JP2010189921A - Working device control circuit and working machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a working device control circuit, applicable to both work in high places and work close to the ground at appropriate speeds. <P>SOLUTION: A remote control valve 15 which pilot-operates an upper boom control valve 13 includes a contracting-side remote control valve 15a for contracting an upper boom cylinder 4a and an extending-side remote control valve 15b for extending the upper boom cylinder 4a. A pilot circuit from the secondary side of the extending-side remote control valve 15b to the upper boom control valve 13 includes a solenoid proportional pressure reducing valve 16 for limiting the pilot pressure. An output part of a controller 19 is connected to a solenoid of the pressure reducing valve 16. The controller 19 throttle-controls, when the tip height of an upper boom detected by a lower boom angle sensor 7 and an upper boom angle sensor 8 is high, the secondary pressure of the extending-side remote control valve 15b detected by a pressure sensor 20 by the pressure reducing valve 16. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a work device control circuit that controls the operating speed of an upper boom provided at the tip of a lower boom, and a work machine equipped with the control circuit.

  There are two types of dismantling work for high-rise buildings, such as dismantling the upper part of the building and dismantling the lower part of the basement (underground structures and foundations). An altitude dismantling machine with an attachment is used. This high place dismantling machine is configured by attaching a work attachment having a long boom that can be raised and lowered to the front of a base machine. On the other hand, at the time of low place demolition work, the work attachment is replaced without changing the base machine, and the low place demolition machine is configured.

  As described above, in the work machine that replaces the work attachment with the base machine as it is and constitutes the high place demolition machine and the low place demolition machine, hydraulic pressure is supplied from among the plurality of boom cylinders for raising and lowering the boom of the work attachment. By switching the number of cylinders to be operated, the cylinder operating speed and total cylinder thrust are switched between the low speed / large thrust (large undulating force) mode and the high speed / small thrust (small undulating force) mode ( For example, see Patent Document 1).

  On the other hand, as shown in FIG. 6 to FIG. 8, a two-piece boom that can dismantle an upper structure such as a building dismantling and a dismantling of a foundation pile without exchanging such work attachments. There is a two-piece boom dismantling machine A equipped with a working device.

  The two-piece boom dismantling work machine A is provided such that the upper swing body 2 is turnable with respect to the lower traveling body 1, and the base end of the lower boom 3 is pivotally connected to the upper swing body 2 so as to be rotatable in the vertical direction. The base of the upper boom 4 is pivotally connected to the tip of the lower boom 3 so as to be rotatable in the vertical direction, and the base of the arm 5 is pivotally connected to the tip of the upper boom 4. A crusher 6 is pivotally connected to the tip of the crusher 6.

  This two-piece boom dismantling work machine A is capable of dismantling the upper structure at a high work position shown in FIG. 6 by the crusher 6 attached to the tip of the arm, and at the ground work posture shown in FIG. 7 or FIG. It is possible to dismantle work near the ground such as underground foundation piles, and to perform work at high places and work near the ground with a single work machine.

  In this way, since the two-piece boom disassembly work machine A disassembles the upper structure by installing the heavy crusher 6 at the arm tip, the extension side meter of the upper boom cylinder 4a is prevented so that the upper boom 4 does not drop suddenly. The return flow rate from the rod side is reduced by using a slow return valve in which a check valve and a manual flow rate adjustment valve are combined in parallel with the rod side return circuit as an outline.

Japanese Patent Laying-Open No. 2005-105522 (page 6-7, FIG. 1-6)

  In this way, the two-piece boom dismantling work machine A that performs high-altitude work and work close to the ground in this way throttles the rod-side return circuit with a slow return valve on the extension side of the upper boom cylinder 4a. When work such as foundation pile dismantling is performed nearby, the operating speed of the upper boom 4 becomes extremely slow, and the workability is poor.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a work device control circuit and a work machine that can handle both high-altitude work and work near the ground at an appropriate speed. And

  According to the first aspect of the present invention, an upper boom cylinder capable of moving a work tool provided through an arm in an up-and-down direction by operating an up-and-down operation of an upper boom that is pivotally connected to the tip of a lower boom. A control circuit for a working device that controls the upper boom cylinder, an upper boom control valve that controls expansion and contraction of the upper boom cylinder, a pilot operation valve that pilot-operates the upper boom control valve with pilot pressure, and an upper boom control from the pilot operation valve When an electromagnetic proportional valve that limits the pilot pressure on the lower side of the upper boom output to the valve, a height detector that detects the tip height of the upper boom, and the tip height of the upper boom detected by this height detector are high With a controller that controls the throttle of an electromagnetic proportional valve for the same pilot operation amount. A device control circuit.

