JP2009047312A - Hydraulic device for excavation turning working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve travelling feeling by preventing deviated travelling due to unexpected operation of a travelling motor in an excavation turning working vehicle. <P>SOLUTION: In the case of communicating so as to return the return oil from an arm cylinder 25 and the return oil from a boom cylinder 23 to a right and a left communication passages 46 and 47, in order to prevent deviated travelling with rotation of traveling hydraulic motors 15 and 15 by supply of the pressure oil due to operation of a counter balance valve 62 of the travelling hydraulic motors 15 and 15, which is communicated with the tank passages 46 and 47 of travelling control valves 35 and 40 in the neutral condition, to a communication side by a pressure difference generated in the right and left tank passages 46 and 47, the return oil from the boom cylinder 23 and the return oil from the arm cylinder 25 are connected to the tank passages 46 and 47 on the same side, and tank passages 58 and 59 on both sides are communicated with each other through an external pipe 70. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a technique of a hydraulic apparatus for preventing a counter balance valve connected to a traveling motor of an excavation turning work vehicle from being operated by a differential pressure of drain oil from a boom cylinder or an arm cylinder.

  Conventionally, driving to operate hydraulic actuators that rotate booms, arms, buckets, etc., which are working machines of excavation turning work vehicles, turn upper bodies, and drive crawler type traveling devices An operation lever, operation pedal, etc. are arranged in the seat. By operating these operating levers or operating pedals, the control valve spool can be slid to switch the valve, or the pilot valve can be switched to slide the spool by the pilot hydraulic pressure to switch the control valve. ing. By switching the control valve, pressure oil is sent to each hydraulic actuator to drive the hydraulic actuator.

As shown in FIG. 5, the control valve for controlling the operation of each hydraulic actuator is connected to the tandem and disposed below the step as a control valve unit. At the center of the control valve unit in FIG. A main passage 45 communicating with P2 is provided, output oil passages are provided on both sides thereof, and tank passages 46 and 47 are provided substantially parallel to the outside thereof.
Japanese Patent Publication No.47-16888

  However, as shown in FIG. 5, in the configuration in which the tank oil passages are provided on the left and right, the return oil from the arm cylinder 25 and the return oil from the boom cylinder 23 are communicated with the left and right tank passages 46 (or 47). Therefore, when the boom 6 and the arm 5 are operated at the same time on an inclined ground, or when either one is operated, the return oil flows into one of the tank oil passages. A pressure difference was generated in 47, and the counter balance valve of the traveling motor actuated due to the pressure difference, and sometimes escaped.

  In order to prevent this runaway, it is conceivable to increase the cracking pressure by increasing the spring force of the spring that biases the spool of the counter balance valve of the travel motor, but the shock at the start and stop of the travel motor increases. The driving feeling will get worse. In addition, it is conceivable to provide a pipe between the control valve and the reservoir tank. However, since the pipe is provided and the pipe becomes long, the cost is increased, and all the differential pressures are not necessarily eliminated.

  The present invention employs the following means in order to solve the above-described problems.

  In the present invention, the boom (6), the arm (5), and the bucket (4) of the excavation turning work vehicle are driven by the boom cylinder (23), the arm cylinder (25), and the bucket cylinder (24), and the left and right crawlers are driven. Each of the control valves for controlling the operation of the hydraulic cylinders (23, 25, 24) and the traveling hydraulic motor (15, 15) is tandem driven by the traveling hydraulic device (1, 1) by the traveling hydraulic motor (15, 15). The control unit (30) is connected to at least the left travel control valve (35), the arm control valve (36), the right travel control valve (40), the bucket control valve (41), In a configuration in which the boom control valve (42) is arranged in tandem, the boom control valve (42) is arranged in the tandem. A pump passage (45) communicating with the hydraulic pump (P) is provided in the left and right center of the control unit (30) so as to penetrate each control valve, and tank passages (58. 59) and when the return oil from the arm cylinder (25) and the return oil from the boom cylinder (23) communicate with each other to return to the left and right tank passages (46, 47), The counter balance valve (15/15) of the traveling hydraulic motor (15/15) communicates with the tank passage (46/47) of the neutral traveling control valve (35/40) due to a pressure difference in the tank passage (46/47). 62) operates on the communication side due to the pressure difference, and supplies the hydraulic oil to the traveling hydraulic motor (15, 15) to rotate and prevent the boom cylinder ( The return oil of 3) and the return oil of the arm cylinder (25) are connected to the tank passages (46, 47) on the same side, and the tank passages (58, 59) on both sides are connected via the external pipe (70). It is a thing.

