JP2017187076A - Hydraulic circuit of hydraulic work machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic circuit capable of operating simultaneously a hydraulic work attachment and a second boom.SOLUTION: There are provided a first control valve unit 101 for operating hydraulic cylinders 20, 21, 23 at a working part 5, an upper machinery 3, hydraulic motors 62, 63, 64 arranged at a travel part 2 and hydraulic cylinders 13, 25; a second control valve unit 102 for operating a second boom cylinder 22 and a hydraulic motor 24; and a pilot hydraulic control part 80 comprising an attachment operation switch 45 and a second boom operating pedal 46 becoming operating means for operating a second boom 72 and a hydraulic work attachment so as to feed a pilot hydraulic signal to an external part taking-out control valve 41 becoming a changing-over valve arranged at the most-downstream side of the first control valve unit 101, attachment control valve 42 and a second boom control valve 43 when the operating means is operated.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a hydraulic circuit of a hydraulic work vehicle such as a hydraulic excavator equipped with an attachment and including a boom including a first boom and a second boom.

  2. Description of the Related Art Conventionally, a hydraulic work vehicle of a two-piece boom specification in which a boom is divided into a first boom and a second boom in order to expand the movable range of the working device is known. In the two-piece boom, the base end side of the first boom on the base side is rotatably connected to the upper swing body via a connection pin, and the base end side of the second boom on the front end side is connected to the tip of the first boom. The first boom is moved up and down by a boom cylinder, and the second boom is moved up and down by a positioning cylinder (see, for example, Patent Document 1).

Japanese Patent Publication No. 6-37779

  In the technique of Patent Document 1, an arm is connected to the tip of the second boom, a hydraulic work attachment is attached to the arm, and the hydraulic work attachment and the boom cannot be operated at the same time and are operated simultaneously. In some cases, a control circuit is provided in which the selection switching valve is automatically operated so that one hydraulic work attachment is operated with priority.

However, even when the hydraulic work attachment is operated, there is a case where it is desired to change the position such as the height while performing the work, and a hydraulic circuit capable of operating both is desired. Further, in order to realize a hydraulic circuit capable of operating the hydraulic work attachment and the second boom at the same time, it is necessary to create a new control valve unit, and thus an increase in cost is inevitable.
Therefore, an attempt is made to provide a hydraulic circuit capable of simultaneously operating the hydraulic work attachment and the second boom by improving the hydraulic circuit.

The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.
That is, according to the first aspect of the present invention, the first control valve unit that operates the hydraulic actuator of the working unit, the hydraulic actuator provided in the upper swing body or the traveling unit, and the second boom and the hydraulic actuator of the hydraulic work attachment are operated. Two control valve units, and operating means for operating the second boom and the hydraulic work attachment, wherein the first control valve unit and the second control valve unit each have a plurality of oil feeds to the hydraulic actuator. A pilot hydraulic pressure switch that includes a pilot-type switching valve and sends a pilot hydraulic pressure signal to the switching valve disposed on the most downstream side of the first control valve unit and the switching valve of the second control valve unit when the operation means is operated. A control unit is provided.

According to a second aspect of the present invention, the output port of the switching valve disposed on the most downstream side of the first control valve unit communicates with the input port of the second control valve unit.
According to a third aspect of the present invention, the pilot hydraulic pressure control section includes a plurality of shuttle valves, and the shuttle hydraulic pressure signal branches to the operation control section of the switching valve of the second control valve unit by the operation of the operation means. Then, a pilot hydraulic pressure signal is input to the operation control unit of the most downstream control valve of the first control valve unit.

As effects of the present invention, the following effects can be obtained.
The hydraulic work attachment and the second boom can be operated simultaneously. Further, it is only necessary to manufacture a control valve unit retrofitted to a conventional control valve unit without newly creating a control unit capable of simultaneously operating the hydraulic work attachment and the second boom, and the cost increase can be minimized.

