JP2006256746A - Hydraulic circuit for crane - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To excellently move a hoisted load in the horizontal direction by connecting a hydraulic actuator to a pipe for supplying pressure oil to a boom hoisting actuator. <P>SOLUTION: The hydraulic circuit of a crane is provided with the boom hoisting actuators 23 connected to a plurality of hydraulic pumps 11 and 12 through control valves 16 and 18 in parallel with each other, the hydraulic actuators 21 and 22 connected from each of the hydraulic pumps 11 and 12 to the pipe for supplying pressure oil to the boom hoisting actuators 23 through each of control valves 15 and 17, a selecting means 30 for selecting at least one of the plurality of hydraulic pumps 11 and 12, and control means 31-34 for controlling flow of the pressure oil from the hydraulic pumps 11 and 12 so that the pressure oil is supplied to the boom hoisting actuator 23 from the only hydraulic pumps 11 or 12 selected by the selecting means. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a crane hydraulic circuit that facilitates horizontal movement of a suspended load.

  When performing work such as hanging a viaduct or installing a steel tower, the suspended load may move horizontally in the front-rear direction with the suspended load suspended from the main hook and auxiliary hook. When the load is horizontally moved forward, the main winch winch and the auxiliary winch are simultaneously hoisted while lowering the hoisting winch. In order to facilitate the horizontal movement in this case, a hydraulic circuit described in Patent Document 1 below is known.

  In the hydraulic circuit described in Patent Document 1, a main winding winch control valve and a relief winch control valve are connected in series to a hydraulic pump, and an auxiliary winding winch control valve and a relief winch for other hydraulic pumps. Control valves are connected in series, and hydraulic oil from a plurality of hydraulic pumps is joined to drive the undulation winch. In addition, each undulation winch control valve is provided with a flow compensation valve so as to regulate the amount of pressure oil supplied from each hydraulic pump to the undulation winch.

JP 2002-274784 A

  However, in the hydraulic circuit described in Patent Document 1, since the undulating winch is driven by always joining pressure oil from a plurality of hydraulic pumps, for example, the suspended load is suspended only on the main winding hook and the suspended load is moved forward. When moving horizontally, the pressure oil supply amount to the main winding winch is insufficient as compared with the pressure oil supply amount to the undulation winch. For this reason, the amount of vertical movement of the suspended load by the main winding winch is insufficient with respect to the amount of vertical movement of the suspended load caused by the boom undulation, which may make it difficult to move the suspended load horizontally.

The hydraulic circuit of the crane according to the present invention includes a boom raising / lowering actuator connected in parallel to a plurality of hydraulic pumps via control valves, and a control valve for each of the pipelines for supplying pressure oil from each hydraulic pump to the boom raising / lowering actuator. The other hydraulic actuators connected to each other, selection means for selecting at least one of the plurality of hydraulic pumps, and pressure oil can be supplied to the boom hoisting actuator only from the hydraulic pump selected by the selection means And control means for controlling the flow of pressure oil from the hydraulic pump.
It is preferable that all of the plurality of hydraulic pumps are selected when the high speed is selected by the selection switch for selecting the high and low speeds of the boom hoisting actuator, and only a part of the plurality of hydraulic pumps is selected when the low speed is selected.
The crane hydraulic circuit according to the present invention includes a main winding actuator that drives a main winding winch according to a main winding operation command, an auxiliary winding actuator that drives an auxiliary winding winch according to an auxiliary winding operation command, and a undulation. The hoisting actuator for driving the hoisting winch according to the operation command, the main hydraulic actuator, the first hydraulic pump for discharging the hoisting hydraulic oil for the hoisting actuator, and the driving hydraulic oil for the auxiliary hoisting actuator and the hoisting actuator A second hydraulic pump for discharging, a main winding control valve for controlling the flow of pressure oil from the first hydraulic pump to the main winding actuator, and a pressure oil from the second hydraulic pump to the auxiliary winding actuator. A supplementary winding control valve for controlling the flow, a first undulation control valve for controlling the flow of pressure oil from the first hydraulic pump to the undulation actuator, and a second hydraulic pump The second hoisting control valve for controlling the flow of pressure oil to the hoisting actuator, the selecting means for selecting the first and / or second hydraulic pump, and the selecting means selected by the hoisting operation command. And control means for controlling the first and second undulation control valves so that pressure oil is supplied from the hydraulic pump to the undulation actuator.

