JP2008266909A - Hydraulic excavator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a control valve and piping from being damaged by improving the balance of weight of a front attachment of a hydraulic excavator. <P>SOLUTION: This hydraulic excavator 1 includes: a hydraulic cylinder 10 for a boom, which drives a boom 3 with respect to a vehicle body 2; a hydraulic cylinder 9 for an arm, which drives an arm 4 with respect to the boom 3; a hydraulic cylinder 8 for a bucket, which drives the bucket 5 with respect to the arm 4; and a control valve 15 for the boom, a control valve 35 for the arm, and a control valve 45 for the bucket, which adjust flow rates of hydraulic fluids supplied to/discharged from the hydraulic cylinders 10, 9 and 8, respectively. The boom 3 is formed in a hollow box shape, and the control valve 45 for adjusting the flow rate of the hydraulic fluid supplied to/discharged from the hydraulic cylinder 8 is provided inside the boom 3. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an improvement of a hydraulic excavator that drives a front attachment including a boom, an arm, and a bucket by a hydraulic cylinder.

  Conventionally, as this type of hydraulic excavator, there is a type in which a distributed control valve is provided on a front attachment and the flow rate of hydraulic oil supplied to and discharged from each hydraulic cylinder is adjusted by each control valve (Patent Documents 1 and 2). reference).

  In the hydraulic excavator disclosed in Patent Document 1, each control valve is disposed in the vicinity of each hydraulic cylinder that drives the front attachment.

In the hydraulic excavator disclosed in Patent Document 2, each control valve is arranged side by side on the outside of the boom.
JP 2004-293089 A JP-A-2005-68718

  However, in such a conventional hydraulic excavator, since the control valve is provided in the front attachment, there is a problem that the weight balance of the front attachment is deteriorated due to the weight of the control valve.

  Further, since the control valve is provided outside the front attachment, there is a possibility that the control valve and its piping hit an obstacle during operation and may be damaged.

  Accordingly, it is an object of the present invention to improve the weight balance of the front attachment of a hydraulic excavator and prevent damage to control valves and piping.

  The present invention drives a boom relative to a vehicle body, a boom rotatably connected to the vehicle body, an arm rotatably connected to the boom, a bucket rotatably connected to the arm, and the vehicle body. The hydraulic cylinder for the boom, the hydraulic cylinder for the arm that drives the arm with respect to the boom, the hydraulic cylinder for the bucket that drives the bucket with respect to the arm, and the flow rate of the hydraulic oil supplied to and discharged from each hydraulic cylinder are adjusted. A hydraulic excavator comprising a boom control valve, an arm control valve, and a bucket control valve, wherein the boom is formed in a hollow box shape, and the flow rate of hydraulic oil supplied to and discharged from the bucket hydraulic cylinder is set inside the boom. A control valve for the bucket to be adjusted is provided.

  According to the present invention, the weight of the bucket control valve is prevented from being applied to the arm, the weight balance of the front attachment is improved, the operation of the front attachment is stabilized, and the bucket control valve and its piping are obstructions. Can be prevented from being damaged.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  As shown in FIG. 1, a hydraulic excavator (construction machine) 1 includes a traveling body 6 that travels, a vehicle body (swivel body) 2 that is turnable on the traveling body 6, and the vehicle body 2. A boom 3 that is pivotally connected via a boom support shaft 7, two hydraulic cylinders 10 that drive the boom 3, and a tip of the boom 3 that is pivotally connected via an arm support shaft 38. Arm 4, one hydraulic cylinder 9 that drives the arm 4, a bucket 5 that is rotatably connected to the tip of the arm 4 via a bucket support shaft 51, and one that drives the bucket 5. The hydraulic cylinder 8 is provided.

  A hydraulic power source unit 21 is mounted on the vehicle body 2, and the hydraulic cylinders 8 to 10 are expanded and contracted by operating hydraulic pressure guided from the hydraulic power source unit 21 to move the bucket 5, the arm 4, and the boom 3, respectively, thereby excavating the ground. And transporting earth and sand.

  The boom 3, the arm 4 and the bucket 5 constitute a multi-indirect type front attachment. Note that the bucket 5 connected to the tip of the arm 4 is not limited to one that performs excavation of the ground or transporting of earth and sand, but may be one that performs other operations (attachment).