  According to a second aspect of the present invention, the upper boom cylinder in the work device control circuit according to the first aspect is attached to the rear side of the lower boom and is connected to the rod side of the upper boom cylinder so that the electromagnetic proportional valve A holding valve having a flow compensation function with pressure compensation that is proportionally controlled in accordance with the output head-side pilot pressure for lowering the upper boom is provided.

  According to a third aspect of the present invention, in the work device control circuit according to the first or second aspect of the present invention, the work device control circuit includes a pressure sensor that detects a pilot pressure on the lower side of the upper boom output from the pilot operation valve. The electromagnetic proportional valve is controlled to be throttled by a signal obtained by multiplying the gain set to decrease when the height is high and the upper boom lowering pilot pressure output from the pilot operation valve.

  According to a fourth aspect of the present invention, in the work device control circuit according to any one of the first to third aspects, an upper boom cylinder that moves a crusher as a work tool in a vertical direction is controlled.

  According to a fifth aspect of the present invention, there is provided an airframe, a lower boom that is pivotally connected to the airframe so as to be pivotable in the vertical direction, an upper boom that is pivotally pivotally connected to the tip of the lower boom, and an upper boom of the upper boom. 5. An arm pivotally connected to the tip, a work tool attached to the tip of the arm, an upper boom cylinder for raising and lowering the upper boom, and controlling the upper boom cylinder. A working machine comprising the working device control circuit described.

  According to the first aspect of the present invention, when the tip height of the upper boom detected by the height detector is high, the controller controls the electromagnetic proportional valve to throttle the same pilot operation amount. Meter-in control of the flow rate supplied to the upper boom cylinder from the control valve for the upper boom that is pilot-operated by the pilot pressure via the proportional valve, so that the upper boom cylinder operates at a low speed so that the upper boom does not drop suddenly during high-altitude work. In addition, the upper boom cylinder speed limit can be released so that the work efficiency can be improved in work near the ground surface, and an appropriate operating flow rate corresponding to each height can be supplied.

  According to the second aspect of the present invention, the holding valve having a flow rate adjusting function with pressure compensation that is proportionally controlled in accordance with the head-side pilot pressure for lowering the upper boom output from the electromagnetic proportional valve allows the rear side of the lower boom to be By controlling meter-out control of the flow rate from the rod side of the upper boom cylinder attached to the upper boom, the weight of the upper boom, arm and work tool can be held securely in place with a pilot operation amount of 0, and the upper boom lowering speed can be controlled by the pilot. It can be controlled to the exact operating speed according to the operation amount.

  According to the invention described in claim 3, the controller sets the gain set so as to decrease when the tip height of the upper boom detected by the height detector is high, and the control valve for the upper boom from the pilot operation valve. The upper boom lowering pilot pressure is limited by the solenoid proportional valve throttle control based on the signal multiplied by the upper boom lowering pilot pressure detected by the pressure sensor. It can be operated at an appropriate speed corresponding to each height at a low speed by the pressure, and at a high speed by the pilot pressure on the lower side of the upper boom with a large gain in the work near the ground surface.

  According to the invention described in claim 4, when performing a high place work for dismantling the upper structure and a work for dismantling the foundation pile near the ground surface by the crusher as the work tool, In the dismantling work, the proportional solenoid valve that receives the control signal from the controller limits the pilot pressure on the lower side of the upper boom when the tip height of the upper boom is high. In addition to preventing the sudden drop of the upper boom due to the weight of the crusher, and when dismantling work such as foundation piles near the ground surface, the restriction of the electromagnetic proportional valve is released, and the upper boom is driven by the pilot pressure according to the pilot operation amount. The operating speed can be obtained and work efficiency can be improved.

