JP2018071572A - Hydraulic travel device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic travel device capable of supplying a sufficient flow rate of working oil to hydraulic actuators other than a travel motor during traveling to drive the hydraulic actuators.SOLUTION: A hydraulic travel device includes: a second left travel control valve 75 configured to control supply of working oil supplied from a first hydraulic pump P1 to a left travel motor 16L; and left travel line selector valves 102, 103 configured to select working oil subjected to supply control by a first left travel control valve 61 or working oil subjected to supply control by the second travel control valve 75 to allow the working oil to be supplied to the left travel motor 16L.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a hydraulic traveling apparatus configured to rotationally drive a first traveling hydraulic motor with oil discharged from a first hydraulic pump and to rotationally drive a second traveling hydraulic motor with oil discharged from a second hydraulic pump. About.

  As an example of what is equipped with such a hydraulic traveling device, a traveling body having left and right crawler mechanisms, a revolving body that is turnable on the traveling body, and an excavation work provided at the front of the revolving body There is a power shovel configured to include a shovel device that performs the above. In such a power shovel, the engine, the first hydraulic pump and the second hydraulic pump driven by the engine, and the left and right traveling hydraulic motors (hereinafter referred to as traveling motors) that respectively rotate and drive the drive wheels of the left and right crawler mechanisms. And the left traveling motor is rotationally driven by the hydraulic oil discharged from the first hydraulic pump, and the right traveling motor is rotationally driven by the hydraulic oil discharged from the second hydraulic pump to travel the power shovel. (For example, refer patent document 1).

JP 2016-53375 A

  In the power shovel as described above, the hydraulic oil discharged from the first and second hydraulic pumps is mounted not only on the left and right traveling motors but also on the swing motor of the swing body, multiple cylinders of the shovel device, and the shovel device. It is also supplied to and driven by a hydraulic actuator or the like of the attached attachment. Therefore, when trying to drive another hydraulic actuator while the power shovel is running, the flow rate of hydraulic oil supplied to the hydraulic actuator is smaller than when the power shovel is stopped, and the operation of the hydraulic actuator There was a problem that the speed became slow.

  The present invention has been made in view of such problems, and provides a hydraulic traveling device capable of supplying a sufficient amount of hydraulic oil to a hydraulic actuator other than the traveling motor and driving it during traveling. For the purpose.

To achieve the above object, a hydraulic traveling apparatus according to the present invention includes a first hydraulic pump and a first hydraulic motor driven by hydraulic fluid discharged from the first hydraulic pump (for example, right traveling in the embodiment). A first control valve (for example, a right travel control valve 62 in the embodiment) that controls supply of hydraulic oil supplied from the first hydraulic pump to the first hydraulic motor, a second hydraulic pump, A second hydraulic motor driven by hydraulic oil discharged from the second hydraulic pump (for example, the left travel motor 16L in the embodiment), and hydraulic oil supplied from the second hydraulic pump to the second hydraulic motor. And a second control valve (for example, the first left travel control valve 61 in the embodiment), which is controlled by the first hydraulic motor and the second hydraulic motor. Configured to be driven. In addition, a third control valve (for example, the second left travel control valve 75 in the embodiment) that performs supply control of hydraulic oil supplied from the first hydraulic pump to the second hydraulic motor, and the second control. A supply oil path switching valve (for example, in the embodiment) that switches between the hydraulic oil supplied and controlled by the valve and the hydraulic oil supplied and controlled by the third control valve to be supplied to the second hydraulic motor. Left travel line switching valves 102, 103). Then, the hydraulic oil that is supplied and controlled by the third control valve is switched to a state in which the hydraulic oil can be supplied to the second hydraulic motor by the supply oil path switching valve, and the first hydraulic pump discharges the first hydraulic pump. The hydraulic motor and the second hydraulic motor are driven, and the hydraulic oil discharged from the second hydraulic pump can be supplied to and driven by another hydraulic actuator.