  In the present invention, the hydraulic device for the excavating and turning work vehicle is configured as described above, and the following effects are obtained.

  The boom (6), the arm (5), and the bucket (4) of the excavation turning work vehicle are driven by the boom cylinder (23), the arm cylinder (25), and the bucket cylinder (24), and the left and right crawler type traveling devices (1 1) is driven by a traveling hydraulic motor (15/15), and each control valve for controlling the operation of the hydraulic cylinder (23/25/24) and the traveling hydraulic motor (15/15) is connected in tandem to control unit The control unit (30) includes at least a left travel control valve (35), an arm control valve (36), a right travel control valve (40), a bucket control valve (41), a boom control valve (42 ) In a tandem configuration, each control bar in the state of being disposed in the tandem. A pump passage (45) communicating with the hydraulic pump (P) is provided in the center of the left and right of the control unit (30) so as to pass through the tank, and tank passages (58, 59) are provided on both sides of the pump passage (45). When the return oil from the arm cylinder (25) and the return oil from the boom cylinder (23) communicate with each other to return to the left and right tank passages (46, 47), the left and right tank passages The counter balance valve (62) of the traveling hydraulic motor (15/15) communicates with the tank passage (46/47) of the traveling control valve (35/40) in the neutral state due to a pressure difference in (46/47). However, in order to prevent the hydraulic oil (15, 15) from supplying pressure oil to the traveling hydraulic motor (15, 15) and rotating to escape, , The return oil of the cylinder cylinder (25) is connected to the tank passages (46, 47) on the same side, and the tank passages (58, 59) on both sides are connected via the external pipe (70). The hydraulic pressure is equalized through the external piping, no differential pressure is generated between both tank passages, and the counter balance valve is switched in the same manner as described above, so that the crawler does not rotate unexpectedly when working on an inclined ground. . Moreover, since external piping can be bent freely, it can pipe using a vacant space.

  Next, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is an overall side view of an excavating and turning work vehicle equipped with a hydraulic device according to the present invention, FIG. 2 is a diagram showing piping connection of another configuration, FIG. 3 is a diagram showing connection between a control valve and a counter balance valve, FIG. 4 is a sectional view of a control valve showing an embodiment of the present invention, and FIG. 5 is a diagram showing a conventional piping configuration.

  First, a schematic configuration of the excavation turning work vehicle according to the present configuration will be described. As shown in FIG. 1, the turning work vehicle supports an upper body 8 so as to be turnable via a swivel bearing 7 having an axis in the vertical direction at the center of the upper portion of the crawler type traveling device 1. A blade 10 is disposed at one end of the front and rear of the apparatus 1 so as to be rotatable up and down. The upper body 8 has an engine, a battery, a fuel tank, and the like placed on a revolving frame 11, these are covered with a bonnet 9, and a steering part is disposed in front of the upper part 8. A traveling lever 26, a work operating lever 27, and the like are disposed, and a canopy 21 is disposed above the bonnet 9 and the seat 19.

  A work machine is attached to the front end of the swing frame 11, and the work bracket has a boom bracket 12 attached to the front end of the swing frame 11 so as to be pivotable in the left-right direction. Is supported so as to be pivotable back and forth. The boom 6 is bent forward in the middle, and is formed in a substantially “<” shape in a side view. An arm 5 is rotatably supported at the other end of the boom 6, and a bucket 4 as a work attachment is rotatably supported at the tip of the arm 5.

  Also, a boom cylinder 23 is interposed between the boom bracket 12 and the middle front surface of the boom 6, and an arm cylinder 25 is interposed between the middle rear surface of the boom 6 and the arm 5 base end, and the bucket A bucket cylinder 24 is interposed between 4 and the arm 5 base.

  Thus, the boom 6 is rotated by the boom cylinder 23, the arm 5 is rotated by the arm cylinder 25, and the bucket 4 is rotated by the bucket cylinder 24. The boom cylinder 23, the arm cylinder 25, and the bucket cylinder 24 are composed of hydraulic cylinders that serve as hydraulic actuators, and the cylinders 23, 25, and 24 are disposed below the step 17 by operating the operation lever disposed on the step 17. It is driven to extend and contract by switching the control valve and supplying pressure oil from the hydraulic pump.

