown in FIG. 3, the current control circuit 82 is electrically connected to the electric motor 41 for generation (coil 43), and has four diodes 84 having a function of flowing a current in a predetermined direction, and can store the current. A possible capacitor 85, a Zener diode 86 for keeping the voltage between the positive and negative electrodes of the capacitor 85 constant, and an electric resistance 87 for restricting the current from the rotation resistance controller 81 to flow directly into the capacitor 85. It is configured with. When the hydraulic motor 40 is rotated by receiving hydraulic oil and the motor drive shaft 42 is driven to rotate, the position of the magnet 42 with respect to the coil 43 changes, so that a current is generated in the coil 43 in accordance with the Fleming right-hand rule. This current is stored in the capacitor 85 via the electric resistance 87. In this way, the current (power) temporarily stored in the capacitor 85 is sent to the battery 90 and stored.

  In FIG. 3, the current control circuit 82 provided corresponding to one coil 43 among the plurality of coils 43 is illustrated, but actually, the current control circuit 82 is associated with each coil 43. Is provided, and current supply control for each coil 43 is independently performed by the rotation resistance controller 81.

  The battery 90 is a battery that can be charged by, for example, a commercial power supply, and as described above, the electric power regenerated in the electric motor 41 for power generation is sent via the current control circuit 82 and stored. The electric power stored in the battery 90 is mainly used as a power source for driving the electric motor 31.

  In the power shovel 1 provided with such a hydraulic circuit 30, the main hydraulic pump 32 and the pilot hydraulic pump 33 are driven by starting the electric motor 31, and the hydraulic oil discharged from the main hydraulic pump 32 is the first. While being supplied to the control valve 60 via the main oil passage 60a, the hydraulic oil discharged from the pilot hydraulic pump 33 is supplied to the pilot valve 50 via the first pilot oil passage 33a and the second pilot oil passage 33b. . In this state, for example, when the right working operation lever 19 is operated, the pilot valve 50 generates a pilot pressure corresponding to this operation, and the generated pilot pressure is output to the control valve 60.

  Then, in the control valve 60, the valve spool is moved according to the input pilot pressure, and the hydraulic oil from the main hydraulic pump 32 is supplied to the hydraulic cylinder 70 in the supply direction and supply amount according to the movement position of the valve spool. Supplied to. In this way, a desired work can be performed by causing the hydraulic cylinder 70 to perform an expansion / contraction operation corresponding to the operation on the right work operation lever 19.

  Up to here, the hydraulic circuit 30 of the power shovel 1 has been described. Below, control of the electric motor 41 for electric power generation is demonstrated, referring the flowchart shown in FIG.

  First, in step S110 shown in FIG. 4, in the state where the electric motor 31 is activated, the pressure sensor 80 detects the pressure of the hydraulic oil in the first pilot oil passage 33a, and the detection result is sent to the rotation resistance controller 81. Entered.

  Subsequently, the process proceeds to step S120, where the rotation resistance controller 81 determines whether or not the pressure detected by the pressure sensor 80 is greater than a predetermined pilot base pressure. If it is determined that the detected pressure is greater than the predetermined pilot original pressure, the process proceeds to step S131, and the rotation resistance controller 81 reduces the rotation resistance of the motor drive shaft 42 with respect to the coil 43. Perform current supply control. By doing so, since the rotational resistance of the motor drive shaft 42, that is, the rotational resistance of the hydraulic motor 40 is reduced, the pressure of the hydraulic oil in the first pilot oil passage 33a is lowered to approach the predetermined pilot original pressure. Can do.

  On the other hand, when it is determined that the pressure detected by the pressure sensor 80 is smaller than the predetermined pilot original pressure, the process proceeds to step S132, and the rotation resistance controller 81 sets the rotation resistance of the motor drive shaft 42 to the coil 43. Increase current supply control. By doing so, since the rotational resistance of the motor drive shaft 42 (rotational resistance of the hydraulic motor 40) is increased, the pressure of the hydraulic oil in the first pilot oil passage 33a can be raised to approach the predetermined pilot original pressure. it can.