  According to the fifth aspect of the present invention, when the lower boom, the upper boom, and the arm are operated upward with respect to the airframe to perform the work with the work tool at a high place, the work tool is operated downward near the ground surface. In both cases, the work machine capable of driving the upper boom cylinder at an appropriate speed capable of corresponding to each work height can be provided.

It is a circuit diagram showing one embodiment of a control circuit for work equipment concerning the present invention. It is a circuit diagram of the holding valve of a control circuit same as the above. It is a control block diagram of the controller of a control circuit same as the above. It is a characteristic view which shows the characteristic of the gain setting device of a control circuit same as the above. It is a characteristic view which shows the pilot pressure characteristic output from the electromagnetic proportional valve of a control circuit same as the above. It is a side view which shows the high place working posture of the 2 piece boom dismantling work machine which is a working machine provided with the control circuit same as the above. It is a side view which shows the working posture in the arm extension state near the ground surface of a 2 piece boom dismantling work machine same as the above. It is a side view which shows the working posture in the arm contraction state near the ground surface of a 2 piece boom dismantling work machine same as the above.

  Hereinafter, the present invention will be described in detail with reference to one embodiment shown in FIGS.

  FIGS. 6 to 8 show a two-piece boom dismantling work machine A as a hydraulic excavator type working machine having a two-piece boom. The body 2 is provided with a body B provided so as to be able to turn. The base end of the lower boom 3 is connected to the body B so as to be pivotable in the vertical direction, and the base of the upper boom 4 is connected to the tip of the lower boom 3. The upper boom 4 is pivotally connected to a shaft, the base of an arm 5 is pivotally connected to the tip of the upper boom 4, and the crusher 6 as a work tool is pivotally connected to the tip of the arm 5. A working device is provided.

  The lower boom 3 is raised and lowered in the vertical direction by a lower boom cylinder 3a provided between the lower boom 3 and the upper body B. The upper boom 4 is raised and lowered in the vertical direction by an upper boom cylinder 4a pivotally supported on the back side of the lower boom 3. The arm 5 is rotated by an arm cylinder 5 a that is pivotally supported on the back side of the upper boom 4, and the bucket substitute crusher 6 is rotated by a bucket cylinder 6 a that is pivotally supported on the back side of the arm 5. .

  A lower boom angle sensor 7 as a height detector for detecting an angle of the lower boom 3 with respect to the airframe B, that is, a lower boom angle, is provided on the proximal support shaft of the lower boom 3. An upper boom angle sensor 8 is provided as a height detector for detecting the angle of the upper boom 4 with respect to the lower boom 3, that is, the upper boom angle.

  As shown in FIG. 1, main hydraulic pumps 10 and 11 driven by the in-vehicle engine 9 are connected to the in-vehicle engine 9, and the discharge lines of these main hydraulic pumps 10 and 11 are connected to the control valve 12. The control valve 12 includes traveling motors 1a and 1b for driving a pair of crawler belts of the lower traveling body 1, a swing motor 2a for rotating the upper swing body 2, a lower boom cylinder 3a, an upper boom cylinder 4a, and an arm. A pilot operated spool valve for controlling the direction and the flow rate of each hydraulic actuator of the cylinder 5a and the bucket cylinder 6a is incorporated.

  The pilot operated spool valve that controls the direction and flow rate of the upper boom cylinder 4a is referred to as an upper boom control valve 13. Further, a holding valve 14 is mounted on the rod side of the upper boom cylinder 4a.

