JP2014206253A - Hydraulic circuit, construction machine having hydraulic circuit, and control method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic circuit which can improve energy utilization efficiency by using a recovery oil passage recovering return oil of a hydraulic actuator and a regeneration oil passage regenerating the return oil to recover and regenerate the return oil, and to provide a construction machine and a control method of the hydraulic circuit.SOLUTION: A hydraulic circuit includes a recovery oil passage 23Rc recovering return oil of a hydraulic actuator 22F, and a regeneration oil passage 23Rr regenerating the return oil of the hydraulic actuator 22F. The recovery oil passage includes a recovery part 21C recovering energy of the return oil, and a discharge part 21ex discharging the recovered return oil. The regeneration oil passage 23Rr re-supplies a part or all of the return oil to the hydraulic actuator 22F.

Description

  The present invention relates to a hydraulic circuit, a construction machine including the hydraulic circuit, and a control method thereof.

  Some hydraulic circuits of construction machines supply pressure oil to hydraulic actuators (for example, hydraulic cylinders, hydraulic motors) to drive attachments. At this time, the hydraulic actuator discharges part or all of the supplied pressure oil as return oil. Here, the discharged return oil has surplus energy (pressure, flow rate, etc.). For this reason, some hydraulic circuits of construction machines resupply (regenerate) the returned return oil to the hydraulic actuator for the purpose of effectively using surplus energy of the return oil.

  Patent Document 1 discloses a technique related to a construction machine including a regeneration circuit that returns pressure oil flowing out from a rod chamber (hydraulic cylinder) to a head chamber (hydraulic cylinder).

JP 2010-14244 A

  However, in the technique disclosed in Patent Document 1, a pressure loss occurs in a throttle (for example, the meter-out control valve Vex in FIG. 4) arranged downstream of the regeneration circuit, and thus energy loss occurs during regeneration. In the technique disclosed in Patent Document 1, pressure oil (return oil) is regenerated through a check valve (for example, Vch in FIG. 4) disposed in an internal passage of a directional control valve (for example, 21V in FIG. 4). Therefore, a pressure loss is generated by the relatively narrow internal passage of the direction control valve (21V) and the check valve (Vch) during regeneration. Furthermore, in the technique disclosed in Patent Document 1, when the regeneration is not necessary due to the operation state of the hydraulic actuator, the pressure oil (return oil) is discharged to the tank as it is, so that the energy (return oil) may not be effectively used. is there.

  The present invention is made under such circumstances, and the energy utilization efficiency is achieved by regenerating or regenerating the return oil using the regenerative oil path for regenerating the return oil of the hydraulic actuator and the regenerated oil path for regenerating. An object of the present invention is to provide a hydraulic circuit capable of improving the pressure. Further, the present invention may be a construction machine including the hydraulic circuit. Furthermore, the present invention may be a method for controlling the hydraulic circuit.

  According to one aspect of the present invention, a hydraulic circuit that supplies pressure oil to a hydraulic actuator to drive the hydraulic actuator, the regenerative oil passage that regenerates return oil of the hydraulic actuator, and the hydraulic actuator A reclaimed oil path for regenerating the return oil, the regenerative oil path comprising a recovery unit for recovering the energy of the return oil, and a discharge unit for discharging the return oil recovered from the energy, The reclaimed oil passage is provided with a hydraulic circuit characterized in that a part or all of the return oil is re-supplied to the hydraulic actuator. The recovery unit may be a hydraulic circuit in which a generator is mechanically connected to an output shaft or a pressure accumulator that accumulates a part or all of the return oil. . In the hydraulic circuit, the hydraulic actuator may further include a branch portion that is disposed in an oil passage through which the return oil flows out and branches the return oil into the regenerative oil passage and the regenerated oil passage. Good. The regenerative oil passage may be a hydraulic circuit characterized by further having a pressure accumulating portion that accumulates a part or all of the return oil flowing. The reclaimed oil passage further includes a pressure oil increasing portion that increases the flow rate of the return oil using the pressure energy of the return oil that circulates, and the pressure oil increasing portion is configured to increase the flow rate of the return oil. It may be a hydraulic circuit characterized in that a part or all of the pressure is accumulated in the pressure accumulating unit. A plurality of the hydraulic actuators, using the regenerative oil passage, regenerating part or all of the return oil of one of the plurality of hydraulic actuators, and using the regenerated oil passage, The hydraulic circuit may be characterized in that part or all of the return oil of one of the hydraulic actuators is re-supplied to the one hydraulic actuator or another hydraulic actuator. The construction machine may include the hydraulic circuit described in any one of the hydraulic circuits.