  According to the present invention, a boom raising and lowering actuator is connected in parallel to a plurality of hydraulic pumps via a control valve, and the hydraulic actuator is connected to a pipeline that supplies pressure oil to the boom raising and lowering actuator, thereby selecting a selected hydraulic pressure. Since the hydraulic oil can be supplied to the boom hoisting actuator only from the pump, the shortage of the hydraulic oil supply to other hydraulic actuators can be solved when the boom hoisting actuator is driven, and the suspended load can be moved horizontally. Etc. can be performed satisfactorily.

Hereinafter, an embodiment of a hydraulic circuit for a crane according to the present invention will be described with reference to FIGS.
FIG. 1 is a side view of a crane to which the present invention is applied. The crane includes a traveling body 1, a revolving body 2 that is turnably mounted on the traveling body 1, and a boom 3 that is pivotally supported by a front portion of the revolving body 2. The revolving body 2 is equipped with a main winding winch drum (hereinafter referred to as main winding drum 4), an auxiliary winding winch drum (hereinafter referred to as auxiliary winding drum 5), and a undulating winch drum (hereinafter referred to as undulating drum 6). A main winding rope 4a, an auxiliary winding rope 5a, and a hoisting rope 6a are wound around the drums 4 to 6, respectively.

  The main winding rope 4a is connected to the main winding hook (hereinafter referred to as main hook 7) via the boom tip, and the auxiliary winding rope 5a is connected to the auxiliary winding hook (hereinafter referred to as auxiliary hook 8) via the boom tip. It is connected to the. The main winding winch is a heavy load winch and the auxiliary winding winch is a light load winch. The number of the main winding rope 4a is larger than the number of the auxiliary winding rope 5a. When the main winding drum 4 is driven, the main hook 7 moves up and down via the main winding rope 4a, and when the auxiliary winding drum 5 is driven, the auxiliary hook 8 moves up and down via the auxiliary winding rope 5a. The hoisting rope 5a is connected via a bridle 9 to the other end of a pendant rope 10 having one end connected to the boom tip. When the hoisting drum 5 is driven, the boom 3 is hoisted via the hoisting rope 6 a and the pendant rope 10.

  A crane hydraulic circuit according to the present embodiment is shown in FIG. The hydraulic pumps 11 to 13 are each driven by the engine 14. A main winding motor 21 and a hoisting motor 23 are connected to the hydraulic pump 11 via direction control valves 15 and 16, and an auxiliary winding motor 22 and a hoisting motor 23 are connected to the hydraulic pump 12 via direction control valves 17 and 18. Has been. In other words, hydraulic pumps 11 and 12 are connected in parallel to the hoisting motor 23.

  When the direction control valve 15 is switched to the position A side or the position B side, the pressure oil PF from the hydraulic pump 11 is supplied to the main winding motor 21 via the direction control valve 15. As a result, the main winding motor 21 is driven, and the main winding drum 4 is driven up or down. When the direction control valve 17 is switched to the position A side or the position B side, the pressure oil PR from the hydraulic pump 12 is supplied to the auxiliary winding motor 22 via the direction control valve 17. As a result, the auxiliary winding motor 22 is driven, and the auxiliary winding drum 5 is driven up or down.

  When only one of the directional control valves 16 and 18 is switched to the position A side or the position B side, the hydraulic oil PF or PR is supplied from the hydraulic pump 11 or 12 to the undulation motor 23. Further, when both of the direction control valves 16 and 18 are switched to the position A side or the position B side, the pressure oils PR and PR are supplied from the hydraulic pumps 11 and 12 to the undulation motor 23. As a result, the hoisting motor 23 is driven, and the hoisting drum 6 is driven up or down. The maximum discharge pressure from the hydraulic pumps 11 and 12 is limited by relief valves 19 and 20, respectively.

