JP2007107616A - Regeneration device for boom energy of operation machine, and regeneration device for energy - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide compatibility between increase of a regeneration amount and improvement of operability at a high level by a simple composition, or design change, and without causing sudden change in operability irrespective of being novel or already existing. <P>SOLUTION: The regeneration device for boom energy of an operation machine is provided with a branch part 40 dividing a return oil passage L4 from a boom cylinder 10 in when lowering a boom into two or more oil passages L5, L6, a regeneration circuit RE conducting one diversion L6 to a tank 44 via a hydraulic motor 41 and a generator 42 (a regenerating means), and a flow rate adjusting circuit FL conducting the other diversion L5 to the tank 44 via an orifice (a flow rate adjusting means) 48. The regeneration circuit RE is arranged in an outer side of a control valve 16A. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an energy regeneration device for a work machine such as a construction machine, and more particularly to a boom energy regeneration device.

  FIG. 5 shows a main part of a typical hydraulic circuit for driving the boom cylinder. The boom cylinder 10 is controlled via the control valve 16 based on the operation of the operation lever 14 by the operator. The control valve 16 corresponds to a portion indicated by a two-dot chain line in the drawing, and in this example, includes two spools 18 and 20.

  The first spool 18 is a two-position / four-port switching valve that switches from the B position to the A position in the figure against the spring 22 when a pilot pressure is applied to the pilot port Pp1. The second spool 20 is a three-position / four-port switching valve. When the pilot pressure is applied to the pilot port Pp3 side, the D position shown in the figure, and when the pilot pressure is applied to the pilot port Pp4, the F position shown in FIG. When pilot pressure is not applied to the pilot ports Pp3 and Pp4, the spring ports 24 and 26 are positioned at the position E in the figure.

  When the boom cylinder 10 is extended, that is, when the boom (not shown) is raised, pilot pressure is generated in the oil passage L1, so that the first spool 18 is in the A position and the second spool 20 is in the D position. The pressure oil from the hydraulic pumps 30 and 32 is supplied to the bottom side 12 of the boom cylinder 10.

  When the boom cylinder 10 is contracted, that is, when the boom is lowered, pilot pressure is generated in the oil passage L2 by the operation of the operation lever 14, so that the first spool 18 is moved to the B position by the urging force of the spring 22. The two spools 20 are respectively switched to the F position, and the return oil on the bottom side 12 of the boom cylinder 10 is drained through the second spool 20.

  In addition, the code | symbol 36 of a figure has shown the holding valve with the poppet 36A.

  On the other hand, in Patent Document 1, a regenerative circuit is formed on the meter-out side (bottom side oil passage corresponding to L3 in FIG. 5), and the regenerative energy of the boom cylinder 10 is obtained by driving a pump motor (not shown) with return oil. A construction machine configured to collect is disclosed.

  The regenerative circuit is switched by a switching valve (not shown), and when performing excavation work or the like, the regenerative circuit is opened and the energy of the return oil is recovered. On the other hand, the regenerative circuit is closed when performing fine manipulation work or the like, and operability is emphasized.

JP 2003-329012 A

  In the construction machine, switching of the switching valve is performed depending on the work mode selected on the monitor panel, and regenerative operation or operability-oriented operation is switched by this switching.

  For this reason, there is a problem that the work is complicated, and depending on the driver, the switching may not be performed properly, and the intended regeneration may not be performed.

  For this, it may be possible to detect or judge the work state by some method and automatically perform this switching. In this case, however, the switching is performed on and off at an unintended timing of the driver. On the contrary, there is a problem that the operability may deteriorate.

  The present invention has been made in order to solve such a conventional problem, and achieves both an increase in the amount of energy regeneration and an improvement in operability at a high level without causing a sudden change in operability. It is an object of the present invention to provide an energy regeneration device for a working machine that can be used, particularly a boom energy regeneration device.