  According to another aspect of the present invention, there is provided a control method for a hydraulic circuit including a regenerative oil passage for regenerating the return oil of a hydraulic actuator and a regenerative oil passage for regenerating the return oil of the hydraulic actuator, wherein the hydraulic pressure A regeneration step of regenerating the return oil of the actuator, and a regeneration step of regenerating the return oil of the hydraulic actuator, wherein the regeneration step uses an energy of the return oil using a recovery unit disposed in the regeneration oil path. And the return oil from which the energy has been recovered is discharged using a discharge unit disposed in the regenerative oil passage, and the regeneration step re-supplyes part or all of the return oil to the hydraulic actuator. A method for controlling a hydraulic circuit is provided. In the hydraulic circuit control method, the regeneration step further includes a pressure accumulation step of accumulating a part or all of the return oil that circulates using a pressure accumulation unit disposed in the regeneration oil path. May be. The regeneration step further includes a pressure oil increasing step of increasing the flow rate of the return oil by using the pressure energy of the return oil flowing through the pressure oil increasing unit disposed in the regeneration oil path. The control method of the hydraulic circuit may be used.

  According to the hydraulic circuit, the construction machine including the hydraulic circuit, or the control method of the hydraulic circuit according to the present invention, the return oil is regenerated using the regenerative oil path that regenerates the return oil and the regenerated oil path that regenerates the hydraulic actuator. The energy utilization efficiency can be improved by regeneration or regeneration.

1 is a schematic external view illustrating an example of a construction machine according to an embodiment of the present invention. It is a schematic circuit diagram explaining an example of the hydraulic circuit of the construction machine which concerns on the 1st Embodiment of this invention. It is a schematic circuit diagram explaining an example of the hydraulic circuit of the construction machine which concerns on the 2nd Embodiment of this invention. It is a schematic circuit diagram explaining the other example of the hydraulic circuit of a construction machine.

  Non-limiting exemplary embodiments of the present invention will be described with reference to the accompanying drawings. In the description of all attached drawings, the same or corresponding members or parts are denoted by the same or corresponding reference numerals, and redundant description is omitted. Also, the drawings are not intended to show the relative ratio between members or parts. Accordingly, specific dimensions can be determined by one skilled in the art in light of the following non-limiting embodiments.

  Hereinafter, the present invention will be described using a construction machine according to an embodiment of the present invention. In addition to the present embodiment, the present invention is provided with a hydraulic actuator (hydraulic cylinder, hydraulic motor, etc.) (machine, equipment, device, unit, system, etc.) and regenerates the return oil from the hydraulic actuator. Any hydraulic circuit can be used. Construction machines that can use the present invention include hydraulic excavators, crane trucks, bulldozers, wheel loaders and dump trucks, pile driving machines, pile removers, water jets, mud drainage treatment equipment, grout mixers, deep Includes foundation and drilling machines. Furthermore, the present invention can also be used for a hybrid excavator, a construction machine (work machine) equipped with a battery, a machine that recovers energy using an accumulator, and the like.

  The present invention will be described in the following order using the construction machine 100 according to the present embodiment.

1. Construction machine construction 2. Hydraulic circuit according to the first embodiment. Hydraulic circuit according to the second embodiment [1. Construction machine construction]
A schematic configuration of a construction machine 100 according to an embodiment of the present invention will be described with reference to FIG.

  As shown in FIG. 1, the construction machine 100 according to the present embodiment includes an upper swing body 10Up on which a cab (cab) 10Cb is mounted, and a lower traveling body 10Dw that moves the construction machine 100 using wheels and the like. Prepare. Further, the construction machine 100 includes, as an attachment, a boom 11 whose base end is pivotally supported by the upper swing body 10Up, an arm 12 pivotally supported by the distal end of the boom 11, and a bucket pivotally supported by the distal end of the arm 12. 13. Further, the construction machine 100 includes, as hydraulic actuators, a boom cylinder 11 a that drives the boom 11, an arm cylinder 12 a that drives the arm 12, and a bucket cylinder 13 a that drives the bucket 13. In addition, the construction machine which can use this invention may use attachments other than a bucket as an attachment (or end attachment) attached to an arm.

  The construction machine 100 according to the present embodiment supplies the hydraulic oil (pressure oil) to the boom cylinder 11a by using a hydraulic circuit (for example, 110 of FIG. 2 described later or 120 of FIG. 3), and thereby the boom cylinder. 11a is expanded and contracted in the longitudinal direction. At this time, the boom 11 is driven in the vertical direction in front of and above the cab 10Cb by expansion and contraction of the boom cylinder 11a. Further, the construction machine 100 controls the boom direction control valve according to the operation amount (and operation direction) of the operation lever of the operator (driver, operator) in the cab 10Cb, and is supplied to the boom cylinder 11a. Control the oil. As a result, the construction machine 100 can perform a desired work according to the operation amount of the operation lever of the operator.