  The remote control valve 15 as a pilot operation valve that pilot-operates the upper boom control valve 13 outputs a pilot pressure corresponding to the amount of lever operation by manually operating with the operation lever, and contracts the upper boom cylinder 4a. A contraction-side remote control valve 15a to be operated and an extension-side remote control valve 15b to extend and operate the upper boom cylinder 4a are guided to the pilot pressure acting portion of the upper boom control valve 13 from the secondary side of the extension-side remote control valve 15b. The pilot circuit is provided with an electromagnetic proportional pressure reducing valve 16 as an electromagnetic proportional valve for limiting the upper boom cylinder extending side pilot pressure, that is, the upper boom lowering side pilot pressure. A pilot pressure source 17 such as a pilot pump is connected to the primary side of the contraction side remote control valve 15a and the extension side remote control valve 15b, and the return side is connected to a tank 18 common to the main hydraulic pumps 10 and 11.

  The solenoid of the electromagnetic proportional pressure reducing valve 16 is connected to the output of the controller 19, and the input of the controller 19 includes a pressure sensor 20 for detecting the secondary pressure of the extension side remote control valve 15b, a lower boom angle sensor 7, The upper boom angle sensor 8 is connected.

  As shown in FIG. 2, the holding valve 14 connected to the rod side of the upper boom cylinder 4a includes an overload relief valve 21, a check valve 22 for preventing outflow from the rod side, and a variable throttle valve 23. Connected in parallel. The variable throttle valve 23 is connected in series with a pressure compensation valve 24 for securing a displacement proportional flow rate that is not affected by the differential pressure across the variable throttle valve 23. Further, the pilot operating portion of the variable throttle valve 23 has an expansion side. A pilot pressure line branched from the secondary pressure line of the electromagnetic proportional pressure reducing valve 16 that limits the pilot pressure output from the remote control valve 15b is connected.

  As shown in FIG. 3, the controller 19 includes a member data storage unit 25 that stores member data such as an inter-axis distance between the lower boom 3 and the upper boom 4, a lower boom angle detected by the lower boom angle sensor 7, and an upper boom angle sensor 8. The posture calculator 26 for obtaining the height of the tip of the upper boom 4 based on the angle of the upper boom detected in step 5 and the member data in the member data storage unit 25, and the height of the tip of the upper boom 4 output from the posture calculator 26 A gain setting unit 27 that sets a gain in a range of ˜1.0, a multiplier 28 that multiplies the upper boom cylinder extension-side remote control pressure detected by the pressure sensor 20 and the gain output from the gain setting unit 27; A driver 29 for driving the electromagnetic proportional pressure reducing valve 16 based on the output of the multiplier 28 is provided.

  Next, the operation and effect of the embodiment shown in FIGS. 1 to 8 will be described.

  In the control block diagram of FIG. 3, signals from the lower boom angle sensor 7, the upper boom angle sensor 8 and the pressure sensor 20 are input to the controller 19. The posture calculator 26 obtains the tip height of the upper boom 4 based on the lower boom angle, the upper boom angle, and the member data in the member data storage unit 25.

  Based on the tip height of the upper boom 4 obtained by the attitude calculator 26, the gain is set by the gain setting unit 27, the gain is multiplied by the signal of the pressure sensor 20, and the electromagnetic wave is passed through the driver 29. The proportional pressure reducing valve 16 is driven.

  FIG. 4 shows the characteristics of the gain setting device 27 in the controller 19, and when the height of the upper boom tip is low as shown in FIG. 7 or FIG. 8, the gain is increased, and as shown in FIG. It has a function of setting the gain low as the height increases. As a result, the excitation signal output from the controller 19 to the solenoid of the electromagnetic proportional pressure reducing valve 16 is large when working with the lower end of the upper boom even if the pilot operation amount is the same, and when working with the upper end of the upper boom. Becomes smaller.

  Therefore, as shown in FIG. 5, the pilot pressure on the extension side of the upper boom cylinder output from the electromagnetic proportional pressure reducing valve 16 is high when the upper boom tip is close to the ground surface even when the pilot operation amount is the same, and the upper boom tip is high. Decreases when working at high altitude.

  Since the holding valve 14 is controlled by the pressure compensation valve 24 so that the differential pressure between the inlet and the outlet of the variable throttle valve 23 becomes constant, the cylinder in the extension direction of the upper boom cylinder 4a according to the opening degree of the variable throttle valve 23. Speed is controlled.