  Further, a swing cylinder 18 is disposed on the side of the swing frame 11, a base portion thereof is pivotally supported by the swing frame 11, and a tip of a cylinder rod of the swing cylinder 18 is connected to the boom bracket 12, With the swing cylinder 18, the boom bracket 12 can be rotated left and right with respect to the revolving frame 11, and the work implement 2 can be rotated left and right.

  Further, the turning frame 11 can be turned left and right by 360 degrees by the operation of a hydraulic motor 13 provided on the upper part of the turntable bearing 7, and the blade 10 is provided between the rear portion of the earth discharging plate and the track frame 3 of the crawler type traveling device 1. The blade cylinder 14 interposed therebetween can be moved up and down. Furthermore, traveling hydraulic motors 15 and 15 are disposed inside the drive sprocket disposed on the front and rear side of the track frame 3 so that the crawler traveling device 1 can be driven to travel.

  Thus, the hydraulic cylinders and hydraulic motors serving as hydraulic actuators are each connected to a control valve disposed below step 17 of the control unit. The control valves are arranged in tandem as shown in FIG. The control unit 30 includes, for example, an option control valve 33, a turning control valve 34, a left travel control valve 35, an arm control valve 36, a bleed switching valve 37, a PTO control valve 38, a blade control valve 39, and a right travel control valve. 40, bucket control valve 41, boom control valve 42, swing control valve 43 are arranged in tandem, and communication valves 31 and 32 are arranged on both sides.

  As shown in FIG. 3, the travel control valve 35 (40) has a spool 51 fitted into the valve case 50, and one end of the spool 51 protrudes from the valve case 50. 26. The other end of the spool 51 is inserted into a spring case 52 attached to the side of the valve case 50, and in the spring case 52, spring seats 53 and 53 are fitted on the spool 51, and the spring seats 53 and 53 are inserted. A spring 54 is disposed between the springs 51 to bias the spool 51 in the neutral direction.

  In addition, a pump oil passage 55 connected to the hydraulic pump is provided in the central portion of the valve case 50, and output ports 56 and 57 are provided on both sides thereof, respectively extending to the spool 51. The output ports 56 and 57 are When neutral, it communicates with tank oil passages 58 and 59 provided on the side thereof. As shown in FIG. 2, the tank oil passages 58 and 59 are connected to tank passages 46 and 47 provided on both sides of the control valve unit 30, and the pump oil passage 55 is connected to a main passage 45 provided in the center. It is communicated.

  The output ports 56 and 57 are connected to a counter balance valve 62. As shown in FIG. 3, the counter balance valve 62 has a valve hole 63a formed in a valve case 63 and a plunger in the valve hole 63a. 64 is slidably accommodated, and the plunger 64 further accommodates valve bodies 65 and 65 and a spring to constitute a check valve. The valve holes 63a on both sides of the plunger 64 are closed with lids, and the spaces on both sides of the plunger 64 are defined as chambers 66L and 66R. The chambers 66L and 66R communicate with the input ports 71 and 72 through the oil passages 63b and 63b. The input ports 71 and 72 are connected to an output port from an oil passage formed in the plunger 64 via a check valve (valve bodies 65 and 65), and the output port is connected to one of the left and right traveling hydraulic motors 15. ing. The other left and right traveling hydraulic motors have the same configuration as described above.

  In the control valve 50 and the counter balance valve 62 configured as described above, if there is a difference in pressure between the tank passage 46 and the tank passage 47 disposed on both sides of the control valve 50 in the neutral state, the tank passage 46 A differential pressure is also generated in the input ports 71 and 72 of the counter balance valve 62 connected to 47, and a pressure difference is also generated in the left and right chambers 66L and 66R connected to the input ports 71 and 72, and the plunger 64 slides due to the pressure. Thus, the input ports 71 and 72 and the hydraulic motor 15 communicate with each other, and the hydraulic motor 15 can rotate. For example, when a turning work vehicle is located on a sloping ground, the crawler rotates and runs away. It will end up.