  In the hydraulic traveling apparatus having the above-described configuration, the traveling operation apparatus adjusts the discharge hydraulic pressure from the pilot hydraulic pump according to the operation of the pilot hydraulic pump and the traveling operation apparatus (for example, the left traveling operation lever 24L in the embodiment). A pilot valve (for example, the left travel pilot valve 81 in the embodiment) that generates pilot pressures of the second control valve and the third control valve according to the operation of the pilot valve, and the pilot pressure generated by the pilot valve It is preferable to include a pilot oil passage switching valve (for example, the pilot oil passage switching valve 101 in the embodiment) that switches between the second control valve and the third control valve. .

  According to the hydraulic travel device of the present invention, the third control valve that controls the supply of hydraulic oil supplied from the first hydraulic pump to the second hydraulic motor, the hydraulic oil that is supplied and controlled by the second control valve, and And a supply oil path switching valve for switching which of the hydraulic oil supplied and controlled by the third control valve is in a state where it can be supplied to the second hydraulic motor. Therefore, the first hydraulic motor and the second hydraulic motor are driven by the hydraulic oil discharged from the first hydraulic pump by switching by the supply oil passage switching valve, and the hydraulic oil discharged from the second hydraulic pump is used as the second hydraulic pressure. Without being supplied to the motor, it can be supplied to another hydraulic actuator and used for driving. Accordingly, it is possible to supply the hydraulic actuator with a sufficient flow rate and drive it even during traveling.

1 is a perspective view of a power shovel that is an example of a work machine equipped with a hydraulic traveling device according to the present invention. It is a block diagram which shows the control structure of the said power shovel. It is a hydraulic circuit diagram which shows the structure of the said hydraulic traveling apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a power shovel 1 as an example of a work machine equipped with a hydraulic traveling apparatus according to the present invention. The power shovel 1 includes a traveling body 10 configured to be able to travel, a revolving body 20 provided on an upper portion of the traveling body 10 so as to be horizontally rotatable, and a shovel device 30 provided at a front portion of the revolving body 20. Configured.

  The traveling body 10 includes crawler mechanisms 15 </ b> L and 15 </ b> R having driving wheels, a plurality of driven wheels, and crawler belts 13 wound around these wheels, on both the left and right sides of the traveling body frame 11. The left and right crawler mechanisms 15L and 15R are respectively configured to have travel motors 16L and 16R that rotationally drive the drive wheels. The traveling body 10 is configured to be able to travel in any direction and speed by controlling the rotational direction and rotational speed of the left and right traveling motors 16L and 16R. A blade 18 is provided at the front portion of the traveling body frame 11 so as to be swingable up and down. The blade 18 is configured to swing up and down by extending and contracting a blade cylinder 19 straddling the traveling body frame 11.

In the upper center of the traveling body frame 11, an inner ring fixed to the traveling body frame 11, an outer ring fixed to the turning body 20, and a turning motor 21 (see FIGS. 2 and 3) provided on the turning body 20, A swivel mechanism (not shown) having left and right travel motors 16L and 16R provided on the traveling body 10 and a rotary center joint for supplying hydraulic oil to the blade cylinder 19 from a hydraulic pump provided on the revolving body 20 Is provided. The turning body 20 is attached to the traveling body frame 11 through the turning mechanism so as to be horizontally turnable, and is configured to turn left and right with respect to the traveling body 10 by rotating the turning motor 21 forward or backward. Yes. A main body side bracket 22 that protrudes forward is provided at the front portion of the revolving structure 20.

  The shovel device 30 has a boom bracket 39 attached to the main body side bracket 22 so as to be pivotable about a vertical axis (horizontal swivel), and can swing up and down (can be raised and lowered) by means of a first swing pin 35a. ) Attached to the tip 31 of the boom 31, the arm 32 attached to the tip of the boom 31 by a second swing pin 35 b so that it can swing up and down (flexible), and the link mechanism 33 provided at the tip of the arm 32. And is configured. The shovel device 30 includes a swing cylinder 34 (see FIGS. 2 and 3) straddling between the swing body 20 and the boom bracket 39, and a boom cylinder 36 straddling between the boom bracket 39 and the boom 31. And an arm cylinder 37 straddling between the boom 31 and the arm 32, and a bucket cylinder 38 straddling between the arm 32 and the link mechanism 33.