  The present invention relates to a boom energy regenerative device for a working machine that includes a working unit having a boom, and that expands and contracts a boom cylinder by switching a control valve so that the boom can be driven. A branch section that divides the return oil passage from the cylinder into two or more oil passages, a regenerative circuit that leads one of the diverted flow to the tank through the regenerative means, and the other divided flow through the flow rate adjusting means And the regenerative circuit that leads to the tank through the regenerative means is arranged outside the control valve, thereby solving the above-mentioned problem.

  According to the present invention, the oil flow from the boom cylinder is divided into two oil passages, one of which is always connected to the regeneration means.

  In this state, by controlling the flow rate of the return oil flowing out to the regeneration circuit and the flow rate adjustment circuit, the boom lowering speed can be controlled and the operability can be improved. Moreover, the amount of energy regeneration can be increased by setting a large flow rate of the return oil flowing out to the regeneration circuit side. In the present invention, it is fundamental to adjust the degree of diversion with the flow rate adjustment circuit, but this does not prohibit the flow rate adjustment on the regenerative circuit side.

  Furthermore, in the present invention, since the regenerative circuit after the diversion is arranged outside the control valve, the boom energy can be applied to an existing work machine only by simple care such as replacing the spool. Can be upgraded to a work machine capable of regenerating In addition, regardless of existing or new, regarding boom energy regeneration, it is possible to very easily design or change the design of the degree of regeneration.

  Various variations are conceivable for the present invention.

  For example, the control valve includes a holding valve that prevents the return oil from flowing when the boom cylinder is held at a predetermined position, and the branch portion is at a downstream position of the holding valve and the control valve. It may be arranged at the upstream position of the spool of the valve. Thereby, it becomes possible to omit the holding valve for holding the boom in the boom energy regeneration circuit, and the circuit can be further simplified (described later).

  Further, two or more spools are provided in the control valve, and a flow rate control circuit for controlling the flow rate of the other branched from the return oil passage from the boom cylinder is provided in the two or more spools. If the boom energy regenerative circuit has a small capacity, the amount of increase or decrease in the diverted flow on the flow control circuit side can be increased. In an emergency, the boom can be lowered only with the control valve.

  The present invention is most effective when applied to a boom cylinder having a large energy regeneration. However, the application target is not necessarily limited to the boom cylinder, and various types of regeneration are possible. The present invention can be applied to a hydraulic cylinder regenerative device, and a corresponding effect can be obtained.

  Regardless of existing or new, with a simple configuration or design change, it is possible to achieve both an increase in the amount of regeneration and an improvement in operability at a high level without causing a sudden change in operability.

  Hereinafter, an example of a preferred embodiment of a boom energy regeneration device for a work machine according to the present invention will be described in detail with reference to the drawings.

  FIG. 4 shows the overall configuration of a hydraulic excavator (work machine) 80 to which the present invention is applied.

  The excavator 80 includes a lower traveling body 82, an upper swing body 84, and a working unit 86.

  The working unit 86 includes a boom 88, an arm 90, and a bucket 92, and protrudes in a cantilevered state from the side of the cab 85 of the upper swing body 84. The boom cylinder 10, the arm cylinder 94, and the bucket cylinder 96 are incorporated in the boom 88, the arm 90, and the bucket 92 of the working unit 86 as hydraulic cylinders that drive the 88, 90, and 92, respectively. In the present embodiment, the present invention is particularly applied to the return oil passage (the oil passage on the meter-out side) when the boom cylinder 10 incorporated in the boom 88 is contracted.

  Hereinafter, the main part of the hydraulic circuit will be described in detail. For ease of understanding, for the sake of convenience, portions that are the same as or similar to the portions described with reference to FIG.