  As in the case of the boom 11, the construction machine 100 drives the arm 12 and the bucket 13 in front of and / or above the cab 10Cb by expansion and contraction of the arm cylinder 12a and the bucket cylinder 13a. As in the case of the boom cylinder 11a, the construction machine 100 controls the hydraulic oil supplied to the arm cylinder 12a and the bucket cylinder 13a by the arm direction control valve and the bucket direction control valve.

  Moreover, the construction machine 100 according to the present embodiment uses the wheels of the lower traveling body 10Dw and the turning motor 14M to travel (moving back and forth and from side to side) and rotate (turn, etc.) the main body of the construction machine 100. Further, the construction machine 100 may further use the traveling direction control valve or the like to travel the construction machine 100 according to the operation amount of the operation lever of the operator in the cab 10Cb.

  Furthermore, the construction machine 100 according to the present invention uses hydraulic oil (pressure oil) supplied to the boom cylinder 11a, the arm cylinder 12a, or the bucket cylinder 13a using a regenerative oil passage (for example, 23Rc in FIG. 2 or FIG. 3 described later). The return oil (energy) is recovered. Further, the construction machine 100 re-supplys the return oil from the boom cylinder 11a or the like to the boom cylinder 11a or the like using a regenerated oil passage (for example, 23Rr in FIG. 2 or FIG. 3 described later). That is, the construction machine 100 performs an operation of regenerating the return oil of the hydraulic actuator using the regenerative oil passage (hereinafter referred to as “regenerative operation”), and regenerates the return oil of the hydraulic actuator using the regenerative oil passage. By performing the operation (hereinafter referred to as “regeneration operation”), the utilization efficiency of energy (for example, the pressure oil discharged from the hydraulic pump) can be improved. The regeneration operation and the reproduction operation according to the present invention will be described later [2. The hydraulic circuit according to the first embodiment will be described.

[2. Hydraulic circuit according to first embodiment]
The hydraulic circuit 110 of the construction machine 100 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 2 is a schematic circuit diagram illustrating an example of the hydraulic circuit 110 according to the present embodiment. Here, the solid line described in FIG. 2 indicates an oil passage (pressure oil passage). A double line shows a mechanical connection (connection of an output shaft). A dotted line indicates a remote control circuit. A solid line to which // is added indicates an electric control system.

  FIG. 2 mainly shows the oil passage of the pressure oil discharged by the hydraulic pump Pmp for the purpose of explaining the present invention, and other portions are omitted. Further, since the configurations of the plurality of hydraulic actuators (boom cylinder 11a and the like) shown in FIG. 1 are the same, only the hydraulic actuator Act is illustrated as a representative in FIG. Furthermore, although FIG. 2 shows an example including one hydraulic pump Pmp, a hydraulic circuit that can use the present invention may include two or more hydraulic pumps.

  As shown in FIG. 2, the hydraulic circuit 110 of the construction machine 100 according to the present embodiment includes a hydraulic pump Pmp that discharges pressure oil (hydraulic oil) and a hydraulic actuator that is supplied with the pressure oil discharged from the hydraulic pump Pmp. Act (boom cylinder 11a of FIG. 1 etc.) is connected. In addition, the hydraulic circuit 110 includes an operation lever Lvr through which an operator inputs a desired operation amount and operation direction, and a pilot port of a control valve 21V described later according to the operation amount (and operation direction) input by the operation lever Lvr. Is connected to a pilot pump Pmp-PL that generates a pilot pressure to be input to. Furthermore, the hydraulic circuit 110 is connected to a control means 24 that controls the overall operation of the hydraulic circuit 110. In addition, the construction machine 100 (FIG. 1) according to the present embodiment includes a plurality of attachments (boom 11, arm 12, bucket 13), turning motor 14M, and lower traveling body 10Dw (crawler, etc.) as the operation lever Lvr. A plurality of operation levers are provided to operate each.

  The hydraulic pump Pmp discharges pressure oil (operating oil) supplied to the hydraulic actuator Act. In this embodiment, the hydraulic pump Pmp is mechanically connected to an output shaft of a power source engine (not shown) and discharges pressure oil using the power of the power source.

  The hydraulic actuator Act indicates a hydraulic cylinder in FIG. Here, the hydraulic cylinder drives the attachment (11 in FIG. 1) by its expansion / contraction operation. The hydraulic cylinder can be composed of, for example, a cylinder container and a piston. The hydraulic cylinder expands and contracts in the longitudinal direction using pressure oil (operating oil) supplied from a control valve 21V (described later). Note that return oil (hydraulic oil) from the hydraulic actuator Act (hydraulic cylinder) is re-supplied (regenerated) to the hydraulic actuator Act via a regeneration oil path 23Rr, which will be described later, during the regeneration operation. Also, the return oil (energy) from the hydraulic actuator Act is recovered (regenerated) by the recovery unit 21C of the regenerative oil passage 23Rr described later during the regenerative operation.