  The boom bracket 39 is configured to be rotatable (swingable) in a horizontal plane with respect to the swing body 20 (main body side bracket 22) by extending and retracting the swing cylinder 34. The boom 31 is configured to be movable up and down in the upper and lower surfaces with respect to the revolving structure 20 by extending and retracting the boom cylinder 36. The arm 32 is configured to be able to bend and extend with respect to the boom 31 by operating the arm cylinder 37 to extend and contract.

  Various attachments such as buckets, breakers, crushers, cutters, auger devices, etc. can be attached to the distal ends of the arm 32 and the link mechanism 33 so as to be able to swing up and down. By doing so, it is configured to be swingable with respect to the arm 32 via the link mechanism 33. First to third attachment connection ports 41 to 43 that can connect hydraulic hoses for supplying hydraulic oil to the hydraulic actuators of these attachments are arranged on the left side surface of the arm 32.

  The revolving unit 20 is provided with an operator cabin 23 having a substantially rectangular box shape. Inside the operator cabin 23, an operator seat for the operator to sit facing forward, a pair of left and right traveling operation levers 24L, 24R (see FIG. 2) for operating the traveling body 10, and a revolving body 20 A pair of left and right work operation levers 25L, 25R and work operation pedals 26L, 26R (see FIG. 2) for operating the shovel device 30 and a blade operation lever 27 for operating the blade 18 are provided. . Various switches operated by an operator are provided inside the operator cabin 23, and an attachment priority switch 28 is provided as one of these switches. The attachment priority switch 28 switches the supply source of hydraulic oil to the left and right traveling motors 16L and 16R to supply a sufficient amount of hydraulic fluid to the hydraulic actuator of the attachment attached to the arm 32 even during traveling. It is operated and is configured to be able to select either “on” or “off”. The switching structure of the hydraulic pressure supply source will be described in detail later.

In such a power shovel 1, when an operator sits on an operator seat and tilts the left and right traveling operation levers 24L and 24R back and forth, the left and right crawler mechanisms 15L and 15R according to the operation direction and operation amount. It is comprised so that the power shovel 1 can be made to drive by driving. Further, the left and right work operation levers 25L and 25R are tilted back and forth and left and right, and the left and right work operation pedals 26L and 26R are operated to drive the shovel device 30 and the like according to the operation direction and operation amount thereof. It is configured so that work such as excavation can be performed.

  Specifically, the left traveling operation lever 24L is tilted forward to drive the left traveling motor 16L in the forward direction, the left crawler mechanism 15L is driven in the forward direction, and the reverse is performed by tilting backward. Drive in the reverse direction. Similarly, the right travel operation lever 24R is tilted forward to drive the right travel motor 16R in the forward direction, the right crawler mechanism 15R is driven in the forward direction, and the rearward tilt operation is performed to reversely drive it. It is configured to drive in the reverse direction. Note that pedal portions are provided at the base ends of the left and right traveling operation levers 24L and 24R, and the operator tilts the left and right traveling operation levers 24L and 24R back and forth by operating these pedal portions with feet. It can also be operated.

  By tilting the right work operation lever 25R back and forth, the boom cylinder 36 is expanded and contracted to swing the boom 31 up and down (raising and lowering), and by tilting it to the left and right, the bucket cylinder 38 is expanded and contracted. Rock the attached attachment up and down. In the left work operation lever 25L, by tilting back and forth, the arm cylinder 37 is expanded and contracted to swing the arm 32 up and down (bend and stretch), and by tilting left and right, the turning motor 21 is driven. The turning body 20 is turned left and right. Further, the left and right work operation pedals 26L and 26R are stepped on, so that the swing cylinder 34 is extended and retracted to rotate the shovel device 30 in the direction of the pedal that is stepped on. Further, the blade operating lever 27 is tilted back and forth, so that the blade cylinder 19 is expanded and contracted to swing the blade 18 up and down.

  As described above, the hydraulic drive device 50 for supplying the hydraulic oil to each hydraulic actuator and driving it according to the operation of each operation lever or the like is provided in the revolving body 20, and the hydraulic drive device 50 is shown in FIGS. This will be described with reference to FIG.

  The hydraulic drive device 50 includes a diesel engine E (hereinafter referred to as the engine E), a first hydraulic pump P1, a second hydraulic pump P2, a third hydraulic pump P3, and a pilot hydraulic pump P4 driven by the engine E, A control valve unit 60 that controls the direction and flow rate of hydraulic oil discharged from the first to third hydraulic pumps P1 to P3 and supplied to each hydraulic actuator, and each of the control valve units 60 according to the operation of each operation lever, etc. And a pilot valve unit 80 that generates a pilot pressure for switching the control valve.