  In this embodiment, the return oil passage L4 from the boom cylinder 10 when the boom 88 is lowered is divided into two oil passages L5 and L6 at the branch portion 40. One of the divided flow is a regenerative circuit RE that leads to the tank 44 via the hydraulic motor 41 and the generator 42, and the other is the flow adjustment circuit FL that leads to the tank 44 via the orifice (flow rate adjusting means) 48. Yes. The regenerative circuit RE is disposed outside the control valve 16A, and mainly includes the holding valve 54, the 2-position switching valve 56, and the pilot switching valve 58 in addition to the hydraulic motor 41 and the generator 42 constituting the regenerating means. It is configured. The holding valve 54 is configured such that the oil passage is opened only when the pilot pressure P <b> 1 generated by the operation of lowering the operation lever 14 is applied via the pilot switching valve 58. Similarly, when the pilot pressure P1 is applied to the pilot port Pp5, the two-position switching valve 56 is switched to the H side in the figure. The pilot switching valve 58 is an electromagnetic valve that switches to the position shown in the figure against the spring 60 when the operation lever 14 is lowered. Furthermore, if the constant pressure hydraulic pressure source is a primary pressure and an electromagnetic proportional pressure reducing valve that generates a secondary pressure in accordance with a command is used, the two-position switching valve 56 to which a flow rate adjusting function is added is controlled. It is possible to prevent fail-safe handling and over-torque when control is not possible.

  In the control valve 16A, the structure at the F position of the second spool 20A having the function of a three-position switching valve is different from the conventional example. That is, in the previous conventional example, at the F position of the second spool 20, the return oil of the oil passage L3 from the bottom side 12 of the boom cylinder 10 is directly drained to the tank 44. In the embodiment, after the diversion, the return oil that has passed through the oil passages L5 and L3 is placed in the F position of the second spool 20A and is drained to the tank 44 through the orifice 48.

  The second spool 20A can be switched in an analog manner (gradually including the intermediate position) toward the extension position D and the contraction position F around the neutral position E in the complete block state. Therefore, the flow rate of the orifice 48 is variable by the function of the second spool 20A. In this embodiment, a pilot pressure generated by the movement of the operation lever 14 is used as it is as a parameter for adjusting the flow rate. For example, a hydraulic sensor (not shown) for detecting the driving pressure on the top side 13 of the boom cylinder 10 is used. If the flow rate is adjusted in consideration of the drive pressure information, finer adjustment is possible.

  Note that reference numerals 62 and 64 in FIG. 1 denote first and second hydraulic pumps.

  Next, the operation of this regenerative device will be described.

  According to the embodiment shown in FIG. 1, when the boom cylinder 10 is extended (when the boom 88 is raised), the pilot pressure depends on the movement of the operation lever 14, and the pilot pressures of the first and second spools 18 and 20A are increased. Applied to the pilot ports Pp1 and Pp3, the first and second spools 18 and 20A are positioned at the extended positions A and D, respectively. For this reason, the pressure oil discharged from the first and second hydraulic pumps 62 and 64 reaches the holding valve with poppet 36 via the oil passages L8 and L3, respectively. In the holding valve with poppet 36, the poppet 36A is pushed upward by this pressure oil, and the pressure oil is supplied to the bottom side 12 of the boom cylinder 10 via the oil passages L5 and L4. Elongate.

  When the boom cylinder 10 is extended, the pilot pressure P1 is not generated in the oil passage L7, so the holding valve 54 is closed and the oil passage L6 is closed. Accordingly, the regenerative circuit RE does not particularly function.

  When the operation lever 14 is in a neutral state where it is not operated, all pilot pressures are tank pressures, and no pilot pressure is derived to any of the pilot ports Pp1 to Pp4 of the first and second spools 18 and 20A. Accordingly, the first and second spools 18 and 20A are positioned at the block positions B and E by the urging forces of the springs 22, 24 and 26. For this reason, the first and second spools 18 and 20A are all in a blocked state, and the movement of oil is prevented.

  In this state, in the holding valve 36 with the poppet, the pressing force of the pressure oil that has circulated to the back side of the poppet 36A becomes larger than the inflow side (due to the area difference between the inflow side and the back side of the poppet 36A). The poppet 36A is pressed against the sheet surface 36B. Therefore, the movement of the oil through the holding valve with poppet 36 is completely prevented, and the cylinder position at that time of the boom cylinder 10 is held. Further, since the holding valve 54 of the regenerative circuit RE remains closed, the regenerative circuit RE does not function in this case.