  The control means 24 controls the discharge operation (for example, the tilt angle of the regulator) of the hydraulic pump Pmp according to the operation amount (and operation direction) of the operation lever Lvr by the operator. Moreover, the control means 24 supplies the discharged pressure oil to the control valve 21V by controlling the discharge operation of the hydraulic pump Pmp. Furthermore, the control means 24 controls the flow rate and direction of hydraulic oil (pressure oil) supplied from the control valve 21V to the hydraulic actuator Act by controlling the operation of the control valve 21V. The control unit 24 may further control the operation of the hydraulic pump Pmp and the like using the detection result (pressure) detected by the pressure sensors Sns1 to Sns3.

  Here, the pressure sensor Sns1 is a sensor for detecting an input pressure (operation amount) in one direction of the operation lever Lvr (for example, the boom raising direction, the arm opening direction, the bucket opening direction, or the right turning direction). is there. The pressure sensor Sns2 is a sensor for detecting an input pressure (operation amount) in another direction of the operation lever Lvr (for example, a boom lowering direction, an arm closing direction, a bucket closing direction, or a left turning direction). The pressure sensor Sns3 is a sensor for detecting the pressure of the hydraulic actuator Act (in this embodiment, in the rod chamber of the hydraulic cylinder).

  The control unit 24 according to the present invention controls the regenerative operation and the regeneration operation according to the operation state of the construction machine 100 (for example, the posture of the boom 11 or the like, the load pressure, etc.). An example of the regenerative operation and the regenerative operation according to the present invention will be described in [Hydraulic circuit control method] to be described later.

  The controller 24 may use a controller mounted to control the operation of the construction machine 100, for example. Here, the controller is composed of an arithmetic processing unit including a central processing unit (CPU), a random access memory (RAM), a read only memory (ROM), and the like.

  Further, the hydraulic circuit 110 according to the present embodiment includes a control valve (for example, a directional control valve) 21V to which pressure oil discharged from the hydraulic pump Pmp is supplied.

  The control valve 21V controls the flow rate and flow direction of pressure oil supplied to the hydraulic actuator Act (such as the boom cylinder 11a in FIG. 1) (such as a boom direction control valve). The control valve 21V changes the path of its internal passage in accordance with the pilot pressure input from the pilot pump Pmp-PL. Specifically, the control valve 21V receives a pilot pressure corresponding to the operation amount (and operation direction) of the operation lever operated by the operator to the pilot port, switches the spool position, and supplies the pressure to the hydraulic actuator Act. The flow rate (operation amount) and the flow direction (operation direction) of the oil (hydraulic oil) are changed. In addition, the construction machine 100 (FIG. 1) according to this embodiment controls a plurality of hydraulic actuators (the boom cylinder 11a, the arm cylinder 12a, the bucket cylinder 13a, and the swing motor 14M in FIG. 1) as the control valve 21V. Control valve (not shown in FIG. 2).

  Furthermore, the hydraulic circuit 110 according to the present invention includes a regenerative oil passage 23Rc for regenerating the return oil of the hydraulic actuator Act (boom cylinder 11a and the like) and a regenerative oil passage 23Rr for regenerating the return oil of the hydraulic actuator Act. Further, the hydraulic circuit 110 according to the present invention further includes a branch portion 23Br that branches the return oil into the regenerative oil passage 23Rc and the regenerated oil passage 23Rr.

  The regenerative oil path 23Rc is an oil path that regenerates (recovers) the energy (surplus energy) of the return oil from the hydraulic actuator Act. The regenerative oil passage 23Rc includes a recovery unit 21C that recovers the energy of the return oil from the hydraulic actuator Act, and a discharge unit 21ex (for example, a tank) that discharges the return oil from which the energy has been recovered.

  In the present embodiment, the recovery unit 21C uses a hydraulic motor in which the generator Gnr is mechanically connected to the output shaft. The collecting unit 21C may use a pressure accumulator (accumulator or the like) that accumulates part or all of the return oil. Here, when the driving force is transmitted from the output shaft of the hydraulic motor (collecting unit 21C), the generator Gnr converts the driving force into electric energy, and the converted electric energy is not shown in a battery (secondary battery). Etc.) is stored (collected).