  Pressure oil (pilot pressure Pp) from the hydraulic pump 13 is guided to pilot valves 24 to 26, respectively. The pilot valve 24 is driven by operating a main winding winch operating lever (hereinafter referred to as main winding lever), the pilot valve 25 is driven by operating an auxiliary winding winch operating lever (hereinafter referred to as auxiliary winding lever), and the pilot valve 26 is It is driven by operation of an operation lever for a hoisting winch (hereinafter, hoisting lever). The pilot pressure Pp from the pilot valve 24 corresponding to the operation amount of the main winding lever acts on the pilot port of the direction control valve 15, and the direction control valve 15 is switched according to the operation amount of the main winding lever. The pilot pressure Pp from the pilot valve 25 corresponding to the operation amount of the auxiliary winding lever acts on the pilot port of the direction control valve 17, and the direction control valve 17 is switched according to the operation amount of the auxiliary winding lever.

  Electromagnetic switching valves 31 and 32 are interposed between the pilot valves 26 and the pilot ports of the directional control valve 16, respectively. Electromagnetic switching valves 33 and 32 are respectively interposed between the pilot valves 26 and the pilot ports of the directional control valve 18. 34 is interposed. When the electromagnetic switching valves 31 to 34 are switched to the position A, the pilot valve 26 and the pilot ports of the direction control valves 16 and 18 communicate with each other. When the raising / lowering lever is operated in this state, the pilot pressure Pp from the pilot valve 26 corresponding to the operation amount acts on the pilot ports of the direction control valves 16 and 18, and the direction control valve 16 corresponds to the operation amount of the raising / lowering lever. , 18 are switched.

  On the other hand, when the electromagnetic switching valves 31 to 34 are switched to the position B, the pilot valve 26 and the pilot ports of the direction control valves 16 and 18 are shut off. In this state, even if the raising / lowering lever is operated, the pilot valves 16 and 18 remain switched to the neutral position.

  The electromagnetic switching valves 31 to 34 are switched by operating the undulation selection switch 30 provided in the cab. The undulation selection switch 30 is a switch (for example, a toggle switch) that can be switched to three positions of “high speed”, “low speed PF”, and “low speed PR”. When the undulation selection switch 30 is switched to “high speed”, the electromagnetic switching valves 31 to 34 are all switched to the position “a”, and when switched to “low speed PF”, only the electromagnetic switching valves 31 and 32 are switched to the position “b”. When switched to "PR", only the electromagnetic switching valves 33 and 34 are switched to the position A.

Next, main operations of the present embodiment will be described.
(1) “Low-speed PR” position For example, when a relatively heavy load is hung on the main hook 7 and the load is horizontally moved in the front-rear direction (in the direction of the arrow in FIG. 1) at a low speed, The undulation selection switch 30 is operated to the “low speed PR” position. As a result, the electromagnetic switching valves 33 and 34 are switched to the position A, and the pilot valve 26 and the pilot port of the direction control valve 18 communicate with each other. In this state, when the raising / lowering lever is lowered and the main winding lever is raised, the pressure oil PR from the hydraulic pump 12 is supplied to the raising / lowering motor 23 via the direction control valve 18, and the pressure oil PF from the hydraulic pump 11 is supplied. Is supplied to the main winding motor 21 via the direction control valve 15. As a result, the hoisting rope 6a is drawn out at a low speed and the boom 3 is turned over, and the main winding rope 4a is taken up, so that the suspended load can be moved horizontally forward slowly.

