JP5305161B2 - Hydraulic control device for attachments in construction machinery - Google Patents

Description

  The present invention relates to a hydraulic control device that controls hydraulic cylinders and hydraulic motors of attachments such as a crusher, a cutting machine, and a fork grab that are detachably and pivotably attached to an arm tip of a construction machine.

  As shown in FIG. 9, when a construction machine 30 having a boom 31 and an arm 32 is used to perform operations such as demolition by crushing or cutting a building, movement of the crushed material after demolition, and loading into a truck, etc. The attachment 40 is attached to the tip of the arm 32 of the construction machine 30 so as to perform the work.

  For convenience of explanation, a dismantling object, a crushed material after cutting, and a cut object are simply referred to as work objects.

  As the attachment 40 used for the dismantling work, the one shown in FIG. 10 is conventionally known. In this attachment 40, a swivel base 42 and a hydraulic motor M for swiveling drive of the swivel base 42 are disposed on a bracket 41 that is detachably attached to the distal end of the arm 32. 44 and 45 are supported to be openable and closable, and the pair of crushing arms 44 and 45 are opened and closed by a hydraulic cylinder S.

  In the crushing / cutting work by the attachment 40, the building is dismantled by opening and closing the pair of crushing arms 44 and 45 and turning the swivel base 42.

  Here, the hydraulic motor M and the hydraulic cylinder S of the attachment 40 are controlled by the hydraulic pressure of the construction machine. If the hydraulic motor M and the hydraulic cylinder S are controlled by independent hydraulic systems, the respective hydraulic systems are controlled. In addition, since the oil feed pipe and the return pipe are required, four pipes must be attached to the boom 31 and the arm 32 and extend to the attachment 40, and the piping work is very troublesome. As a result, the hydraulic piping becomes complicated and the cost increases.

  In order to solve such a problem, in Patent Document 1, the hydraulic motor M and the hydraulic cylinder S provided in the attachment 40 can be controlled by applying only two pipes to the boom 31 and the arm 32. The proposed hydraulic control device is proposed.

Japanese Patent No. 3190618

  By the way, in the hydraulic control apparatus described in Patent Document 1, the feed pipe and the return pipe to the hydraulic cylinder are branched, the branch feed pipe and the branch return pipe are connected to the hydraulic motor, and the branch feed pipe is sequenced. When the hydraulic cylinder contracts and reaches the stroke end and the pressure in the feed pipe rises above a predetermined pressure, the sequence motor is switched to operate the hydraulic motor. Only the hydraulic motor cannot be turned immediately and the sequence valve is not manually operated and cannot be switched unless the hydraulic cylinder is contracted to the stroke end. There is an inconvenience that it cannot be done.

  In addition, since the hydraulic motor is rotated with the hydraulic cylinder contracted, the orientation of the work object is determined with the pair of claws necessary for a fork grab closed and the work object gripped. There is also an inconvenience that it cannot be changed.

  Furthermore, since the switching from the hydraulic cylinder to the hydraulic motor is performed by a sequence valve, the hydraulic pressure supply direction to the hydraulic motor is one direction, and the swivel base can be swung only in one direction. There is also the inconvenience of being bad.

  An object of the present invention is to provide a hydraulic control device for an attachment in a construction machine that can quickly switch between the operation of a hydraulic cylinder and a hydraulic motor and can immediately turn when necessary.

  In order to solve the above problems, in the present invention, an extension oil passage is connected to the bottom chamber of the hydraulic cylinder for opening and closing the work arm, and a contraction oil passage is connected to the rod chamber of the hydraulic cylinder. An operation valve for switching and supplying the pressure oil discharged from the hydraulic pump to the oil passage and the contraction oil passage, the first branch oil passage connected to the hydraulic motor is branched from the extension oil passage, and A solenoid-operated switching valve that branches a second branch oil passage connected to the hydraulic motor from the contracting oil passage, and controls each of the first branch oil passage and the second branch oil passage. Is connected to the second branch oil passage, and a check valve for preventing the pressure oil from being fed toward the switching valve is incorporated into the extension oil passage from the branch position of the first branch oil passage to the bottom chamber. In the part leading to The pressure oil supplied to the motor is had adopted a structure incorporating a directional control valve pilot-operated to be held in the closed state as the pilot pressure.