  The regeneration oil passage 23Rr is an oil passage that returns to the hydraulic actuator Act to regenerate (re-supply) part or all of the oil. In this embodiment, the reclaimed oil passage 23Rr includes a pressure oil increasing unit 22F that increases the flow rate of the return oil and a pressure accumulating unit 22A that accumulates the return oil whose flow rate has been increased. Further, the regeneration oil passage 23Rr is provided with a regeneration control valve 22Va and a regeneration control valve 22Vb on the upstream side of the pressure oil increasing portion 22F and the downstream side of the pressure accumulating portion 22A, respectively.

  The pressure oil increasing unit 22F increases the flow rate of the return oil using the pressure energy of the return oil from the hydraulic actuator Act. As the pressure oil increasing unit 22F, for example, hydraulic cylinders having different pressure receiving areas on the inflow side and pressure receiving areas on the outflow side can be used. The pressure oil increasing unit 22F increases the flow rate of the returned return oil according to the ratio between the pressure receiving area on the inflow side and the pressure receiving area on the outflow side. The pressure oil increasing unit 22F may use a rotary hydraulic system.

  The accumulator 22A can use an accumulator (accumulator or the like) that accumulates part or all of the return oil. Further, the pressure accumulating unit 22A accumulates a part or all of the pressure oil (return oil) whose flow rate is increased by the pressure oil increasing unit 22F.

  The regeneration control valve 22Va and the regeneration control valve 22Vb control the flow rate (and flow direction) of the circulating pressure oil. The opening degree of the regeneration control valve 22Va and the regeneration control valve 22Vb is controlled by the control means 24. In other words, the hydraulic circuit 110 (control means 24) according to the present invention controls the opening degree of the regeneration control valve 22Va, and thereby the flow rate of the pressure oil flowing into the pressure oil increasing portion 22F from the first regeneration oil passage 23Rra. To control. Further, the hydraulic circuit 110 (control means 24) controls the opening degree of the regeneration control valve 22Vb, thereby controlling the flow rate of the pressure oil accumulated in the pressure accumulator 22A and the pressure oil supplied to the second regeneration oil passage 23Rrb. The flow rate can be controlled. As a result, the hydraulic circuit 110 (control unit 24) can store and release the pressure in the pressure accumulating unit 22A with a desired pressure. Further, the hydraulic circuit 110 (control means 24) can be re-supplied to the hydraulic actuator Act at a desired flow rate.

  The branch portion 23Br branches the return oil into the regenerative oil passage 23Rc and the regenerated oil passage 23Rr. The branch portion 23Br is arranged in an oil passage through which the hydraulic actuator Act flows out. That is, it is arranged in the oil passage through which the return oil upstream of the regenerative oil passage 23Rc and the regenerated oil passage 23Rr flows.

[Control method of hydraulic circuit]
An example of the regenerative operation (operation for regenerating the return oil) and the regeneration operation (operation for resupplying the return oil) of the hydraulic circuit 110 according to the first embodiment of the present invention will be described. The regenerative operation and the regeneration operation of the hydraulic circuit 110 according to the present invention are not limited to those described below.

  The hydraulic circuit 110 (control means 24) according to the present invention regenerates (recovers) surplus energy of the return oil of the hydraulic actuator Act (FIG. 2) as a regeneration step. Here, in the regeneration step, the hydraulic circuit 110 recovers the energy of the return oil discharged from the hydraulic actuator Act using the recovery unit 21C (FIG. 2) disposed in the regenerative oil path 23Rc (FIG. 2). Moreover, the return oil from which energy has been recovered is discharged using the discharge portion 21ex (FIG. 2) disposed in the regenerative oil passage 23Rc.

  For example, when an accumulator (pressure accumulator) is used as the recovery unit 21 </ b> C, the hydraulic circuit 110 accumulates the accumulator using return oil (pressure oil) as a regeneration step, and stores surplus energy (pressure energy) of the return oil. It can be recovered. For example, when a hydraulic motor is used as the recovery unit 21C, the hydraulic circuit 110 uses the generator Gnr (FIG. 2) as a regeneration step to convert the pressure energy of the return oil into electrical energy, and returns the return oil. The surplus energy (pressure energy) can be recovered.

  The hydraulic circuit 110 (control means 24) according to the present invention regenerates (re-supplys) the return oil from the hydraulic actuator Act to the hydraulic actuator Act as a regeneration step. Here, in the regeneration step, as shown in FIG. 2, the hydraulic circuit 110 re-supplys part or all of the return oil to the hydraulic actuator Act via the regeneration oil path 23Rr (f1 to f3 in FIG. 2). To do.