  By repeating step S120, step S131, and step S132 described above, for example, the right working operation lever 19 is operated and pilot pressure is generated in the pilot valve 50, so that the operation in the first pilot oil passage 33a is performed. Even when the oil pressure is temporarily lowered, it is possible to quickly raise the oil pressure to return to the predetermined pilot original pressure.

  In this way, when the electric motor 31 is activated, the hydraulic oil discharged from the pilot hydraulic pump 33 is regulated to a predetermined pilot original pressure and is constantly supplied to the pilot valve 50. A pilot pressure can be quickly generated in response to an operation on the operation lever 19 and the like, and the operation response of the hydraulic actuator can be ensured. Further, by providing the hydraulic motor 40 and the electric motor 41 for power generation, the energy of the hydraulic oil that is always discharged from the pilot hydraulic pump 33 to the first pilot oil passage 33a can be recovered and stored as electric energy. This makes it possible to effectively use the energy of the hydraulic oil without wasting it.

  In particular, in the conventional configuration, when the operation lever is not operated, the energy of the hydraulic oil is wasted by being converted into heat energy by the relief valve. On the other hand, in the power shovel 1 to which the present invention is applied, The energy of the hydraulic oil is converted into electric energy, and is effectively used as a power source for driving the electric motor 31, for example. Furthermore, the electric power stored in the battery 90 is consumed by starting the electric motor 31, but at the same time, the electric power recovered by the electric motor 41 for power generation is stored in the battery 90. The power shovel 1 can be operated for a long time by charging, and the work efficiency of excavation work can be improved.

  In the above-described embodiment, the power shovel 1 using the electric motor 31 as a drive source has been described as an example, but the present invention is not limited to this configuration. The present invention can be applied to a work machine equipped with, for example, an engine (diesel engine) instead of the electric motor. In addition, in the case of a configuration in which an engine is mounted as a drive source in this manner, an alternator that generally generates power using the rotational driving force of the engine is mounted, and the obtained electric power is stored in a battery so that an electrical component (e.g. It is used as a power source for lighting. Therefore, by applying the present invention to a configuration equipped with an engine and an alternator, the energy of hydraulic oil can be collected in addition to the alternator and electric power can be stored in the battery. For example, a small alternator is installed. Even in this case, sufficient power can be stored in the battery.

  In the above-described embodiment, a configuration in which the hydraulic oil 40 and the electric motor 41 for power generation are provided in the pilot oil passage 36 to collect and effectively use the energy of the hydraulic oil discharged from the pilot hydraulic pump 33 is exemplified. Although described, the present invention is not limited to this configuration. For example, instead of the main oil passage relief valve provided in the first main oil passage 60a, a hydraulic motor and an electric motor for power generation are provided to recover the energy of the hydraulic oil in both the main oil passage and the pilot oil passage. You may comprise. In such a configuration, the energy of the hydraulic oil in the main oil passage can be recovered in addition to the pilot oil passage, so that waste of energy can be further reduced as the entire power shovel. If the hydraulic oil and the electric motor for power generation can be collected more efficiently in the main oil path than in the pilot oil path, the hydraulic motor and the electric motor for power generation can be used only for the main oil path. The structure provided in can also be possible.

  The current control circuit 82 shown in the above-described embodiment is an example, and it is possible to supply the current from the rotation resistance controller 81 to the coil 43 and to collect and temporarily store the current generated in the coil 43. Any other configuration may be used.

  In the above embodiment, the pilot valve 50 is generated according to the operation of the operation lever in the pilot valve 50 and the movement of the valve spool is controlled by the pilot pressure. However, the present invention is limited to this configuration. It does not apply. For example, the present invention can be applied to a power shovel having a configuration in which movement of the valve spool is controlled based on the electric signal by converting the operation on the operation lever into an electric signal and outputting the electric signal to the control valve. In this case, instead of the relief valve for the main oil passage, a hydraulic motor and an electric motor for power generation are provided, so that the energy of the hydraulic oil in the main oil passage is recovered and stored as electric power.