  Here, the work arm refers to a crushing arm that crushes a work object, a claw that grips the crushed object, a cutting arm that cuts a cutting object, a fork, or the like.

  In the hydraulic control apparatus having the above configuration, when the operation valve is switched to the forward position where the pressure oil from the hydraulic pump is sent to the extension oil passage by the operation of the operator, the pressure oil discharged from the hydraulic pump is in the open state. Since the directional control valve is fed into the bottom chamber of the hydraulic cylinder, the hydraulic cylinder extends. At this time, the oil in the rod chamber of the hydraulic cylinder is returned from the contracting oil passage to the tank.

  When the operation valve is switched to the reverse position where the pressure oil from the hydraulic pump is sent to the contraction oil passage, the pressure oil discharged from the hydraulic pump is sent to the contraction oil passage and enters the rod chamber of the hydraulic cylinder. The hydraulic cylinder contracts due to the inflow. At this time, the oil in the bottom chamber of the hydraulic cylinder is returned from the extending oil passage to the tank through the direction control valve.

  In the state where the operation valve is switched to the forward position, when the switching valve is switched to the forward position where the first branch oil passage communicates with the hydraulic motor, the pressure oil discharged from the hydraulic pump is sent to the hydraulic motor. The hydraulic motor rotates. At this time, the oil discharged from the hydraulic motor flows into the second branch oil passage through the switching valve, flows from the contraction oil passage through the operation valve, and is returned to the tank.

  In addition, since a part of the pressure oil supplied to the hydraulic motor is sent to the pilot oil passage of the direction control valve, the direction control valve is held in the closed state. For this reason, the pressure oil sent to the extension oil passage is not sent to the bottom chamber of the hydraulic cylinder, and the hydraulic cylinder does not operate. For this reason, even if the pair of work arms that swing in the closing direction due to the extension of the hydraulic cylinder hold the work object, the work object is held in the held state and does not fall.

  When the hydraulic motor is operated, even if the hydraulic cylinder is operated due to a slight leak of pressure oil from the direction control valve, the hydraulic cylinder moves in the extending direction. Will move. For this reason, the work object is more strongly held by the pair of work arms, and the work object does not fall.

  Even if the operation valve is in the reverse position and the work arm is open, the work arm is closed or opened by switching the operation valve to the forward position and the switching valve to the forward or reverse position. Regardless of whether the hydraulic motor can be operated.

  In this way, the hydraulic motor can be started immediately by switching the operation valve to the forward position and switching the solenoid operation switching valve whenever rotation is required, regardless of whether the work arm is open or closed. Therefore, operations such as crushing and dismantling can be performed efficiently.

  Here, when the hydraulic motor is a one-way rotation motor, a single solenoid / spring offset type two-position switching valve may be employed as the switching valve. As the switching valve, a solenoid operated four-port three-position switching valve capable of switching and supplying pressure oil to the forward rotation port and the reverse rotation port of the hydraulic motor is used to move the hydraulic motor in the normal rotation direction and the reverse rotation direction. Therefore, the direction of the work object clamped by the work arm can be quickly changed to a direction suitable for the work, and the work efficiency can be further improved.

  In the hydraulic control apparatus for an attachment in a construction machine according to the present invention, the direction control valve may be a logic valve or may be a pilot check valve.

  As described above, in the present invention, since the hydraulic motor can be immediately operated by switching the switching valve in a state where the pressure oil discharged from the hydraulic pump is supplied to the extension oil passage, Work such as loading can be performed efficiently.

  In addition, the operation is switched from the hydraulic cylinder to the hydraulic motor while the pressure oil discharged from the hydraulic pump is supplied to the extension oil passage, so that the switching valve is erroneously set to the neutral position during turning. When switched, the hydraulic cylinder swings the pair of work arms in the closing direction, so that even if the pair of work arms is holding the work object, the pair of work arms holds the work object. Safety can be secured without canceling.