  The control valve unit 60 includes a first left travel control valve 61 that controls the direction and flow rate of hydraulic oil supplied to the left travel motor 16L, and a right travel control that controls the direction and flow rate of hydraulic oil supplied to the right travel motor 16R. A valve 62, a swing control valve 63 that controls the direction and flow rate of hydraulic fluid supplied to the swing motor 21, an arm control valve 64 that controls the direction and flow rate of hydraulic fluid supplied to the arm cylinder 37, and the boom cylinder 36. A boom control valve 65 that controls the direction and flow rate of hydraulic fluid to be supplied, a bucket control valve 66 that controls the direction and flow rate of hydraulic fluid supplied to the bucket cylinder 38, and the direction and flow rate of hydraulic fluid supplied to the swing cylinder 34. A swing control valve 67 that controls the direction of hydraulic oil supplied to the blade cylinder 19 and Constructed and a blade control valve 68 for controlling the flow rate.

The control valve unit 60 is connected to a first attachment control valve 71 that controls the direction and flow rate of hydraulic fluid supplied to the hydraulic actuator of the attachment connected to the first attachment connection port 41, and to the second attachment connection port 42. The direction and flow rate of hydraulic oil supplied to the hydraulic actuator of the attachment connected to the second attachment control valve 72 connected to the hydraulic actuator of the attached attachment and the third attachment connection port 43 are controlled. And a third attachment control valve 73 to be controlled. Furthermore, the control valve unit 60 includes a second left travel control valve 75 that is provided separately from the first left travel control valve 61 and controls the direction and flow rate of hydraulic oil supplied to the left travel motor 16L. Composed.

  The first hydraulic pump P <b> 1 is driven by the engine E and discharges the hydraulic oil sucked up from the hydraulic oil tank T to the first pump oil passage 51. As shown in FIG. 3, in the first pump oil passage 51, the second left traveling control valve 75, the right traveling control valve 62, the boom control valve 65, and the bucket control are sequentially arranged from the first hydraulic pump P1 side (upstream side). A valve 66 is provided. Each of these control valves 75, 62, 65, 66 is an open center type three-position switching valve that is switched by driving a valve spool by a pilot pressure generated by a pilot valve unit 80, and the valve spool is in a neutral position. When it is located, the hydraulic oil discharged to the first pump oil passage 51 is returned to the hydraulic oil tank T via the tank oil passage 54. When the valve spool is switched by the pilot pressure, the hydraulic oil discharged to the first pump oil passage 51 is supplied to each hydraulic actuator in the supply direction and supply amount corresponding to the switching position. Yes. A branch oil passage 55 branched from the first pump oil passage 51 upstream of the second left travel control valve 75 is connected to the right travel control valve 62. The right travel control valve 62 bypasses the second left travel control valve 75 through the branch oil passage 55 and supplies the hydraulic oil discharged from the first hydraulic pump P1 to the right travel motor 16R. It is configured to be able to.

  The second hydraulic pump P <b> 2 is driven by the engine E and discharges the hydraulic oil sucked up from the hydraulic oil tank T to the second pump oil passage 52. The second pump oil passage 52 is provided with a first left travel control valve 61, a swing control valve 67, a first attachment control valve 71, and an arm control valve 64 in order from the second hydraulic pump P2 side (upstream side). Yes. These control valves 61, 67, 71 and 64 are open center type three-position switching valves similar to the right travel control valve 62 and the like. When the valve spool is located at the neutral position, the second pump The hydraulic oil discharged to the oil passage 52 is returned to the hydraulic oil tank T via the tank oil passage 54. When the valve spool is switched by the pilot pressure from the pilot valve unit 80, the hydraulic oil discharged to the second pump oil passage 52 is supplied to each hydraulic actuator in the supply direction and supply amount corresponding to the switching position. It is configured as follows.