  For example, when the pressure accumulating portion 22A (FIG. 2) disposed in the reclaimed oil passage 23Rr (FIG. 2) is used, the hydraulic circuit 110 performs a pressure accumulating step of accumulating a part or all of the returned return oil as a regeneration step. Further, it may be included. Further, when using the pressure oil increasing unit 22F (FIG. 2) disposed in the reclaimed oil passage 23Rr, the hydraulic circuit 110 uses the pressure energy of the return oil flowing into the pressure oil increasing unit 22F as a regeneration step. The pressure oil increasing step for increasing the flow rate of the pressure oil (return oil) may be further included.

  Hereinafter, specific examples of the regenerative operation and the regenerating operation of the construction machine 100 including the hydraulic circuit 110 according to the first embodiment of the present invention will be described. Note that the regenerative operation and regeneration operation of the construction machine 100 (hydraulic circuit 110) according to the present invention are not limited to those described below.

  (1) The construction machine 100 (hydraulic circuit 110) uses the reclaimed oil passage 23Rr and the like for the bottom of the boom cylinder 11a in the regenerating operation during the lowering operation of the boom 11 (FIG. 1) (the retracting operation of the boom cylinder 11a). Re-supply pressure oil (return oil) flowing out from the side to the rod side. Further, in the regenerating operation during the closing operation of the arm 12 (FIG. 1) (the extending operation of the arm cylinder 12a), the construction machine 100 uses the reclaimed oil passage 23Rr and the pressure oil that has flowed out from the rod side of the arm cylinder 12a. (Return oil) is resupplied to the bottom side. Thereby, the construction machine 100 can reduce the discharge flow rate of the hydraulic pump Pmp (FIG. 2) of the hydraulic circuit 110. At this time, the construction machine 100 uses the pressure oil increasing portion 22F (FIG. 2) of the regenerated oil passage 23Rr to further increase the flow rate of the pressure oil (convert from the high pressure fluid to the low pressure fluid), thereby resupplying the pressure oil. And the pressure oil (a part) increased by using the pressure accumulating portion 22A (FIG. 2) can be accumulated (recovered). That is, the construction machine 100 can improve energy efficiency by collecting energy that is not used for regeneration (re-supply) with the surplus energy of the return oil using the pressure accumulating unit 22A. Moreover, the construction machine 100 can reduce the loss (fluid loss, friction loss, etc.) generated at high pressure by further converting the pressure oil from the high pressure fluid to the low pressure fluid using the pressure oil increasing portion 22F. Furthermore, the construction machine 100 can stop the discharge of the hydraulic pump Pmp by further increasing the pressure oil by, for example, twice using the pressure oil increasing unit 22F.

  (2) The construction machine 100 (hydraulic circuit 110) uses the regenerative oil passage 23Rc or the like in the regenerative operation and the regenerating operation during the lowering operation of the boom 11 (FIG. 1) or the closing operation of the arm 12 (FIG. 1). The energy of the pressure oil (return oil) flowing out from the bottom side of the boom cylinder 11a or the rod side of the arm cylinder 12a is regenerated. Further, the construction machine 100 regenerates using the regenerated oil passage 23Rr and the like in the same manner as (1) above. Thereby, the construction machine 100 can improve energy efficiency by collect | recovering the surplus energy of return oil. Moreover, since the construction machine 100 supplies the regeneration oil 23Rr with the pressure oil that is not regenerated, the flow rate of the pressure oil flowing through the regeneration circuit 23Rr can be reduced, and the generated loss (fluid loss, friction loss, etc.) Can be reduced.

  When the construction machine 100 (hydraulic circuit 110) descends by its own weight, for example, when the boom cylinder 11a is retracted (when the boom 11 is lowered), the construction machine 100 (hydraulic circuit 110) uses pressure oil (return oil) that flows out from the bottom side of the boom cylinder 11a. The pressure oil increasing unit 22F is driven to increase the flow rate of the pressure oil, and the increased pressure oil is replenished (resupplied) to the rod side of the boom cylinder 11a. At this time, the construction machine 100 (hydraulic circuit 110), for example, increases the pressure oil by a factor of four, thereby driving the pressure oil increasing portion 22F with a flow rate of 1/8 of the pressure oil flowing out from the bottom side. The discharge operation of Pmp can be made unnecessary. In addition, the construction machine 100 (hydraulic circuit 110) can regenerate energy from the remaining pressure oil flowing out from the bottom side.

  (3) The construction machine 100 (hydraulic circuit 110) controls the opening degree of the regeneration control valves 22Va and 22Vb of the regeneration circuit 23Rr when the load pressure varies depending on the posture and load of the construction machine 100 (such as the boom 11). Thus, the pressure of the pressure oil regenerated using the pressure oil increasing unit 22F and the pressure accumulating unit 22A is changed to a desired pressure. Thereby, the construction machine 100 (hydraulic circuit 110) can change the pressure of the pressure oil to a pressure (pressure accumulation range, pressure release range) at which the pressure accumulation unit 22A (accumulator) can be used with high efficiency, for example.