Hydraulic circuit diagram showing a first embodiment of an attachment hydraulic control device in a construction machine according to the present invention Hydraulic circuit diagram showing the extension of the hydraulic cylinder Hydraulic circuit diagram showing the contraction state of the hydraulic cylinder Hydraulic circuit diagram showing the normal rotation state of the hydraulic motor Hydraulic circuit diagram showing reverse rotation state of hydraulic motor Hydraulic circuit diagram showing a second embodiment of the hydraulic control device Hydraulic circuit diagram showing a third embodiment of the hydraulic control device Hydraulic circuit diagram showing a fourth embodiment of the hydraulic control device Front view showing construction machinery Partially cutaway front view of the attachment shown in FIG.

  FIG. 1 for explaining an embodiment of the present invention is based on the attached drawings. FIG. 1 shows a hydraulic control apparatus in which a hydraulic motor M and a hydraulic cylinder S of an attachment 40 including a crusher shown in FIG. 1st Embodiment is shown. As shown in the figure, the operation valve 1 composed of a neutral block type four-port three-position switching valve is switched by an operator's pedal operation. The P port of the operation valve 1 and the tank 2 are connected by an oil supply passage 3, and a hydraulic pump 4 is incorporated in the oil supply passage 3.

  The T port of the operation valve 1 and the tank 2 are connected by a return passage 5.

  The A port of the operation valve 1 and the bottom chamber a of the hydraulic cylinder S are connected by an extension oil passage 6, while the B port of the operation valve 1 and the rod chamber b of the hydraulic cylinder S are connected by a contraction oil passage 7. Yes.

The first branch oil passage 11 that branches from the extended oil passage 6 is connected to the P port of the switching valve V _1, while the second branch oil passage 12 that branches from a retracted oil passage 7 T port of the switching valve V ₁ It is connected to the.

The switching valve V ₁ is a solenoid operated 4-port 3-position switching valve, and the forward rotation oil passage 13 connected to the A port of the switching valve V ₁ is connected to the forward rotation port MP ₁ of the hydraulic motor M. . Further, the reverse rotation oil passage 14 connected to the B port of the switching valve V ₁ is connected to the reverse rotation port MP ₂ of the hydraulic motor M.

Solenoid SOL ₁ at one end of the changeover valve _{V 1} was operated by the operation of the operation switch SW _1, when the ON the operation switch SW _1, the switching valve _{V 1} was the first branch oil passage 11 and a positive rotation passage 13 It switches to the forward position where it communicates.

Further, the solenoid SOL _{2 at} the other end of the switching valve V ₁ is activated by the operation of the operation switch SW ₂ operated by the operator. When the operation switch SW ₂ is turned on, the switching valve V ₁ is switched to the first branch oil passage 11. And the reverse oil passage 14 are switched to a reverse position where they communicate with each other.

A check valve 15 is incorporated in the second branch oil passage 12. Check valve 15, pressure oil is fed to the second branch oil passage 12 is adapted to prevent flow toward the switching valve V _1.

  In the extension oil passage 6 communicating with the bottom chamber a of the hydraulic cylinder S, a logic valve 20 as a pilot operation type direction control valve is provided in a portion from the branch position of the first branch oil passage 11 to the bottom chamber a. It is incorporated.

  On the other hand, a shuttle valve 21 having two supply ports and one discharge port is incorporated between the forward oil passage 13 and the reverse oil passage 14. In this case, the shuttle valve 21 is incorporated so that one supply port communicates with the forward rotation oil passage 13 and the other supply port communicates with the reverse rotation oil passage 14.

  The logic valve 20 operates using the pressure oil discharged from the discharge port of the shuttle valve 21 as a pilot pressure. When the pilot pressure is applied, the logic valve 20 is closed and the pressure oil supplied to the extension oil passage 6 is hydraulic. The cylinder S is prevented from flowing into the bottom chamber a.

  The hydraulic control apparatus shown in the first embodiment has the above-described structure. When the hydraulic cylinder S is extended, as shown in FIG. 2, the pressure oil discharged from the hydraulic pump 4 is extended by the pedal operation by the operator. The operation valve 1 is switched to the forward position supplied to the oil passage 6.