  When the boom cylinder 10 is contracted (when the boom 88 is lowered), the pilot pressure is applied to the pilot port Pp4 of the second spool 20A depending on the movement of the operation lever 14. Therefore, after all, the first spool 18 is positioned at the block position B and the second spool 20A is positioned at the contracted position F by the urging force of the spring 22. As a result, the pressure oil discharged from the second hydraulic pump 64 reaches the oil passage L9 via the F position of the second spool 20A, flows into the top side 13 of the boom cylinder 10, and the boom cylinder 10 contracts.

  As the boom cylinder 10 contracts, the pressure oil present on the bottom side 12 of the boom cylinder 10 reaches the branching section 40 via the oil path L4 and is divided into oil paths L5 and L6 from here. Further, when the boom cylinder 10 contracts, the pilot pressure P1 is generated in the oil passage L7, so the holding valve 54 is opened and the two-position switching valve 56 is switched to the regenerative position H side.

  As a result, the return oil branched to the oil passage L6 side flows into the oil passage L10 through the regenerative position H of the holding valve 54 and the two-position switching valve 56, and rotates the hydraulic motor 41. For this reason, the generator 42 connected to the hydraulic motor 41 rotates, and the regenerative power is stored in a battery (not shown).

  On the other hand, the return oil branched to the oil passage L5 side flows into the holding valve 36 with the poppet, and pushes up the poppet 36A that has been pressed against the seat surface 36B by the area difference. Therefore, the return oil can pass through the holding valve with poppet 36, passes through the orifice 48 at the F position of the second spool 20A via the oil passage L3, and is drained into the tank 44 while the flow rate is adjusted by the orifice 48. Is done.

  Eventually, the return oil from the boom cylinder 10 when lowering the boom 88 is divided into two oil passages L5 and L6 at the branching portion 40, and the return oil divided into the oil passage L6 side passes through the hydraulic motor 41. The return oil branched to the oil passage L5 is guided to the tank 44 through the (variable) orifice 48 while the flow rate is adjusted while the generator 42 is driven.

  As is apparent from a comparison between FIGS. 5 and 1, in this embodiment, since the regenerative circuit RE is provided outside the control valve 16A, the second spool 20 is moved to the F position on the control valve 16 side. It is only necessary to change to those having a variable orifice 48 (20A). Therefore, the regenerative energy of the boom cylinder 10 can be recovered with a simple design change regardless of whether it is an existing or new case.

  FIG. 2 shows another embodiment of the present invention.

  This embodiment is different from the previous embodiment in that the branch portion 70 is located downstream of the holding valve with poppet 36 (from the viewpoint of the flow of return oil of the boom cylinder 10: the first and second pumps 62 and 64. The upstream position of the second spool 20A in the control valve 16B (same as the downstream position when viewed from the first and second pumps 62 and 64). . The return oil is here divided into two oil passages L11 and L12. Further, the holding valve 54 is omitted.

  As a result, in the oil passage of L3 → L12 sandwiching the branching portion 70, the same configuration as that of the embodiment of FIG. On the other hand, in the oil passage of L3 → L11, a configuration similar to the configuration in which the holding valve 54 on the oil passage L6 in the embodiment of FIG. 1 is omitted is formed. Even if the holding valve 54 is omitted, since the holding valve with poppet 36 also serves as its function, an operation substantially equivalent to the operation in the embodiment of FIG. 1 can be obtained.

  Thus, the working machine according to this embodiment has the advantage that the holding valve 54 in the embodiment of FIG. 1 can be omitted, and the overall configuration can be further simplified.

  FIG. 3 shows still another embodiment of the present invention.

  This embodiment is based on the embodiment shown in FIG. 2, and is characterized in that the first spool 18A in the control valve 16C is a spool having the function of a three-position switching valve. Therefore, a pilot pressure generated when the operation lever 14 is operated to the boom lowering side is introduced into the pilot port Pp2 of the first spool 18A.

  The first spool 18A is in the A position when the operation lever 14 is operated to the boom raising side, the C position when the operation lever 14 is operated to the boom lowering side, and the operation lever 14 is in the boom holding state (ascending operation). In this state, the springs 21 and 22 are held at the B position (block position). Similar to the second spool 20A, the first spool 18A can also be switched in an analog manner (gradually including the intermediate position) toward the extended position A and the contracted position C around the neutral position B in the complete block state. It is. Accordingly, the flow rate of the orifice 74 is variable by the function of the first spool 18A.