  The third hydraulic pump P <b> 3 is driven by the engine E and discharges hydraulic oil sucked up from the hydraulic oil tank T to the third pump oil passage 53. In the third pump oil passage 53, a third attachment control valve 73, a second attachment control valve 72, a blade control valve 68, and a turning control valve 63 are provided in this order from the third hydraulic pump P3 side (upstream side). . Each of these control valves 72, 68, 63 is an open center type three-position switching valve similar to the right travel control valve 62 and the like, and when the valve spool is in the neutral position, the third pump oil passage 53 is connected to a position between the swing control valve 67 and the first attachment control valve 71 in the second pump oil passage 52 through an oil passage 59 and discharged to the third pump oil passage 53. The hydraulic oil is supplied to the first attachment control valve 71 and the arm control valve 64. When the valve spool is switched by the pilot pressure from the pilot valve unit 80, the hydraulic oil discharged to the third pump oil passage 53 is supplied to each hydraulic actuator in the supply direction and supply amount corresponding to the switching position. It is configured as follows.

The third attachment control valve 73 is a two-position switching valve that is switched by driving the valve spool by the pilot pressure from the pilot valve unit 80, and when the valve spool is in the neutral position (position shown in FIG. 3). The hydraulic oil discharged to the third pump oil passage 53 is supplied to the first attachment control valve 71 and the arm control valve 64 through the oil passage 59 in the same manner as the second attachment control valve 72 and the like. When the valve spool is switched by the pilot pressure, the hydraulic oil discharged to the third pump oil passage 53 is supplied to the third attachment connection port with a supply amount corresponding to the switching position. .

  A supply line switching valve 74 is provided in the third pump oil passage 53 upstream of the third attachment control valve 73 (on the third hydraulic pump P3 side). The supply line switching valve 74 is a two-position switching valve that is switched by driving the valve spool by the pilot pressure from the pilot valve unit 80. When the valve spool is in the neutral position (position shown in FIG. 3), the supply line switching valve 74 is configured to supply the hydraulic oil discharged to the third pump oil passage 53 as described above to the third attachment control valve 73. To the boom control valve 65 and the bucket control valve 66 through the first oil passage 56. When the valve spool is switched by the pilot pressure, the hydraulic oil discharged to the third pump oil passage 53 is supplied to the boom control valve 65 and the bucket control valve 66 through the first oil passage 56. The second oil passage 57 is supplied to the swing control valve 67 to restrict the supply to the third attachment control valve 73 and the like. At this time, the hydraulic oil discharged by the second hydraulic pump P2 is also supplied to the boom control valve 65 and the bucket control valve 66 via the second oil passage 57 and the first oil passage 56.

  A branch oil passage 58 branched from the third pump oil passage P3 on the upstream side (third hydraulic pump P3 side) of the supply line switching valve 74 is connected to the turning control valve 63. The turning control valve 63 bypasses the supply line switching valve 74, the third attachment control valve 73, the second attachment control valve 72, and the blade control valve 68 via the branch oil passage 58 and bypasses the third hydraulic pump P3. It is comprised so that the hydraulic fluid discharged from can also be supplied to the turning motor 21.

  The pilot hydraulic pump P <b> 4 is driven by the engine E and discharges hydraulic oil sucked up from the hydraulic oil tank T to the pilot pump oil passage 91. The pressure oil discharged into the pilot pump oil passage 91 is adjusted to a predetermined pilot pressure by a pressure regulating valve (not shown). A pilot valve unit 80 is provided in the pilot pump oil passage 91.

  As shown in FIG. 2, the pilot valve unit 80 generates a pilot pressure for switching the valve spools of the first left travel control valve 61 and the second left travel control valve 75 in accordance with the operation of the left travel operation lever 24L. Depending on the operation of the left traveling pilot valve 81, the right traveling pilot valve 82 for generating the pilot pressure for switching the valve spool of the right traveling control valve 62 according to the operation of the right traveling operation lever 24R, and the operation of the left working operation lever 25L The swing / arm pilot valve 83 for generating a pilot pressure for switching the spools of the swing control valve 63 and the arm control valve 64, and the boom control valve 65 and the bucket control valve 66 according to the operation of the right work operation lever 25R. Pilot pressure for switching spool Boom / bucket pilot valve 84, swing pilot valves 85 and 86 for generating a pilot pressure for switching the valve spool of the swing control valve 67 according to the operation of the left and right work operation pedals 26L and 26R, and a blade operation lever And a blade pilot valve 87 for generating a pilot pressure for switching the valve spool of the blade control valve 68 according to the operation of the blade control valve 68. In FIG. 3, illustrations other than the left and right traveling pilot valves 81 and 82 are omitted.