  In this case, the pressure oil PF from the hydraulic pump 11 is supplied only to the main winding motor 21, and the pressure oil PR from the hydraulic pump 12 is supplied only to the undulation motor 23. For this reason, sufficient drive pressure can be supplied to the main winding motor 21, and the horizontal movement of a favorable suspended load is attained. On the other hand, when the pressure oil from the hydraulic pump 11 is supplied not only to the main winding motor 21 but also to the undulation motor 23, the pump discharge oil is relieved from the relief valve 19 and sufficient driving pressure is supplied to the main winding motor 21. May not be supplied, and the horizontal movement of the suspended load is difficult.

(2) “Low-speed PF” position When a suspended load is hung on the auxiliary winding hook 8 and horizontally moved at a low speed, the operator operates the undulation selection switch 30 to the “low-speed PF” position. As a result, the electromagnetic switching valves 31 and 32 are switched to the position A, and the pilot valve 26 and the pilot port of the direction control valve 16 communicate with each other. In this state, when the raising / lowering lever is lowered and the auxiliary winding lever is raised, the pressure oil PF from the hydraulic pump 11 is supplied to the raising / lowering motor 23 via the direction control valve 16, and the pressure oil PR from the hydraulic pump 12 is supplied. Is supplied to the auxiliary winding motor 22 via the direction control valve 17. As a result, the hoisting rope 6a is drawn out at a low speed and the boom 3 is turned over, and the auxiliary winding rope 5a is wound up, so that the suspended load can be moved horizontally forward slowly.

  In this case, the pressure oil PF from the hydraulic pump 11 is supplied only to the undulation motor 23, and the pressure oil PR from the hydraulic pump 12 is supplied only to the auxiliary winding motor 22. For this reason, a sufficient driving pressure can be supplied to the auxiliary winding motor 22, and a good horizontal movement of the suspended load is possible without the pump discharge oil being relieved from the relief valve 20. The main winding winch and the auxiliary winding winch may be properly used according to the weight of the suspended load, and the undulation selection switch 30 may be operated accordingly. The horizontal movement speed of the suspended load can be changed by adjusting the operation amount of the operation lever or the engine speed.

(3) “High-speed” position When a suspended load is suspended from the main hook 7 and moved horizontally at high speed, the operator operates the undulation selection switch 30 to the “high-speed” position. As a result, the electromagnetic switching valves 31 to 34 are all switched to the position A, and the pilot valve 26 and the pilot ports of the direction control valves 16 and 18 communicate with each other. In this state, when the raising / lowering lever is lowered and the main winding lever is raised, the pressure oil PF from the hydraulic pump 11 is supplied to the main winding motor 21 and the raising motor 23, respectively, and the pressure oil PR from the hydraulic pump 12 is supplied. Is supplied to the hoisting motor 23. As a result, the hoisting rope 6a is drawn out at a high speed and the boom 3 is turned over, and the main winding rope 4a is taken up, and the suspended load can be horizontally moved forward at a high speed. That is, when the load of the suspended load is small and the relief from the relief valve 19 does not cause a problem, the switch 30 may be operated to the “high speed” position. When the suspended load is hung from the auxiliary winding hook 8 and moved horizontally at high speed, the raising / lowering lever 30 is lowered and the auxiliary winding lever is raised by operating the raising / lowering selection switch 30 to the “high speed” position. do it.

  On the other hand, when a suspended load is hung on both the main winding hook 7 and the auxiliary winding hook 8 and moved horizontally, the operator operates the undulation selection switch 30 to the “high speed” position. When the hoisting lever is lowered, and the main winding lever and the auxiliary winding lever are simultaneously hoisted, the pressure oil PF from the hydraulic pump 11 is supplied to the main winding motor 21 and the hoisting motor 23, respectively. Are supplied to the auxiliary winding motor 22 and the undulation motor 23, respectively. As a result, the hoisting rope 6a is drawn out and the boom 3 is turned over, and the main winding rope 4a and the auxiliary winding rope 5a are wound up, and the suspended load can be moved horizontally forward. In this case, the pressure oil from the hydraulic pumps 11 and 12 can be efficiently distributed to the motors 21 to 23, and a good horizontal movement of the suspended load is possible.