  (4) The construction machine 100 (hydraulic circuit 110) regenerates part or all of the return oil of one of the plurality of hydraulic actuators using the regenerative oil passage 23Rc. Further, the construction machine 100 (hydraulic circuit 110) uses the regenerated oil path 23Rr to transfer a part or all of the return oil of one hydraulic actuator among a plurality of hydraulic actuators to one hydraulic actuator or another hydraulic actuator. Re-supply. Thereby, the construction machine 100 (hydraulic circuit 110) can effectively utilize the pressure oil discharged by the hydraulic pump Pmp.

  As described above, according to the hydraulic circuit 110 or the construction machine 100 including the hydraulic circuit 110 according to the first embodiment of the present invention, the regenerative oil path 23Rc that regenerates the return oil of the hydraulic actuator Act and the regenerated oil path 23Rr that regenerates. The energy utilization efficiency can be improved by regenerating or regenerating the return oil using. Further, according to the hydraulic circuit 110 or the construction machine 100 according to the present invention, compared to a case where energy loss occurs due to, for example, the throttle (meter-out control valve) Vex disposed in the hydraulic circuit 300 (FIG. 4) during the regeneration operation. , Energy loss can be reduced. Furthermore, according to the hydraulic circuit 110 or the construction machine 100 according to the present invention, the pressure difference between the pressure of the return oil and the pressure accumulated in the recovery unit 21C (for example, the operating pressure of the accumulator) is compared with the case where the pressure difference is regulated by the continuously variable transmission. Since the continuously variable transmission is unnecessary, the configuration of the hydraulic circuit can be simplified. In other words, according to the hydraulic circuit 110 or the construction machine 100 according to the present invention, there are advantageous effects that miniaturization and control are easy, versatility is high, and it can be easily applied to various uses.

[3. Hydraulic circuit according to second embodiment]
The hydraulic circuit 120 of the construction machine 100 according to the second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a schematic circuit diagram illustrating an example of the hydraulic circuit 120 according to the present embodiment. A solid line shown in FIG. 3 indicates an oil passage (pressure oil passage). A double line shows a mechanical connection (connection of an output shaft). A dotted line indicates a remote control circuit. A solid line to which // is added indicates an electric control system.

  The hydraulic circuit 120 according to the present embodiment shown in FIG. 3 has the same parts as the hydraulic circuit 110 according to the first embodiment, and therefore different parts will be mainly described.

  As shown in FIG. 3, the hydraulic circuit 120 according to the present embodiment includes a hydraulic actuator Act (for example, the boom cylinder 11a in FIG. 1) to which pressure oil discharged from a hydraulic pump (not shown) is supplied. Further, the hydraulic circuit 120 according to the present embodiment includes a regenerative oil path 23Rc that regenerates the return oil of the hydraulic actuator Act and a regenerative oil path 23Rr that regenerates the return oil of the hydraulic actuator Act.

  In the hydraulic circuit 120 according to the present embodiment, the regeneration oil passage 23Rr is disposed (intervened) in the hydraulic line of the hydraulic pump Pmp (the oil passage that supplies the discharged pressure oil), and the pressure oil increasing portion 22F. Is different from the hydraulic circuit 110 according to the first embodiment. Other parts (for example, the configuration and functions of the recovery unit 21C, the pressure accumulating unit 22A, and the like) are the same as those of the hydraulic circuit 110 according to the first embodiment, and thus description thereof is omitted.

  The hydraulic circuit 120 according to the present embodiment collects the return oil (energy thereof) from the hydraulic actuator Act by the collecting unit 21C (the regenerative oil passage 23Rc) as a regeneration step. In addition, the hydraulic circuit 120 according to the present embodiment uses the pressure oil of the pressure accumulating unit 22A that has previously accumulated pressure during other operations as the regeneration step, and the pressure oil accumulated in the pressure oil discharged by the hydraulic pump Pmp. Are combined and supplied to the hydraulic actuator Act.

  The construction machine 100 (hydraulic circuit 120) according to the present embodiment accumulates the back pressure of the hydraulic cylinder in the recovery unit 21C (accumulator or the like), for example, when the hydraulic cylinder is extended (when the boom 11 is raised). Thereby, the construction machine 100 (hydraulic circuit 120) can assist (supplement pressure oil) by releasing the pressure of the collection unit 21C, for example, during a contraction operation of the hydraulic cylinder (when the boom 11 is lowered). . In other words, the construction machine 100 (hydraulic circuit 120) can effectively use the holding pressure of its own weight drop as regeneration, and not as regeneration.