  As shown in FIG. 3, the pilot pressure generated by the left travel pilot valve 81 is supplied to either the first left travel control valve 61 or the second left travel control valve 75 in the oil passage that supplies the pilot pressure. A pilot line switching valve 101 for switching between these is provided. The pilot line switching valve 101 is a two-position switching valve in which the valve spool is switched by a drive signal (electrical signal) output via the controller C (see FIG. 2) when the attachment priority switch 28 is operated. In the pilot line switching valve 101, when the attachment priority switch 28 is in the OFF state, the valve spool is switched to the neutral position (position moved downward from the position shown in FIG. 3), and the pilot generated by the left traveling pilot valve 81 The pressure is supplied to the first left travel control valve 61 so that the valve spool of the first left travel control valve 61 can be switched. Further, when the attachment priority switch 28 is turned on, the pilot line switching valve 101 switches the valve spool to the position shown in FIG. 3, and the pilot pressure generated by the left travel pilot valve 81 is controlled by the second left travel control. The valve 75 is supplied to the valve 75 so that the valve spool of the second left travel control valve 75 can be switched.

  To the oil passage (the suction port side oil passage and the discharge port side oil passage of the left travel motor 16L) that supplies the hydraulic oil controlled by the first left travel control valve 61 and the second left travel control valve 75 to the left travel motor 16L. Are provided with left travel line switching valves 102 and 103 for switching which of the first left travel control valve 61 and the second left travel control valve 75 is supplied with hydraulic oil to the left travel motor 16L. Similarly to the pilot line switching valve 101, each of the left travel line switching valves 102 and 103 is a drive signal (electrical signal) output via the controller C (see FIG. 2) when the attachment priority switch 28 is operated. This is a 2-position switching valve in which the valve spool is switched. When the attachment priority switch 28 is in the OFF state, the left travel line switching valves 102 and 103 are switched to the neutral position (the position moved down from the position shown in FIG. 3), respectively, and the first left travel control valve The hydraulic oil controlled by 61 is supplied to the left traveling motor 16L so that the left traveling motor 16L can be rotated. Further, when the attachment priority switch 28 is turned on, the left travel line switching valves 102 and 103 are respectively switched to the position shown in FIG. 3 and the hydraulic oil controlled by the second left travel control valve 75. Is supplied to the left traveling motor 16L so that the left traveling motor 16L can be rotationally driven.

According to the hydraulic drive device 50 configured as described above, when the attachment priority switch 28 is not operated and is in the OFF state, as described above, the valve spool of the pilot line switching valve 101 is in the neutral position (the position shown in FIG. 3). The pilot pressure generated by the left travel pilot valve 81 can be supplied to the first left travel control valve 61. Further, the valve spools of the left travel line switching valves 102 and 103 are switched to the neutral position (position moved downward from the position shown in FIG. 3), and hydraulic oil controlled by the first left travel control valve 61 is supplied to the left travel motor 16L. Ready to be supplied. Accordingly, when the left and right travel operation levers 24L and 24R are operated, the pilot pressures corresponding to the operation directions and operation amounts are supplied to the first left travel control valve 61 and the right travel control valve 62, respectively, and the first left travel control is performed. The valve spools of the valve 61 and the right travel control valve 62 are switched. Then, the hydraulic oil discharged from the second hydraulic pump P2 is controlled by the first left travel control valve 61 in the supply direction and supply amount according to the operation direction and operation amount of the left travel operation lever 24L, and the left travel motor 16L. The left traveling motor 16L is rotationally driven. Further, the hydraulic oil discharged from the first hydraulic pump P1 is controlled by the right traveling control valve 62 to be supplied to the right traveling motor 16R by being controlled in the supply direction and the supply amount according to the operation direction and the operation amount of the right traveling operation lever 24R. Then, the right travel motor 16R is rotationally driven. As described above, the left and right traveling motors 16L using the hydraulic oil discharged from both the first and second hydraulic pumps P1 and P2 are used.
, 16R are rotationally driven, and the excavator 1 travels.