  Therefore, in this configuration, as shown in FIG. 2, the oil passage on the secondary side (output side) of the control valve 42 communicating with the cylinder head (bottom) side of the boom cylinder 23 is replaced with one of the left and right tank oil passages (tank oil passage). ) 59 (or 58) and the oil passage on the secondary side (output side) of the control valve 36 connected to the cylinder head side of the arm cylinder 25 is connected to the other tank oil passage (tank passage 46) 58 (or 59 (47) )) And connected.

  By configuring in this way, even if the boom 6 and the arm 5 are driven simultaneously, even if a large amount of hydraulic oil is drained from the cylinder head side with a large amount of oil, it is distributed to the left and right tank passages 46 and 47. The differential pressure is unlikely to occur, the counter balance valve 62 does not switch, and the crawler does not rotate unexpectedly when working on an inclined land.

  Further, as an embodiment of the present invention for solving the above problems, it can be configured as shown in FIG. That is, when the drain oil passages of the boom cylinder 23 and the arm cylinder 25 are configured to communicate with the same tank passage as shown in FIG. 5, the arm control valve 36 or the boom control valve 42 is disposed in the vicinity thereof. The control valve valve case 63 is provided with take-out oil passages 68 and 69 communicating with the left and right tank oil passages (tank passages) 58 and 59, and the take-out oil passages 68 and 69 communicate with each other through an external pipe 70. To do.

  With this configuration, even if the boom cylinder 23 and the arm cylinder 25 are simultaneously operated and drained into one tank oil passage, if a differential pressure is generated, the drain oil is reduced so that the differential pressure is reduced. Flows to the other tank oil passage (tank passage) through the external pipe 70 so that the pressure becomes substantially equal, so that the counter balance valve 62 is not switched, and the crawler unexpectedly moves when working on an inclined ground. Prevents rotation. Although there is a technique in which an oil passage that communicates the left and right tank oil passages 58 and 59 is integrally provided in the valve case, it is necessary to form an oil passage for communicating with the lower position of the valve case. The case becomes large and processing is required, and the size of the communication part is different from that of other control valves, making it difficult to arrange them as a unit. By using external piping, the degree of freedom of arrangement position is increased, and the piping can pass through a vacant space.

1 is an overall side view of an excavating and turning work vehicle equipped with a hydraulic device according to the present invention. It is a figure which shows the piping connection of another structure. It is a figure which shows the connection of a control valve and a counter balance valve. It is sectional drawing of the control valve which shows the Example of this invention. It is a figure which shows the conventional piping structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Crawler type traveling device 4 Bucket 5 Arm 6 Boom 23 Boom cylinder 25 Arm cylinder 35/40 Travel control valve 36 Arm control valve 42 Boom control valve 58/59 Tank oil passage

Claims (1)

  The boom (6), the arm (5), and the bucket (4) of the excavation turning work vehicle are driven by the boom cylinder (23), the arm cylinder (25), and the bucket cylinder (24), and the left and right crawler type traveling devices (1 1) is driven by a traveling hydraulic motor (15/15), and each control valve for controlling the operation of the hydraulic cylinder (23/25/24) and the traveling hydraulic motor (15/15) is connected in tandem to control unit The control unit (30) includes at least a left travel control valve (35), an arm control valve (36), a right travel control valve (40), a bucket control valve (41), a boom control valve (42 ) In a tandem configuration, each control bar in the state of being disposed in the tandem. A pump passage (45) communicating with the hydraulic pump (P) is provided in the center of the left and right of the control unit (30) so as to pass through the tank, and tank passages (58, 59) are provided on both sides of the pump passage (45). When the return oil from the arm cylinder (25) and the return oil from the boom cylinder (23) communicate with each other to return to the left and right tank passages (46, 47), the left and right tank passages The counter balance valve (62) of the traveling hydraulic motor (15/15) communicates with the tank passage (46/47) of the traveling control valve (35/40) in the neutral state due to a pressure difference in (46/47). However, in order to prevent the hydraulic oil (15, 15) from supplying pressure oil to the traveling hydraulic motor (15, 15) and rotating to escape, , Excavation swirl characterized in that the return oil of the cylinder cylinder (25) is connected to the tank passages (46, 47) on the same side and the tank passages (58, 59) on both sides are connected via the external pipe (70). Hydraulic equipment for work vehicles.

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