  As shown in FIG. 5, since the pilot pressure on the extension side of the upper boom cylinder output from the electromagnetic proportional pressure reducing valve 16 is controlled, the same lever operation is performed when working at a higher place than when working near the ground surface. The displacement amount of the upper boom control valve 13 that is pilot-operated by the pilot pressure that has passed through the electromagnetic proportional pressure reducing valve 16 is reduced with respect to the amount, and the upper boom cylinder 4a passes through the upper boom control valve 13 from the main hydraulic pumps 10 and 11. Since the meter-in control is performed so that the flow rate supplied to the engine is more restricted, the cylinder speed in the extension direction of the upper boom cylinder 4a is more restricted when working at a high place than when working near the ground surface.

  Furthermore, as shown in FIG. 5, since the pilot pressure on the extension side of the upper boom cylinder output from the electromagnetic proportional pressure reducing valve 16 is controlled, the same lever is used when working at high places than when working near the ground. The amount of displacement of the variable throttle valve 23 of the holding valve 14 becomes smaller than the amount of operation, and the hydraulic oil that flows out of the upper boom cylinder 4a according to the amount of displacement of the variable throttle valve 23 compensated for pressure by the pressure compensation valve 24 Since the meter-out control is performed so that the flow rate is further reduced, the upper boom cylinder 4a operates at a low speed in accordance with the operation of the remote control valve 15 in a high-altitude operation, and operates at a normal speed in an operation near the ground surface.

  As described above, when the tip height of the upper boom 4 detected by the lower boom angle sensor 7 and the upper boom angle sensor 8 is high, the controller 19 controls the electromagnetic proportional pressure reducing valve 16 to control the same pilot operation amount, Since the flow supplied to the head side of the upper boom cylinder 4a from the upper boom control valve 13 pilot-operated by the pilot pressure passing through the electromagnetic proportional pressure reducing valve 16 is meter-in controlled, the upper boom 4 suddenly drops in high-altitude work. The upper boom cylinder 4a can be operated at low speeds, and the speed limit of the upper boom cylinder 4a can be released so that work efficiency can be improved when working near the ground, and an appropriate operating flow rate is supplied according to each height. it can.

  An upper boom cylinder 4a attached to the rear side of the lower boom 3 by a holding valve 14 having a flow rate adjusting function with pressure compensation that is proportionally controlled according to the head side pilot pressure for lowering the upper boom output from the electromagnetic proportional pressure reducing valve 16 The meter-out control of the flow rate flowing out from the rod side allows the weights of the upper boom 4, the arm 5 and the crusher 6 to be securely held at a fixed position with a pilot operation amount of 0, and the pressure compensation valve 24 compensated the pressure. With the variable throttle valve 23, the upper boom lowering speed can be controlled to an accurate operating speed according to the pilot operation amount.

  The controller 19 outputs the gain set by the gain setting unit 27 so as to decrease when the tip height of the upper boom 4 detected by the lower boom angle sensor 7 and the upper boom angle sensor 8 is high, and the extension side remote control valve 15b. The upper boom lowering pilot pressure is limited by the throttle control of the electromagnetic proportional pressure reducing valve 16 based on the signal multiplied by the upper boom lowering pilot pressure detected by the pressure sensor 20. The upper boom 4 can be moved in the lowering direction at a high speed by the upper boom lowering pilot pressure having a gain of 1.0 or close to that at a low speed due to the pressure, and an operation speed suitable for each height can be obtained.

  A work at a high place where the superstructure is dismantled in the work posture shown in FIG. 6 by the crusher 6 as a work tool, and a work where the foundation pile near the ground surface is dismantled in the work posture shown in FIGS. When the upper structure is disassembled, the tip of the upper boom 4 is high, and the electromagnetic proportional pressure reducing valve 16 receiving the control signal from the controller 19 that recognizes the height of the upper boom 4 reduces the pilot pressure on the lower side of the upper boom. When the extension side remote control valve 15b is rapidly operated to the upper boom lowering side, it is possible to prevent the upper boom 4 from being suddenly dropped due to the weight of the crusher 6 and to dismantle foundation piles near the ground surface. Since the restriction of the electromagnetic proportional pressure reducing valve 16 is released, the upper boom operating speed can be obtained by the pilot pressure corresponding to the pilot operation amount, and the working efficiency can be improved.