  When the hydraulic pump 4 is driven in the switching state of the operation valve 1 as described above, the pressure oil discharged from the hydraulic pump 4 is sent from the oil supply passage 3 to the extension oil passage 6 and the first branch oil passage 11.

At this time, since the changeover valve V ₁ was in the neutral position (closed), the hydraulic motor M is not rotated. Further, since no pressure oil is supplied to the shuttle valve 21, no pilot pressure is applied to the logic valve 20, and the logic valve 20 can be opened.

  Therefore, the pressure oil supplied to the extension oil passage 6 flows through the logic valve 20 and flows into the bottom chamber a of the hydraulic cylinder S, and the hydraulic cylinder S extends. At this time, the oil in the rod chamber b of the hydraulic cylinder S flows into the contracting oil passage 7, flows into the return passage 5, and is returned to the tank 2.

  By the extension of the hydraulic cylinder S, the crushing arms 44 and 45 as the working arms shown in FIG. 10 swing in the closing direction and a large force is applied to the work object in the sandwiched state. Things can be crushed.

  When the hydraulic valve 4 is switched to the reverse position where the pressure oil from the hydraulic pump 4 is fed into the contracting oil passage 7 as shown in FIG. The discharged pressure oil is sent from the oil supply passage 3 to the contracting oil passage 7 and flows into the rod chamber b, and the hydraulic cylinder S contracts. At this time, the oil in the bottom chamber a of the hydraulic cylinder S flows through the logic valve 20 and is returned from the extension oil passage 6 to the tank 2. By the contraction of the hydraulic cylinder S, the crushing arms 44 and 45 shown in FIG.

During contraction operation of the hydraulic cylinder S as described above, but will be the oil flows into the first branch oil passage 11 and the second branch oil passage 12, the switching valve V ₁ was in the neutral position, the second branch oil passage 12 Since the check valve 15 is also provided, the hydraulic oil does not flow into the hydraulic motor M, and the hydraulic motor M does not rotate.

As shown in FIG. 2, in the state of switching the operation valve 1 in the forward direction position, by operating the operation switch SW ₁ shown in FIG. 1, the switching valve V _1, as shown in FIG. 4, the first branch oil passage 11 and the forward oil passage 13 communicate with each other and the second branch oil passage 12 communicates with the reverse oil passage 14, the pressure oil discharged from the hydraulic pump 4 is indicated by an arrow in FIG. As described above, the oil is supplied from the extension oil passage 6 to the first branch oil passage 11 and circulates in the switching valve V ₁ , and flows from the normal rotation oil passage 13 to the forward rotation port MP ₁ of the hydraulic motor M. Rotates forward.

The oil discharged from the reverse rotation port MP ₂ of the hydraulic motor M flows from the reverse rotation oil passage 14 through the switching valve V ₁ into the second branch oil passage 12 and enters the operation valve 1 from the contraction oil passage 7. It flows and returns to the tank 2.

  During forward rotation of the hydraulic motor M, part of the pressure oil is sent from the forward oil passage 13 to the supply port of the shuttle valve 21 and discharged from the discharge port, and pilot pressure is applied to the logic valve 20.

  With the addition of the pilot pressure, the logic valve 20 is closed and the extension oil passage 6 is closed. For this reason, pressure oil does not flow into the bottom chamber a of the hydraulic cylinder S, and the hydraulic cylinder S does not operate.

Further, in the state of switching the operation valve 1 in the forward direction position, by operating the operation switch SW ₂ of FIG. 1, as shown in FIG. 5, the switching valve V _1, the first branch oil passage 11 is oil for reverse When the second branch oil passage 12 communicates with the passage 14 and is switched to the reverse position where the second branch oil passage 12 communicates with the forward rotation oil passage 13, the pressure oil discharged from the hydraulic pump 4 is expanded as shown by the arrows in FIG. from the oil passage 6 is fed to the first branch oil passage 11 flows through the switching valve V _1, flows from the reverse rotation passage 14 in the reverse port MP ₂ of the hydraulic motor M, a hydraulic motor M rotates in the reverse direction.