  A hydraulic power source unit 21 is mounted on the vehicle body 2, and the hydraulic cylinders 8 to 10 are expanded and contracted by operating hydraulic pressure guided from the hydraulic power source unit 21 to move the bucket 5, the arm 4, and the boom 3, respectively, thereby excavating the ground. And transporting earth and sand.

The boom hydraulic cylinders (actuators) 10 provided in pairs are arranged so as to sandwich the boom 3 from the left and right. Each boom hydraulic cylinder 10 is expanded and contracted by the piston rod 12 moving relative to the cylinder tube 11 by the hydraulic pressure received by a piston (not shown). A base end portion of each cylinder tube 11 is rotatably connected to the vehicle body 2 via a support shaft 13, and a distal end portion of each piston rod 12 is rotatably connected to the boom 3 via a support shaft 14. The hydraulic oil for the two booms 10 is supplied and discharged through the control valve 15 and is expanded and contracted in synchronization with each other by the hydraulic pressure to drive the boom 3 and the arm hydraulic cylinder (actuator) that drives the arm 4. ) 9 is arranged on the back of the boom 3. The arm hydraulic cylinder 9 is expanded and contracted by the piston rod 32 being moved relative to the cylinder tube 31 by the hydraulic pressure received by a piston (not shown). A base end portion of the cylinder tube 31 is rotatably connected to the boom 3 via the support shaft 33, and a distal end portion of the piston rod 32 is rotatably connected to the arm 4 via the support shaft 34. The hydraulic cylinder 9 for arm is supplied and discharged with hydraulic oil via the control valve 35, and expands and contracts by this hydraulic pressure to drive the arm 4.

  A bucket hydraulic cylinder (actuator) 8 that drives the bucket 5 is disposed on the back of the arm 4. A base end portion of the cylinder tube 41 is rotatably connected to the arm 4 via the support shaft 43, and a distal end portion of the piston rod 42 is rotatably connected to the bucket 5 via the support shaft 44.

  As shown in FIG. 2, a piston rod 42 is inserted into a cylinder tube 41 of the bucket hydraulic cylinder 8 so as to be able to advance and retreat, and a piston 46 is connected to a base end portion of the piston rod 42. The piston 46 is slidably disposed along the inner periphery of the cylinder tube 41, and defines an anti-rod side oil chamber 47 and a rod side oil chamber 48 in the cylinder tube 41. The anti-rod side oil chamber 47 and the rod side oil chamber 48 are supplied and discharged with hydraulic oil via the control valve 45, and the bucket hydraulic cylinder 8 is expanded and contracted by this hydraulic pressure to drive the bucket 5.

  FIG. 2 shows a hydraulic circuit provided in the bucket hydraulic cylinder 8. The control valve 45 includes four electromagnetic valves V1 to V4 interposed in a bridge circuit, and opens and closes so that the hydraulic cylinder 8 is expanded and contracted by an output from the controller 30.

  A supply passage 25 through which hydraulic oil supplied to the hydraulic cylinder 8 flows is connected to the discharge side of the hydraulic pump 22. The supply passage 25 is connected to branch passages 26 and 27 branched in two directions. 27 is connected again to a return passage 23 through which hydraulic oil discharged from the hydraulic cylinder 8 flows, and the return passage 23 is connected to the suction side of the hydraulic pump 22.

  The branch passages 26 and 27 are provided with a meter-in solenoid valve V1 for controlling the flow rate of the hydraulic oil supplied to the anti-rod side oil chamber 47 of the hydraulic cylinder 8 and the flow rate of the hydraulic oil supplied to the rod side oil chamber 48. The meter-in solenoid valve V3 to be controlled is interposed in parallel.

  The branch passages 26 and 27 include a meter-out solenoid valve V 2 that controls the flow rate of hydraulic oil discharged from the non-rod side oil chamber 47 of the hydraulic cylinder 8 and hydraulic oil discharged from the rod side oil chamber 48. The meter-out solenoid valve V4 for controlling the flow rate of the gas is arranged in parallel with each other.

  In this manner, the meter-in solenoid valve V1 and the meter-out solenoid valve V2 are interposed in series in the branch passage 26, and the meter-in solenoid valve V3 and the meter-out solenoid valve V4 are disposed in the branch passage 27. It is inserted in series.