  When the lower boom 3 and the upper boom 4 are operated upward as shown in FIG. 6 with respect to the machine body B to perform work by the crusher 6 at a high place, these are operated downward as shown in FIG. 7 and FIG. Thus, in both cases where the work is performed by the crusher 6 near the ground surface, the single two-piece boom dismantling work machine A can drive the upper boom cylinder 4a at an appropriate speed corresponding to each work height.

  As described above, in the two-piece boom disassembly work machine A shown in FIGS. 6 to 8, the circuit on the extension side of the upper boom cylinder 4a is assumed on the assumption that the heavy crusher 6 is attached and the upper structure is disassembled. In the past, when the foundation pile near the ground was disassembled, there was a problem that the movement of the upper boom 4 was extremely slow and the workability was poor. For example, when the tip height of the up boom 4 is high, the pilot pressure in the extension side circuit of the upper boom cylinder 4a is limited to adjust the throttle of the upper boom control valve 13 and the holding valve 14, and the tip of the up boom 4 When the height is close to the ground surface, the upper boom control valve 13 and the holding valve 14 are released so that the upper structure and the lower foundation pile are disassembled smoothly. It can, it is possible to improve the work efficiency.

  INDUSTRIAL APPLICABILITY The present invention can be used for a work device control circuit for controlling a hydraulic excavator type work device and a work machine equipped with the control circuit.

A 2 piece boom dismantling machine as work machine B Airframe 3 Lower boom 4 Upper boom
4a Upper boom cylinder 5 Arm 6 Crusher as work tool 7 Lower boom angle sensor as height detector 8 Upper boom angle sensor as height detector
13 Upper boom control valve
14 Holding valve
15 Remote control valve as pilot operated valve
16 Solenoid proportional pressure reducing valve
19 Controller
20 Pressure sensor

Claims (5)

It is a control circuit for a work device that controls an upper boom cylinder that can move a work tool provided through an arm in a vertical direction by raising and lowering an upper boom that is pivotally connected to the tip of the lower boom. And
An upper boom control valve for extending and contracting the upper boom cylinder;
A pilot operated valve that pilot-operates the upper boom control valve with a pilot pressure; and
An electromagnetic proportional valve that limits the pilot pressure on the lower side of the upper boom that is output from the pilot operation valve to the upper boom control valve;
A height detector for detecting the tip height of the upper boom;
A control circuit for a working device, comprising: a controller for controlling the throttle of an electromagnetic proportional valve for the same pilot operation amount when the tip height of the upper boom detected by the height detector is high. The upper boom cylinder is attached to the rear side of the lower boom,
A holding valve connected to the rod side of the upper boom cylinder and having a flow rate adjusting function with pressure compensation that is proportionally controlled according to the head-side pilot pressure for lowering the upper boom output from the electromagnetic proportional valve. The work device control circuit according to claim 1. A pressure sensor that detects the pilot pressure on the lower side of the upper boom output from the pilot operated valve is provided.
The controller
Provided with a function to throttle the proportional solenoid valve using a signal obtained by multiplying the gain set to decrease when the tip of the upper boom tip is high and the pilot pressure on the lower side of the upper boom output from the pilot operated valve. The work device control circuit according to claim 1, wherein: The work device control circuit according to any one of claims 1 to 3, wherein an upper boom cylinder that moves a crusher as a work tool in a vertical direction is controlled. The aircraft,
A lower boom that is axially connected to the machine body so as to be rotatable in the vertical direction;
An upper boom that is pivotally connected to the tip of the lower boom so as to be vertically rotatable;
An arm pivotally connected to the tip of the upper boom,
A work tool attached to the tip of this arm,
An upper boom cylinder for raising and lowering the upper boom,
A work machine comprising: the work device control circuit according to any one of claims 1 to 4 that controls the upper boom cylinder.

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