The side view which showed the whole structure of the hydraulic working vehicle provided with the hydraulic circuit of this invention. The hydraulic circuit diagram of a hydraulic work vehicle. 1 is a hydraulic circuit diagram of the present invention. The hydraulic circuit diagram when operating the hydraulic work attachment. The hydraulic circuit diagram when operating the second boom. The hydraulic circuit diagram when operating the hydraulic work attachment and the second boom. The side view which showed the whole structure of the hydraulic work vehicle of 1 piece boom specification. The hydraulic circuit diagram of the hydraulic work vehicle of 1 piece boom specification. The hydraulic circuit diagram of the hydraulic work vehicle only for 2 piece boom specifications.

  Below, the whole structure of the backhoe (hydraulic excavator) 1 which is an Example of the hydraulic working vehicle which comprises the hydraulic circuit based on this invention is demonstrated using FIG. 1 and FIG. In FIG. 1, the direction of arrow F is the front.

  As shown in FIG. 1, the backhoe 1 mainly includes a traveling unit 2, an upper swing body 3, a working unit 5, and the like. The main body is composed of the traveling unit 2 and the upper swing body 3.

  The traveling unit 2 is a member that forms a lower structure of the backhoe 1 and includes a pair of left and right crawlers 11 and 11 wound between a driving wheel and a driven wheel, respectively. A blade 12 and a blade cylinder 13, which is a hydraulic actuator for rotating the blade 12 in the vertical direction, are provided forward from the center of the left and right sides of the track frame that supports the blade 12. The drive wheels are driven by traveling hydraulic motors 63 and 64 attached to the track frame. That is, the traveling unit 2 is driven to travel by the right traveling hydraulic motor 63 and the left traveling hydraulic motor 64 as hydraulic actuators.

  The upper swing body 3 includes a cabin 10 that houses an engine 15 and a control unit on a swing frame 4 that is a member constituting the upper structure, and the upper portion of the traveling unit 2 via a swing bearing from the front, rear, left, and right centers of the track frame. Can be pivotally attached. A swing hydraulic motor 62 is mounted on the swing frame 4, and the swing drive gear fixed on the output shaft of the swing hydraulic motor 62 is engaged with a ring gear fixed on the track frame to operate the swing hydraulic motor 62. By doing so, the upper swing body 3 can be turned left and right.

  An engine 15 as a drive source and a first pump P1, a second pump P2, a third pump P3, and a fourth pump P4 driven by the engine 15 are disposed on the rear portion of the turning frame 4. The front upper part of the swivel frame 4 is a control unit, and a seat 6 is disposed above the engine 15, work operation levers 7 and 8 on the left and right of the seat 6, travel levers 9L and 9R on the front, an attachment operation switch 45, A 2-boom operation pedal 46 and the like are provided. The control unit is covered with the cabin 10. A boom bracket 19 for attaching the working unit 5 to the front left and right center of the revolving frame 4 is disposed.

  The working unit 5 mainly includes an arm 17, a first boom 71, a second boom 72, a boom bracket 19, a bucket 16, a bucket cylinder 20, an arm cylinder 23, a first boom cylinder 21, a second boom cylinder 22, and a swing cylinder 25. Etc., and is provided at the front part of the turning frame 4 of the backhoe 1.

The bucket 16 is attached to the distal end of the arm 17, and the base portion of the arm 17 is pivotally attached to the distal end portion of the second boom 72 so as to be rotatable up and down.
The boom includes a first boom 71 and a second boom 72, and the base of the first boom 71 is pivotally attached to the boom bracket 19 via a pin so as to be able to be lifted and lowered, and the second boom 72 is attached to the tip of the first boom 71. The base portion of the arm 17 is supported via a pin so as to be able to be turned up and down, and the base portion of the arm 17 is supported at the tip of the second boom 72 so as to be able to be raised and lowered through the pin.
The boom bracket 19 is a member that forms the base of the working unit 5, and a rear end portion of the boom bracket 19 is pivotally attached to the front end portion of the revolving frame 4 so as to be able to turn left and right.

  The bucket cylinder 20 is a hydraulic cylinder for rotating the bucket 16 back and forth with respect to the arm 17. A cylinder end of the bucket cylinder 20 is pivotally attached to a bracket 17 a provided at the base of the arm 17. The rod end of the bucket cylinder 20 is pivotally attached to the bucket 16 via a link. In addition, when a clamshell bucket, a grapple, a breaker, or the like is mounted as a hydraulic work attachment instead of the bucket 16, it is controlled by the hydraulic circuit of the present invention.