  When the right work operation lever 25R is operated while the excavator 1 is traveling in this way, the hydraulic oil discharged from the first hydraulic pump P1 is controlled by the boom control valve 65 and the bucket control valve 66. The boom cylinder 36 and the bucket cylinder 38 are supplied to the boom cylinder 36 and the bucket cylinder 38, and the boom cylinder 36 and the bucket cylinder 38 are driven to extend and contract, so that the attachment attached to the boom 31 and the arm 32 can be swung up and down. However, since the boom control valve 65 and the bucket control valve 66 are on the downstream side of the first pump oil passage 51 with respect to the right travel control valve 62, the flow rate of the hydraulic oil supplied to the boom cylinder 36 and the bucket cylinder 38 is This is less than when the power shovel 1 is stopped, and the operating speeds of the boom cylinder 36 and the bucket cylinder 38 become slower. Therefore, as described above, the hydraulic oil discharged from the second and third hydraulic pumps P2 and P3 is supplied via the supply line switching valve 74, the first oil passage 56, and the second oil passage 57 to the boom control valve 65 and The bucket control valve 66 can be supplied to the boom cylinder 36 and the bucket cylinder 38.

  When the left work operation lever 25L and the blade operation lever 27 are operated while the excavator 1 is traveling as described above, the hydraulic oil discharged from the third hydraulic pump P3 is supplied to the turning control valve 63 and the blade. It is controlled by the control valve 68 and supplied to the turning motor 21 and the blade cylinder 19, and the turning motor 21 is driven to rotate and the blade cylinder 19 is driven to extend and retract to turn the turning body 20 and swing the blade 18 up and down. .

  If the left work operation lever 25L and the left and right work operation pedals 26L and 26R are operated while the power shovel 1 is traveling as described above, the hydraulic oil discharged from the second hydraulic pump P2 is arm-controlled. Controlled by the valve 64 and the swing control valve 67 and supplied to the arm cylinder 37 and the swing cylinder 34, the arm cylinder 37 and the swing cylinder 34 are driven to extend and contract to swing the arm 32 up and down and rotate the shovel device 30. Can do. However, since the swing control valve 67 and the arm control valve 64 are located on the downstream side of the second pump oil passage 52 relative to the first left travel control valve 61, the flow rate of the hydraulic oil supplied to the swing cylinder 34 and the arm cylinder 37 Is smaller than when the power shovel 1 is stopped, and the operating speed of the swing cylinder 34 and the arm cylinder 37 becomes slower. In addition, since the first attachment control valve 71 is also on the downstream side of the second pump oil passage 52 with respect to the first left travel control valve 61, the flow rate of the hydraulic oil supplied to the first attachment connection port 41 is the power shovel. It is less than when 1 is stopped.

  Therefore, the hydraulic drive device 50 is configured to include the attachment priority switch 28, the second left travel control valve 75, the pilot line switching valve 101, and the left travel line switching valves 102 and 103 described above. When the attachment priority switch 28 is turned on, the valve spool of the pilot line switching valve 101 is switched to the position shown in FIG. 3 as described above, and the pilot pressure generated by the left travel pilot valve 81 is changed to the second left travel. The control valve 75 can be supplied. Further, the valve spools of the left travel line switching valves 102 and 103 are switched to the positions shown in FIG. 3, and the hydraulic oil controlled by the second left travel control valve 75 can be supplied to the left travel motor 16L.

Accordingly, when the left and right travel operation levers 24L and 24R are operated, the pilot pressures corresponding to the operation directions and operation amounts are supplied to the second left travel control valve 75 and the right travel control valve 62, respectively, and the second left travel control is performed. The valve spools of the valve 75 and the right travel control valve 62 are switched. Then, the hydraulic oil discharged from the first hydraulic pump P1 is controlled by the second left travel control valve 75 to the supply direction and supply amount corresponding to the operation direction and operation amount of the left travel operation lever 24L, and the left travel motor 16L. The left traveling motor 16L is rotationally driven. Further, the hydraulic oil discharged from the first hydraulic pump P1 is controlled by the right traveling control valve 62 to be supplied to the right traveling motor 16R by being controlled in the supply direction and the supply amount according to the operation direction and the operation amount of the right traveling operation lever 24R. Then, the right travel motor 16R is rotationally driven. Thus, the left and right traveling motors 16L, 16R are rotationally driven using only the hydraulic oil discharged from the first hydraulic pump P1, and the power shovel 1 travels.