  The meter-in solenoid valve V <b> 1 and the meter-out solenoid valve V <b> 2 in the branch passage 26 communicate with the anti-rod side oil chamber 47 through the first supply / discharge passage 28. The meter-in solenoid valve V3 and the meter-out solenoid valve V4 in the branch passage 27 communicate with the rod-side oil chamber 48 via the second supply / discharge passage 29.

  The meter-in solenoid valve V1, the meter-out solenoid valve V2, the meter-in solenoid valve V3, and the meter-out solenoid valve V4 are electromagnetic control valves (flow control valves), and each solenoid valve V1 to V4 is a controller 30. The opening area is adjusted in accordance with this current, and the flow rate of the hydraulic oil passing through each of the solenoid valves V1 to V4 is individually controlled. The controller 30 receives signals from pressure sensors 18 and 19 that detect pressures in the first supply / discharge passage 28 and the second supply / discharge passage 29, respectively.

  Since the boom control valve 15 and the arm control valve 35 have the same configuration as the bucket control valve 45 and are controlled by the output current from the controller 30, the control valves 15, 35 and 45 are dispersed. Can be arranged.

  Conventionally, distributed control valves have been provided in the vicinity of hydraulic cylinders, and the length of hydraulic piping connected to them has been shortened (see Patent Document 1).

  However, when the bucket control valve is provided in the vicinity of the bucket hydraulic cylinder, there is a problem that the weight balance of the front attachment including the boom, arm, and bucket is deteriorated due to the weight of the bucket control valve. Moreover, since it moves together with the arm, there is a possibility that the control valve for the bucket, its piping, etc. will hit the obstacle and be damaged.

  In response to this, the present invention provides a distributed control bucket control valve 45 inside the boom 3 to improve the weight balance of the front attachment and prevent damage to the bucket control valve 45 and piping. And

  In the present embodiment, the distributed control valves 15, 35, 45 are respectively provided inside the boom 3.

  The boom 3 is formed of a steel plate in a hollow box shape, a space for accommodating each control valve 15, 35, 45 is defined inside thereof, and each control valve 15, 35, 45 is supported via a support member (not shown). The

  Each control valve 15, 35, 45 is provided above the boom support shaft 7 that supports the boom 3 to the vehicle body 2 so as to be rotatable. That is, the control valves 15, 35, and 45 are located at a position higher than the boom support shaft 7 regardless of the rotation position of the boom 3, and the control valves 15, 35, and 45 are controlled by the rotation position of the boom 3. The configuration is located vertically above.

  Each control valve 15, 35, 45 is accommodated in the rear part of the boom 3. In the boom 3, the direction extending from the boom support shaft 7 for the vehicle body 2 to the arm support shaft 38 for the boom 3 is the front of the boom 3, and the opposite direction is the rear of the boom 3.

  The control valves 15, 35, 45 are arranged side by side in the front-rear direction of the boom 3, the bucket control valve 45 is arranged between the boom control valve 15 and the arm control valve 35, and the boom control valve 15 is connected to the bucket. The arm control valve 35 is disposed in front of the bucket control valve 45.

  A part of each supply / discharge passage 16, 17, 36, 37, 28, 29 extending from each control valve 15, 35, 45 to each hydraulic cylinder 10, 9, 8 is accommodated inside the boom 3.

  Constructed as described above, the supply and discharge of hydraulic oil to and from each control cylinder 15, 9, 8 is switched from each control valve 15, 35, 45 to cause each hydraulic cylinder 10, 9, 8 to expand and contract, The multi-indirect type front attachment composed of the arm 4 and the bucket 5 is driven, and excavation of the ground and transport of earth and sand are performed via the bucket 5 connected to the tip of the arm 4.

  In the present embodiment, a boom 3 rotatably connected to the vehicle body 2, an arm 4 rotatably connected to the boom 3, a bucket 5 rotatably connected to the arm 4, A boom hydraulic cylinder 10 for driving the boom 3 with respect to the vehicle body 2; an arm hydraulic cylinder 9 for driving the arm 4 with respect to the boom 3; and a bucket hydraulic cylinder 8 for driving the bucket 5 with respect to the arm 4; The hydraulic excavator 1 includes a boom control valve 15, an arm control valve 35, and a bucket control valve 45 that respectively adjust the flow rate of hydraulic oil supplied to and discharged from the hydraulic cylinders 10, 9, and 8. 3 is formed in a hollow box shape, and a bucket control valve 4 that adjusts the flow rate of hydraulic oil supplied to and discharged from the bucket hydraulic cylinder 8 inside the boom 3. Therefore, the weight of the bucket control valve is prevented from being applied to the arm 4, the weight balance of the front attachment is improved, the operation of the front attachment is stabilized, and the bucket control valve 45 and its piping are obstructed. It is possible to prevent damage from hitting objects.