  The arm cylinder 23 is a hydraulic cylinder for rotating the arm 17 with respect to the second boom 72. The cylinder end of the arm cylinder 23 is pivotally attached to a bracket 72 a provided on the base side upper surface of the second boom 72. The rod end of the arm cylinder 23 is pivotally attached to the bracket 17a.

The first boom cylinder 21 is a hydraulic cylinder for rotating the first boom 71.
The cylinder end of the first boom cylinder 21 is pivotally attached to the front end of the boom bracket 19 so as to be rotatable. Further, the rod end portion of the first boom cylinder 21 is pivotally attached to a bracket 71 a provided on the front surface of the distal end portion of the first boom 71.
The second boom cylinder 22 is a hydraulic cylinder for rotating the second boom 72.
The cylinder end portion of the second boom cylinder 22 is pivotally attached to the rear surface of the first boom 71 so as to be rotatable. The rod end of the second boom cylinder 22 is pivotally attached to a bracket 72 a provided at the base of the second boom 72.

  The swing cylinder 25 is a hydraulic cylinder for rotating the working unit 5 left and right with respect to the turning frame 4. The swing cylinder 25 is interposed between the boom bracket 19 and the turning frame 4.

Next, the configuration of a hydraulic circuit 100 that is an embodiment of the hydraulic circuit according to the present invention will be described with reference to FIG.
The hydraulic circuit 100 is driven by pressure oil discharged from the first pump P1, the second pump P2, and the third pump P3 driven by the engine 15 being sent to each hydraulic actuator via each control valve. Then, the pressure oil discharged from the fourth pump P4 driven by the engine 15 is sent to the operation control unit of the control valve via each remote control valve to switch the control valve. The control valve is composed of a hydraulic pilot type switching valve, and is switched by sending the pilot hydraulic pressure to the operation control unit, and is provided in each of the first control valve unit 101 and the second control valve unit 102. The first control valve unit 101 includes a right travel control valve 31, a first boom control valve 32, a bucket control valve 33, a left travel control valve 34, a swing control valve 35, a PTO control valve 36, an arm control valve 37, and a swing control valve 38. The second control valve unit 102 includes an attachment control valve 42, a second boom control valve 43, and a flow path control unit 80.

  From the first pump P1, the left travel hydraulic motor 63 as a hydraulic actuator via the right travel control valve 31 from the discharge oil passage 26, the first boom cylinder 21 as a hydraulic actuator via the first boom control valve 32, and the bucket A hydraulic circuit is formed so that oil can be fed to the bucket cylinder 20 as a hydraulic actuator via the control valve 33.

  Furthermore, the hydraulic motor 24, the second boom control as the hydraulic actuator of the hydraulic work attachment through the attachment control valve 42 from the external take-off control valve 41 arranged at the most downstream of the flow path to which the pressure oil is supplied from the first pump P1. Oil can be supplied to the second boom cylinder 22 as a hydraulic actuator via the valve 43. This oil feeding control will be described later.

  From the second pump P2, oil can be supplied from the discharge oil passage 27 to the left travel hydraulic motor 64 as a hydraulic actuator via the left travel control valve 34 and to the swing cylinder 25 as a hydraulic actuator via the swing control valve 35. When a hydraulic circuit is formed and the merging control valve 40 is switched to the communication state, a PTO hydraulic motor 65 serving as a hydraulic actuator via the PTO control valve 36 and an arm serving as a hydraulic actuator via the arm control valve 37 are provided. A hydraulic circuit is formed in each cylinder 23 so that oil can be fed.

  From the third pump P3, the discharge hydraulic passage 28 is connected via a swing control valve 38 via a swing hydraulic motor 62 as a hydraulic actuator, via a blade control valve 39 via a blade cylinder 13 as a hydraulic actuator, and a PTO control valve 36. A hydraulic circuit is formed in the PTO hydraulic motor 65 so that oil can be supplied to the arm cylinder 23 via the arm control valve 37.