  As described above, in the present embodiment, the hydraulic pumps 11 and 12 and the hoisting motor 23 are connected via the direction control valves 16 and 18, and the electromagnetic switching valves 31 to 31 are provided between the pilot valve 26 and the direction control valves 16 and 18. 33 is provided, and pressure oil is supplied to the undulation motor 23 from one or both of the hydraulic pumps 11 and 12 by switching the electromagnetic switching valves 31 to 34. Thereby, the pressure oil from one hydraulic pump 11 or 12 can be supplied only to the main winding motor 21 or the auxiliary winding motor 22, and the pressure oil from the other hydraulic pump 12 or 11 can be supplied only to the undulation motor 23. . As a result, it is possible to prevent a shortage of the amount of pressure oil supplied to the main winding motor 21 and the auxiliary winding motor 22, and a good horizontal movement of the suspended load becomes possible. Further, the pump capacity can be maximized, and the pressure oil from the hydraulic pumps 11 and 12 can be efficiently distributed to the motors 21 to 23. Since the electromagnetic switching valves 31 to 34 are switched by operating the undulation selection switch 30, the flow of pressure oil from the hydraulic pumps 11 and 12 to the undulation motor 23 can be arbitrarily changed according to the work contents. Speed adjustment is easy. It can be easily applied to an existing hydraulic circuit only by adding the electromagnetic switching valves 31 to 34.

  In the above embodiment, the hoisting winch is used as the boom hoisting actuator, but the boom 42 may be hoisted using the hoisting cylinder 41 as shown in FIG. Also in this case, as shown in FIG. 4, the undulation cylinder 41 is connected to the hydraulic pumps 11 and 12 via the direction control valves 16 and 18, and between the pilot valve 26 and the pilot ports of the direction control valves 16 and 18 The switching valves 31 to 34 may be interposed, and the electromagnetic switching valves 31 to 34 may be switched by operating the undulation selection switch 30.

  As shown in FIG. 3, the boom 42 may be a telescopic boom that can be expanded and contracted. In this case, when the boom length is long, the rotation speed of the boom tip portion with the boom base end portion as a fulcrum is fast, and when the boom length is short, the boom speed is slow. Therefore, in order to move the suspended load horizontally, it is necessary to adjust the relative speed of the hooks 7 and 8 with respect to the driving speed of the hoisting cylinder 41 according to the boom length. The relative speeds of the hooks 7 and 8 can be adjusted by switching the electromagnetic switching valves 31 to 34.

  In the above embodiment, the electromagnetic switching valves 31 to 34 as the control means are provided on the pipes (pilot pipes) for supplying the pilot pressure to the direction control valves 16 and 18. You may provide in the pipe line which connects the undulation motor 23. FIG. If the flow of pressure oil from the hydraulic pumps 11 and 12 is controlled so that pressure oil can be supplied to the hoisting motor 23 from only the selected hydraulic pumps 11 and 12, the configuration of the control means is as described above. Not limited to this, electromagnetic switching valves 31 to 34 may be used. Although the pumps 11 and 12 for supplying pressure oil to the undulation motor 23 are selected by the undulation selection switch 30, other selection means may be used.

  A plurality of hydraulic pumps 11 and 12 are connected in parallel to the hoisting actuators (the hoisting motor 23 and the hoisting cylinder 41) via the control valves 16 and 18, and pressure oil is supplied from the hydraulic pumps 11 and 12 to the hoisting actuators. The main winding motor 21 (main winding actuator) and the auxiliary winding motor 22 (auxiliary winding actuator) are connected to the pipelines through the control valves 15 and 17, respectively, but other hydraulic actuators may be connected. Although the two hydraulic pumps 11 and 12 are connected in parallel to the undulation actuator, three or more hydraulic pumps may be connected in parallel. That is, a control valve 15 (main winding control valve) for controlling the flow of pressure oil from the hydraulic pump 11 (first hydraulic pump) to the main winding motor 21 and a hydraulic pump 12 (second hydraulic pump) in the hydraulic circuit. ) From the hydraulic pump 11 to the undulation motor 23, and a control valve 16 (first control valve) that controls the flow of pressure oil from the hydraulic pump 11 to the undulation motor 23. Control valve 18 (second hoisting control valve) for controlling the flow of pressure oil from the hydraulic pump 12 to the hoisting motor 23 is provided, but another control valve is provided for selection. The flow of the pressure oil from the hydraulic pump thus made to the undulation motor 23 may be controlled.