  In the present embodiment, the boom support shaft 7 that rotatably supports the boom 3 with respect to the vehicle body 2 is provided, and the bucket control valve 45 is provided above the boom support shaft 7, so that the weight balance of the front attachment is improved. In addition, the operation of the front attachment can be stabilized.

  In the present embodiment, the boom control valve 15 and the arm control valve 35 are provided inside the boom 3 along with the bucket control valve 45, so that the weight balance of the front attachment is improved and the operation of the front attachment is stabilized. It is possible to prevent the control valves 45, 15, 35 and their piping from being damaged.

  In the present embodiment, the bucket hydraulic cylinder 8 includes an anti-rod side oil chamber 47 and a rod side oil chamber 48 that are partitioned by a piston 46, and the bucket control valve 45 is actuated to be supplied to the anti-rod side oil chamber 47. A meter-in solenoid valve V1 that controls the flow rate of oil, a meter-out solenoid valve V2 that controls the flow rate of hydraulic oil discharged from the non-rod-side oil chamber 47, and a hydraulic fluid supplied to the rod-side oil chamber 48. Meter-in solenoid valve V3 for controlling the flow rate, meter-out solenoid valve V4 for controlling the flow rate of the hydraulic oil discharged from the rod side oil chamber 48, and the flow rates of the hydraulic oil passing through the solenoid valves V1 to V4 are individually set. And the controller 30 for controlling the bucket control valve 45 has less restrictions on the arrangement of the bucket control valve 45, and the bucket control valve 45 is disposed inside the boom 3. It is possible to arrange.

  The present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

1 is a side view of a hydraulic excavator showing an embodiment of the present invention. Similarly hydraulic circuit diagram.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hydraulic excavator 2 Car body 3 Boom 4 Arm 5 Bucket 7 Boom support shaft 8 Bucket hydraulic cylinder 9 Arm hydraulic cylinder 10 Boom hydraulic cylinder 15 Boom control valve 30 Controller 35 Arm control valve 45 Bucket control valve 47 Anti rod Side oil chamber 48 Rod side oil chamber V1 Mail rod side oil chamber Tine solenoid valve V2 Meter-out solenoid valve V3 Meter-in solenoid valve V4 Meter-out solenoid valve

Claims (4)

  A boom that is pivotally connected to the vehicle body, an arm that is pivotally coupled to the boom, a bucket that is pivotally coupled to the arm, and a boom that drives the boom relative to the vehicle body A hydraulic cylinder, an arm hydraulic cylinder that drives the arm with respect to the boom, a bucket hydraulic cylinder that drives the bucket with respect to the arm, and a flow rate of hydraulic oil supplied to and discharged from each hydraulic cylinder. A hydraulic excavator including a boom control valve, an arm control valve, and a bucket control valve that are respectively adjusted, wherein the boom is formed in a hollow box shape, and is supplied to and discharged from the bucket hydraulic cylinder inside the boom. A hydraulic excavator comprising the bucket control valve for adjusting a flow rate of hydraulic oil.   The hydraulic excavator according to claim 1, further comprising a boom support shaft that rotatably supports the boom with respect to the vehicle body, wherein the bucket control valve is provided above the boom support shaft.   The hydraulic excavator according to claim 1 or 2, wherein the boom control valve and the arm control valve are provided inside the boom along with the bucket control valve.   The bucket hydraulic cylinder has an anti-rod side oil chamber and a rod side oil chamber partitioned by a piston, and the bucket control valve controls the flow rate of hydraulic oil supplied to the anti-rod side oil chamber. A valve, a meter-out solenoid valve that controls the flow rate of hydraulic oil discharged from the anti-rod side oil chamber, a meter-in solenoid valve that controls the flow rate of hydraulic oil supplied to the rod side oil chamber, A meter-out solenoid valve for controlling the flow rate of the hydraulic oil discharged from the rod-side oil chamber, and a controller for individually controlling the flow rate of the hydraulic oil passing through each of the meter-in solenoid valve and each of the meter-out solenoid valves; The hydraulic excavator according to any one of claims 1 to 3, further comprising:

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