  From the fourth pump P4, the right remote control valve 51, the left remote control valve 52, the PTO remote control valve 53, the swing remote control valve 54, the traveling remote control valve 55, the blade remote control valve 58, the attachment remote control valve 56, and the second boom are discharged from the discharge oil passage 29. Pilot pressure can be supplied to the remote control valve 57.

When the work control lever 8 disposed on the right side of the seat 6 of the control unit is rotated back and forth, the right remote control valve 51 is switched and a pilot hydraulic pressure signal is sent to the operation control unit of the first boom control valve 32. The first boom cylinder 21 can be expanded and contracted to rotate the first boom 71.
When the operation control lever 8 of the control unit is rotated left and right, the right remote control valve 51 is switched, the pilot hydraulic signal is sent to the operation control unit of the bucket control valve 33 and switched, and the bucket cylinder 20 is expanded and contracted. The bucket 16 can be rotated.
When the work control lever 7 on the left side of the control unit is rotated back and forth, the left remote control valve 52 is switched, the pilot hydraulic signal is sent to the operation control unit of the arm control valve 37 and switched, and the arm cylinder 23 is switched. The arm 17 can be rotated by expanding and contracting.
When the operation control lever 7 of the control unit is rotated left and right, the left remote control valve 52 is switched, and the pilot hydraulic signal is sent to the operation control unit of the swing control valve 38 to be switched, and the swing hydraulic motor 62 is rotated. Thus, the turning frame 4 can be turned left and right.

  When the right travel lever 9R is rotated, the travel remote control valve 55 is switched, and the pilot hydraulic signal is sent to the operation control unit of the right travel control valve 31 and switched, and the right travel hydraulic motor 63 is rotated forward or reverse. Can be made. When the left travel lever 9L is rotated, the travel remote control valve 55 is switched, the pilot hydraulic signal is sent to the operation control unit of the left travel control valve 34 and switched, and the left travel hydraulic motor 64 is rotated forward or backward. be able to. Thus, the backhoe 1 can be moved forward, backward, and turned left and right.

When the PTO operation switch arranged in the control unit is operated, the PTO remote control valve 53 is switched, the pilot hydraulic pressure signal is sent to the operation control unit of the PTO control valve 36 and switched, and the PTO hydraulic motor 65 is rotated forward. Or it can be reversed.
When the swing pedal disposed on the control unit is depressed and operated, the swing remote control valve 54 is switched, and the pilot hydraulic pressure signal is sent to the operation control unit of the swing control valve 35 to be switched. Can be reduced. Further, when the blade lever provided in the control unit is operated, the blade remote control valve 58 is switched, and the pilot hydraulic pressure signal is sent to the operation control unit of the blade control valve 39 to be switched, and the blade cylinder 13 is extended or Can be reduced.

Further, when the attachment operation switch 45 or the second boom operation pedal 46 disposed in the control unit is operated, the hydraulic oil is controlled by the second control valve unit 102 and the external work machine 24 or the second boom cylinder 22 is operated. The
The second control valve unit 102 can be retrofitted to the first control valve unit 101 having a one-piece boom specification. That is, as shown in FIG. 8, the hydraulic circuit of the backhoe of the one-piece boom specification as shown in FIG. 7 is provided with the attachment control valve 42 (or the external take-off control valve 41) on the most downstream side of the first pump P1. It can be connected to the hydraulic motor 24 to operate. When this hydraulic circuit is applied to the two-piece boom specification, as shown in FIG. 9, an attachment control valve 42 and a second boom control valve 43 are connected to the most downstream side of the first pump P1, and a new control valve unit is installed. I was making it.

  In the present invention, as shown in FIG. 3, the second control valve unit 102 includes an attachment control valve 42, a second boom control valve 43, and a flow path control unit 80 including a plurality of shuttle valves, and the attachment control valve 42 The second boom control valve 43 is composed of a pilot hydraulically operated switching valve, and the second control valve unit 102 is retrofitted using the external take-off control valve 41 of the one-piece boom specification as it is. That is, the output port of the external take-out control valve 41 arranged on the most downstream side of the first control valve unit 101 is easily retrofitted so as to communicate with the input port of the second control valve unit 102. I can do it.