  As described above, according to the hydraulic circuit 120 or the construction machine 100 including the hydraulic circuit 120 according to the second embodiment of the present invention, the regenerative oil path 23Rc that regenerates the return oil of the hydraulic actuator Act and the regenerated oil path 23Rr that regenerates. The energy utilization efficiency can be improved by regenerating or regenerating the return oil using. Further, according to the hydraulic circuit 120 according to the second embodiment of the present invention, the same effect as the hydraulic circuit 110 according to the first embodiment can be obtained.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not restrict | limited to embodiment mentioned above. The present invention can be variously modified or changed in light of the appended claims.

100: Construction machine 110, 120: Hydraulic circuit 10Cb: Cab (cab)
10Up: Upper turning body 10Dw: Lower traveling body 11: Boom 11a: Boom cylinder 12: Arm 12a: Arm cylinder 13: Bucket 13a: Bucket cylinder 14M: Swing motor 21C: Recovery part (hydraulic motor, accumulator, etc.)
21ex: Discharge part (tank, etc.)
21V: Control valve 22A: Pressure accumulator (accumulator, accumulator, etc.)
22F: Pressure oil increase part (cylinder, etc.)
22V, 22Va, 22Vb: control valve for regeneration 22vc: control valve (directional control valve, etc.)
23Rc: Regenerative oil passage 23Rr: Regenerated oil passage 23Br: Branching portion 24: Control means (controller, etc.)
Pmp: Hydraulic pump Pmp-PL: Pilot pump Act: Hydraulic actuator Gnr: Generator Tnk: Tank (hydraulic oil tank)
Lvr: Operation lever Sns1, Sns2, Sns3: Pressure sensor

Claims (10)

A hydraulic circuit for supplying pressure oil to the hydraulic actuator to drive the hydraulic actuator,
A regenerative oil passage for regenerating the return oil of the hydraulic actuator;
A regeneration oil path for regenerating the return oil of the hydraulic actuator,
The regenerative oil path includes a recovery unit that recovers the energy of the return oil, and a discharge unit that discharges the return oil from which the energy has been recovered,
The regenerated oil path re-supplyes part or all of the return oil to the hydraulic actuator,
A hydraulic circuit characterized by that. The recovery unit is a hydraulic motor mechanically connected to an output shaft of a generator, or a pressure accumulator that accumulates part or all of the return oil.
The hydraulic circuit according to claim 1, wherein: The hydraulic actuator is disposed in an oil passage through which the return oil flows out, and further includes a branch portion that branches the return oil into the regenerative oil passage and the regenerated oil passage.
The hydraulic circuit according to claim 2, wherein: The regenerated oil path further includes a pressure accumulating unit that accumulates a part or all of the return oil that circulates.
The hydraulic circuit according to any one of claims 1 to 3, wherein the hydraulic circuit is characterized. The regenerated oil path further includes a pressure oil increasing unit that increases the flow rate of the return oil using the pressure energy of the return oil that circulates,
The pressure oil increasing part accumulates a part or all of the return oil whose flow rate is increased in the pressure accumulating part,
The hydraulic circuit according to claim 4, wherein: A plurality of the hydraulic actuators;
Using the regenerative oil path, regenerate part or all of the return oil of one hydraulic actuator among the plurality of hydraulic actuators,
Re-feeding part or all of the return oil of one hydraulic actuator of the plurality of hydraulic actuators to the one hydraulic actuator or another hydraulic actuator using the regenerated oil path;
The hydraulic circuit according to any one of claims 1 to 5, wherein the hydraulic circuit is characterized.   A construction machine comprising the hydraulic circuit according to any one of claims 1 to 6. A method for controlling a hydraulic circuit comprising a regenerative oil path for regenerating return oil of a hydraulic actuator and a regenerated oil path for regenerating the return oil of the hydraulic actuator,
A regeneration step for regenerating the return oil of the hydraulic actuator;
A regeneration step of regenerating the return oil of the hydraulic actuator,
The regeneration step recovers the energy of the return oil using a recovery unit disposed in the regenerative oil path, and discharges the return oil recovered from the energy using a discharge unit disposed in the regenerative oil path. And
In the regeneration step, part or all of the return oil is re-supplied to the hydraulic actuator.
A method for controlling a hydraulic circuit. The regeneration step further includes a pressure accumulation step of accumulating a part or all of the return oil that circulates using a pressure accumulation unit disposed in the regeneration oil path.
The method for controlling a hydraulic circuit according to claim 8, wherein: The regeneration step further includes a pressure oil increasing step of increasing the flow rate of the return oil using the pressure energy of the return oil flowing through the pressure oil increasing unit disposed in the regeneration oil path.
The method for controlling a hydraulic circuit according to claim 9, wherein:

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