  Therefore, in this embodiment, the branching portion is formed at a position indicated by reference numeral 72 in addition to 70 in FIG. That is, the flow is first divided into the first flow rate adjustment circuit FL1 side (oil passage L13) and the regenerative circuit RE side (oil passage L3) by the branching portion 72, and further at the branching portion 70, the second flow rate adjustment circuit FL2 side (oil flow). The path L12) and the regenerative circuit RE side (oil path L11) are divided. As a result, when the boom cylinder 10 contracts, the return oil on the bottom side 12 of the boom cylinder 10 is drained (while adjusting the flow rate) not only at the F position of the second spool 20A but also at the C position of the first spool 18A. In particular, when the capacity of the regenerative circuit RE is small, the amount of return oil flowing to the flow rate adjustment circuit FL (FL1 + FL2) side can be increased. Further, even when some abnormality occurs on the regenerative circuit RE side, the boom 88 can be lowered only on the control valve 16C side.

  The present invention can be particularly effectively applied to a regenerative device for a work machine that includes a working unit having a boom and can drive the boom by extending and contracting a boom cylinder. However, the present invention need not dare to limit the application target to only the boom cylinder, but can be applied to various hydraulic cylinder regenerative devices capable of regenerating, and the corresponding effects can be obtained.

The skeleton figure which shows the desired structure of an example of embodiment of the regeneration apparatus of the boom energy which concerns on this invention Skeleton diagram showing the main configuration of another embodiment Skeleton diagram showing the main configuration of still another embodiment The front view which shows the whole structure of the hydraulic shovel (work machine) to which this invention was applied Diagram showing the structure of the main part of a conventional hydraulic circuit for driving a typical boom

Explanation of symbols

DESCRIPTION OF SYMBOLS 12 ... Boom cylinder 16A, 16B, 16C ... Control valve 18, 18A ... 1st spool 36 ... Holding valve with a poppet 20A ... 2nd spool 40, 70, 72 ... Branch 80 ... Hydraulic excavator 88 ... Boom 48, 74 ... Orifice (Flow rate adjusting means)
41 ... Hydraulic motor (regenerative means)
42 ... Generator (regenerative means)
44 ... Tank 54 ... Holding valve RE ... Regenerative circuit FL, FL1, FL2 ... Flow rate adjustment circuit

Claims (4)

In a boom energy regenerative device of a work machine that includes a working unit having a boom, extends and contracts a boom cylinder by switching a control valve, and enables the boom to be driven.
A branch portion for diverting a return oil passage from the boom cylinder to two or more oil passages when lowering the boom;
A regenerative circuit for guiding one of the divided currents to the tank via regenerative means;
A flow rate adjusting circuit for guiding the other divided flow to the tank via the flow rate adjusting means;
A boom energy regenerative device for a work machine, characterized in that a regenerative circuit that leads to the tank via the regenerative means is disposed outside the control valve. In claim 1,
The control valve includes a holding valve that prevents the return oil from flowing when the boom cylinder is held at a predetermined position, and the branch portion is at a downstream position of the holding valve and the control valve A boom energy regeneration device for a working machine, wherein the boom energy regeneration device is disposed at an upstream position of a spool. In claim 1 or 2,
Two or more spools are provided in the control valve, and a flow rate control circuit for controlling the flow rate of the other branched from the return oil passage from the boom cylinder is provided in the two or more spools. A boom energy regenerative device for a work machine characterized by the above. In the energy regeneration device of the work machine that can drive the working part by the expansion and contraction of the hydraulic cylinder,
A branch portion for diverting the oil passage on the meter-out side of the hydraulic cylinder into two or more oil passages;
A regenerative circuit for guiding one of the divided currents to the tank via regenerative means;
A flow rate adjusting circuit for guiding the other divided flow to the tank via the flow rate adjusting means, and a regenerative circuit for guiding the tank to the tank via the regenerative means is disposed outside the control valve. Energy recovery device for work machines.

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