  Thus, when the left and right traveling motors 16L and 16R are driven to rotate using only the hydraulic oil discharged from the first hydraulic pump P1, the left work operation lever 25L and the left and right operation levers 25L and When the operation pedals 26L and 26R are operated, the hydraulic oil discharged from the second hydraulic pump P2 is supplied to the swing cylinder 34, the first attachment connection port 41, and the arm cylinder 37 without being supplied to the left travel motor 16L. And can be used for driving. Therefore, even when the excavator 1 is traveling, it is possible to prevent the flow rate of the hydraulic oil supplied to the swing cylinder 34, the first attachment connection port 41, and the arm cylinder 37 from decreasing. Note that the frequency of driving the swing cylinder 34 and the attachment (hydraulic actuator) connected to the first attachment connection port 41 is low at the same time. When the swing cylinder 34 is not driven, the hydraulic oil discharged from the second hydraulic pump P2 is used. The maximum flow rate can be supplied to the attachment to drive the attachment.

  The embodiments of the present invention have been described so far, but the scope of the present invention is not limited to the above-described embodiments. For example, in the above-described embodiment, the configuration in which the supply source of hydraulic oil to the left traveling motor 16L is switched from the second hydraulic pump P2 to the first hydraulic pump P1, but the arrangement of the left traveling motor 16L and the right traveling motor 16R is described. It is good also as a structure which reverses these and switches the supply source of the hydraulic fluid to the right traveling motor 16R. In the above-described embodiment, the case where the present invention is applied to a crawler traveling type excavator has been described. However, the present invention can also be applied to a wheel traveling type excavator and a work machine other than the power shovel. Is possible.

P1 First hydraulic pump P2 Second hydraulic pump P4 Pilot hydraulic pump 16L Left traveling motor (second hydraulic motor)
16R Right travel motor (first hydraulic motor)
24L Left travel control lever (travel control device)
50 Hydraulic drive device (hydraulic travel device)
61 First left travel control valve (second control valve)
62 Right travel control valve (first control valve)
75 Second left travel control valve (third control valve)
81 Left-running pilot valve (pilot valve)
101 Pilot line switching valve (Pilot oil path switching valve)
102,103 Left travel line switching valve (supply oil path switching valve)

Claims (2)

A first hydraulic pump;
A first hydraulic motor driven by hydraulic oil discharged from the first hydraulic pump;
A first control valve that controls supply of hydraulic fluid supplied from the first hydraulic pump to the first hydraulic motor;
A second hydraulic pump;
A second hydraulic motor driven by hydraulic oil discharged from the second hydraulic pump;
A second control valve that controls supply of hydraulic oil supplied from the second hydraulic pump to the second hydraulic motor;
In the hydraulic travel device driven to rotate by the first hydraulic motor and the second hydraulic motor,
A third control valve for controlling supply of hydraulic oil supplied from the first hydraulic pump to the second hydraulic motor;
A supply oil passage switching valve for switching which of the hydraulic oil supplied and controlled by the second control valve and the hydraulic oil supplied and controlled by the third control valve can be supplied to the second hydraulic motor; Prepared,
The hydraulic oil that is supplied and controlled by the third control valve is switched to a state in which the hydraulic oil can be supplied to the second hydraulic motor by the supply oil path switching valve, and the first hydraulic motor is discharged by the hydraulic oil discharged from the first hydraulic pump. And a hydraulic travel device configured to drive the second hydraulic motor and supply the hydraulic oil discharged from the second hydraulic pump to another hydraulic actuator for driving. A pilot hydraulic pump,
A pilot valve that regulates the hydraulic pressure discharged from the pilot hydraulic pump according to the operation of the travel operation device to generate the pilot pressure of the second control valve and the third control valve according to the operation of the travel operation device;
And a pilot oil passage switching valve for switching to which state the pilot pressure generated by the pilot valve can be supplied to either the second control valve or the third control valve. The hydraulic travel device according to claim 1.

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