  In addition, the present invention is also applied to a power shovel having a configuration in which the operation lever and the control valve are connected by a wire, and the operation of the operation lever is transmitted to the control valve through the wire, thereby controlling the movement of the valve spool. Is possible. When the present invention is applied to this configuration, a hydraulic motor and an electric motor for power generation are provided in place of the relief valve of the main oil passage, and the energy of the hydraulic oil in the main oil passage is recovered and stored as electric power. The

  In the above-mentioned embodiment, although the example which applied this invention to the power shovel 1 was demonstrated, this invention is limited to the power shovel 1 and is not applied. The present invention can be applied to all work machines including a hydraulic actuator that is operated by hydraulic oil discharged from a hydraulic pump, and can also be applied to, for example, a skid steer loader.

1 Excavator (work machine)
32 Main hydraulic pump (operating oil supply source for actuator)
33 Pilot hydraulic pump (pilot hydraulic oil supply source)
33a First pilot oil passage (pilot supply oil passage)
33b Second pilot oil passage (pilot supply oil passage)
40 Hydraulic motor (hydraulic pressure adjusting means)
41 Electric motor for power generation (regenerative power generation means)
50 Pilot valve (pilot pressure generating means)
60 Control valve 60a First main oil passage (actuator supply oil passage)
70 Hydraulic cylinder (hydraulic actuator)
80 Pressure sensor (pressure detection means)
81 Rotation resistance controller (rotation resistance control means)

Claims (5)

A control valve for controlling the supply of hydraulic fluid for the actuator to the hydraulic actuator that operates upon receiving the supply of hydraulic fluid;
An actuator hydraulic oil supply source for supplying the actuator hydraulic oil to the control valve;
Pilot pressure generating means for generating a pilot pressure for controlling the operation of the control valve;
A working machine having a pilot hydraulic fluid supply source for supplying pilot hydraulic fluid as a basis for the pilot pressure to the pilot pressure generating means;
An actuator supply oil path for supplying the actuator hydraulic oil from the actuator hydraulic oil supply source to the control valve, and the pilot hydraulic oil from the pilot hydraulic oil supply source to the pilot pressure generating means Provided in at least one of the pilot supply oil passages for receiving the actuator hydraulic oil or the pilot hydraulic oil and being driven to rotate, thereby providing the actuator supply oil passage or the pilot supply. Hydraulic oil pressure adjusting means for adjusting the hydraulic oil in the oil passage to a pressure corresponding to the rotational resistance in the rotational drive;
The rotational resistance is applied to the hydraulic oil pressure adjusting means, and the hydraulic oil pressure adjusting means includes regenerative power generating means for regeneratively generating rotational drive energy received from the actuator hydraulic oil or the pilot hydraulic oil. Features a working machine. Corresponding to the hydraulic oil pressure adjusting means, provided in the actuator supply oil passage or the pilot supply oil passage, the pressure of the hydraulic oil in the actuator supply oil passage or the pilot supply oil passage is detected. Pressure detecting means for
Based on the detection result in the pressure detecting means, the regenerative power generation means adjusts the hydraulic oil pressure adjusting means so that the pressure of the hydraulic oil in the actuator supply oil path or the pilot supply oil path becomes a predetermined pressure. The work machine according to claim 1, further comprising: a rotation resistance control unit configured to control the rotation resistance acting on the machine.   3. The work machine according to claim 1, wherein the hydraulic oil pressure adjusting unit is configured by a hydraulic motor that is rotationally driven in response to the actuator hydraulic fluid or the pilot hydraulic fluid. 4. The regenerative power generation means is constituted by an electric motor,
The electric motor is configured to cause the rotational resistance corresponding to the applied electric power to act on the hydraulic oil pressure adjusting means, and to generate regenerative power when the rotational driving force in the hydraulic oil pressure adjusting means is input. The work machine according to any one of claims 1 to 3.   The work machine according to claim 1, wherein the hydraulic oil pressure adjusting means is provided in the pilot supply oil passage.

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