  The primary side (pump port and tank port) that is the input port of the attachment control valve 42 is connected to the secondary side that is the output port of the external take-out control valve 41, and the secondary side of the attachment control valve 42 is the hydraulic work attachment. Connected to a hydraulic motor 24 serving as an actuator. The operation control unit of the attachment control valve 42 is connected to the attachment remote control valve 56 through pilot oil passages 74 and 75. The attachment remote control valve 56 is constituted by an electromagnetic proportional valve, and by operating the attachment operation switch 45, the pressure oil from the fourth pump P4 is sent to the operation control unit of the attachment control valve 42 so as to be switched.

  The pilot oil passages 74 and 75 are connected to a flow passage control unit 80 through oil passages 76 and 77. The flow path control unit 80 includes a first shuttle valve 81, a second shuttle valve 82, and a third shuttle valve 83. Each shuttle valve has two input ports and one output port. The input port is connected to the output ports of the second shuttle valve 82 and the third shuttle valve 83, and the output port of the first shuttle valve 81 is connected to the operation control unit of the external take-out control valve 41 via the oil passage 78. .

  The input port of the second shuttle valve 82 is connected to the oil passages 76 and 77. The input ports of the third shuttle valve 83 are connected to pilot oil passages 84 and 85 that connect the second boom remote control valve 57 and the operation control unit of the second boom control valve 43 via oil passages 86 and 87, respectively. In this way, the first shuttle valve 81, the second shuttle valve 82, and the third shuttle valve 83 constitute the flow path control unit 80 with a simple configuration in which the same configuration of the shuttle valves is disposed symmetrically.

  The primary side of the second boom control valve 43 is connected to the secondary side of the external take-out control valve 41, and the secondary side of the second boom control valve 43 is connected to the second boom cylinder 22. The second boom remote control valve 57 is switched by operating the second boom operation pedal 46, and the pressure oil from the fourth pump P 4 is sent to the operation control unit of the second boom control valve 43 to send the second boom cylinder 22. Can be stretched.

  For example, when the actuator of the hydraulic work attachment is the hydraulic motor 24 and the attachment operation switch 45 is operated, an operation signal is sent to the solenoid of the attachment remote control valve 56 as shown in FIG. The remote control valve is opened. With this valve opening, the pressure oil from the fourth pump P4 is switched by sending a pilot hydraulic pressure signal to the operation control unit of the attachment control valve 42 via the oil passage 74 (or the oil passage 75). At the same time, the oil is fed to the second shuttle valve 82 of the pilot oil pressure control unit 80 through the oil passage 76 (or the oil passage 77) branched from the oil passage 74 (or the oil passage 75). 1 The shuttle valve 81 is opened and sent to the operation control unit of the external take-off control valve 41 via the oil passage 78, and the external take-out control valve 41 is switched, so that the hydraulic oil is supplied to the hydraulic motor 24 from the first pump P1. Oil is fed and rotated.

  Further, when the second boom operation pedal 46 is operated, one of the second boom remote control valves 57 is switched, and the pressure oil from the fourth pump P4 is supplied to the oil passage 84 (or the oil as shown in FIG. 5). A pilot hydraulic pressure signal is sent to the operation control unit of the second boom control valve 43 via the path 85) and switched. At the same time, the oil is sent to the third shuttle valve 83 of the pilot hydraulic control unit 80 via the oil passage 86 (or the oil passage 87) branched from the oil passage 84 (or the oil passage 85). 1 Shuttle valve 81 is opened and sent to the operation control unit of the external take-off control valve 41 through the oil passage 78 to switch the external take-out control valve 41, and the pressure from the first pump P1 is switched to the second boom cylinder 22. Oil is fed and driven to extend (or shrink).