Further, the oil discharged from the forward rotation port MP ₁ of the hydraulic motor M flows from the forward rotation oil passage 13 into the second branch oil passage 12 through the switching valve V _1, and passes through the operation valve 1 from the contraction oil passage 7. It flows and returns to the tank 2.

  During the reverse rotation of the hydraulic motor M as described above, part of the pressure oil is sent from the reverse oil passage 14 to the supply port of the shuttle valve 21 and discharged from the discharge port, and pilot pressure is applied to the logic valve 20. It will be.

  With the addition of the pilot pressure, the logic valve 20 is closed and the extension oil passage 6 is closed as in the case shown in FIG. For this reason, pressure oil does not flow into the bottom chamber a of the hydraulic cylinder S, and the hydraulic cylinder S does not operate.

As described above, in a state where the operation valve 1 is switched to the forward position, the operation switch SW ₁ or SW ₂ is operated to connect the switching valve V ₁ to the first branch oil passage 11 and the forward rotation oil passage 13. Alternatively, by switching to a state where the oil passage 14 communicates with the reverse oil passage 14, the hydraulic motor M can be immediately rotated when necessary, and can be rotated in either the forward or reverse direction. For this reason, operations such as dismantling can be performed efficiently.

  Further, during the rotation of the hydraulic motor M, a part of the pressure oil supplied to the hydraulic motor M is sent to the pilot oil passage of the logic valve 20 and the logic valve 20 is in the closed state. The hydraulic oil sent to the hydraulic cylinder S is not sent to the bottom chamber a of the hydraulic cylinder S, and the hydraulic cylinder S does not operate. For this reason, even if the pair of crushing arms 44 and 45 are in a state of sandwiching the work object, the work object is held in a sandwiched state by the pair of crushing arms 44 and 45.

  Even if the hydraulic cylinder S is activated due to a slight leak of pressurized oil in the logic valve portion, the hydraulic cylinder S operates in the extending direction, so that the work object is moved by the pair of crushing arms 44 and 45. It will be held more securely in the sandwiched state, and it is possible to completely prevent the occurrence of inconvenience that the work object falls. Therefore, the operation can be switched from the hydraulic cylinder S to the hydraulic motor M in a state where safety is ensured.

FIG. 6 shows a second embodiment of the hydraulic control apparatus according to the present invention. In this embodiment, the shuttle valve 21 shown in the first embodiment is omitted, a hydraulic motor for one-way rotation is adopted as the hydraulic motor M, and the first branch oil passage 11 is incorporated. The switching valve V ₁ is different from the hydraulic control apparatus shown in the first embodiment in that a solenoid operated two-position switching valve that is switched by operating the switch SW ₁ is employed.

  For this reason, the same components as those of the hydraulic control apparatus shown in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

It said even in the hydraulic control device shown in the second embodiment, the operation valve 1 in the forward direction located switching the compression crushing work state, when the need of the rotation occurs, by operating the operation switch SW ₁ switch by switching the valve V ₁ in a state where the first branch oil passage 11 is communicated with the regular rotation oil passage 13, it is possible to immediately rotate the hydraulic motor M.

  FIG. 7 shows a third embodiment of the hydraulic control apparatus according to the present invention. In this embodiment, a pilot check valve 21 is employed instead of the logic valve 20 shown in the first embodiment, and flows into the pressure oil and the contraction oil passage 7 discharged from the discharge port of the shuttle valve 21. This is different from the hydraulic control apparatus shown in the first embodiment in that the pressure oil is used as the pilot pressure.

  For this reason, the same components as those of the hydraulic control apparatus shown in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

Said even in the hydraulic control system shown in the third embodiment, the operation state switch SW ₁ or SW ₂ a switching valve V ₁ by operating the first branch oil passage 11 is communicated with the regular rotation oil passage 13, or By switching to the state of communicating with the reverse oil passage 14, the hydraulic motor M can be immediately rotated and can be rotated in either the forward or reverse direction.