  Although the hoisting actuator is used for boom hoisting, the same effect can be obtained by using it for jib hoisting. When the boom hoisting motor 23 and the jib hoisting motor are provided in the hydraulic circuit, a pair of control valves arranged in series with the control valves 16 and 18 in a pipeline that supplies pressure oil from the hydraulic pumps 11 and 12 to the boom hoisting motor 23. The jib hoisting motor is connected via the control valve, and the control valves may be controlled so that the pressure oil flows from the selected hydraulic pumps 11 and 12 to the jib hoisting motor. The main winding motor 21 and the auxiliary winding motor 22 are used for raising and lowering the heavy load hook 7 and the light load hook 8, respectively. Good. That is, the present invention is not limited to the hydraulic circuit of the embodiment as long as the features and functions of the present invention can be realized. The above description is merely an example, and when interpreting the invention, there is no limitation or restriction on the correspondence between the items described in the embodiment and the items described in the claims.

The side view of the crane with which this invention is applied. 1 is a hydraulic circuit diagram according to an embodiment of the present invention. The figure which shows the modification of FIG. The figure which shows the modification of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11, 12 Hydraulic pump 15-18 Direction control valve 21 Main winding motor 22 Supplementary winding motor 23 Undulating motor 30 Undulating selection switch 31-34 Electromagnetic switching valve

Claims (3)

Boom hoisting actuators connected in parallel to a plurality of hydraulic pumps through control valves,
A hydraulic actuator connected via a control valve to a pipeline that supplies pressure oil from each of the hydraulic pumps to the boom hoisting actuator;
Selecting means for selecting at least one of the plurality of hydraulic pumps;
And a control means for controlling the flow of pressure oil from the hydraulic pump so that the pressure oil can be supplied to the boom hoisting actuator only from the hydraulic pump selected by the selection means. Hydraulic circuit. In the hydraulic circuit of the crane according to claim 1,
The selection means is a selection switch for selecting high and low speeds of the boom raising and lowering actuator, and when the high speed is selected by the selection switch, all of the plurality of hydraulic pumps are selected, and when the low speed is selected, the plurality of the plurality of hydraulic pumps are selected. The crane hydraulic circuit, wherein only a part of the hydraulic pump is selected. A main winding actuator for driving the main winding winch in accordance with the main winding operation command;
An auxiliary winding actuator for driving the auxiliary winding winch according to the auxiliary winding operation command;
A hoisting actuator that drives a hoisting winch in response to an hoisting operation command;
A first hydraulic pump that discharges drive pressure oil of the main winding actuator and the undulation actuator;
A second hydraulic pump that discharges drive pressure oil of the auxiliary winding actuator and the undulation actuator;
A main winding control valve that controls the flow of pressure oil from the first hydraulic pump to the main winding actuator;
An auxiliary winding control valve that controls the flow of pressure oil from the second hydraulic pump to the auxiliary winding actuator;
A first undulation control valve that controls the flow of pressure oil from the first hydraulic pump to the undulation actuator;
A second undulation control valve that controls the flow of pressure oil from the second hydraulic pump to the undulation actuator;
Selecting means for selecting the first and / or second hydraulic pump;
Control means for controlling the first and second undulation control valves so that pressure oil is supplied from the hydraulic pump selected by the selection means to the undulation actuator in response to the undulation operation command. A hydraulic circuit of a crane characterized by that.

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