  Further, when the attachment operation switch 45 and the second boom operation pedal 46 are operated simultaneously, one of the attachment remote control valve 56 and the second boom remote control valve 57 is switched, and as shown in FIG. The pressure oil from the pump P4 is switched by sending a pilot hydraulic signal to the operation control unit of the attachment control valve 42 via the oil path 74 (or oil path 75), and the second boom control valve 43 is also switched. It is done. At the same time, the oil is fed to the second shuttle valve 82 and the third shuttle valve 83 of the pilot hydraulic control unit 80 via the oil passage 76 (or the oil passage 77) and the oil passage 86 (or the oil passage 87). The shuttle valve 81 is opened and sent to the operation control unit of the external take-out control valve 41 via the oil passage 78 to switch the external take-out control valve 41, and the first pump P1 is switched to the hydraulic motor 24 and the second boom cylinder 22. The pressure oil from is fed and driven.

  As described above, the hydraulic cylinders 20, 21, and 23 as the hydraulic actuators of the working unit 5, the hydraulic motors 62, 63, and 64 and the hydraulic cylinders 13 and 25 as hydraulic actuators provided in the upper swing body 3 and the traveling unit 2 are provided. A first control valve unit 101 to be operated, a second boom cylinder 22 to be a hydraulic actuator for a second boom and a hydraulic work attachment, a second control valve unit 102 to operate a hydraulic motor 24, and the second boom 72 An attachment operation switch 45 and a second boom operation pedal 46 serving as operation means for operating the hydraulic work attachment are provided, and the first control valve unit 101 and the second control valve unit 102 respectively supply oil to the hydraulic actuator. Multiple pilot-type switching valves When the operation means is operated, the external take-off control valve 41 serving as a switching valve disposed on the most downstream side of the first control valve unit 101 and the attachment control valve 42 serving as a switching valve for the second control valve unit 102 are used. Since the pilot hydraulic pressure control unit 80 for supplying a pilot hydraulic pressure signal to the second boom control valve 43 is provided, the second boom cylinder 22 and the hydraulic work attachment can be operated simultaneously. Therefore, it is possible to increase the working efficiency rather than operating separately.

  The pilot hydraulic pressure control unit 80 includes a plurality of shuttle valves 81, 82, and 83, and the shuttle valves are pilot hydraulic pressures to the operation control unit of the switching valve of the second control valve unit 102 by the operation of the operation means. Since the signal is branched and a pilot hydraulic pressure signal is input to the operation control unit of the external take-off control valve 41 which becomes the most downstream control valve of the first control valve unit 101, the second control valve is supplied to the first control valve unit 101. A hydraulic circuit that operates the second boom cylinder 22 and the hydraulic work attachment at the same time can be realized only by adding a pilot hydraulic control unit 80 having a simple structure combining the unit 102 and the shuttle valve.

DESCRIPTION OF SYMBOLS 2 Traveling part 3 Upper turning body 5 Working part 24 Hydraulic motor 41 External extraction control valve 45 Attachment operation switch 46 2 Boom operation pedal 72 2nd boom 80 Pilot hydraulic control part 101 1st control valve unit 102 2nd control valve unit

Claims (3)

  A first control valve unit that operates a hydraulic actuator of the working unit, an upper swing body, and a traveling unit, a second control valve unit that operates a hydraulic actuator of the second boom and the hydraulic work attachment, Operating means for operating a second boom and a hydraulic work attachment, wherein each of the first control valve unit and the second control valve unit includes a plurality of pilot-type switching valves for feeding oil to the hydraulic actuator; A pilot hydraulic pressure control section is provided that sends a pilot hydraulic pressure signal to the switching valve disposed on the most downstream side of the first control valve unit and the switching valve of the second control valve unit when operating the operating means. And hydraulic work vehicle hydraulic circuit.   2. The hydraulic work according to claim 1, wherein an output port of a switching valve disposed on the most downstream side of the first control valve unit communicates with an input port of the second control valve unit. Car hydraulic circuit.   The pilot hydraulic control unit includes a plurality of shuttle valves, and the shuttle valve branches a pilot hydraulic signal to the operation control unit of the switching valve of the second control valve unit by the operation of the operation means. 2. The hydraulic circuit for a hydraulic work vehicle according to claim 1, wherein a pilot hydraulic pressure signal is input to an operation control unit of the most downstream control valve of the control valve unit.

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