  FIG. 8 shows a fourth embodiment of the hydraulic control apparatus according to the present invention. In this embodiment, a pilot check valve 22 is adopted in place of the logic valve 20 shown in the second embodiment, and the pilot oil is supplied to the pressure oil flowing in the contracting oil passage 7 and the pressure oil flowing in the forward rotation oil passage 13. This is different from the hydraulic control apparatus shown in the second embodiment in that the pressure is used.

  For this reason, the same components as those of the hydraulic control apparatus shown in the second embodiment are denoted by the same reference numerals, and description thereof is omitted.

Said even in the hydraulic control device shown in the fourth embodiment, the operation in the state in which switches the valve 1 in the forward direction position, the switching valve V ₁ by operating the operation switch SW ₁ is first branched oil passage 11 forward rotation The hydraulic motor M can be immediately rotated by switching to the state of communicating with the oil passage 13.

In the above description of the embodiment, first, by operating the operating valve 1, by performing the expansion and contraction of the hydraulic cylinder S, on the assumption that rotating the hydraulic motor M then switching the switching valve V ₁ Yes. On the other hand, even when the switching valve V1 is actuated _first and then the operation valve 1 is operated to the forward position, the crusher is turned to position the crushing arms 44 and 45 in an appropriate direction for work. Therefore, workability is improved.

  Further, since the crushing arms 44 and 45 can be turned in any open / closed state such as full open, middle open, and full closed, the crushing arms 44 and 45 are always fully opened in order to grasp the work object. There is no need, and the crushing arms 44 and 45 may be opened to an appropriate degree, so that the work efficiency is improved accordingly.

DESCRIPTION OF SYMBOLS 1 Operation valve 4 Hydraulic pump 6 Extension oil path 7 Contraction oil path 11 First branch oil path 12 Second branch oil path 13 Forward rotation oil path 14 Reverse rotation oil path 15 Check valve 20 Logic valve (direction control valve)
21 Shuttle valve 22 Pilot check valve (Directional control valve)
M hydraulic motor S hydraulic cylinder V ₁ switching valve MP ₁ forward rotation port MP ₂ reverse rotation port

Claims (5)

  An extension oil passage is connected to the bottom chamber of the hydraulic cylinder for opening and closing the work arm, and a contraction oil passage is connected to the rod chamber of the hydraulic cylinder, and the extension oil passage and the contraction oil passage are discharged from the hydraulic pump. An operation valve for switching and supplying the pressure oil to be supplied, branching a first branch oil passage connected to the hydraulic motor from the extension oil passage, and a second connected to the hydraulic motor from the contraction oil passage A branch oil passage is branched, and each of the first branch oil passage and the second branch oil passage is connected to a solenoid operated switching valve for controlling the operation of the hydraulic motor, and the switching valve is connected to the second branch oil passage. A check valve for preventing the pressure oil from being fed toward the valve is incorporated, and in the extension oil passage, the pressure oil supplied to the hydraulic motor in a portion from the branch position of the first branch oil passage to the bottom chamber Closed with pilot pressure The hydraulic control device for the attachment of a construction machine which incorporates a directional control valve pilot-operated to be held.   The switching valve comprises a four-port three-position switching valve, and a part of a forward oil passage connecting the A port of the switching valve and the forward rotation port of the hydraulic motor is connected to one supply port of the shuttle valve; and A part of the reverse oil passage connecting the B port of the switching valve and the reverse port of the hydraulic motor is connected to the other supply port of the shuttle valve, and the pressure oil discharged from the discharge port of the shuttle valve is The hydraulic control device for an attachment in a construction machine according to claim 1, wherein a pilot pressure of the direction control valve is used.   2. The switching valve comprises a single solenoid / spring offset type two-position switching valve, and pressure oil supplied from the A port of the switching valve to the hydraulic motor is used as a pilot pressure of the directional control valve. Hydraulic control device for attachments in Japanese construction machinery.   The hydraulic control device for an attachment in a construction machine according to any one of claims 1 to 3, wherein the directional control valve is a logic valve.   The hydraulic control apparatus for an attachment in a construction machine according to any one of claims 1 to 3, wherein the directional control valve is a pilot check valve.

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